CN116032140A - ANPC type three-level inverter in train traction transmission system and control method thereof - Google Patents

Abstract

The invention discloses an ANPC type three-level inverter in a train traction drive system and a control method thereof. By establishing a parameter model of the stray inductance of the power module of the train traction drive system and different commutation paths for the ANPC type three-level inverter The mathematical model of the influence of the converter, using the power loss thermal balance method to achieve a controller design with robust performance, based on the thermal balance management method and the robust repetitive control to switch the actual commutation path stably, avoiding the The system instability is caused by repeated switching of the critical points of different operating states, and the energy exchange between the inner and outer tubes and the clamp tube is used to realize the system balance control.

Description

ANPC type three-level inverter and its control method in train traction drive system

technical field

The invention relates to power electronic control technology, in particular to an ANPC type three-level inverter in a train traction drive system and a control method thereof.

Background technique

With the continuous development of high-power electric drives, three-level inverters have been widely used in the rail transit industry. Compared with two-level inverters, ANPC three-level inverters for traction drive systems have the advantages of small output voltage and current harmonics and reduced voltage and loss borne by power devices. Although the number of power switching devices has increased, the loss of power tubes can be balanced by optimizing the control strategy to achieve high-capacity transmission at higher voltage levels. The overall design of the system is still better than that of two-level converters of the same power level. The three-level topology can achieve higher performance power conversion.

Traditional control strategies easily lead to serious uneven heating of the inner and outer tubes of the single-phase bridge arm of the inverter in the traction drive system, which affects the working stability of the inverter and the actual output power. At present, the three-level topology of ANPC (active neutral point clamping), as the number of switching tubes to be controlled increases, the diversification of the midpoint commutation path and the complexity of the control process may lead to unbalanced voltage and current. And some power tubes are subjected to overvoltage or overcurrent, and even serious failures will cause the inverter module to fail. Adding detection equipment to obtain the state of parameters such as voltage, current and temperature of the inverter online, which will increase the size of the inverter design and maintenance costs, and the reliability will also be reduced.

In order to ensure that the operation of the train traction system achieves the purpose of energy saving, the improvement of the power level of the inverter will become the mainstream railway development model. Therefore, it is very important to improve the power density and optimize the control strategy in the design of the power module to improve the efficiency and operational reliability of the whole train three-level inverter system.

In the existing traction drive system, the inverter still has problems such as overvoltage and uneven current of some power devices, and there are changes in additional resistance when the train runs for a long time under complex road conditions, such as passing through curves, tunnels, and slopes. Considering the change of external wind speed, the aging of mechanical and electrical components, and the fluctuation of network voltage, the power device of the inverter will also be subjected to loads during the switching process of the train's traction-cruising-coasting-braking and other operating conditions. Unbalanced power loss limits the improvement of the power density of the inverter module. How to control the voltage and current of power devices to ensure the stable operation of the three-level ANPC topology is an urgent technical problem to be solved.

Contents of the invention

The technical problem to be solved by the present invention is to provide an ANPC-type three-level inverter in a train traction drive system and its control method in view of the deficiencies in the prior art, so as to avoid system instability caused by repeated switching of critical points and realize Power module balance control.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a control method for an ANPC type three-level inverter in a train traction drive system, the input side of the ANPC type three-level inverter and the ANPC type three-level rectifier connection; the output side of the ANPC type three-level inverter is connected to multiple motors through an LCL filter; the method includes:

Use the following formula to control the output voltage of the ANPC type three-level inverter:

and / or,

Use the following formula to control the output current of the ANPC type three-level inverter:

Among them, u _d u _q are the components on the d-axis and q-axis of the output voltage of the ANPC type three-level inverter; i _d and i _q represent the components of the output current of the ANPC type three-level inverter on the d-axis and q-axis respectively, i _d and i _q ^* represent the given values of i _d and i _q respectively, and R represents the LCL filter Equivalent resistance value, L represents the equivalent inductance value of the LCL filter, u _gd and u _gq are the components of the output voltage u _g of the motor terminal on the d-axis and the component on the q-axis respectively; e is the tracking error, e=i ^* -i, i represents the output current of the motor, i ^* represents the reference current; T ^* _e represents the electromagnetic torque value of the motor, 2n is the number of pole pairs of the motor, and Ψ is the flux linkage amplitude of the motor; is the given value of the bus voltage, v _dc is the bus voltage (that is, the voltage at both ends of the capacitor branch); K _v is the gain of the voltage control link, τ _s is the time constant of the voltage control link, T _v is set to be N times the time constant of the voltage control link, N is a constant; s is a complex variable; L _s is the ANPC type three-level inverter The sum of the stray inductance of the device;

