CN113690913B - Control method of energy storage railway power regulator and terminal equipment - Google Patents

Abstract

The invention is applicable to the technical field of electric energy quality and energy storage control, and provides a control method and terminal equipment of an energy storage railway power regulator, which are applied to an energy storage railway power regulator formed by connecting a half-bridge converter and an energy storage unit in parallel, wherein the method comprises the following steps: carrying out current compensation on load currents of each phase corresponding to the energy storage railway power regulator to obtain a first modulation signal; performing circulation control based on each phase compensation current of the energy storage railway power regulator, each half-bridge converter unit and capacitance voltage of each energy storage half-bridge converter unit to obtain a second modulation signal; performing double-loop control based on the capacitor voltage, the actual current of the energy storage battery of each energy storage half-bridge converter unit and the actual state of charge of the energy storage battery to obtain a third modulation signal; and controlling the energy storage railway power regulator according to the first to third modulation signals. The method can realize automatic compensation of energy, has fewer control instructions and lower coupling between the control instructions.

Description

Energy storage railway power regulator control method and terminal equipment

Technical Field

The present invention belongs to the technical field of power quality and energy storage control, and in particular relates to a control method and terminal equipment of an energy storage railway power regulator.

Background Art

Railway Power Conditioner (RPC) is a comprehensive compensation device used in railway power quality management. It can balance the active power of the load, compensate for reactive power, and balance the current of the power grid. The railway power conditioner based on Modular Multilevel Converter (MMC) is called MRPC. MRPC has the advantages of high topological modularity, high AC output quality, and small filtering device. It is very suitable for high-voltage and large-capacity compensation occasions, and can save the step-down transformer when connected to the traction network. Therefore, it is widely used in railway power quality management. If an energy storage system is added to the DC side of the MRPC submodule, it can not only solve the three-phase imbalance problem in the railway traction system and improve the power quality, but also rely on the energy storage system to fully utilize the energy of train braking, improve system efficiency, and ensure the performance stability of the locomotive system.

However, in the research of energy storage MRPC, it is usually necessary to add a DC/DC converter (DC/DC converter) on the DC side of each MRPC submodule to connect the energy storage device so that the MRPC has energy storage capacity. However, there are many MRPC submodules, and the cost of using this method is high and the economy is not good. In addition, the existing control method has strong control coupling between control instructions and complex control. When the energy storage system of some submodules fails, the reliability of the energy storage MRPC system cannot be guaranteed.

Summary of the invention

In view of this, an embodiment of the present invention provides a control method and terminal device for an energy storage railway power regulator, aiming to solve the problems of strong coupling and complex control of the energy storage railway power regulator control method in the prior art.

To achieve the above-mentioned purpose, a first aspect of an embodiment of the present invention provides a control method for an energy storage railway power regulator, which is applied to an energy storage railway power regulator in which an energy storage half-bridge converter unit is composed of a half-bridge converter, a DC stabilizing capacitor and an energy storage unit connected in parallel, and the method comprises:

The current compensation processing is performed on the load current of each phase of the electric locomotive load corresponding to the obtained energy storage railway power regulator, and a first modulation signal for AC current control is calculated; based on the obtained compensation current of each phase of the energy storage railway power regulator, each half-bridge converter unit and the capacitor voltage of each energy storage half-bridge converter unit, a circulating current control processing is performed to calculate a second modulation signal for circulating current control; based on the capacitor voltage and the actual current of the energy storage battery and the actual charge state of the energy storage battery obtained for each energy storage half-bridge converter unit, a dual-loop control is performed to calculate a third modulation signal for unit control; according to the first modulation signal, the second modulation signal and the third modulation signal, the half-bridge converter unit and the energy storage half-bridge converter unit in the energy storage railway power regulator are controlled.

A second aspect of an embodiment of the present invention provides a terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect when executing the computer program.

Compared with the prior art, the embodiments of the present invention have the following beneficial effects: compared with the prior art, the present invention is applied to an energy storage railway power regulator in which the energy storage half-bridge converter unit is composed of a half-bridge converter unit, a DC voltage stabilizing capacitor and an energy storage unit in parallel. Since the energy storage half-bridge converter unit in the energy storage railway power regulator is composed of a half-bridge converter and an energy storage unit in parallel, the switching states of the switching devices in the half-bridge converter and the energy storage unit can be decoupled, which facilitates the independent control of the half-bridge converter and the energy storage unit, thereby reducing the coupling of the energy storage railway power regulator control method. The energy storage railway power regulator control method of the present invention performs current compensation processing on the load current of each phase of the electric locomotive load corresponding to the energy storage railway power regulator, and calculates the first modulation signal of the AC current control; performs circulating current control processing based on the obtained compensation current of each phase of the energy storage railway power regulator, each half-bridge converter unit and the capacitor voltage of each energy storage half-bridge converter unit, and calculates the second modulation signal of the circulating current control; performs dual-loop control based on the capacitor voltage and the actual current of the energy storage battery and the actual charge state of the energy storage battery of each energy storage half-bridge converter unit, and calculates the third modulation signal of the unit control; controls the half-bridge converter unit and the energy storage half-bridge converter unit in the energy storage railway power regulator according to the first modulation signal, the second modulation signal and the third modulation signal. The energy storage system composed of all energy storage units in the energy storage railway power regulator can automatically compensate the energy used by the energy storage railway power regulator to compensate the load, reduce the calculation of reference instructions in the control process, reduce the coupling between control instructions, and thus reduce the control complexity.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

FIG1 is a structural topological diagram of an energy storage railway power regulator provided by an embodiment of the present invention;

FIG2 is a structural topological diagram of an energy storage half-bridge converter unit provided in an embodiment of the present invention;

FIG3 is a structural topology diagram of a half-bridge converter unit provided in an embodiment of the present invention;

4 is a schematic diagram of an implementation flow of a method for controlling an energy storage railway power regulator according to an embodiment of the present invention;

5 is an overall control block diagram of an energy storage railway power regulator provided by an embodiment of the present invention;

FIG6 is a block diagram of AC current control provided by an embodiment of the present invention;

7 is a block diagram of generating a compensation current reference instruction provided by an embodiment of the present invention;

8 is a calculation flow chart of the first equivalent current and the second equivalent current provided by an embodiment of the present invention;

FIG9 is a block diagram of circulation control provided by an embodiment of the present invention;

10 is a block diagram of generating a phase balance control signal and a bridge arm balance control signal provided in an embodiment of the present invention;

11 is a control block diagram of unit capacitor voltage balancing control and direct current control provided by an embodiment of the present invention;

12 is a block diagram of generating a first control signal and a second control signal provided by an embodiment of the present invention;

13 is a waveform diagram of compensation currents of each phase corresponding to simulation condition 1 provided in an embodiment of the present invention;

14 is a capacitor voltage waveform diagram of each unit corresponding to the simulation condition 1 provided in an embodiment of the present invention;

15 is a waveform diagram of the energy storage battery charging current corresponding to the simulation working condition 1 provided in an embodiment of the present invention;

16 is a waveform diagram of the actual SOC of the energy storage battery corresponding to the simulation working condition 1 provided in an embodiment of the present invention;

17 is a schematic diagram of a control device for an energy storage railway power regulator provided in an embodiment of the present invention;

FIG. 18 is a schematic diagram of a terminal device provided in an embodiment of the present invention.

DETAILED DESCRIPTION

In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

Electrified railways have large passenger capacity, strong transportation capacity, safety, reliability, high punctuality, etc. However, the power supply mode and load characteristics of the traction power supply system bring a series of power quality problems to the railway power supply system, affecting the safe and reliable operation of the loaded locomotives, reducing the power supply quality of the power grid, and even threatening the stable operation of the adjacent power supply/consumption systems (such as wind farms/photovoltaic power stations).

Grid current imbalance is currently a major power quality issue in rail transit. The traction power supply network is a symmetrical three-phase grid, but the railway load is a single-phase load, which results in a three-phase current imbalance, forming a negative sequence current on the grid side, which has an adverse effect on electrical equipment and loads. RPC can balance active current, compensate for reactive current and harmonic current, and solve the negative sequence current problem.

Traditional RPC uses a two-level converter as the converter structure. The traction feeder needs to be connected to the converter through a step-down transformer. Due to the limitation of switching devices, the system voltage is low and the capacity is limited. In large-capacity applications, multiple RPCs are often required to operate in parallel, so the system cost is high and the control is complex. Based on this problem, MRPC is proposed. Compared with traditional RPC, MRPC has the characteristics of high voltage level, large compensation capacity, small AC filter device, low device switching frequency, high degree of modularization, good scalability and redundancy, and no need for step-down transformer. Among the two-arm MRPC, three-arm MRPC and four-arm MRPC, the three-arm MRPC has the advantages of low DC bus voltage, few switching devices, simple control, low loss, and no need for isolation transformer.

In addition, electric locomotives generate a lot of energy when braking. If the braking energy is dissipated, it will be wasted, and the braking process may also deteriorate the performance of the locomotive system (such as heat generation, etc.); if the braking energy is fed back to the power grid or stored through energy storage equipment, it is of great significance.

Therefore, adding an energy storage system to the traditional RPC DC bus can solve the current imbalance problem and the braking energy recovery problem at the same time. If an energy storage system is added to the DC side of the MRPC submodule, the distributed energy storage of the system can be realized, which can not only reduce the voltage of the energy storage module and improve the energy storage efficiency, but also increase the modularity and redundancy of the energy storage system. However, the railway power conditioner based on MMC also needs to solve the problem of balanced control of the submodule capacitor voltage and the battery state of charge (State of Charge, SOC). Moreover, the energy storage railway power conditioner in the prior art also has the problems of high energy storage cost, poor reliability, strong coupling of control methods, inflexible control, and complex control methods.

