CN117748568B - Energy storage converter IGBT economic type selection method considering multi-mode safe operation - Google Patents

Abstract

The present invention provides an IGBT economic selection method for energy storage converters taking into account multi-mode safe operation, including: a circuit response calculation model outputs voltage parameters and current parameters at IGBT nodes in an energy storage converter; an operation loss evaluation model outputs operation loss expressions of various types of IGBT devices under multiple parallel quantity schemes; a safe operation evaluation model outputs the minimum parallel number of IGBTs that meets the safe working area under multiple models of the energy storage converter; an economic evaluation model outputs the optimal economic IGBT selection scheme for the energy storage converter; and the actual working circuit structure of the energy storage converter is determined based on the optimal economic IGBT selection scheme for the energy storage converter. In this method, while ensuring the safe and reliable operation of the IGBT in the multi-mode of the energy storage converter, the economic efficiency of the full life cycle operation of the IGBT in the peak shaving and valley filling and reactive power support modes can be improved.

Description

Economic selection method of IGBT for energy storage converter considering multi-mode safe operation

Technical Field

The present invention relates to the technical field of battery energy storage systems, and in particular to an economical selection method for an IGBT of an energy storage converter taking into account multi-mode safe operation.

Background technique

In order to reduce the cost, operation and maintenance expenses, and device size of power quality management in distributed power generation systems and microgrids, and improve the cost-effectiveness of existing grid-connected inverters, some scholars have proposed the concept of multifunctional grid-connected inverters, which enables distributed power sources to complete additional functions such as power quality control while being connected to the grid, thereby expanding the application functions and scenarios of the inverter.

However, most of the existing multifunctional inverters are used to control current quality problems such as reactive power, harmonics and three-phase imbalance, and most of the existing theoretical results focus on the control priority of the converter and the compensation current distribution strategy. In the selection and design process of IGBT (Insulate-Gate Bipolar Transistor), based on the maximum voltage and current stress of IGBT devices when the converter is working, designers mainly use empirical methods to select and design the IGBT of the converter. The voltage and current design margin of IGBT devices are usually 2 to 3 times the actual operating voltage and current, which undoubtedly causes extremely high cost waste. At the same time, the safety and economy of IGBT in the actual operating conditions of the converter in multiple modes have not been further considered, especially the safe working performance of IGBT under low frequency and short-term overload operation. There is a lack of scientific and quantitative IGBT selection and design methods to improve the economy of the converter IGBT under the full life cycle operation on the basis of compatible IGBT safe working performance under the multi-mode operation of the converter.

Summary of the invention

In view of this, the purpose of the present invention is to provide an energy storage converter IGBT economic selection method taking into account multi-mode safe operation, so as to ensure the safe and reliable operation of the IGBT in the multi-mode of the energy storage converter, improve the economic performance of the IGBT full life cycle operation in the peak shaving and valley filling and reactive power support modes, and achieve the optimal comprehensive performance and overall cost of the IGBT of the energy storage converter. It can provide a basis for the safe and economic selection of the IGBT of the energy storage converter in the project, and guide the actual working structure of the energy storage converter with the best economy.

In a first aspect, an embodiment of the present invention provides an IGBT economic selection method for an energy storage converter taking into account multi-mode safe operation, the method comprising: inputting output power parameters of a battery energy storage system in a peak shaving and valley filling mode, a reactive power support mode, and a voltage sag control mode into a circuit response calculation model, and outputting voltage parameters and current parameters at an IGBT node of the energy storage converter; inputting voltage parameters and current parameters at an IGBT node in the energy storage converter and parameters of various types of IGBT devices into an operation loss evaluation model, and outputting operation loss expressions of various types of IGBT devices under multiple parallel quantity schemes; inputting operation losses of various types of IGBT devices under multiple parallel quantity schemes into a safe operation evaluation model, and outputting a minimum parallel number of IGBTs that meets a safe working area under multiple models of the energy storage converter; inputting the minimum parallel number of IGBTs that meets a safe working area under multiple models of the energy storage converter, operation losses of various types of IGBT devices under multiple parallel quantity schemes, and device cost parameters into an economic evaluation model, and outputting an optimal economic IGBT selection scheme for the energy storage converter; and determining the actual working circuit structure of the energy storage converter based on the optimal economic IGBT selection scheme for the energy storage converter.

In an optional embodiment of the present application, the energy storage converter includes a Buck-Boost DC converter and a three-phase inverter.

In an optional embodiment of the present application, the above-mentioned step of inputting the output power parameters of the battery energy storage system in the peak shaving and valley filling mode, the reactive power support mode, and the voltage sag control mode into the circuit response calculation model, and outputting the voltage parameters and current parameters at the IGBT node in the energy storage converter, includes: inputting the output power parameters and voltage parameters of the battery energy storage system into the circuit response calculation model; wherein the output power parameters include: the rated operating power of the battery energy storage system in the peak shaving and valley filling mode, the rated operating power in the reactive power support mode, and the maximum operating power in the voltage sag control mode; based on the power transfer relationship of the three-phase full-bridge inverter, the circuit response calculation model determines the voltage parameters and current parameters at the IGBT node in the three-phase inverter according to the output power parameters and the voltage parameters; based on the power transfer relationship of the energy storage converter, the circuit response calculation model determines the voltage parameters and current parameters of the Buck-Boost DC converter according to the output power parameters and the voltage parameters.