The determination process of the first weight coefficient ξ includes: if the stray inductance value of the upper half bridge arm of the ANPC type three-level inverter is equal to the stray inductance value of the lower half bridge arm, then ξ is set as the first preset value; if ANPC The stray inductance value of the upper half-bridge arm of the ANPC type three-level inverter is smaller than the stray inductance value of the lower half-bridge arm, then ξ is set to the second preset value; if the stray inductance value of the upper half-bridge arm of the ANPC type three-level inverter If the inductance value is greater than the stray inductance value of the lower half-bridge arm, then ξ is set to the third preset value; wherein, the second preset value<the second preset value<the third preset value;

The determination process of the second weight coefficient μ includes: if the sum of the case temperatures of all the switch tubes of the upper half-bridge arm of the ANPC type three-level inverter is equal to the sum of the case temperatures of all the switch tubes of the lower half-bridge arm, then μ is set as The first preset value; if the sum of the case temperatures of all the switch tubes of the upper half-bridge arm of the ANPC type three-level inverter is less than the sum of the case temperatures of all the switch tubes of the lower half-bridge arm, then μ is set to the second preset value ; If the sum of the case temperatures of all the switch tubes of the upper half-bridge arm of the ANPC type three-level inverter is greater than the sum of the case temperatures of all the switch tubes of the lower half-bridge arm, then μ is set to the third preset value.

The present invention introduces two weight coefficient parameters of ξ and μ to optimize the control performance, take into account the stability of the intermediate DC link voltage, achieve the effect of suppressing fluctuations, and can also stably control the size of the output voltage and current, so that the inverter can be safe and stable according to the set parameters In operation, the present invention avoids the instability phenomenon of the system caused by repeated switching of the critical point, and utilizes the energy exchange between the inner and outer tubes and the clamp tube to realize the balance control of the power module.

The method of the present invention also includes: converting the component u _d on the d-axis and the component u _q on the q-axis of the output voltage of the ANPC type three-level inverter into a voltage in the three-phase ABC stationary coordinate system, through the sinusoidal Pulse width modulation to control the turn-on and turn-off of the power device of the ANPC type three-level inverter. In order to further improve the control accuracy, the method of the present invention also includes: comparing the output voltage of the ANPC type three-level inverter with the output voltage target value, if the output voltage of the ANPC type three-level inverter and the output voltage target value deviation is less than Set the threshold, then end; otherwise, adjust the stray inductance value of the ANPC three-level inverter, and then adjust the output voltage of the ANPC three-level inverter until the output voltage of the ANPC three-level inverter is equal to The output voltage target value deviation is smaller than the set threshold.

In order to further improve control accuracy, the method of the present invention also includes: comparing the output current of the ANPC type three-level inverter with the output current target value, if the output current of the ANPC type three-level inverter and the output current target value deviation are less than Set the threshold, then end; otherwise, adjust the stray inductance value of the ANPC three-level inverter, and then adjust the output current of the ANPC three-level inverter until the output current of the ANPC three-level inverter is equal to The output current target value deviation is smaller than the set threshold.

In order to take into account the stability of the intermediate DC link voltage and achieve the effect of suppressing fluctuations, the present invention provides a three-level inverter system in a train traction drive system, including an ANPC-type three-level inverter; the ANPC-type three-level inverter The input side of the transformer is connected to the ANPC three-level rectifier; the ANPC three-level rectifier is connected to the power grid through the traction transformer; the output side of the ANPC three-level inverter is connected to multiple motors through the LCL filter; the ANPC The type three-level inverter includes a capacitor branch; the capacitor branch includes two capacitors connected in series; the capacitor branch is connected in parallel with the first bridge arm; the first bridge arm includes four power devices connected in series, The middle two power devices are connected in parallel with the second bridge arm; the second bridge arm includes two power devices connected in series; both ends of the capacitor branch are respectively connected to both ends of the first bridge arm through an inductor; The midpoint of the capacitor branch is connected to the midpoint of the first bridge arm through an inductor.