In order to illustrate the technical solution of the present invention, a specific embodiment is provided below for illustration.

The energy storage railway power regulator control method of the embodiment of the present invention is applied to an energy storage railway power regulator in which the energy storage half-bridge converter unit is composed of a half-bridge converter unit and an energy storage unit connected in parallel.

FIG1 shows a structural topology diagram of an energy storage railway power conditioner applied in an embodiment of the present invention. As shown in FIG1 , the energy storage railway power conditioner 10 in an embodiment of the present invention may include a first bridge arm module 11, a second bridge arm module 12 and a third bridge arm module 13 connected in parallel.

Among them, the first end of the first bridge arm module 11, the first end of the second bridge arm module 12 and the first end of the third bridge arm module 13 are respectively used to connect to the traction power supply network.

Each bridge arm module includes an AC filter inductor _Ls and an upper bridge arm submodule and a lower bridge arm submodule with the same connection structure and connected in series with each other. One end of the AC filter inductor _Ls is connected between the upper bridge arm submodule and the lower bridge arm submodule, and the other end serves as the first end of the corresponding bridge arm module; each bridge arm submodule includes at least two converter units connected in series and with the same number, and at least two converter units of at least one bridge arm submodule in each bridge arm submodule include both a half-bridge converter unit HB _Mjk and an energy storage half-bridge (Half Bridge with Integrated Battery, HBIB) converter unit HBIB _Njk , and the energy storage half-bridge converter unit HBIB _Njk is composed of an energy storage unit, a half-bridge converter and a DC stabilizing capacitor connected in parallel.

Optionally, each bridge arm submodule may further include a bridge arm filter inductor L _arm , and the bridge arm filter inductor L _arm is connected in series with at least two converter units included in each bridge arm submodule.

Among them, since at least two converter units of at least one bridge arm submodule of the energy storage railway power conditioner of this embodiment include both a half-bridge converter unit and an energy storage half-bridge converter unit, it can be called an energy storage railway power conditioner (Hybrid MMC Railway Power Conditioner, HMRPC) based on a hybrid modular multi-level converter. As shown in Figure 1, in the figure, the three-phase power grid u _A , u _B , and u _C supplies power to the α and β phase electric locomotive loads through the V/v traction transformer, and the α and β phase load currents are i _αL and i _βL respectively. The first end of the first bridge arm module 11, the first end of the second bridge arm module 12, and the first end of the third bridge arm module 13, that is, the other end of the AC filter inductor _Ls in each bridge arm module are respectively used to connect the three ports of the secondary coil of the V/v traction transformer. Since the load is a single-phase load, the primary currents i _A , i _B , and i _C of the V/v traction transformer are unbalanced, and the phase compensation currents i _acomp , i _{bcomp ,} and i _ccomp of the HMRPC are required to achieve active power balance, negative sequence compensation, and balance of the three-phase current on the grid side.

The HMRPC proposed in the embodiment of the present invention has the advantages of high modularity, high output quality, large system capacity, low device switching frequency, and can save isolation transformers and step-down transformers. And because the number of converter units included in each bridge arm submodule of the energy storage railway power conditioner is the same, as long as there are at least two converter units of at least one bridge arm submodule that include both half-bridge converter units and energy storage half-bridge converter units, when there are multiple bridge arm submodules that include both half-bridge converter units and energy storage half-bridge converter units, the number of HBIB converter units in each bridge arm submodule can be configured differently, thereby reducing the energy storage cost while improving the flexibility of the topology structure of the energy storage railway power conditioner. Moreover, since the energy storage half-bridge converter unit is composed of an energy storage unit, a half-bridge converter and a DC stabilizing capacitor connected in parallel, the switching states of the switching devices in the half-bridge converter and the energy storage unit can be decoupled to achieve independent control of the half-bridge converter and the energy storage unit, thereby achieving independent control of the output power of the energy storage unit in the energy storage half-bridge converter unit, which is beneficial to reducing the coupling of the energy storage railway power regulator control method, designing a simple and versatile energy storage railway power regulator control method, improving the flexibility of the energy storage railway power regulator control method, being able to cope with the working conditions of some energy storage unit failures, and improving the reliability of the energy storage railway power regulator.

Optionally, as shown in FIG2 , each energy storage half-bridge converter unit HBIB _Njk may include: an energy storage battery Bat, an energy storage battery filter inductor L _b , switch tubes S ₅ , S ₆ , a diode D ₅ , a diode D ₆ and an energy storage unit, a half-bridge converter HB and a DC stabilizing capacitor C ₂ .

Among them, the positive electrode of the energy storage battery Bat is connected to one end of the energy storage battery filter inductor L _b , and the negative electrode of the energy storage battery Bat is respectively connected to the source electrode of the switch tube S ₆ , the positive electrode of the diode D ₆ , one end of the DC voltage stabilizing capacitor C ₂ and the first end of the half-bridge converter HB; the first end of the half-bridge converter HB serves as the input end or output end of the energy storage half-bridge converter unit HBIB _Njk ; the other end of the energy storage battery filter inductor L _b is connected between the source electrode of the switch tube S ₅ and the drain electrode of the switch tube S ₆ ; the source electrode of the switch tube S ₅ is also connected to the positive electrode of the diode D ₅ , and the drain electrode of the switch tube S ₅ is respectively connected to the negative electrode of the diode D ₅ , the other end of the DC voltage stabilizing capacitor C ₂ and the third end of the half-bridge converter HB; the drain electrode of the switch tube S ₆ is also connected to the negative electrode of the diode D ₆ ; the gate electrode of the switch tube S ₅ and the gate electrode of the switch tube S ₆ are used to input the first control signal; the second end of the half-bridge converter HB serves as the energy storage half-bridge converter unit HBIB The output or input of _Njk .

Optionally, as shown in FIG3 , each half-bridge converter unit HB _Mjk may include: a switch tube S ₁ , a switch tube S ₂ , a half-bridge converter HB formed by a diode D ₁ and a diode D ₂ , and a capacitor C ₁ .

The drain of the switch tube _S1 and the cathode of the diode _D1 are connected to serve as the third end of the half-bridge converter HB, and the source of the switch tube _S2 and the anode of the diode _D2 are connected to serve as the first end of the half-bridge converter HB; the source of the switch tube _S1 and the drain of the switch tube _S2 are connected to serve as the second end of the half-bridge converter HB; the source of the switch tube _S1 is also connected to the anode of the diode _D1 ; the drain of the switch tube _S2 is also connected to the cathode of the diode _D2 ; one end of the capacitor _C1 is connected to the third end of the half-bridge converter HB, and the other end of the capacitor _C1 is connected to the first end of the half-bridge converter HB; the gate of the switch tube _S1 and the gate of the switch tube _S2 are used to input the second control signal.

The first end of the half-bridge converter HB serves as the input end or the output end of the half-bridge converter unit HB _Mjk ; the second end of the half-bridge converter HB serves as the output end or the input end of the half-bridge converter unit HB _Mjk .

In this embodiment, the DC side of the HB converter unit is connected to the capacitor _C1 , and the HBIB converter unit adds a battery energy storage structure on the basis of the HB converter unit, and is connected to the DC capacitor _C2 through a half-bridge converter, and _Lb is the energy storage battery filter inductor. By changing the switching state of the switch tubes _S1 ~ _S4 through the second control signal, the unit output voltage can be controlled to be equal to the capacitor voltage or equal to zero, and the bridge arm submodule output voltage is equal to the sum of the unit output voltages. The HBIB converter unit can change the switching state of the switch tubes _S5 and _S6 through the first control signal, thereby controlling the battery energy storage and release. The switching state decoupling of the switching devices in the half-bridge converter unit and the energy storage unit is achieved, so that the energy storage system and the HMRPC system exchange energy, and the HMRPC system then exchanges energy with the load through the AC end.

The first control signal and the second control signal can be obtained by the energy storage railway power regulator control method applied to the energy storage railway power regulator of this embodiment. All energy storage units in the energy storage railway power regulator constitute an energy storage system. As shown in FIG4 , the control method is described in detail as follows:

Before the energy storage railway power regulator is controlled, the operating parameters of the energy storage railway power regulator need to be obtained. The operating parameters may include the load currents i _αL and i _βL of each phase of the electric locomotive load corresponding to the energy storage railway power regulator, the compensation currents i _acomp , i _bcomp and i _ccomp of each phase of the energy storage railway power regulator, the first capacitor voltage U _{jkl_sm} of each half-bridge converter unit in the energy storage railway power regulator, and the second capacitor voltage U _{jkz_sm} of each energy storage half-bridge converter unit in the energy storage railway power regulator, the actual current i _{jkz_bat} of the energy storage battery, and the actual state of charge SOC _jkz of the energy storage battery.

Among them, the variable subscript j=a, b, c represents phase a, phase b or phase c in the HMRPC, k=p, n represents the upper bridge arm submodule p or the lower bridge arm submodule n, l=1,2,…M _jk represents the number of the HB converter unit, M _jk represents the total number of HB converter units included in the k bridge arm submodule of the bridge arm module corresponding to j in the HMRPC, z=1,2,…N _jk represents the number of the HBIB converter unit, N _jk represents the total number of HBIB converter units included in the k bridge arm submodule of the bridge arm module corresponding to j in the HMRPC.

Among them, the variables in the energy storage railway power conditioner system are defined as follows in conjunction with Figure 1 (where the voltage is referenced to the feeder ground):

The α and β phase load voltages u _α and u _β are respectively:

Among them, _Us is the feeder voltage amplitude, and ω is the grid angular frequency.