In an optional embodiment of the present application, the above-mentioned step of inputting the voltage parameters and current parameters at the IGBT nodes in the energy storage converter and the parameters of various types of IGBT devices into the operating loss evaluation model, and outputting the operating loss expressions of various types of IGBT devices under multiple parallel quantity schemes, includes: inputting the voltage parameters and current parameters at the IGBT nodes in the energy storage converter and the parameters of various types of IGBT devices into the operating loss evaluation model; the operating loss evaluation model determines the maximum operating voltage parameters based on the voltage parameters of the energy storage converter and the voltage parameters at the IGBT nodes in the three-phase inverter, and calculates the operating loss parameters of various types of IGBT devices based on the maximum operating voltage parameters to meet the requirements of the energy storage converter. The operating loss evaluation model is based on the number of series connections of various types of IGBT devices that meet the operating voltage safety requirements of the energy storage converter, and is based on the voltage parameters and current parameters at the IGBT nodes in the three-phase inverter and the parameters of various types of IGBT devices to determine the expression for the operating loss of a single IGBT of the three-phase inverter and the expression for the total loss of the three-phase inverter; The operating loss evaluation model is based on the number of series connections of various types of IGBT devices that meet the operating voltage safety requirements of the energy storage converter, and determines the expression for the operating loss of a single IGBT of the Buck-Boost DC converter and the expression for the total loss of the Buck-Boost DC converter.

In an optional embodiment of the present application, the above-mentioned step of inputting the operating losses of multiple types of IGBT devices under multiple parallel quantity schemes into the safe operation evaluation model, and outputting the minimum parallel number of IGBTs that meets the safe working area under multiple models of the energy storage converter, includes: inputting the preset time of the voltage sag control operation, multiple types of IGBT device parameters, and the operating losses of multiple types of IGBT devices under multiple parallel quantity schemes into the safe operation evaluation model; the safe operation evaluation model calculates the critical safety threshold of the accumulated heat of multiple types of IGBT devices after the preset time of the operating voltage sag control operation based on the multiple types of IGBT device parameters; the safe operation evaluation model calculates the single accumulated heat of multiple types of IGBT devices after the preset time of the operating voltage sag control operation when the parallel number is a first value based on the operating losses of multiple types of IGBT devices under multiple parallel quantity schemes; if the single accumulated heat is less than the critical safety threshold of the accumulated heat and meets the steady-state operation conditions, the safe operation evaluation model uses the first value as the minimum parallel number of IGBTs that meets the safe working area under multiple models of the energy storage converter.

In an optional embodiment of the present application, after the step of calculating the single accumulated heat of multiple types of IGBT devices after a preset time of operating voltage sag management operation when the parallel number is a first value based on the operating losses of multiple types of IGBT devices under multiple parallel number schemes, the method also includes: if the single accumulated heat is not less than the critical safety threshold of the accumulated heat, or the steady-state operation conditions are not met, the safe operation evaluation model adds one to the first value and continues to calculate the single accumulated heat of multiple types of IGBT devices after a preset time of operating voltage sag management operation when the parallel number is a first value based on the operating losses of multiple types of IGBT devices under multiple parallel number schemes.

In an optional embodiment of the present application, the above-mentioned step of inputting the minimum parallel number of IGBTs that meet the safe working area under multiple models of the energy storage converter, the operating losses of multiple types of IGBT devices under multiple parallel quantity schemes, and device cost parameters into the economic evaluation model to output the optimal economic IGBT selection scheme for the energy storage converter, includes: inputting the minimum parallel number of IGBTs that meet the safe working area under multiple models of the energy storage converter, the operating losses of multiple types of IGBT devices under multiple parallel quantity schemes, and device cost parameters into the economic evaluation model; the economic evaluation model calculates multiple types of IGBT selection schemes based on the minimum parallel number of IGBTs that meet the safe working area under multiple models of the energy storage converter, and the operating losses of multiple types of IGBT devices under multiple parallel quantity schemes. The total steady-state operation loss of IGBT devices during the full life cycle when the parallel number is not less than the minimum parallel number; the economic evaluation model calculates the total cost of multiple IGBT selection schemes of various types based on the total steady-state operation loss of multiple types of IGBT devices during the full life cycle when the parallel number is not less than the minimum parallel number and device cost parameters; wherein the total cost of the IGBT selection scheme includes device cost and power loss; the minimum total cost is determined from the total costs of multiple IGBT selection schemes of various types, the IGBT device type and the parallel number of IGBT devices corresponding to the minimum total cost are determined, and the most economical IGBT selection scheme for the energy storage converter is determined based on the IGBT device type and the parallel number of IGBT devices corresponding to the minimum total cost.

In an optional embodiment of the present application, the above method further includes: a sensor of the battery energy storage system detects grid voltage, output current data and battery information;

Based on the grid voltage, output current data and battery information, the operating mode of the battery energy storage system is determined to be peak shaving and valley filling mode, reactive power support mode or voltage sag control mode.

The embodiments of the present invention bring the following beneficial effects:

The embodiment of the present invention provides an energy storage converter IGBT economic selection method taking into account multi-mode safe operation, which can ensure the safe and reliable operation of the IGBT in the multi-mode of the energy storage converter, improve the economic performance of the IGBT full life cycle operation in the peak shaving and valley filling and reactive power support modes, and achieve the optimal comprehensive performance and overall cost of the IGBT of the energy storage converter. It can provide a basis for the safe and economic selection of the IGBT of the energy storage converter in the project, and guide the actual working structure of the energy storage converter with the best economy.

Other features and advantages of the present disclosure will be set forth in the following description, or some features and advantages may be inferred or unambiguously determined from the description, or may be learned by implementing the above-mentioned technology of the present disclosure.