As an inventive concept, the present invention also provides an ANPC type three-level inverter control system in a train traction drive system, which includes:

one or more processors;

A memory, on which one or more programs are stored, and when the one or more programs are executed by the one or more processors, the one or more processors are made to implement the steps of the above method of the present invention.

Compared with the prior art, the present invention has the beneficial effects that: the present invention establishes a power module stray inductance parameter and a power module influence model of different commutation path pairs, and adopts a method of power loss heat balance to realize a robust The controller design with excellent performance, based on the heat balance management method and combined with the robust repetitive control to switch the actual commutation path stably, avoids the instability of the system caused by the repeated switching of the critical point, and utilizes the energy of the inner and outer tubes and the clamping tube Swapping enables power module balance control.

Description of drawings

Fig. 1 is the application schematic diagram of ANPC type three-level inverter system of the embodiment of the present invention;

Fig. 2 is the distribution diagram of the stray inductance of the ANPC type three-level inverter of the embodiment of the present invention;

Fig. 3 (a)～Fig. 3 (d) are three level switch state diagrams of the embodiment of the present invention; Fig. 3 (a) P state; Fig. 3 (b) O1 state; Fig. 3 (c) O2 state; Fig. 3 ( d) N state;

FIG. 4 is a diagram of a robust repetitive controller according to an embodiment of the present invention;

Fig. 5 is a control circuit diagram of an ANPC type three-level inverter system according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In this document, the terms "first", "second" and other similar words are not intended to imply any order, quantity and importance, but are only used to distinguish different elements. In this document, the terms "a", "an" and other similar words are not intended to mean that there is only one of the said things, but that the description is only for one of the said things, which may have one or more . In this document, the terms "comprising", "comprising" and other similar words are intended to indicate logical interrelationships, and cannot be regarded as denoting spatial structural relationships. For example, "A includes B" is intended to mean that B logically belongs to A, but not that B is spatially inside A. Additionally, the meanings of the terms "comprising", "comprising" and other similar words are to be regarded as open rather than closed. For example, "A includes B" means that B belongs to A, but B does not necessarily constitute the whole of A, and A may also include C, D, E and other elements.

The embodiment of the present invention establishes a power module stray inductance parameter and the influence relationship model of different commutation paths on the power module, adopts the method of power loss heat balance to realize the controller design with robust performance, and based on the heat balance management method (controller It is related to the parameters ξ and μ, that is, the relevant stray inductance and the device case temperature), and cooperates with the robust repetitive control to stably switch the actual commutation path, avoiding the instability of the system caused by the repeated switching of the critical point, and using the internal and external The energy exchange of the tube and the clamp tube realizes the balance control of the power module.

Example 1

The system structure of the ANPC type three-level inverter applied in this embodiment is shown in FIG. 1 .

The input end of the ANPC type three-level inverter is connected to the power grid through the ANPC type three-level rectifier, and the output end is connected to multiple traction motors. The traction transformer takes power, passes through the ANPC type three-level rectifier to obtain stable DC power, and then passes through the ANPC type three-level inverter to output three-phase AC power to control single or multiple motor systems. The ANPC type three-level inverter includes a three-port DC bus link (P, O, N), a three-level ANPC topology circuit composed of six power devices IGBT or IGCT or SiC, and a three-phase AC copper bar output(A,B,C). This embodiment can take into account the stability of the intermediate DC link voltage to achieve the effect of suppressing fluctuations, and can also stably control the magnitude of the output voltage and current, so that the inverter can operate safely and stably according to the set parameters.

Figure 2 is a distribution diagram of stray inductance inside the ANPC type three-level inverter. In Figure 2, the positive and negative bus capacitor voltage Vc1=Vc2, there will be stray inductance Ls1-Ls6 inside the power module. In the figure, there are three working states: P, O, and N. The O state is more flexible, and the output current can flow out through _D5 and _T2 , or _T6 and _D3 . In the process of switching from the traditional positive or negative level to zero level, the inner tube and the outer tube can be controlled to take turns in a fixed period. In this way, part of the switching loss of the outer tube can be transferred to the inner tube and the clamp tube. Above, when the designed parameters corresponding to Ls1 and Ls6, Ls2 and Ls5 are not equal, the conventional control method cannot completely balance the loss of power devices.