The α and β phase load currents i _αL and i _βL are respectively:

Among them, I _α and I _β are the load current amplitudes of α and β phases respectively, and θ _α and θ _β are the load power factor angles.

The compensation currents i _acomp , i _bcomp and i _ccomp of phases a, b and c are defined as:

Wherein, I _a and I _b are the compensation current amplitudes of phase a and phase b respectively, and θ _a and θ _b are the compensation current phase angles with u _α and u _β as reference phases respectively.

The actual circulating current i _jcir of each phase is defined as:

i _jcir = (i _jp +i _jn )/2 (4);

Among them, i _jp and i _jn are the bridge arm currents of the upper and lower bridge arm submodules of phase j respectively.

The common mode voltage u _com is defined as:

Among them, u _a , u _b and u _c are the AC terminal voltages of HMRPC.

Exemplarily, the overall control function of the energy storage railway power regulator is described as follows in conjunction with FIG5:

The current reference instruction generation module collects the α and β phase load currents i _αL and i _βL and calculates the compensation current reference instructions of each phase on the AC side of the HMRPC. To balance the three-phase current on the grid side. The AC current control module refers the compensation current of each phase to the instruction The error of the compensation current i _jcomp of each phase of the HMRPC is input into a proportional resonant regulator (PR) to generate a first modulation signal u _jc to control the compensation current of each phase of the HMRPC to track its given value (the reference instruction of the compensation current of each phase). In this embodiment, since the total energy control loop of all converter units of the energy storage railway power regulator will change the power exchanged between the HMRPC and the load, the power exchanged between the load and the HMRPC under the reference instruction of the compensation current of each phase after removing the total energy control loop of all converter units is equal to the power output of the expected energy storage system. Therefore, this embodiment does not use the total energy control loop of all converter units to adjust the reference instruction of the compensation current of each phase.

The circulating current control module suppresses the double frequency fluctuation of the circulating current and balances the capacitor voltage between the phase modules and the capacitor voltage between the bridge arm submodules. The error between the actual circulating current i _jcir of each phase and the phase balance control signal are obtained through the calculation module. Bridge arm balance control signal The proportional integral resonant regulator (PIR) is inputted together to obtain the second modulation signal u _jcc to realize the functions of circulating current control and balancing control. By changing the algorithm of the calculation module, the actual current i _{jkz_bat} of the energy storage battery can be used as the feedforward battery current to perform feedforward control on the interphase balancing control and the bridge arm balancing control. On this basis, since the third modulation signal of the unit control is obtained by the dual-loop control calculation based on the voltage outer loop and the current inner loop, the actual state of charge of each energy storage battery is prone to differences. Therefore, the actual state of charge SOC _jkz of the energy storage battery can also be used to perform SOC balancing control on the interphase balancing control and the bridge arm balancing control. To improve the capacitor voltage balancing effect of the sub-modules between phases and bridge arms.

Unit balancing control is used to balance the capacitor voltages between units in the bridge arm submodule. Since the energy storage battery control is based on the dual-loop control of the voltage outer loop and the current inner loop, the actual state of charge of each energy storage battery is prone to differences. The energy storage half-bridge converter unit SOC balancing control is achieved by adjusting the modulation wave of the half-bridge converter unit in the energy storage half-bridge converter unit. Since the energy storage battery control is based on the dual-loop control of the voltage outer loop and the current inner loop, the actual current of the energy storage battery is determined by the second capacitor voltage outer loop. When the actual state of charge of the energy storage battery is lower than the average state of charge of the bridge arm energy storage battery, the second capacitor voltage is increased, and the energy storage battery is charged under the action of the second capacitor voltage outer loop to increase the actual state of charge of the energy storage battery; conversely, when the actual state of charge of the energy storage battery is higher than the average state of charge of the bridge arm energy storage battery, the second capacitor voltage is reduced, and the energy storage battery is discharged under the action of the second capacitor voltage outer loop to reduce the actual state of charge of the energy storage battery. Therefore, the first capacitor voltage U _{jkl_sm} of the half-bridge converter unit and the second capacitor voltage U _{jkz_sm} of the energy storage half-bridge converter unit are sampled, and the average capacitor voltage of the bridge arm submodule is calculated. The error between the first capacitor voltage and the first capacitor voltage is adjusted by a proportional integral regulator (PI) to obtain a first sub-modulation signal u _jklc . The error between the first capacitor voltage and the second capacitor voltage is adjusted by PI, and then the energy storage half-bridge converter unit SOC balancing control is added to obtain a second sub-modulation signal u _jkzc . Finally, the first sub-modulation signal u _jklc and the second sub-modulation signal u _jkzc in the third modulation signal are also related to the direction of the bridge arm current i _jk . The energy storage battery control works in a dual-loop control mode of a voltage outer loop and a current inner loop. The second capacitor voltage U _{jkz_sm} and the capacitor reference voltage are used to adjust the difference between the first capacitor voltage and the second capacitor voltage. The difference between the adjustment result and the actual current i _{jkz_bat} of the energy storage battery is subjected to PI adjustment again to generate the third sub-modulation signal u _{jkz_bat} in the third modulation signal.

The modulation output part, the modulation signal of the half-bridge converter unit on the MMC side, i.e., the control signal of the switch tubes S ₁ to S ₄ in FIG. 2 and FIG. 3, is jointly generated by u _jc , u _jcc , u _jklc and u _jkzc , and generates (second control signal) switch signals S _jkl and S _jkz under the modulation effect, respectively controlling the switch tubes S ₁ , S ₂ and S ₃ , S _4. S _{jkz_bat} is the (first control signal) switch signal of the half-bridge converter unit on the battery side, i.e., the switch signal of S ₅ , S ₆ , which is generated by u _{jkz_bat} .

Through the above-mentioned energy storage railway power conditioner control method, the purpose of balancing the grid current and improving the energy utilization rate by using the energy storage system can be achieved. In addition, the second capacitor voltage, the actual current of the energy storage battery, the actual state of charge of the energy storage battery, and the first capacitor voltage of each half-bridge converter unit are used in the control process. When the energy storage unit of any energy storage half-bridge converter unit fails, the corresponding energy storage unit can be directly bypassed, thereby ensuring the reliability of the entire energy storage railway power conditioner. Improve the flexibility of the control method of the energy storage railway power conditioner. Based on the first capacitor voltage, the second capacitor voltage, and the actual current of the energy storage battery and the actual state of charge of the energy storage battery of each energy storage half-bridge converter unit, the third modulation signal of the unit control is calculated, which can make the energy storage system composed of all energy storage units in the energy storage railway power conditioner automatically compensate the energy used by the energy storage railway power conditioner to compensate the load, reduce the calculation of reference instructions in the control process, and thus reduce the control complexity.

The control functions of each part of the energy storage railway power regulator control method are described as follows through steps 101 to 104 in conjunction with FIG. 4 to FIG. 12:

Step 101, current compensation processing is performed on the load current of each phase of the electric locomotive load corresponding to the acquired energy storage railway power regulator, and a first modulation signal for AC current control is calculated.

In this embodiment, the load current of each phase is compensated by the energy storage system, reactive current compensation, active current balance and negative sequence current compensation to obtain the compensated load current. The compensated load current is subtracted from the actual load current to obtain the compensation current reference instruction. The error value of the compensation current i _jcomp of each phase of the HMRPC is formed into a first modulation signal u _jc through the PR regulator to control the compensation current of each phase of the HMRPC to track its given value (reference instruction of the compensation current of each phase).

Optionally, in combination with FIG. 6 and FIG. 7 , current compensation processing is performed on each phase load current of the electric locomotive load corresponding to the acquired energy storage railway power regulator to calculate the first modulation signal for AC current control, which may include:

Obtain a first equivalent current and a second equivalent current; perform current compensation processing according to the load current of each phase, the first equivalent current and the second equivalent current, and calculate the d-axis component of the compensation current; perform dq transformation on the load current of each phase, and calculate the q-axis component of the load current; multiply the q-axis component of the load current by -1 to obtain the q-axis component of the compensation current; perform dq inverse transformation according to the d-axis component of the compensation current and the q-axis component of the compensation current, and calculate the reference instruction of the compensation current of each phase; calculate the first modulation signal of the AC current control according to the compensation current of each phase and the reference instruction of the compensation current of each phase.

Among them, the first equivalent current is the equivalent current on the AC side of the energy storage railway power regulator when the energy storage system outputs active power to the α phase through the energy storage railway power regulator, and the second equivalent current is the equivalent current on the AC side of the energy storage railway power regulator when the energy storage system outputs active power to the β phase through the energy storage railway power regulator.

Optionally, obtaining the first equivalent current and the second equivalent current may include:

Obtain the α-phase load active power and β-phase load active power of the electric locomotive load corresponding to the energy storage railway power regulator, the maximum output power of the energy storage system of the energy storage railway power regulator, the maximum allowable state of charge of the energy storage battery of each energy storage half-bridge converter unit in the energy storage railway power regulator, and the minimum allowable state of charge of the energy storage battery.

It is determined whether the α-phase load active power, the β-phase load active power and the actual state of charge of the energy storage battery meet preset conditions, the preset conditions being that the sum of the α-phase load active power and the β-phase load active power is greater than zero and the actual state of charge of each energy storage battery is greater than the minimum allowable state of charge of the corresponding energy storage battery, or the sum of the α-phase load active power and the β-phase load active power is less than zero and the actual state of charge of each energy storage battery is less than the maximum allowable state of charge of the corresponding energy storage battery.

If the α-phase load active power, the β-phase load active power and the actual charge state of the energy storage battery meet the preset conditions, the absolute value of the difference between the α-phase load active power and the β-phase load active power is calculated, and it is determined whether the absolute value is less than or equal to the maximum output power of the energy storage system.