In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG1 is a typical circuit topology diagram of a battery energy storage system provided by an embodiment of the present invention;

2 is a flow chart of an economical selection method for an energy storage converter IGBT taking into account multi-mode safe operation provided by an embodiment of the present invention;

FIG3 is a schematic diagram of a battery energy storage system provided by an embodiment of the present invention;

FIG4 is a schematic diagram of an operation mode of a battery energy storage system provided by an embodiment of the present invention;

FIG5 is a flow chart of IGBT parameter design for a battery energy storage system provided by an embodiment of the present invention;

FIG6 is a flow chart of a circuit response calculation model provided by an embodiment of the present invention;

FIG7 is a flow chart of an operation loss assessment model provided by an embodiment of the present invention;

FIG8 is a flow chart of a safe operation assessment model provided by an embodiment of the present invention;

FIG9 is a flow chart of an economic evaluation model provided by an embodiment of the present invention;

FIG. 10 is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

At present, the existing multifunctional inverters are mostly used to control current quality problems such as reactive power, harmonics and three-phase imbalance, and the existing theoretical results are mostly carried out around the control priority of the converter and the compensation current distribution strategy. In the IGBT selection and design process, based on the maximum voltage and current stress of the IGBT device when the converter is working, the designers mainly use empirical determination to select and design the IGBT of the converter. The voltage and current design margin of the IGBT device is usually 2 to 3 times the actual operating voltage and current, which undoubtedly causes extremely high cost waste. At the same time, the safety and economy of the IGBT under the actual operating conditions of the converter in multiple modes have not been further considered, especially the safe working performance of the IGBT under low frequency and short-term overload operation. There is a lack of scientific and quantitative IGBT selection and design methods to improve the economy of the converter IGBT under the full life cycle operation on the basis of compatible IGBT safe working performance under the multi-mode operation of the converter.

Based on this, the embodiment of the present invention provides an energy storage converter IGBT economic selection method taking into account multi-mode safe operation, specifically providing an energy storage converter IGBT economic selection method taking into account multi-mode operation safe working area, which can ensure the safe and reliable operation of IGBT in multi-mode of energy storage converter, improve the economic performance of IGBT full life cycle operation in peak shaving and valley filling and reactive power support mode, and achieve the optimal comprehensive performance and overall cost of IGBT safe operation of energy storage converter. It can provide a basis for the safe and economic selection of IGBT of energy storage converter in engineering, and guide the actual working structure of energy storage converter with the best economy.

To facilitate understanding of this embodiment, firstly, a method for economical selection of IGBTs for energy storage converters taking into account multi-mode safe operation disclosed in an embodiment of the present invention is introduced in detail.

Embodiment 1:

The embodiment of the present invention provides an energy storage converter IGBT economic selection method considering multi-mode safe operation, firstly introduces the typical topology of battery energy storage system. In some embodiments, the energy storage converter includes a Buck-Boost DC converter and a three-phase inverter.

Refer to the typical circuit topology of a battery energy storage system shown in Figure 1, which consists of a battery pack, a bidirectional Buck-Boost (buck-boost) DC converter, a three-phase inverter and an LCL (input inductor, series capacitor, output inductor) filter. The energy storage converter consists of a bidirectional Buck-Boost DC converter and a three-phase inverter. The battery pack is boosted by the bidirectional Buck-Boost DC converter and then outputs the required AC power to the outside through the three-phase inverter. The main control goal of the bidirectional Buck-Boost DC converter is to maintain the DC side voltage stability of the three-phase inverter. The three-phase inverter can switch different operation control modes according to the actual needs of the power grid to achieve different control goals.

Referring to the flowchart of a method for economically selecting an IGBT for an energy storage converter taking into account multi-mode safe operation shown in FIG2 , the method for economically selecting an IGBT for an energy storage converter taking into account multi-mode safe operation includes the following steps:

Step S202, input the output power parameters of the battery energy storage system in the peak shaving and valley filling mode, the reactive power support mode, and the voltage sag control mode into the circuit response calculation model, and output the voltage parameters and current parameters at the IGBT nodes in the energy storage converter.

Referring to a schematic diagram of a battery energy storage system shown in FIG3 , the battery energy storage system transmits the detection data collected at the output end to the information acquisition unit, and outputs a control signal to drive the bidirectional Buck-Boost DC converter and the three-phase inverter to operate according to the operation processing result.

In some examples, sensors of the battery energy storage system detect grid voltage, output current data, and battery information; based on the grid voltage, output current data, and battery information, the operation mode of the battery energy storage system is determined to be a peak shaving and valley filling mode, a reactive power support mode, or a voltage sag control mode.

The main operation modes of the battery energy storage system mentioned in this embodiment are: peak shaving and valley filling mode, reactive power support mode and voltage sag control mode. Referring to the schematic diagram of the operation mode of a battery energy storage system shown in FIG4, the peak shaving and valley filling mode and the reactive power support mode belong to normal steady-state operation, and the voltage sag control mode belongs to short-term overload critical operation. First, the battery energy storage system sensor needs to detect the grid voltage u _grid , the output current I _o data and the battery information (battery temperature T , voltage U _b and current I _b ) to determine the current operation mode of the energy storage system. When the grid voltage is normal, the energy storage system is in the peak shaving and valley filling mode, and exchanges power with the grid according to the preset charging and discharging strategy. When the grid voltage is less than 90% of the rated value or greater than 110% of the rated value, the energy storage system preferentially enters the reactive power support mode. On the basis of the peak shaving and valley filling mode, it starts to output reactive power to the outside to increase the grid connection point voltage, and pays real-time attention to the output current of the three-phase inverter. If the output current in the reactive power support mode is too large and close to the rated value of the switch tube, the energy storage system will operate in the voltage sag management mode. At this time, the bypass circuit breaker and the bidirectional switch will disconnect the grid from the load, and the sensitive load will be powered solely by the energy storage system until the sag ends.