In this embodiment, the stray inductance parameter model takes into account the parasitic inductance parameters of the DC bus capacitor itself, the stray inductance parameters of the laminated busbar in a symmetrical structure, and the stray inductance parameters of the internal and external connecting copper bars of the power device. The stray inductance parameter model construction process: the positive bus capacitance is between the bus P and the bus O, a parasitic inductance parameter of the positive bus capacitor itself, and then the stray inductance from the positive port of the capacitor through the positive bus to the terminal of the power device T1 Scattered inductance parameters, these two parts are combined to form Ls1; the connection between the positive bus capacitor and the negative bus capacitor comes out through the bus bar O to reach the connection between the power devices T5 and T6 to form Ls3; the negative bus capacitor is between the bus O and the bus N , a parasitic inductance parameter of the negative bus capacitor itself, and then the stray inductance parameter from the negative port of the capacitor through the positive bus to the terminal of the power device T4. These two parts are composed of Ls6; the midpoint of the power devices T1 and T5 The connection part of the power device T2 end is formed into Ls2; the connection part of the power device T6 and T4 midpoint and the power device T3 end is formed into Ls5; the power device T6 and T4 midpoint and the three-phase AC output port of the inverter are formed into Ls4.

The train ANPC type three-level inverter corresponds to the three voltages of the switching states P, O, and N, where each current passes through the DC bus capacitor, the laminated bus bar, and the specific switch position. It is necessary to quantitatively obtain the coincidence degree of the current path and consider the worst case. In actual operation, each capacitor will flow to the power module, and the current paths at the DC input end overlap to a certain extent.

In this embodiment, a robust repetitive controller is designed to control the output of the ANPC-type three-level inverter, and the input signal y(s) and output signal u of the controller K(s) are regarded as a system (ANPC-type three-level inverter Transformer) evaluation output, by introducing two weight coefficient parameters ξ and μ to optimize the performance of the controller.

It is divided into 5 processes to carry out detailed design of the robust repetitive controller based on the hybrid solution method. The two weight coefficients of ξ and μ range from 0 to 1, and the initial value takes the middle value of 0.5. The stray inductance parameter in the actual operation process is greater than or less than the previous preset value, correspondingly increase or decrease the ξ weight coefficient. Similarly, when the temperature of the power device case increases or decreases during the temperature change process, the μ weight coefficient is increased or decreased in time until the adjusted controller parameters can meet stable operating conditions of the system.

In this embodiment, the controller design process is as follows: select the initial ξ and μ weight coefficient values, obtain the stray inductance, adjust the input ξ weight coefficient, obtain the power device case temperature, adjust the output μ weight coefficient, and determine the controller parameters And judge the system stability. As shown in Figure 2, the method of adjusting ξ is: obtain the stray inductance parameter L _s1 +L _s2 of the upper half bridge arm and the stray inductance parameter L _s5 +L _s6 of the lower half bridge arm, when the two are equal, the default initial value is 0.5 unchanged, if L _s1 +L _s2 <L _s5 +L _s6 ξ is adjusted to 0, and if L _s1 +L _s2 >L _s5 +L _s6 , ξ is adjusted to 1. Compare the case temperature T _c1 +T _c2 +T _c5 of all power tubes in the upper half bridge arm with the case temperature T _c3 +T _c4 +T _c6 of the power tubes in the lower half bridge arm. When the two are equal, the default initial value of μ is 0.5. , T _c1 +T _c2 +T _c5 <T _c3 +T _c4 +T _c6 , at this time μ is adjusted to 0, if T _c1 +T _c2 +T _c5 >T _c3 +T _c4 +T _c6 , μ is adjusted to 1. Compare the actual output voltage and current value of the inverter with the target value, and when the deviation is less than 5%, it is judged that the controller is stable, and the design of the controller is completed.

Switching laws usually depend on the state or time of the system, and operate the corresponding subsystem for a certain period of time. In practical applications, all state variables of the system cannot be accurately obtained in real time, making it difficult to realize system switching based on the full state. The switching behavior of the actuator is closely connected with the system state, and the switching process of the same switching law is different in different system states.