If the absolute value is less than or equal to the maximum output power of the energy storage system, then according to A first equivalent current and a second equivalent current are obtained.

If the absolute value is greater than the maximum output power of the energy storage system, then according to A first equivalent current and a second equivalent current are obtained.

If the α-phase load active power, the β-phase load active power and the actual charge state of the energy storage battery do not meet the preset conditions, it is determined that the first equivalent current and the second equivalent current are both zero.

Wherein, i _αb is the first equivalent current, i _βb is the second equivalent current, P _bm is the maximum output power of the energy storage system, U _s is the feeder voltage amplitude, P _αL is the α-phase load active power, P _βL is the β-phase load active power, F ₁ = sin(ωt-π/6), F ₂ = sin(ωt-π/2), ω is the grid angular frequency, and f ₁ , f ₂ , and f ₃ are coefficients.

FIG8 is used for explanation. In the figure, “&&” represents a logical “AND” and “||” represents a logical “OR”. P _bm is the maximum output power of the energy storage system, which can be directly obtained. P _αL and P _βL are the active powers of the α-phase and β-phase loads, which can be calculated by formula (6). i _αLd and i _βLd are the active currents of the α-phase and β-phase loads, which are obtained by current and active power separation. SOC _jkz , SOC _max and SOC _min are the actual SOC of the energy storage battery of the HBIB converter unit, the maximum allowable SOC of the energy storage battery and the minimum allowable SOC of the energy storage battery, respectively.

Wherein, I _αLd and I _βLd are the load active current amplitudes of α and β phases.

Among them, first determine whether the SOC of the energy storage system meets the energy storage or energy release conditions. If P _αL +P _βL >0, that is, the total load of the α and β phases consumes active power. At this time, if the actual SOC of each energy storage battery satisfies SOC _jkz >SOC _min , the energy storage device is allowed to release energy; if P _αL +P _βL <0, it means that the total load of the α and β phases feeds back active power to the grid. At this time, if SOC _jkz <SOC _max , the energy storage device is allowed to store energy; otherwise, let i _αb =i _βb =0, that is, the energy storage system does not work.

Further judge whether the energy storage system can balance the active power of phases α and β. If |P _αL -P _βL |≤P _bm , it means that the active power of phases α and β is equal after the energy storage system is compensated; if |P _αL -P _βL |>P _bm , it means that the active power after the energy storage system is compensated cannot be evenly distributed, and at this time the energy storage system compensates the phase with a larger absolute value of the active power of the load. Therefore, i _αb and i _βb can be calculated according to Figure 8, in which F ₁ =sin(ωt-π/6), F ₂ =sin(ωt-π/2), f ₁ , f ₂ and f ₃ are coefficients, and the calculation formula is:

Among them, before and after the energy storage system works, not only the active power output of the HMRPC to the α and β phases is changed, but also the negative sequence compensation output will change. Therefore, this embodiment gives priority to the compensation effect of the energy storage system when calculating the compensation current. In Figure 7, the α and β phase load currents i _αL and i _βL are added to the first equivalent current i _αb and the second equivalent current i _βb respectively, giving priority to the compensation effect of the energy storage system, and obtaining the current after the energy storage system compensation effect, recorded as i _αl and i _βl , and then calculating the HMRPC compensation reactive current, negative sequence current and balanced active current. Specifically, active separation is performed on i _αl and i _βl according to the instantaneous reactive power theory to obtain the currents i _αlp and i _βlp after reactive compensation. Therefore, the grid current is calculated according to the α and β load currents by formula (8), and then the grid current is transformed into the dq coordinate system by formula (9). The d-axis current DC component is extracted by the second-order generalized integrator (SOGI) and multiplied by the proportional coefficient G to obtain I _d . I _d is the d-axis component of i _αl and i _βl in the dq coordinate system when the three-phase grid is balanced after compensation, and the q-axis component after compensation is zero. Finally, the initial compensation current can be obtained by subtracting the compensated load current from the load current of each phase in the dq coordinate system. Specifically, i _αL and i _βL are transformed into the dq coordinate system, I _d is subtracted from the d-axis component of the load current i _d to obtain the d-axis component of the compensation current, and the q-axis component of the load current i _q is multiplied by -1 to obtain the q-axis component of the compensation current. The obtained d-axis and q-axis components of the compensation current can be obtained by inverse transformation to obtain the final reference instructions for the compensation currents of each phase. In Figure 7, the proportionality coefficient θ is the phase of u _A obtained by phase locking, and i _dd is the d-axis component of the current after energy storage system compensation and reactive power compensation.

Where _kt is the transformation ratio of the traction transformer.

Where i _d and i _q are the d-axis component and q-axis component of the load current in the dq coordinate system respectively.

In this embodiment, since the energy storage system compensates energy automatically when the HMRPC exchanges energy with the load, causing the unit voltage to change, the physical quantity change and energy transfer principle of the system under this control method are analyzed: the compensation current reference instruction is changed, and the load is controlled to output positive (negative) power to the HMRPC. At this time, the unit capacitor voltage has an increasing (decreasing) trend. The HB converter unit has no energy storage battery, so the corresponding voltage increases (decreases), and the HBIB converter unit capacitor voltage remains stable under the control of the energy storage battery capacitor voltage loop. Under the unit balancing control, the HB converter unit voltage begins to decrease (increase), and finally all converter unit voltages remain stable, realizing energy exchange between the load and the energy storage system. Since the total energy control loop of all converter units of the energy storage railway power regulator will change the power exchanged between the HMRPC and the load, when this embodiment obtains the compensation current reference instruction of each phase, it is not necessary for all converter unit total energy control loops to be adjusted.

Step 102, performing circulating current control processing based on the acquired compensation current of each phase of the energy storage railway power regulator, each half-bridge converter unit and the capacitor voltage of each energy storage half-bridge converter unit, and calculating a second modulation signal of circulating current control.

Referring to FIG9 , the reference value of the circulating current of each phase can be calculated based on the compensation current of each phase, the first capacitor voltage and the second capacitor voltage. Phase balance control signal and bridge arm balance control signal Reference value of circulating current of each phase The error value of the actual circulating current i _jcir of each phase and the phase balance control signal formed by the phase-to-phase capacitor voltage balance control and the bridge arm submodule capacitor voltage balance control and bridge arm balance control signal The sum is used as the input of the PIR regulator to form the second modulation signal u _jcc , stabilize the DC circulating current, suppress the secondary circulating current, and balance the capacitor voltages between phases and between bridge arm submodules.

Optionally, referring to FIG9 and FIG10, the circulating current control processing is performed based on the acquired compensation current of each phase of the energy storage railway power regulator, each half-bridge converter unit in the energy storage railway power regulator, and the capacitor voltage of each energy storage half-bridge converter unit, and the second modulation signal of the circulating current control is calculated, which may include:

The compensation current of each phase is decomposed, and the circulating current reference value of each phase is calculated according to the decomposition result; the per-unit value of the first capacitor total energy of all converter units in each upper bridge arm submodule and the per-unit value of the second capacitor total energy of all converter units in each lower bridge arm submodule are calculated according to the first capacitor voltage and the second capacitor voltage; the per-unit value of the first capacitor total energy reference value of each bridge arm module is calculated according to the obtained capacitor reference voltage; the initial phase balancing control power reference value of each phase is calculated according to the proportional integral adjustment of the difference between the sum of the per-unit value of the first capacitor total energy and the per-unit value of the second capacitor total energy and the per-unit value of the first capacitor total energy reference value; the initial phase balancing control power reference value of each phase is adjusted according to the actual current of the energy storage battery and the actual charge state of the energy storage battery. The balanced control power reference value is feedforward regulated and the state of charge balanced regulated to calculate the phase balanced control signal of each phase; the proportional integral regulation is performed according to the difference between the per-unit value of the total energy of the first capacitor and the per-unit value of the total energy of the second capacitor to calculate the initial bridge arm balanced control power reference value of each phase; according to the actual current of the energy storage battery and the actual state of charge of the energy storage battery, the initial bridge arm balanced control power reference value is feedforward regulated and the state of charge balanced regulated to calculate the bridge arm balanced control signal of each phase; the actual circulating current of each phase, the circulating current reference value of each phase, the phase balanced control signal of each phase and the bridge arm balanced control signal of each phase of the obtained energy storage railway power regulator are adjusted by a proportional integral resonant regulator to calculate the second modulation signal of the circulating current control.

The actual circulating current i _jcir of each phase of the energy storage railway power regulator can be calculated according to formula (4) using the acquired bridge arm current, or can be directly obtained by measuring the actual circulating current i _jcir of each phase.

The process of decomposing the compensation current of each phase and calculating the reference value of the circulating current of each phase according to the decomposition result can be:

By decomposing the active current and reactive current of the compensation current of phases a and b in formula (3), we can obtain:

Among them, I _P1 is the amplitude of the in-phase component of the a-phase compensation current and the α-phase load voltage, and I _Q1 is the amplitude of the current component of the a-phase compensation current lagging the α-phase load voltage by 90°; I _P2 is the amplitude of the in-phase component of the b-phase compensation current and the β-phase load voltage, and I _Q2 is the amplitude of the current component of the b-phase compensation current lagging the β-phase load voltage by 90°.

Calculate the instantaneous power _Pj of phase j as:

P _j =U _dc i _jcir +(u _j +u _com )i _jcomp (13);

Among them, U _dc is the DC bus voltage.