For the IGBT parameter design method of the battery energy storage system, please refer to the IGBT parameter design flow chart of a battery energy storage system shown in Figure 5. The whole consists of five parts: calculation of IGBT node voltage and current of the energy storage converter, calculation of operating losses of different types of IGBT parallel schemes, determination of the minimum parallel number of IGBTs that meet multi-mode safe operation, determination of the most economical IGBT selection scheme and determination of the actual working circuit structure.

As shown in Figure 5, the power parameters of the battery energy storage system in the peak shaving and valley filling _, reactive power support and voltage sag management modes are first preset, and the rated operating power Ppc and _Prs of the peak shaving and valley filling mode and the reactive power support mode and the maximum operating power Psag of the voltage _sag management mode are input into the circuit response calculation model to obtain the voltage and current parameters at the bidirectional Buck-Boost DC converter and the three-phase inverter bridge arm IGBT nodes.

Step S204, inputting voltage parameters and current parameters at the IGBT nodes in the energy storage converter and parameters of various types of IGBT devices into the operation loss evaluation model, and outputting operation loss expressions of various types of IGBT devices under multiple parallel quantity schemes.

As shown in Figure 5, the voltage and current parameters of the IGBT nodes of the energy storage converter in the three modes and the parameters of different types of IGBT devices are then input into the operation loss evaluation model to obtain the operation loss expressions of the bidirectional Buck-Boost DC converter and the three-phase inverter under different IGBT parallel schemes.

Step S206 , inputting the operating losses of various types of IGBT devices under multiple parallel connection number schemes into the safe operation evaluation model, and outputting the minimum parallel number of IGBTs that satisfies the safe operating area under multiple models of the energy storage converter.

As shown in Figure 5, the operating losses of the energy storage converter under different types of IGBT parallel schemes are then input into the safe operation evaluation model to characterize the IGBT safe operating area boundary of the energy storage converter under multi-mode operation, and obtain the minimum parallel number of IGBTs for the bidirectional Buck-Boost DC converter and three-phase inverter.

Step S208, inputting the minimum parallel number of IGBTs that meets the safe operating area under multiple models of the energy storage converter, the operating losses of various types of IGBT devices under multiple parallel quantity schemes, and device cost parameters into the economic evaluation model, and outputting the most economical IGBT selection scheme for the energy storage converter.

As shown in Figure 5, the IGBT device cost, minimum parallel number and operating loss are further input into the economic evaluation model to calculate the power loss cost and device cost of the bidirectional Buck-Boost DC converter and three-phase inverter under different types of IGBT parallel schemes throughout the life cycle, and determine the most economical energy storage converter IGBT selection scheme.

Step S210: determining the actual working circuit structure of the energy storage converter based on the most economical IGBT selection scheme of the energy storage converter.

As shown in FIG5 , the actual working circuit structure of the energy storage converter is finally determined based on the most economical IGBT selection scheme.

The above method provided by the embodiment of the present invention can, on the basis of taking into account the safe working area of IGBT under multi-mode operation of the energy storage converter, further take the lowest cost of the entire life cycle of IGBT under steady-state operation of peak shaving and valley filling and reactive support as the goal, and proposes an economic selection method for IGBT of energy storage converter under multi-mode operation. It can provide a basis for the safe and economical selection of IGBT of energy storage converter in engineering, and guide the actual working structure of the energy storage converter with the best economy.

The embodiment of the present invention provides an energy storage converter IGBT economic selection method taking into account multi-mode safe operation, which can ensure the safe and reliable operation of the IGBT in the multi-mode of the energy storage converter, improve the economic performance of the IGBT full life cycle operation in the peak shaving and valley filling and reactive power support modes, and achieve the optimal comprehensive performance and overall cost of the IGBT of the energy storage converter. It can provide a basis for the safe and economic selection of the IGBT of the energy storage converter in the project, and guide the actual working structure of the energy storage converter with the best economy.

Embodiment 2:

This embodiment provides another method for economic selection of IGBTs for energy storage converters taking into account multi-mode safe operation, and this method is implemented on the basis of the above embodiment.

For the circuit response calculation model, in some embodiments, the output power parameters and voltage parameters of the battery energy storage system are input into the circuit response calculation model; wherein the output power parameters include: the rated operating power of the battery energy storage system in the peak shaving and valley filling mode, the rated operating power in the reactive power support mode, and the maximum operating power in the voltage sag management mode; based on the power transfer relationship of the three-phase full-bridge inverter, the circuit response calculation model determines the voltage parameters and current parameters at the IGBT nodes in the three-phase inverter according to the output power parameters and voltage parameters; based on the power transfer relationship of the energy storage converter, the circuit response calculation model determines the voltage parameters and current parameters of the Buck-Boost DC converter according to the output power parameters and voltage parameters.

Referring to a flow chart of a circuit response calculation model shown in FIG6 , the circuit response calculation model is used to calculate voltage and current parameters at IGBT nodes in a bidirectional Buck-Boost DC converter and a three-phase inverter in an energy storage converter.

First, for the three-phase inverter, under the bipolar SPWM modulation mode, the voltage parameter u _tpi and current parameter i _tpi at any bridge arm IGBT node are expressed as:

Where ω and φ are the angular frequency and phase angle of the output voltage and current of the three-phase inverter respectively; U _C and I _p are the DC voltage on the input capacitor C of the three-phase inverter and the peak value of the output current of the three-phase inverter respectively, which can be expressed as:

Where U _BES and P _BES are the preset output voltage and power of the battery energy storage system respectively, and M is the modulation ratio of the three-phase inverter.