In this embodiment, by switching the control mode, the temperature of the three power devices located in the upper half bridge arm or the lower half bridge arm is controlled within a reasonable range, and the switching is stopped when the temperature difference is small, so that the heat distribution is balanced. As shown in Figure 3(a) to Figure 3(d), in this embodiment, the ANPC three-level inverter has four working states, and the inverter can realize the two-way flow of energy after four-quadrant operation, as shown in Figure 3( In a) the P state current flows out through T ₁ and T ₂ , and the current flows in through D ₂ and D ₁ ; in the O1 state in Figure 3(b), the current flows out through D ₅ and T ₂ , and the current flows in through D ₂ and T ₅ ; The O2 state current flows out through T ₆ and D ₃ in Figure 3(c), and the current flows in through T ₃ and D ₆ ; the O2 state current flows out through T ₆ and D ₃ in Figure 3(d), and the current flows in through T 6 ₃ with _D6 . The ANPC type is based on the NPC type three-level topology and replaces the uncontrollable device in the clamping part. The biggest difference is that two controllable power devices T are connected in antiparallel to the two clamping diodes _D5 and _D6 . ₅ and T ₆ , so when the bridge arm modulates the positive half-wave voltage, when it outputs zero level, it can flow to the two branches of T ₂ and T ₆ to D ₃ through D ₅ . Similarly, when modulating the negative half-wave voltage, when outputting zero level, it can flow to the two branches of _T5 and _T3 to _D6 through _D2 . Compared with the NPC type three-level can only generate zero level by closing the outer tube _T1 or _T4 , the ANPC type three-level can also achieve zero level output by turning off the inner tube _T2 and _T3 , so the original external The switching action undertaken by the tube alone is jointly undertaken by the outer tube and the inner tube, thereby effectively reducing the switching loss of the outer tube and further improving the conduction current capability of the bridge arm. Since the design of the power module cannot fully make these spurious parameters equal, the paths from the P state to the O1 and O2 states will be different, and the paths from the N state to the O1 and O2 states will be different. When the deviation between the two is large, the thermal deviation of turning off the power device will also be large, which will limit the ability of the power module to output current.

Each phase has 6 switching tubes and the corresponding anti-parallel freewheeling diodes. When the switching tubes are turned on and off according to their specific requirements, a variety of commutation paths will be formed, and the corresponding outputs are P level and O level respectively. level or N level.

(1) In the P state, the bridge arm outputs a positive level, the voltage of T ₁ is 0, the voltage of T ₂ is 0, the voltage of T ₃ is V _dc /2, the voltage of T ₄ is V _dc /2, and the voltage of T ₅ is V _dc / 2. The voltage of T ₆ is 0, and T ₆ and D ₆ clamp the emitter potential of T ₃ .

(2) In the O state, the bridge arm outputs zero level, the voltage of T ₁ is V _dc /2, the voltage of T ₂ is 0, the voltage of T ₃ is 0, the voltage of T ₄ is V _dc /2, the voltage of T 5 is 0, and the voltage of T ₅ is 0. ₆ voltage is 0.

(3) In the N state, the bridge arm outputs a negative level, the voltage of T ₁ is V _dc /2, the voltage of T ₂ is V _dc /2, the voltage of T ₃ is 0, the voltage of T ₄ is 0, the voltage of T ₅ is 0, and the voltage of T _{6 is 0} . The voltage is _Vdc /2, and _T5 and _D5 clamp the emitter potential of _T1 .

Figures 4 and 5 are the overall control diagrams of the robust repetitive controller and the inverter system. According to the mathematical model, there is a feedback controller in the control system that matches the gain of the low-pass filter, and the steady state of the system in which the two parameters affect each other performance. The total stray inductance of the external input in Figure 4 is expressed as L _s , L _s = L _s1 + L _s2 + L _s3 + L _s4 + L _s5 + L _s6 , and the product of it and the ξ weight coefficient is L _s ξ. The external input of the control system can be the voltage u _g at the motor terminal, the current i, and the reference current i ^* signal. The tracking error of the control system is e=i ^* -i. The front-end input of the controller K(s) is y=L _s ξ+e, and the back-end output of the controller K(s) is u=Ky. The controller can realize the processing of the tracking error of the control system.