Combining formulas (1), (5), (12) and (13), when the HMRPC system is working stably, there is no DC component in the instantaneous power of phase j, that is, the DC component in the formula is 0, and the three-phase circulating current reference value is obtained:

Combined with Figure 10, the phase-to-phase balance control and bridge arm balance control can ensure the stability of the capacitor voltage between the phases and the bridge arm submodules, which can be achieved by controlling the DC circulating current and the fundamental AC circulating current respectively. In the following analysis, the unit value of the capacitor energy of the HB and HBIB converter units is defined as and Per-unit quantities are indicated by a superscript ^# .

The per unit value of the total energy of the first capacitor of all converter units in each corresponding upper bridge arm submodule of the MMC is and the per unit value of the total energy of the second capacitor of all converter units in the lower bridge arm submodule It can be calculated as:

In order to balance the energy of the phase submodule capacitor, the initial phase balance control phase power reference value of each phase It can be calculated by PI regulator:

in, is the per unit value of the total energy reference value of the first capacitor of each corresponding bridge arm module, is the per-unit value of the total energy of the first capacitor and the per-unit value of the total energy of the second capacitor The sum of k _p1 and k _i1 are the proportional coefficient and integral coefficient of the phase balancing control respectively.

According to the actual current and charge state of the energy storage battery, the initial phase balance control power reference value is By performing feedforward regulation and charge state balancing regulation, the phase balancing control signal of each phase can be calculated.

Per unit value of the total energy of the first capacitor and the per-unit value of the total energy of the second capacitor The difference between the initial bridge arm balanced control power reference value can be calculated through the PI regulator. for:

Among them, k _p2 and k _i2 are the proportional coefficient and integral coefficient of bridge arm balance control respectively.

According to the actual current and the actual state of charge of the energy storage battery, the initial bridge arm balance control power reference value is feedforward regulated and the state of charge balance regulated, and the bridge arm balance control signal of each phase is calculated.

The obtained actual circulating current of each phase of the energy storage railway power regulator, the circulating current reference value of each phase, the phase balance control signal of each phase and the bridge arm balance control signal of each phase are adjusted through a proportional-integral resonant regulator to calculate and obtain a second modulation signal of the circulating current control.

Optionally, according to the actual current and the actual state of charge of the energy storage battery, the initial phase balance control power reference value is feedforward regulated and the state of charge balance regulated to calculate the phase balance control signal of each phase, which may include:

According to the actual current of the energy storage battery, the total current of the third energy storage battery of each bridge arm module and the average current of the energy storage battery of each bridge arm module are calculated; proportional adjustment is performed according to the difference between the total current of the third energy storage battery and the average current of the energy storage battery, and the first feedforward adjustment amount of each phase is calculated; according to the actual state of charge of the energy storage battery, the average state of charge of the energy storage batteries of all energy storage half-bridge converter units in the energy storage railway power conditioner and the average state of charge of the phase energy storage batteries corresponding to each bridge arm module are calculated; proportional integral adjustment is performed according to the difference between the average state of charge of the energy storage battery and the average state of charge of the phase energy storage battery, and the first state of charge balancing adjustment amount of each phase is calculated; the sum of the initial phase balancing control power reference value, the first feedforward adjustment amount and the first state of charge balancing adjustment amount is calculated to obtain the phase balancing control power reference value of each phase; according to the phase balancing control power reference value, the phase balancing control signal of each phase is calculated.

Optionally, the average state of charge of the bridge arm energy storage battery includes the average state of charge of the upper bridge arm energy storage battery and the average state of charge of the lower bridge arm energy storage battery. According to the actual current and the actual state of charge of the energy storage battery, the initial bridge arm balance control power reference value is feedforward regulated and the state of charge balance regulated, and the bridge arm balance control signal of each phase is calculated, which may include:

According to the actual current of the energy storage battery, the total current of the first energy storage battery of each upper bridge arm submodule and the total current of the second energy storage battery of each lower bridge arm submodule are calculated; proportional adjustment is performed according to the difference between the total current of the second energy storage battery and the total current of the first energy storage battery, and the second feedforward adjustment amount of each phase is calculated; proportional integral adjustment is performed according to the difference between the average state of charge of the upper bridge arm energy storage battery and the average state of charge of the lower bridge arm energy storage battery, and the second state of charge balance adjustment amount of each phase is calculated; the sum of the initial bridge arm balance control power reference value, the second feedforward adjustment amount and the second state of charge balance adjustment amount is calculated to obtain the bridge arm balance control power reference value of each phase; according to the bridge arm balance control power reference value, the bridge arm balance control signal of each phase is calculated.

Among them, when the number of HBIB converter units included in different corresponding bridge arm modules or different bridge arm sub-modules is different, or the power of the energy storage batteries in different HBIB converter units is different, the energy stored or released by the energy storage system is transferred not only between the HB and HBIB converter units, but also between the phases and the bridge arm sub-modules.

Among them, i _{jkz_bat} is the actual current of the energy storage battery of each energy storage half-bridge converter unit in the energy storage railway power conditioner. When the actual current of the energy storage battery is positive, the capacitor of the corresponding energy storage half-bridge converter unit releases energy, the capacitor voltage decreases, and the capacitor voltage of the corresponding energy storage half-bridge converter unit needs to be increased; when the actual current of the energy storage battery is negative, the capacitor voltage of the corresponding energy storage half-bridge converter unit increases, and the capacitor voltage of the corresponding energy storage half-bridge converter unit needs to be reduced. Considering all the energy storage half-bridge converter units of each corresponding bridge arm module or bridge arm submodule as a whole, the total current i _{jp_bat} of the first energy storage battery of each upper bridge arm submodule, the total current i _{jn_bat} of the second energy storage battery of each lower bridge arm submodule, the total current i _{j_bat} of the third energy storage battery of each bridge arm module, and the average current i _{phav_bat} of the energy storage battery of each bridge arm module in the energy storage railway power conditioner are calculated respectively:

If the total current i _{j_bat} of the third energy storage battery is greater than the average current i _{phav_bat} of the energy storage battery, it means that the energy storage power of the phase energy storage system is greater than the three-phase average value or the energy release power of the phase energy storage system is less than the three-phase average value, then the average value of the phase module capacitor voltage tends to decrease compared with the average value of the capacitor voltage of all modules in the system, and the average value of the phase module capacitor voltage needs to be increased; if the total current i _{j_bat} of the third energy storage battery is less than the average current i _{phav_bat} of the energy storage battery, the average value of the phase module voltage needs to be reduced.

When the total current i _{jp_bat} of the first energy storage battery is greater than the total current i _{jn_bat} of the second energy storage battery, it is necessary to increase the average capacitor voltage of the upper bridge arm submodule and reduce the average capacitor voltage of the lower bridge arm submodule; when the total current i _{jp_bat} of the first energy storage battery is less than the total current i _{jn_bat} of the second energy storage battery, it is necessary to reduce the average capacitor voltage of the upper bridge arm submodule and increase the average capacitor voltage of the lower bridge arm submodule.

Therefore, the first feedforward adjustment value ΔP ₁ of each phase is:

ΔP ₁ =k _p3 (i _{j_bat} -i _{phav_bat} ) (19);

Wherein, _kp3 is the phase battery current feedforward control proportional coefficient.

The second feedforward adjustment value ΔP ₂ of each phase is:

ΔP ₂ =k _p4 (i _{jn_bat} -i _{jp_bat} ) (20);

Wherein, _kp4 is the proportional coefficient of the bridge arm battery current feedforward control.

The capacitor voltage of the HBIB converter unit is controlled by the energy storage battery voltage outer loop, so the SOC of each energy storage battery is prone to differences, requiring a systematic SOC balancing control strategy. If you want to increase the SOC of the energy storage battery, you need to charge the energy storage battery, you can increase the second capacitor voltage, and then the energy storage battery is charged under the action of the second capacitor voltage outer loop; if you want to reduce the SOC of the energy storage battery, you need to reduce the second capacitor voltage. It can be seen that SOC balancing control can be achieved by adjusting the second capacitor voltage.

According to the actual state of charge of the energy storage battery, the average state of charge SOC _av of the energy storage battery of all energy storage half-bridge converter units in the energy storage railway power conditioner, the average state of charge SOC _j of the phase energy storage battery corresponding to each bridge arm module, and the average state of charge SOC _jp of the upper bridge arm energy storage battery and the average state of charge SOC _jn of the lower bridge arm energy storage battery in the average state of charge of the bridge arm energy storage battery of each bridge arm submodule are calculated as follows:

Phase SOC balancing control can be achieved by adjusting the DC circulating current, so the first state of charge balancing adjustment amount ΔP ₁₁ is:

ΔP ₁₁ =k _p6 (SOC _av -SOC _j )+k _i6 ∫ (SOC _av -SOC _j )dt (22);

Wherein, k _p6 and k _i6 are the phase SOC balancing control proportional coefficient and integral coefficient respectively.

The bridge arm SOC balancing control can be achieved by adjusting the AC circulating current, so the second state of charge balancing adjustment amount ΔP ₂₂ is:

ΔP ₂₂ =k _p7 (SOC _jp -SOC _jn )+k _i7 ∫ (SOC _jp -SOC _jn )dt (23);

Among them, _kp7 and _ki7 are the bridge arm SOC balance control proportional coefficient and integral coefficient respectively.

After the first feedforward adjustment value _ΔP1 and the first state of charge balance adjustment value _ΔP11 are calculated, the phase balance control power reference value of each phase is calculated according to formula (24):

Then the phase balance control signal of each phase is:

After calculating the second feedforward adjustment value ΔP ₂ and the second state of charge balance adjustment value ΔP ₂₂ , the bridge arm balance control power reference value of each phase is calculated according to formula (26):

The AC circulation degree of freedom is 3, among which the fundamental positive sequence circulation and fundamental negative sequence circulation can be used for bridge arm balance control. Suppose the bridge arm balance control signal The expression is:

Among them, _Iz+ and _Iz- are the positive-sequence circulating current amplitude and the negative-sequence circulating current amplitude respectively, and θ ₊ and _θ- are the positive-sequence circulating current phase angle and the negative-sequence circulating current phase angle respectively.