Secondly, for the bidirectional Buck-Boost DC converter, the voltage parameter u _bb and current parameter i _bb at the IGBT are expressed as:

Wherein, u _ce is the forward on-state voltage characteristic curve provided in the IGBT device manual, f _bb and D _bb are the operating frequency and switch duty cycle of the bidirectional Buck-Boost DC converter IGBT, and U _b is the battery pack voltage.

According to the above method, the voltage and current parameters at the IGBT nodes of the three-phase inverter and bidirectional Buck-Boost DC converter are calculated respectively under the rated operating power P _pc in the peak shaving and valley filling mode, the rated operating power P _rs in the reactive power support mode and the maximum operating power P _sag in the voltage sag management mode.

For the operation loss assessment model, in some embodiments, the voltage parameters and current parameters at the IGBT nodes in the energy storage converter and the parameters of various types of IGBT devices are input into the operation loss assessment model; the operation loss assessment model determines the maximum operating voltage parameters based on the voltage parameters at the IGBT nodes in the energy storage converter, and calculates the number of series connections of various types of IGBT devices that meet the operating voltage safety requirements of the energy storage converter based on the maximum operating voltage parameters; the operation loss assessment model determines the expression of the operation loss of a single IGBT of the three-phase inverter and the expression of the total loss of the three-phase inverter based on the number of series connections of various types of IGBT devices that meet the operating voltage safety requirements of the energy storage converter and the voltage parameters and current parameters at the IGBT nodes in the three-phase inverter and the parameters of various types of IGBT devices; the operation loss assessment model determines the expression of the operation loss of a single IGBT of the Buck-Boost DC converter and the expression of the total loss of the Buck-Boost DC converter based on the number of series connections of various types of IGBT devices that meet the operating voltage safety requirements of the energy storage converter.

Referring to a flow chart of an operating loss evaluation model shown in FIG7 , the operating loss evaluation model is used to calculate the operating loss of the energy storage converter under m different types of IGBT devices in parallel, specifically including the calculation of the operating loss and total loss expression of a single IGBT of a three-phase inverter and a bidirectional Buck-Boost DC converter.

Under the ith specific IGBT device, firstly, the series number N _series ( i ) of the ith IGBT that meets the voltage safety requirement is calculated based on the IGBT long-term operating voltage parameters and the energy storage converter IGBT node voltage parameters provided in the device manual:

Wherein, u _max is the maximum operating voltage parameter at the IGBT node of the energy storage converter, which is the same for the three-phase inverter and the bidirectional Buck-Boost DC converter, both of which are U _C ; V _ce ( i ) is the long-term operating voltage of the i -th IGBT device.

Then calculate the operating loss P _{tpi_unit} of a single IGBT device on the three-phase inverter bridge arm:

In the formula, P _{tpi_d} and P _{tpi_SW} are the conduction loss and switching loss of the IGBT device respectively, f _s is the operating frequency of the IGBT of the three-phase inverter, u _ce is the forward on-state voltage characteristic curve provided by the IGBT device manual, E _on and E _off are the turn-on loss and turn-off loss energy under the nominal voltage U _set and current I _set test conditions provided by the IGBT device manual, and n ₀ is the parallel number of the bridge arm IGBTs of the three-phase inverter.

The total _loss Ptpi of the three-phase inverter IGBT can be further expressed as:

The operating loss P _{bb_unit} of a single IGBT in a bidirectional Buck-Boost DC converter is expressed as:

Where P _{bb_d} and P _{bb_SW} are the conduction loss and switching loss of the IGBT device respectively, and n ₁ is the number of IGBTs in parallel at the node of the bidirectional Buck-Boost DC converter. The total IGBT loss P _bb of the entire bidirectional Buck-Boost DC converter is:

Finally, according to the above method, the single IGBT loss and total loss expressions of m types of IGBT devices in the three-phase inverter and bidirectional Buck-Boost DC converter are calculated one by one.

For the safe operation evaluation model, in some embodiments, the preset time of voltage sag management operation, parameters of multiple types of IGBT devices, and operating losses of multiple types of IGBT devices under multiple parallel quantity schemes are input into the safe operation evaluation model; the safe operation evaluation model calculates the critical safety threshold of accumulated heat after the preset time of voltage sag management operation of multiple types of IGBT devices based on the parameters of multiple types of IGBT devices; the safe operation evaluation model calculates the single accumulated heat of multiple types of IGBT devices after the preset time of voltage sag management operation when the parallel number is a first value based on the operating losses of multiple types of IGBT devices under multiple parallel quantity schemes; if the single accumulated heat is less than the critical safety threshold of accumulated heat and meets the steady-state operation conditions, the safe operation evaluation model uses the first value as the minimum parallel number of IGBTs that meets the safe working area under multiple models of the energy storage converter.

In addition, in some embodiments, if the single accumulated heat is not less than the critical safety threshold of the accumulated heat, or does not meet the steady-state operation conditions, the safe operation assessment model adds one to the first value and continues to calculate the single accumulated heat of multiple types of IGBT devices after the operating voltage sag control operation for a preset time when the parallel number is the first value based on the operating losses of multiple types of IGBT devices under multiple parallel number schemes.

Referring to a flow chart of a safe operation evaluation model shown in FIG8 , the safe operation evaluation model is used to evaluate the safe state of the IGBT of the energy storage converter under short-term overload critical operation, peak shaving and valley filling, and reactive support steady-state operation, characterize the safe working boundary of the IGBT, and provide the minimum parallel number of different types of IGBT devices that meet the multi-mode operation safety working area of the energy storage converter, so as to provide a safe operation basis for the IGBT selection and design of the energy storage converter, and ensure the safe operation of the energy storage converter under short-term overload and steady-state operation.