This control method is aimed at the link of the bus voltage, through the stray inductance parameters obtained above, input L _s ξ to repeatedly compensate the fluctuation of the bus voltage, the given value of the bus voltage It is input to the transfer function G ₁ (s) after being compared with v _dc .

Among them, K _v is the gain of the voltage control link, τ _s is the time constant of the voltage control link, and T _v is generally four times the time constant of the voltage control link.

The d-axis given value of the inverter control output current can be given by the voltage link

The given value of inverter control output current q-axis can be given by motor parameter M

Among them, T ^* _e represents the electromagnetic torque value of the motor, 2n is the number of pole pairs of the motor, and Ψ is the flux linkage amplitude of the motor.

The expressions of the control output voltage u _d and u _q of the three-level inverter are

u _d and u _q represent the components of the inverter control output voltage on the d-axis and q-axis respectively, In order to robustly repeat the controller parameters, i _d represents the component of the inverter control output current on the d axis, i ^* _d represents the given value of i _d , R represents the equivalent resistance value of the LCL filter, and L represents the LCL filter The equivalent inductance value of the device is L ₁ +L ₂ , and _ugd is the component of the voltage _ug at the motor terminal on the d-axis.

For the voltage components u _d and u _q output by the ANPC type three-level inverter, they are converted into voltages in the three-phase ABC static coordinate system through the above-mentioned 3s/2r coordinate transformation, and then the power device is turned on and off by the sinusoidal pulse width modulation strategy. Turn off, equalize the loss of each power tube. By adjusting the controller in real time through the stray inductance parameters in the early stage, the efficiency of motor operation can be improved and the safety of the system can be guaranteed.

Example 2

Embodiment 2 of the present invention provides a terminal device corresponding to Embodiment 1 above. The terminal device may be a processing device for a client, such as a mobile phone, a notebook computer, a tablet computer, a desktop computer, etc., to execute the method of the above embodiment.

The terminal device in this embodiment includes a memory, a processor, and a computer program stored in the memory; the processor executes the computer program in the memory to implement the steps of the method in Embodiment 1 above.

In some implementations, the memory may be a high-speed random access memory (RAM: Random Access Memory), and may also include a non-volatile memory, such as at least one disk memory.

In other implementations, the processor may be various types of general-purpose processors such as a central processing unit (CPU) and a digital signal processor (DSP), which are not limited herein.

Example 3

Embodiment 3 of the present invention provides a computer-readable storage medium corresponding to Embodiment 1 above, on which computer programs/instructions are stored. When the computer program/instruction is executed by the processor, the steps of the method in Embodiment 1 above are implemented.

A computer readable storage medium may be a tangible device that holds and stores instructions for use by an instruction execution device. A computer readable storage medium may be, for example, but is not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination of the foregoing.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein. The solutions in the embodiments of the present application can be realized by using various computer languages, for example, the object-oriented programming language Java and the literal translation scripting language JavaScript.

The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

While preferred embodiments of the present application have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, the appended claims are intended to be construed to cover the preferred embodiment and all changes and modifications which fall within the scope of the application.

Obviously, those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. In this way, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims (6)

1. ANPC type three-level inverter control method in a kind of train traction drive system, ANPC type three-level inverter input side is connected with ANPC type three-level rectifier; ANPC type three-level inverter output side passes The LCL filter is connected with a plurality of motors; it is characterized in that the method comprises: Use the following formula to control the output voltage of the ANPC type three-level inverter:

and / or, Use the following formula to control the output current of the ANPC type three-level inverter:

Among them, u _d u _q are the components on the d-axis and q-axis of the output voltage of the ANPC type three-level inverter;

i _d and i _q represent the components of the output current of the ANPC three-level inverter on the d-axis and q-axis respectively, i _d ^* and i _q ^* represent the given values of i _d and i _q respectively, and R represents the LCL filter The equivalent resistance value of the LCL filter, L represents the equivalent inductance value of the LCL filter, u _gd and u _gq are the components of the output voltage u _g of the motor terminal on the d-axis and the component on the q-axis respectively; e is the tracking error, e=i ^* -i, i represents the output current of the motor, i ^* represents the reference current; T ^* _e represents the electromagnetic torque value of the motor, 2n is the number of pole pairs of the motor, and Ψ is the flux linkage amplitude of the motor;

is the given value of the bus voltage, v _dc is the bus voltage;