Let θ ₊ = 0, we can get:

in,

In this embodiment, when the number of HBIB converter units included in different corresponding bridge arm modules or different bridge arm submodules is different, or the power of the energy storage batteries in different HBIB converter units is different, the energy stored or released by the energy storage system is not only transferred between the HB and HBIB converter units, but also between the phases and the bridge arm submodules. And because the SOC of each energy storage battery in the HBIB converter unit controlled by the energy storage battery voltage outer loop is prone to differences, a system SOC balancing control strategy is required. Therefore, the introduction of battery current feedforward control and phase SOC balancing control and bridge arm SOC balancing control can speed up the energy balancing of the energy storage system between the phase bridge arm modules and the bridge arm submodules, improve the energy storage system energy exchange speed between the HMRPC phases and bridge arms, and is conducive to stabilizing the submodule capacitor voltage.

Step 103 , performing dual-loop control based on the capacitor voltage and the acquired actual current of the energy storage battery and the actual state of charge of the energy storage battery of each energy storage half-bridge converter unit, and calculating a third modulation signal for unit control.

In this embodiment, as shown in FIG11 , the energy storage battery of the HBIB converter unit adopts a dual-loop control of a voltage outer loop and a current inner loop. Since the actual state of charge of each energy storage battery is likely to differ at this time, the SOC balance control of the energy storage half-bridge converter unit can be achieved by adjusting the modulation wave of the half-bridge converter unit in the energy storage half-bridge converter unit. Since the energy storage battery is controlled based on the dual-loop control of the voltage outer loop and the current inner loop, the actual current of the energy storage battery is determined by the second capacitor voltage outer loop. When the actual state of charge of the energy storage battery is lower than the average state of charge of the bridge arm energy storage battery, the second capacitor voltage is increased, and the energy storage battery is charged under the action of the second capacitor voltage outer loop to increase the actual state of charge of the energy storage battery; conversely, when the actual state of charge of the energy storage battery is higher than the average state of charge of the bridge arm energy storage battery, the second capacitor voltage is reduced, and the energy storage battery is discharged under the action of the second capacitor voltage outer loop to reduce the actual state of charge of the energy storage battery.

Optionally, performing dual-loop control based on the capacitor voltage and the actual current of the energy storage battery and the actual state of charge of the energy storage battery of each energy storage half-bridge converter unit to calculate a third modulation signal for unit control may include:

According to the actual current of the energy storage battery, the average energy storage battery current of the bridge arm of each bridge arm submodule is calculated; according to the first capacitor voltage and the second capacitor voltage, the average capacitor voltage of each bridge arm submodule is calculated; according to the first capacitor voltage, the average capacitor voltage, the average energy storage battery current of the bridge arm and the acquired bridge arm current of each bridge arm submodule, the first sub-modulation signal of each half-bridge converter unit is calculated; according to the actual state of charge of the energy storage battery, the average state of charge of the bridge arm energy storage battery of each bridge arm submodule is calculated; according to the second capacitor voltage, the actual current of the energy storage battery, the average capacitor voltage, the average energy storage battery current of the bridge arm, the actual state of charge of the energy storage battery, the average state of charge of the bridge arm energy storage battery and the bridge arm current, the second sub-modulation signal of each energy storage half-bridge converter unit is calculated; according to the acquired capacitor reference voltage of the energy storage railway power regulator, the second capacitor voltage and the actual current of the energy storage battery, the voltage outer loop and the current inner loop are adjusted to calculate the third sub-modulation signal of each energy storage half-bridge converter unit; the first sub-modulation signal, the second sub-modulation signal and the third sub-modulation signal are used as the third modulation signal of the unit control.

Optionally, adjusting according to the second capacitor voltage, the actual current of the energy storage battery, the average capacitor voltage, the average current of the bridge arm energy storage battery, the actual state of charge of the energy storage battery, the average state of charge of the bridge arm energy storage battery and the bridge arm current, and calculating the second sub-modulation signal of each energy storage half-bridge converter unit may include:

A first difference between the average capacitor voltage and the second capacitor voltage is calculated, and the first difference is proportionally adjusted to obtain an initial modulation signal of each energy storage half-bridge converter unit; a second difference between the actual current of the energy storage battery and the average energy storage battery current of the bridge arm is calculated, and the second difference is proportionally adjusted to obtain a battery current feedforward control signal of each energy storage half-bridge converter unit; a third difference between the average state of charge of the bridge arm energy storage battery and the actual state of charge of the energy storage battery is calculated, and the third difference is proportionally adjusted to obtain a state of charge balance adjustment signal of each energy storage half-bridge converter unit; a sum of the initial modulation signal, the battery current feedforward control signal and the state of charge balance adjustment signal is calculated to obtain an initial second sub-modulation signal of each energy storage half-bridge converter unit; the positive and negative of the initial second sub-modulation signal is determined according to the positive and negative of the bridge arm current, and the second sub-modulation signal of each energy storage half-bridge converter unit is obtained according to the initial second sub-modulation signal after the positive and negative are determined.

Optionally, the voltage outer loop and current inner loop are regulated according to the obtained capacitor reference voltage, the second capacitor voltage and the actual current of the energy storage battery of the energy storage railway power regulator, and the third sub-modulation signal of each energy storage half-bridge converter unit is calculated, which may include:

A fourth difference between the obtained capacitor reference voltage of the energy storage railway power conditioner and the second capacitor voltage is calculated, and the fourth difference is proportionally and integrally adjusted to obtain a discharge current reference value of the energy storage battery of each energy storage half-bridge converter unit; the inverse of the discharge current reference value of the energy storage battery is taken to obtain a charging current reference value of the energy storage battery of each energy storage half-bridge converter unit; a fifth difference between the charging current reference value of the energy storage battery and the actual current of the energy storage battery is calculated, and the fifth difference is proportionally and integrally adjusted to obtain a third sub-modulation signal of each energy storage half-bridge converter unit.

In this embodiment, the average energy storage battery current i _{jk_batav} of each bridge arm submodule in the energy storage railway power regulator is defined as:

When the actual current i _{jkz_bat} of the energy storage battery is positive, the unit capacitor voltage has a downward trend and needs to be increased; when the actual current i _{jkz_bat} of the energy storage battery is negative, that is, when the energy storage battery is discharged, the unit capacitor voltage needs to be reduced. When the actual current of the energy storage battery (the actual current of the HB converter unit energy storage battery is recorded as 0) is greater than the average current i _{jk_batav of the bridge arm, the unit capacitor voltage needs to be increased. When it is less than the average current i jk_batav of} the bridge arm, the unit capacitor voltage needs to be reduced. Thus, the battery current feedforward control method can be obtained. The difference between the actual current i _{jkz_bat} of the energy storage battery (0 for the HB converter unit) and the average current i _{jk_batav} of the bridge arm is used as the battery feedforward control signal through the proportional regulator, and the unit modulation signal is adjusted to achieve the purpose of feedforward control.

The average capacitor voltage U _{jk_armav} of the bridge arm submodule in the energy storage railway power regulator is:

The error value between the capacitor average voltage U _{jk_armav} and the first capacitor voltage U _{jkl_sm} is summed with the battery feedforward control signal through the PI regulator as the first initial sub-modulation signal of each HB converter unit in the energy storage railway power regulator. The direction of the bridge arm current i _jk affects the positive or negative of the final first sub-modulation signal u _jklc . When i _jk is positive, the first initial sub-modulation signal is multiplied by 1, increasing the duty cycle of the converter unit with a lower unit capacitor voltage to increase the charging time; when i _jk is negative, the first initial sub-modulation signal is multiplied by -1 to reduce its discharge time.

Combined with formula (21), according to the actual state of charge SOC _jkz of the energy storage battery, the average state of charge SOC _jk of the bridge arm energy storage battery of each bridge arm submodule can be calculated, that is, the average state of charge SOC _jp of the upper bridge arm energy storage battery or the average state of charge SOC _jn of the lower bridge arm energy storage battery. On this basis, the first difference between the average capacitor voltage U _{jk_armav} and the second capacitor voltage U _{jkz_sm} is used as the initial modulation signal of each HBIB converter unit in the energy storage railway power conditioner through the PI regulator, and the second difference between the actual current i _{jkz_bat} of the energy storage battery and the average energy storage battery current i _{jk_batav} of the bridge arm is used as the battery current feedforward control signal after the P regulator, and the third difference between the average state of charge SOC _jk of the bridge arm energy storage battery and the actual state of charge SOC _jkz of the energy storage battery is used as the state of charge balancing adjustment signal after the PI regulator, as the initial second sub-modulation signal u _jkzc of each HBIB converter unit in the energy storage railway power conditioner. Similar to determining the positive and negative of the first sub-modulation signal u _jklc , the positive and negative of the final second sub-modulation signal u _jkzc is determined according to the direction of the bridge arm current i _jk .

Directly obtain the capacitor reference voltage The second capacitor voltage U _{jkz_sm} and the capacitor reference voltage The difference between the adjustment result and the actual current i _{jkz_bat} of the energy storage battery is subjected to PI adjustment again to generate the third sub-modulation signal u _{jkz_bat} in the third modulation signal.