The minimum parallel number of IGBTs that meets the multi-mode operation safety operating area of the energy storage converter is determined, specifically including two parts: the three-phase inverter and the bidirectional Buck-Boost DC converter, and the calculation method of each part is the same.

Taking the determination of the minimum parallel number of IGBTs of a three-phase inverter that meets the multi-mode operation safety operating area as an example, under the i -th specific IGBT device, first, the cumulative thermal critical safety threshold E _SOA ( i ) of the device under the short-term overload voltage sag management operation time Tsag is calculated according to the IGBT dissipation power P _Dp ( i ) provided in the device manual, and the safe working boundary of the i -th IGBT device is characterized:

Secondly, calculate the cumulative heat E _s ( i , j ) of a single IGBT when the three -phase inverter is in voltage sag control operation and the number of j IGBT devices in parallel is:

Where P _{tpi_unit_sag} ( i , j, t ) represents the single IGBT loss power curve corresponding to the maximum output power of the three-phase inverter under the voltage sag control mode, which is obtained by the operation loss calculation model.

Then determine whether the cumulative heat Es ₍ i , j ) of the i -th IGBT device with the jth parallel number is less than the critical safety threshold ESOA ( i ) _of the cumulative heat. If so, this IGBT selection scheme meets the safe operating area under the three-phase inverter voltage sag management mode; if not, continue to increase the parallel number until the cumulative heat of a single IGBT meets the condition of being less than the critical safety threshold of the cumulative heat.

Further verification of whether the IGBT selection scheme meets the safe working area of the three-phase inverter under the peak shaving and valley filling and reactive power support mode steady-state operation is made according to the following formula:

Where P _{tpi_unit_pc} ( i , j ) and P _{tpi_unit_rs} ( i , j ) are the power losses of a single IGBT in the peak shaving and valley filling and reactive power support modes of the three-phase inverter respectively. If the above IGBT parallel connection scheme satisfies the safe operating area in the three modes, then the parallel connection number j is the minimum parallel connection number N _min ( i ) of the i -th IGBT device of the three-phase inverter.

Finally, the minimum parallel number N _min of m IGBT devices that meets the multi-mode operation safety zone of the three-phase inverter is calculated one by one according to the above method; the minimum parallel number N _min of IGBTs that meets the multi-mode operation safety zone of the bidirectional Buck-Boost DC converter can also be calculated according to the above method.

For the economic evaluation model, in some embodiments, the minimum parallel number of IGBTs that meets the safe working area under multiple models of the energy storage converter, the operating losses of multiple types of IGBT devices under multiple parallel quantity schemes, and device cost parameters are input into the economic evaluation model; the economic evaluation model calculates the total steady-state operating losses of multiple types of IGBT devices in the full life cycle when the parallel number is not less than the minimum parallel number based on the minimum parallel number of IGBTs that meets the safe working area under multiple models of the energy storage converter and the operating losses of multiple types of IGBT devices under multiple parallel quantity schemes; the economic evaluation model calculates the total cost of multiple types of multiple IGBT selection schemes based on the total steady-state operating losses of multiple types of IGBT devices in the full life cycle when the parallel number is not less than the minimum parallel number and device cost parameters; wherein the total cost of the IGBT selection scheme includes device cost and power loss; the minimum total cost is determined from the total costs of multiple types of multiple IGBT selection schemes, the IGBT device type and the parallel quantity of the IGBT devices corresponding to the minimum total cost are determined, and the optimal economical IGBT selection scheme for the energy storage converter is determined based on the IGBT device type and the parallel quantity of the IGBT devices corresponding to the minimum total cost.

Referring to the flowchart of an economic evaluation model shown in FIG9 , the economic evaluation model is used to evaluate the economic efficiency of different IGBT selection parallel schemes for energy storage converters. Under the condition of meeting the multi-mode operation safety operating area of the energy storage converter, the total cost of the full life cycle of different IGBT selection parallel schemes is calculated, and an IGBT selection parallel scheme that takes into account multi-mode operation safety and economy is provided for the design of energy storage converters in the project. Specifically, it includes the economic selection of IGBTs for three-phase inverters and bidirectional Buck-Boost DC converters, and the economic selection methods of the two parts are the same.

Taking the optimal economic IGBT selection of a three-phase inverter as an example, first calculate the total loss of the i- th IGBT device in the life cycle T _life under the j -parallel number:

Where λ is the average working time coefficient of the energy storage converter during its entire life cycle, ranging from 0 to 1.

Secondly, calculate the total cost C ( i , j ) of the i -th IGBT device during its life cycle with j parallel connections:

Where C _d ( i , j ) and C _p ( i , j ) are the total cost and power loss cost of the IGBT device in this parallel scheme, C _IGBT ( i , j ) is the unit price of the i -th IGBT device, and C _electricity is the unit price of the power cost. N _num is the number of IGBT nodes in the energy storage converter: 6 for the three-phase inverter and 2 for the bidirectional Buck-Boost DC converter.

Then, the i -th IGBT parallel connection scheme with the minimum total cost is obtained by increasing the number of IGBT devices in parallel j , and the minimum total cost C _min ( i ) and the number of IGBT devices in parallel N _best ( i ) are recorded.

Furthermore, according to the above method, the minimum total cost and the number of IGBTs in parallel of each of the m types of IGBT devices are found one by one, so as to obtain the IGBT device type k , series number N _series and parallel number N _best with the lowest economic cost during the whole life cycle of the three-phase inverter, and determine that this scheme is the optimal economic IGBT device selection and parallel scheme for the three-phase inverter that meets the multi-mode operation safety working area.