K _v is the gain of the voltage control link, τ _s is the time constant of the voltage control link, T _v is set to be N times the time constant of the voltage control link, N is a constant; s is a complex variable; L _s is the ANPC type three-level inverter The sum of the stray inductance of the inverter; the determination process of the first weight coefficient ξ includes: if the stray inductance value of the upper half bridge arm of the ANPC type three-level inverter is equal to the stray inductance value of the lower half bridge arm, then ξ is set as the first preset value; if the stray inductance value of the upper half-bridge arm of the ANPC type three-level inverter is less than the stray inductance value of the lower half-bridge arm, then ξ is set to the second preset value; if the ANPC type three-level inverter The stray inductance value of the upper half bridge arm is greater than the stray inductance value of the lower half bridge arm, then ξ is set to the third preset value; wherein, the second preset value<the second preset value<the third preset value; The determination process of the second weight coefficient μ includes: if the sum of the case temperatures of all the switch tubes of the upper half-bridge arm of the ANPC type three-level inverter is equal to the sum of the case temperatures of all the switch tubes of the lower half-bridge arm, then μ is set as The first preset value; if the sum of the case temperatures of all the switch tubes of the upper half-bridge arm of the ANPC type three-level inverter is less than the sum of the case temperatures of all the switch tubes of the lower half-bridge arm, then μ is set to the second preset value ; If the sum of the case temperatures of all the switch tubes of the upper half-bridge arm of the ANPC type three-level inverter is greater than the sum of the case temperatures of all the switch tubes of the lower half-bridge arm, then μ is set to the third preset value. 2. the ANPC type three-level inverter control method in the train traction drive system according to claim 1, is characterized in that, also comprises: on the d axis of described ANPC type three-level inverter output voltage The component u _d and the component u _q on the q axis are transformed into the voltage in the three-phase ABC stationary coordinate system, and the power device of the ANPC three-level inverter is controlled to be turned on and off through sinusoidal pulse width modulation. 3. the ANPC type three-level inverter control method in the train traction drive system according to claim 1, is characterized in that, also comprises: compare the output voltage and the output voltage target value of the ANPC type three-level inverter, If the deviation between the output voltage of the ANPC type three-level inverter and the output voltage target value is less than the set threshold, then end; otherwise, adjust the stray inductance value of the ANPC type three-level inverter, and then adjust the ANPC type three-level inverter The output voltage of the inverter until the deviation between the output voltage of the ANPC type three-level inverter and the output voltage target value is less than the set threshold. 4. the ANPC type three-level inverter control method in the train traction drive system according to claim 1, is characterized in that, also comprises: compare the output current and the output current target value of the ANPC type three-level inverter, If the deviation between the output current of the ANPC type three-level inverter and the output current target value is less than the set threshold, then end; otherwise, adjust the stray inductance value of the ANPC type three-level inverter, and then adjust the ANPC type three-level inverter The output current of the inverter until the deviation between the output current of the ANPC type three-level inverter and the output current target value is less than the set threshold. 5. A three-level inverter system in a train traction drive system, comprising an ANPC type three-level inverter; the input side of the ANPC type three-level inverter is connected with the ANPC type three-level rectifier; the ANPC type three-level inverter The type three-level rectifier is connected to the grid through a traction transformer; the output side of the ANPC type three-level inverter is connected to a plurality of motors through an LCL filter; it is characterized in that the ANPC type three-level inverter includes a capacitor branch; The capacitor branch includes two capacitors in series; the capacitor branch is connected in parallel with the first bridge arm; the first bridge arm includes four power devices connected in series, and the middle two power devices are connected in parallel with the second bridge arm The second bridge arm includes two power devices connected in series; both ends of the capacitor branch are connected to both ends of the first bridge arm through an inductor; the midpoint of the capacitor branch is connected to the first bridge arm through an inductor The midpoint connection of the bridge arm. 6. ANPC type three-level inverter control system in a train traction drive system, is characterized in that, comprises: one or more processors; A memory on which one or more programs are stored, and when the one or more programs are executed by the one or more processors, the one or more processors implement any one of claims 1-4 The steps of the method.

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