In this embodiment, since the energy storage battery of the HBIB converter unit adopts a dual-loop control of the voltage outer loop and the current inner loop, it is easy to cause differences in the actual state of charge of each energy storage battery. Therefore, the SOC balance control of the energy storage half-bridge converter unit can be achieved by adjusting the modulation wave of the half-bridge converter unit in the energy storage half-bridge converter unit. The energy storage battery control is carried out by adopting the dual-loop control of the voltage outer loop and the current inner loop. When the HMRPC exchanges energy with the load, the energy exchanged between the HMRPC and the load can be automatically compensated, and the energy storage system can be controlled to stabilize the HMRPC energy, maintain the stability of the unit capacitor voltage, and ensure the normal operation of the system. Moreover, this control strategy has few reference instructions, simple calculations, and when the power of the energy storage system is known, it is not necessary to calculate and issue current control instructions to the energy storage unit. It should be noted that since the energy storage battery adopts a dual-loop control of the voltage outer loop and the current inner loop, the unit voltage is in a fluctuating state when the MMC is operating normally, so it is necessary to set a unit capacitor voltage dead zone to avoid frequent charging and discharging of the energy storage battery.

Step 104, controlling the half-bridge converter unit and the energy storage half-bridge converter unit in the energy storage railway power regulator according to the first modulation signal, the second modulation signal and the third modulation signal.

Exemplarily, as shown in FIG12, the first modulation signal u _jc generated by AC current control, the modulation signals of the upper and lower bridge arm submodules are reversed, and are respectively subtracted from the second modulation signal u _jcc of the circulating current control, and then summed with the first sub-modulation signal u _jklc and the second sub-modulation signal u _jkzc , and the MMC side half-bridge switch signals (second control signals) S _jkl and S _jkz are generated by carrier phase shift modulation. The third sub-modulation signal u _{jkz_bat} is pulse width modulated (PWM) to generate the energy storage battery side switch signal (first control signal) S _{jkz_bat} .

The control method of the above-mentioned energy storage railway power regulator is further explained below through specific embodiments.

The simulation was performed using PSCAD and MATLAB Simulink. The simulation circuit topology is shown in Figure 1. The secondary side of the V/V transformer is used as the voltage source, and the feeder voltage is 27.5 kV. The simulation circuit parameters are shown in Table 1.

Table 1 Simulation parameters of three-arm energy storage HMRPC

Design simulation condition 1, simulation step size 1e-5s, simulation time 3.5s, start HMPRC at 0s, and transfer power from phase α to phase β is 8WM, and put into operation in the energy storage system at 0.3s. At 0.3s, remove the total energy control outer loop of all converter unit capacitors in the control, and adjust the AC side compensation current reference command so that the load input power of HMPRC is 1.6MW, and energy is stored through the energy storage system.

The compensation current waveform of each phase is shown in Figure 13. The dotted line is the reference instruction of the compensation current of each phase, and the solid line is the compensation current of each phase. The solid line and the dotted line basically coincide, indicating that the compensation current can follow the given value before and after the energy storage system is put into use. Figure 14 is a unit voltage waveform. When the load inputs power to the HMRPC, the unit voltage has an upward trend, but the capacitor voltage of the HBIB converter unit is stable at about 3700V under the capacitor voltage outer loop control, and the unit capacitor voltage of the HB converter unit is also stable near the reference value under the balanced control strategy.

Figure 15 is a charging current waveform of the energy storage battery. When the unit capacitor voltage rises to the upper limit of the set voltage dead zone, the energy storage battery is charged under the unit capacitor voltage outer loop control to maintain the capacitor voltage stable. The actual SOC of the unit energy storage battery of the HBIB converter under the balanced control strategy is shown in Figure 16.

The above-mentioned energy storage railway power regulator control method is applied to an energy storage railway power regulator in which the energy storage half-bridge converter unit is composed of a half-bridge converter unit and an energy storage unit in parallel. Since the energy storage half-bridge converter unit in the energy storage railway power regulator is composed of a half-bridge converter unit and an energy storage unit in parallel, the switching states of the switching devices in the half-bridge converter unit and the energy storage unit can be decoupled, which is convenient for realizing independent control of the half-bridge converter unit and the energy storage unit, thereby reducing the coupling of the energy storage railway power regulator control method. And the number of energy storage half-bridge converter units is not limited. As long as the number of converter units included in each bridge arm submodule is the same, the number of energy storage half-bridge converter units included in the bridge arm submodule can be set arbitrarily. While reducing the energy storage cost, the flexibility of the topological structure and control method of the energy storage railway power regulator can be improved, which is convenient for designing a simple control and highly versatile energy storage railway power regulator control method, and improving the reliability of the energy storage railway power regulator. The energy storage railway power regulator control method of the present invention performs current compensation processing on the load current of each phase of the electric locomotive load corresponding to the energy storage railway power regulator, and calculates the first modulation signal of the AC current control; performs circulating current control processing based on the obtained compensation current of each phase of the energy storage railway power regulator, each half-bridge converter unit and the capacitor voltage of each energy storage half-bridge converter unit, and calculates the second modulation signal of the circulating current control; performs dual-loop control based on the capacitor voltage and the actual current of the energy storage battery and the actual charge state of the energy storage battery of each energy storage half-bridge converter unit, and calculates the third modulation signal of the unit control; controls the half-bridge converter unit and the energy storage half-bridge converter unit in the energy storage railway power regulator according to the first modulation signal, the second modulation signal and the third modulation signal. The energy storage system composed of all energy storage units in the energy storage railway power regulator can automatically compensate the energy used by the energy storage railway power regulator to compensate the load, reduce the calculation of reference instructions in the control process, and thus reduce the control complexity.

It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

The following is an embodiment of the device of the present invention. For details not described in detail, reference may be made to the corresponding method embodiment described above.

Corresponding to the energy storage railway power regulator control method described in the above embodiment, FIG17 shows an example diagram of an energy storage railway power regulator control device provided by an embodiment of the present invention. As shown in FIG17 , the device may include: a first processing module 171 , a second processing module 172 , a third processing module 173 and a control module 174 .

The first processing module 171 is used to perform current compensation processing on the load current of each phase of the electric locomotive load corresponding to the acquired energy storage railway power regulator, and calculate a first modulation signal for AC current control;

A second processing module 172 is used to perform circulating current control processing based on the acquired compensation current of each phase of the energy storage railway power regulator, each half-bridge converter unit in the energy storage railway power regulator, and the capacitor voltage of each energy storage half-bridge converter unit, and calculate a second modulation signal for circulating current control;

A third processing module 173 is used to perform dual-loop control based on the capacitor voltage and the actual current and actual charge state of the energy storage battery of each energy storage half-bridge converter unit, and calculate a third modulation signal for unit control;

The control module 174 is used to control the half-bridge converter unit and the energy storage half-bridge converter unit in the energy storage railway power conditioner according to the first modulation signal, the second modulation signal and the third modulation signal.

The above-mentioned energy storage railway power regulator control device has the same beneficial effects as the energy storage railway power regulator control method described in the above embodiment.

FIG18 is a schematic diagram of a terminal device provided by an embodiment of the present invention. As shown in FIG18 , the terminal device 180 of this embodiment includes: a processor 181, a memory 182, and a computer program 183 stored in the memory 182 and executable on the processor 181, such as an energy storage railway power regulator control program. When the processor 181 executes the computer program 403, the steps in the above-mentioned energy storage railway power regulator control method embodiment are implemented, such as steps 101 to 104 shown in FIG4 . When the processor 181 executes the computer program 183, the functions of each module in the above-mentioned device embodiments are implemented, such as the functions of modules 171 to 174 shown in FIG17 .

Exemplarily, the computer program 183 can be divided into one or more program modules, and the one or more program modules are stored in the memory 182 and executed by the processor 181 to complete the present invention. The one or more program modules can be a series of computer program instruction segments that can complete specific functions, and the instruction segments are used to describe the execution process of the computer program 183 in the energy storage railway power conditioner control device or terminal device 180. For example, the computer program 183 can be divided into a first processing module 171, a second processing module 172, a third processing module 173 and a control unit 174. The specific functions of each module are shown in Figure 17, and they are not repeated here.

In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims (8)