Similarly, the above method is used to find the optimal economic IGBT device selection scheme for the bidirectional Buck-Boost DC converter. Finally, the optimal economic selection combination of the three-phase inverter and the bidirectional Buck-Boost DC converter is obtained, forming the optimal economic IGBT device selection parallel scheme for the entire energy storage converter to meet the multi-mode operation safety working area, and outputting the actual working circuit structure of the energy storage converter.

The above method provided by the embodiment of the present invention mainly includes the following contents:

(1) IGBT selection method considering the safe operating area of multi-mode operation of energy storage converters: Considering the short-term overload operation, peak shaving and valley filling, and reactive power support steady-state operation conditions of the energy storage converter under voltage sag control, a safe operation evaluation model is designed to characterize the safe operating area of IGBT devices under multi-mode operation of the energy storage converter, and a basis for judging the safe operation of the IGBT of the energy storage converter is established.

(2) The most economical IGBT selection method for energy storage converters over their entire life cycle: Considering the operating losses and costs of IGBTs over their entire life cycle, an economic evaluation model was designed, and a method for selecting IGBTs with the lowest economic cost over their entire life cycle was developed.

The above method provided by the embodiment of the present invention has the following advantages:

(1) Taking into account the short-term overload operation in the voltage sag control mode and the steady-state operation conditions in the peak shaving and valley filling and reactive power support modes of the energy storage converter, the safe working area of the IGBT device under the multi-mode operation of the energy storage converter is characterized, the judgment basis for the safe operation of the IGBT of the energy storage converter is formulated, and the selection method for the safe operation of the IGBT is given to ensure the safe and stable operation of the IGBT of the energy storage converter under all operating conditions.

(2) Taking into account the full life cycle operation loss and cost of the energy storage converter IGBT device, and considering the multi-mode operation safety, a full life cycle optimal economic IGBT selection method is further developed to improve the operation economy of the energy storage converter during its life cycle. This can provide a basis for the safe and economic selection of energy storage converter IGBTs in engineering projects, and guide the actual working structure of the energy storage converter with the best economy.

Embodiment three:

An embodiment of the present invention also provides an electronic device for running the above-mentioned method for economically selecting IGBTs for energy storage converters taking into account multi-mode safe operation; referring to the structural schematic diagram of an electronic device shown in FIG10 , the electronic device includes a memory 100 and a processor 101, wherein the memory 100 is used to store one or more computer instructions, and the one or more computer instructions are executed by the processor 101 to implement the above-mentioned method for economically selecting IGBTs for energy storage converters taking into account multi-mode safe operation.

Furthermore, the electronic device shown in FIG. 10 further includes a bus 102 and a communication interface 103 , and the processor 101 , the communication interface 103 and the memory 100 are connected via the bus 102 .

Among them, the memory 100 may include a high-speed random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 103 (which can be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. can be used. The bus 102 can be an ISA bus, a PCI bus or an EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one bidirectional arrow is used in Figure 10, but it does not mean that there is only one bus or one type of bus.

The processor 101 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the processor 101. The above processor 101 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present invention can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present invention can be directly embodied as a hardware decoding processor for execution, or a combination of hardware and software modules in the decoding processor for execution. The software module may be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 100, and the processor 101 reads the information in the memory 100 and completes the steps of the method of the above embodiment in combination with its hardware.

An embodiment of the present invention also provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement the above-mentioned method for economic selection of IGBT for energy storage converter taking into account multi-mode safe operation. The specific implementation can be found in the method embodiment, which will not be repeated here.

The computer program product of the method for economically selecting IGBTs for energy storage converters taking into account multi-mode safe operation provided in an embodiment of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods in the previous method embodiments. For specific implementation, please refer to the method embodiments, which will not be repeated here.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system and/or device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

Finally, it should be noted that the above embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate 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. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (5)

1. An energy storage converter IGBT economic model selection method considering multi-mode safe operation, which is characterized by comprising the following steps:

Outputting voltage parameters and current parameters at IGBT nodes in the energy storage converter by responding to a calculation model by an output power parameter input circuit of the battery energy storage system in a peak clipping and valley filling mode, a reactive support mode and a voltage sag management mode;

Inputting voltage parameters and current parameters at IGBT nodes in the energy storage converter and parameters of a plurality of types of IGBT devices into an operation loss evaluation model, and outputting operation loss expressions of the plurality of types of IGBT devices under a plurality of parallel quantity schemes;

inputting the running loss of the IGBT devices of the multiple types under the multiple parallel quantity schemes into a safe running evaluation model, and outputting the minimum parallel quantity of the IGBT meeting the safe working area under the multiple models of the energy storage converter;

Inputting the minimum parallel number of the IGBTs meeting the safety working area of the energy storage converter under the multi-model, the running loss of the IGBT devices of the multiple types under the multiple parallel number schemes and the device cost parameters into an economic evaluation model, and outputting an optimal economic IGBT model selection scheme of the energy storage converter;

determining an actual working circuit structure of the energy storage converter based on an optimal economical IGBT (insulated gate bipolar transistor) type selection scheme of the energy storage converter;

The step of inputting the running loss of the IGBT devices of the multiple types under the multiple parallel quantity schemes into a safe running evaluation model and outputting the minimum parallel quantity of the IGBT meeting the safe working area under the multi-model of the energy storage converter comprises the following steps: inputting the preset time of voltage sag management operation, parameters of a plurality of types of IGBT devices and the operation loss of the plurality of types of IGBT devices under a plurality of parallel quantity schemes into a safe operation evaluation model; the safety operation evaluation model calculates accumulated heat critical safety threshold after the voltage sag management operation of the IGBT devices of the multiple types is performed for a preset time based on the parameters of the IGBT devices of the multiple types; the safe operation evaluation model calculates single accumulated heat after the voltage sag management operation preset time when the parallel quantity of the IGBT devices of the multiple types is a first value based on the operation loss of the IGBT devices of the multiple types under the multiple parallel quantity schemes; if the single accumulated heat is smaller than the accumulated heat critical safety threshold and meets steady-state operation conditions, the safe operation evaluation model takes the first value as the minimum number of the IGBTs in parallel in a safe working area under the multi-model of the energy storage converter;

The safe operation evaluation model calculates a single accumulated heat after the voltage sag management operation for a preset time when the parallel quantity is a first value of the plurality of types of IGBT devices based on the operation loss of the plurality of types of IGBT devices under the plurality of parallel quantity schemes, and the method further comprises the following steps: if the single accumulated heat is not smaller than the accumulated heat critical safety threshold or does not meet the steady-state operation condition, the safe operation evaluation model adds one to the first value and then continues to calculate the single accumulated heat after the voltage sag management operation preset time for the plurality of types of IGBT devices based on the operation loss of the plurality of types of IGBT devices under the plurality of parallel quantity schemes when the parallel quantity is the first value;

Inputting the minimum parallel number of the IGBTs meeting the safety working area of the energy storage converter under the multi-model, the running loss of the IGBT devices of the multiple types under the multiple parallel number schemes and the device cost parameters into an economic evaluation model, and outputting an optimal economic IGBT selection scheme of the energy storage converter, wherein the method comprises the following steps of: inputting the minimum parallel number of the IGBTs meeting the safety working area under the multi-model of the energy storage converter, the running loss of the IGBT devices of the multiple types under the multiple parallel number schemes and the device cost parameters into an economic evaluation model; the economic evaluation model calculates total steady-state operation loss of the IGBT devices of the multiple types in a whole life cycle when the parallel number is not less than the minimum parallel number based on the minimum parallel number of the IGBT meeting the safety working area of the energy storage converter under multiple models and the operation loss of the IGBT devices of the multiple types under multiple parallel number schemes; the economic evaluation model calculates the total cost of a plurality of IGBT type schemes of a plurality of types based on the total steady-state operation loss of the IGBT devices of the plurality of types in the whole life cycle when the parallel number is not less than the minimum parallel number and the device cost parameter; wherein the total cost of the IGBT option includes device cost and power loss; determining a minimum total cost from total cost of a plurality of IGBT type selection schemes of various types, determining an IGBT device type corresponding to the minimum total cost and the parallel connection number of the IGBT devices, and determining an optimal economical IGBT type selection scheme of the energy storage converter based on the IGBT device type corresponding to the minimum total cost and the parallel connection number of the IGBT devices.

2. The method of claim 1, wherein the energy storage converter comprises a Buck-Boost dc converter and a three-phase inverter.

3. The method of claim 2, wherein the step of inputting the output power parameters of the battery energy storage system in the peak load mode, the reactive support mode, and the voltage sag remediation mode into the circuit response calculation model to output the voltage parameters and the current parameters at the IGBT nodes in the energy storage converter comprises:

Inputting output power parameters and voltage parameters of the battery energy storage system into a circuit response calculation model; wherein the output power parameters include: rated operating power of the battery energy storage system in a peak clipping and valley filling mode, rated operating power of the battery energy storage system in a reactive power supporting mode and maximum operating power of the battery energy storage system in a voltage sag management mode;

Based on a power transfer relation of the three-phase full-bridge inverter, the circuit response calculation model determines voltage parameters and current parameters at IGBT nodes in the three-phase inverter according to the output power parameters and the voltage parameters;

And based on the power transfer relation of the energy storage converter, the circuit response calculation model determines the voltage parameter and the current parameter of the Buck-Boost direct-current converter according to the output power parameter and the voltage parameter.

4. A method according to claim 3, wherein the step of inputting the voltage parameter and the current parameter at the IGBT node in the energy storage converter, the plurality of types of IGBT device parameters into the operation loss evaluation model, and outputting the operation loss expression of the plurality of types of IGBT devices under the plurality of parallel number schemes comprises:

inputting voltage parameters and current parameters at IGBT nodes in the energy storage converter and parameters of various IGBT devices into an operation loss evaluation model;

The operation loss evaluation model determines a maximum working voltage parameter based on a voltage parameter and a current parameter at an IGBT node in the energy storage converter, and calculates the number of series connection of a plurality of types of IGBT devices meeting the working voltage safety requirement of the energy storage converter based on the maximum working voltage parameter;

The operation loss evaluation model is based on the number of series connection of the IGBT devices of various types meeting the safety requirement of the working voltage of the energy storage converter, and determines the expression of the operation loss of a single IGBT of the three-phase inverter and the expression of the total loss of the three-phase inverter based on the voltage parameter and the current parameter at the IGBT node in the three-phase inverter and the parameters of the IGBT devices of various types;

The operation loss evaluation model determines an expression of the operation loss of a single IGBT of the Buck-Boost direct-current converter and an expression of the total loss of the Buck-Boost direct-current converter based on the serial number of the IGBT devices of various types meeting the safety requirement of the working voltage of the energy storage converter.

5. The method according to any one of claims 1-4, further comprising:

the sensor of the battery energy storage system detects power grid voltage, output current data and battery information;

And determining that the operation mode of the battery energy storage system is the peak clipping and valley filling mode, the reactive power support mode or the voltage sag management mode based on the power grid voltage, the output current data and the battery information.