1. A control method for an energy storage railway power regulator, characterized in that it is applied to an energy storage railway power regulator in which an energy storage half-bridge converter unit is composed of a half-bridge converter, a DC voltage stabilizing capacitor and an energy storage unit connected in parallel, comprising: Performing current compensation processing on the load current of each phase of the electric locomotive load corresponding to the acquired energy storage railway power regulator, and calculating a first modulation signal for AC current control; performing circulating current control processing based on the acquired compensation current of each phase of the energy storage railway power regulator, each half-bridge converter unit and the capacitor voltage of each energy storage half-bridge converter unit, and calculating a second modulation signal for circulating current control; performing dual-loop control based on the capacitor voltage and the acquired actual current of the energy storage battery and the actual charge state of the energy storage battery of each energy storage half-bridge converter unit, and calculating a third modulation signal for unit control; controlling the half-bridge converter unit and the energy storage half-bridge converter unit in the energy storage railway power regulator according to the first modulation signal, the second modulation signal and the third modulation signal; The energy storage railway power conditioner includes a first bridge arm module, a second bridge arm module and a third bridge arm module connected in parallel, each bridge arm module includes an upper bridge arm submodule and a lower bridge arm submodule with the same connection structure and connected in series, each bridge arm submodule includes at least two converter units connected in series and of the same number, at least two converter units of at least one bridge arm submodule in each bridge arm submodule include both a half-bridge converter unit and an energy storage half-bridge converter unit, the energy storage half-bridge converter unit is composed of an energy storage unit, a half-bridge converter and a DC stabilizing capacitor connected in parallel, and all energy storage units in the energy storage railway power conditioner constitute an energy storage system; The capacitor voltage includes a first capacitor voltage of each half-bridge converter unit in the energy storage railway power conditioner and a second capacitor voltage of each energy storage half-bridge converter unit in the energy storage railway power conditioner; The dual-loop control is performed based on the capacitor voltage and the actual current of the energy storage battery and the actual charge state of the energy storage battery of each energy storage half-bridge converter unit, and the third modulation signal for unit control is calculated, including: According to the actual current of the energy storage battery, the average energy storage battery current of each bridge arm submodule is calculated; Calculating an average capacitor voltage of each bridge arm submodule according to the first capacitor voltage and the second capacitor voltage; The first sub-modulation signal of each half-bridge converter unit is calculated and adjusted according to the first capacitor voltage, the average capacitor voltage, the average energy storage battery current of the bridge arm and the acquired bridge arm current of each bridge arm submodule; According to the actual state of charge of the energy storage battery, the average state of charge of the bridge arm energy storage battery of each bridge arm submodule is calculated; The second sub-modulation signal of each energy storage half-bridge converter unit is calculated and adjusted according to the second capacitor voltage, the actual current of the energy storage battery, the average capacitor voltage, the average current of the bridge arm energy storage battery, the actual state of charge of the energy storage battery, the average state of charge of the bridge arm energy storage battery and the bridge arm current; Perform voltage outer loop and current inner loop regulation according to the obtained capacitor reference voltage of the energy storage railway power regulator, the second capacitor voltage and the actual current of the energy storage battery, and calculate and obtain the third sub-modulation signal of each energy storage half-bridge converter unit; The first sub-modulation signal, the second sub-modulation signal and the third sub-modulation signal are used as a third modulation signal for unit control. 2. The energy storage railway power regulator control method according to claim 1 is characterized in that the second sub-modulation signal of each energy storage half-bridge converter unit is calculated and obtained according to the second capacitor voltage, the actual current of the energy storage battery, the average capacitor voltage, the average bridge arm energy storage battery current, the actual state of charge of the energy storage battery, the average state of charge of the bridge arm energy storage battery and the bridge arm current, and the second sub-modulation signal of each energy storage half-bridge converter unit is calculated, including: Calculating a first difference between the capacitor average voltage and the second capacitor voltage, and performing proportional-integral adjustment on the first difference to obtain an initial modulation signal of each energy storage half-bridge converter unit; Calculating a second difference between the actual current of the energy storage battery and the average energy storage battery current of the bridge arm, and proportionally adjusting the second difference to obtain a battery current feedforward control signal of each energy storage half-bridge converter unit; Calculating a third difference between the average state of charge of the bridge arm energy storage battery and the actual state of charge of the energy storage battery, and performing proportional-integral adjustment on the third difference to obtain a state of charge balancing adjustment signal for each energy storage half-bridge converter unit; Calculating the sum of the initial modulation signal, the battery current feedforward control signal and the state of charge balancing adjustment signal to obtain an initial second sub-modulation signal of each energy storage half-bridge converter unit; The positive and negative of the initial second sub-modulation signal is determined according to the positive and negative of the bridge arm current, and the second sub-modulation signal of each energy storage half-bridge converter unit is obtained according to the initial second sub-modulation signal after the positive and negative are determined. 3. The energy storage railway power regulator control method according to claim 1 is characterized in that the voltage outer loop and current inner loop regulation are performed according to the obtained capacitor reference voltage of the energy storage railway power regulator, the second capacitor voltage and the actual current of the energy storage battery to calculate the third sub-modulation signal of each energy storage half-bridge converter unit, including: Calculate the fourth difference between the obtained capacitor reference voltage of the energy storage railway power regulator and the second capacitor voltage, and perform proportional integral adjustment on the fourth difference to obtain a reference value of the energy storage battery discharge current of each energy storage half-bridge converter unit; Taking the inverse of the energy storage battery discharge current reference value to obtain the energy storage battery charging current reference value of each energy storage half-bridge converter unit; A fifth difference between the energy storage battery charging current reference value and the energy storage battery actual current is calculated, and the fifth difference is proportionally and integrally adjusted to obtain a third sub-modulation signal of each energy storage half-bridge converter unit. 4. The energy storage railway power conditioner control method according to any one of claims 1 to 3, characterized in that the current compensation processing is performed on the load current of each phase of the electric locomotive load corresponding to the acquired energy storage railway power conditioner to calculate the first modulation signal of the AC current control, including: Obtain a first equivalent current and a second equivalent current; the first equivalent current is the current supplied by the energy storage system to the energy storage railway power regulator; The equivalent current of the phase output active power on the AC side of the energy storage railway power regulator, the second equivalent current is the energy storage system through the energy storage railway power regulator to The equivalent current of the phase output active power on the AC side of the energy storage railway power regulator; Performing current compensation processing according to the load current of each phase, the first equivalent current and the second equivalent current to calculate a d-axis component of the compensation current; Performing dq transformation on the load current of each phase to calculate the q-axis component of the load current; Multiplying the load current q-axis component by -1 to obtain a compensation current q-axis component; Performing dq inverse transformation according to the compensation current d-axis component and the compensation current q-axis component to calculate and obtain the compensation current reference instruction of each phase; A first modulation signal for AC current control is calculated based on the compensation current of each phase and the compensation current reference instruction of each phase. 5. The energy storage railway power conditioner control method according to any one of claims 1 to 3, characterized in that the circulating current control processing is performed based on the acquired compensation current of each phase of the energy storage railway power conditioner, each half-bridge converter unit in the energy storage railway power conditioner, and the capacitor voltage of each energy storage half-bridge converter unit, and the second modulation signal of the circulating current control is calculated, including: Decomposing the compensation current of each phase, and calculating the reference value of the circulating current of each phase according to the decomposition result; According to the first capacitor voltage and the second capacitor voltage, a per unit value of the first capacitor total energy of all converter units in each upper bridge arm submodule and a per unit value of the second capacitor total energy of all converter units in each lower bridge arm submodule are calculated; According to the obtained capacitor reference voltage, a per unit value of a first capacitor total energy reference value of each bridge arm module is calculated; Performing proportional-integral adjustment according to the difference between the sum of the per-unit value of the total energy of the first capacitor and the per-unit value of the total energy of the second capacitor and the per-unit value of the total energy reference value of the first capacitor, and calculating an initial phase balancing control power reference value of each phase; According to the actual current of the energy storage battery and the actual state of charge of the energy storage battery, feedforward adjustment and state of charge balance adjustment are performed on the initial phase balance control power reference value to calculate and obtain a phase balance control signal of each phase; Proportional-integral adjustment is performed according to the difference between the per-unit value of the total energy of the first capacitor and the per-unit value of the total energy of the second capacitor, and an initial bridge arm balanced control power reference value of each phase is calculated; According to the actual current of the energy storage battery and the actual state of charge of the energy storage battery, feedforward adjustment and state of charge balance adjustment are performed on the initial bridge arm balance control power reference value to calculate and obtain the bridge arm balance control signal of each phase; The obtained actual circulating current of each phase of the energy storage railway power regulator, the circulating current reference value of each phase, the phase balancing control signal of each phase and the bridge arm balancing control signal of each phase are adjusted by a proportional-integral resonant regulator to calculate and obtain a second modulation signal for circulating current control. 6. The energy storage railway power regulator control method according to claim 5, characterized in that the initial phase balance control power reference value is feedforward regulated and state of charge balanced regulated according to the actual current of the energy storage battery and the actual state of charge of the energy storage battery, and the phase balance control signal of each phase is calculated, including: According to the actual current of the energy storage battery, the total current of the third energy storage battery of each bridge arm module and the average current of the energy storage batteries of each bridge arm module are calculated; Proportional adjustment is performed according to the difference between the total current of the third energy storage battery and the average current of the energy storage battery, and a first feedforward adjustment amount of each phase is calculated; According to the actual state of charge of the energy storage battery, the average state of charge of the energy storage batteries of all energy storage half-bridge converter units in the energy storage railway power conditioner and the average state of charge of the phase energy storage batteries corresponding to each bridge arm module are calculated; Proportional integral adjustment is performed according to the difference between the average state of charge of the energy storage battery and the average state of charge of the phase energy storage battery, and a first state of charge balancing adjustment amount of each phase is calculated; Calculating the sum of the initial phase balance control power reference value, the first feedforward adjustment amount and the first state of charge balance adjustment amount to obtain a phase balance control power reference value of each phase; A phase balance control signal of each phase is calculated according to the phase balance control power reference value. 7. The energy storage railway power regulator control method according to claim 5, characterized in that the average state of charge of the bridge arm energy storage battery includes the average state of charge of the upper bridge arm energy storage battery and the average state of charge of the lower bridge arm energy storage battery; The feedforward adjustment and the state of charge balance adjustment are performed on the initial bridge arm balance control power reference value according to the actual current of the energy storage battery and the actual state of charge of the energy storage battery, and the bridge arm balance control signal of each phase is calculated, including: According to the actual current of the energy storage battery, the total current of the first energy storage battery of each upper bridge arm submodule and the total current of the second energy storage battery of each lower bridge arm submodule are calculated; Proportional adjustment is performed according to the difference between the total current of the second energy storage battery and the total current of the first energy storage battery, and a second feedforward adjustment amount of each phase is calculated; Proportional integral adjustment is performed according to the difference between the average state of charge of the upper bridge arm energy storage battery and the average state of charge of the lower bridge arm energy storage battery, and a second state of charge balancing adjustment amount of each phase is calculated; Calculating the sum of the initial bridge arm balanced control power reference value, the second feedforward adjustment amount and the second state of charge balanced adjustment amount to obtain a bridge arm balanced control power reference value of each phase; According to the bridge arm balance control power reference value, a bridge arm balance control signal of each phase is calculated. 8. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in any one of claims 1 to 7 when executing the computer program.