Control method and system of modular converter equipment, storage medium and equipment

Abstract

The embodiment of the invention discloses a control method and system for modular converter equipment. The method comprises the following steps: acquiring current data of each converter in the modular converter equipment in a current instruction period; determining the loss of a power module of each converter according to the current data of each converter; determining the junction temperature of each converter power module according to the loss of each converter power module; constructing a multi-objective optimization function based on the loss and the junction temperature; and determining current data output by each converter in the modular converter equipment in the next instruction period according to the multi-objective optimization function. According to the method, the current data is collected, the loss and the junction temperature are calculated, the multi-objective optimization function is constructed, and the optimal current distribution scheme is searched by using the optimization algorithm, so that the shunting control of the modular converter equipment is realized, and the purposes of reducing the loss and balancing the junction temperature are achieved.

Description

Technical Field

[0001] The present invention relates to the field of circuit control technology, and in particular to a control method, system, storage medium and device for modular current conversion equipment. Background Art

[0002] With the rapid development of power electronics technology, high-power power electronics equipment is increasingly being used in various fields. These devices usually use modular converters in parallel to meet high power requirements. However, due to differences in the manufacturing precision and aging of power modules, even devices of the same model may have different internal parameters. When these devices are fed with the same current, the losses they generate and the changes in junction temperature they cause will also be different.

[0003] Traditional modular converter control methods usually adopt a current balancing strategy, that is, each converter outputs the same current. This strategy can ensure the junction temperature of each converter is balanced under ideal conditions, that is, when the internal parameters of each power module are exactly the same. However, in practical applications, due to the differences in power module parameters, the current balancing strategy will cause differences in the junction temperature of each converter, and some devices will exceed the maximum junction temperature that the device can withstand, resulting in device overheating and failure, affecting the normal operation of the equipment. Summary of the invention

[0004] Based on this, it is necessary to propose a control method for modular power conversion equipment to address the above problems.

[0005] A control method for a modular current conversion device, the method comprising the following steps:

[0006] Obtaining current data of each converter in the modular converter device under the current instruction cycle;

[0007] Determine the loss of each converter power module according to the current data of each converter;

[0008] Determining the junction temperature of each converter power module according to the loss of each converter power module;

[0009] Constructing a multi-objective optimization function based on the loss and the junction temperature;

[0010] The current data output by each converter in the modular converter device in the next instruction cycle is determined according to the multi-objective optimization function.

[0011] In the above scheme, each converter power module includes an insulated gate bipolar transistor chip IGBT and a freewheeling diode FWD, and the loss of each converter power module is determined according to the conduction loss and switching loss of each converter power module.

[0012] In the above scheme, the loss of each converter power module is determined according to the conduction loss and switching loss of each converter power module, specifically including:

[0013]

[0014] P Tcon (k) = d(k)v ce (k)i a (k)

[0015]

[0016] P Dcon (k) = d(k)v F (k)i a (k)

[0017]

[0018] Where P Tcon (k) is the conduction loss of the insulated gate bipolar transistor chip IGBT, P Tsw (k) is the switching loss of the insulated gate bipolar transistor chip IGBT, P Dcon (k) is the conduction loss of the freewheeling diode FWD, P Dsw (k) is the switching loss of the freewheeling diode FWD, v ce (k) is the on-state voltage drop of the insulated gate bipolar transistor chip IGBT, v F (k) is the conduction voltage drop of the freewheeling diode FWD; E Ton (k) and E Toff (k) are the turn-on energy and turn-off energy of the insulated gate bipolar transistor chip IGBT, E Doff (k) is the turn-off energy of the freewheeling diode FWD; d(k) is the on-duty ratio, v ce_ref and v F_ref is the reference voltage of the insulated gate bipolar transistor chip IGBT, T s is the switching period, P loss (k) is the power module loss.

[0019] In the above solution, the step of determining the junction temperature of each converter power module according to the loss of each converter power module specifically includes:

[0020]

[0021]

[0022] Where P loss (k) is the power module loss, Z Ti (T s) is the equivalent thermal impedance of the fourth-order junction-shell thermal network model and shell-heat sink thermal network model, ΔT i (k-1) is the temperature difference between the two ends of the equivalent thermal impedance in the previous switching cycle, T a is the ambient temperature, DT i (k) is the junction temperature of the converter power module.

[0023] In the above solution, the multi-objective optimization function is constructed based on the loss and the junction temperature, specifically including:

[0024]

[0025] Where P lossi (t+1) is the loss of the i-th converter power module in the next instruction cycle predicted by the optimization algorithm, x(t+1) is the maximum value of the junction temperature difference of the insulated gate bipolar transistor chip IGBT of all converter power modules in the next instruction cycle predicted by the optimization algorithm, λ is the weight coefficient, T jm (t) and T jq (t) are the junction temperature differences of the insulated gate bipolar transistor chip IGBT of the mth converter and the qth converter power modules in the current instruction cycle, respectively; x(t) is the maximum junction temperature difference of the insulated gate bipolar transistor chip IGBT of all converter power modules in the current instruction cycle.

[0026] The above scheme also includes: determining the weight coefficient λ according to the following formula:

[0027]

[0028] Where, T min and T max are the minimum and maximum allowable junction temperature differences, T d is the junction temperature difference when the junction temperature and loss weight ratio is 50, and a, b, and c are known coefficients.

[0029] In the above scheme, the current data output by each converter in the modular converter device in the next instruction cycle is determined according to the multi-objective optimization function, specifically including:

[0030] Using the current data of each converter in the modular converter device under the current instruction cycle, the junction temperature and loss of the insulated gate bipolar transistor chip IGBT of each converter power module in the modular converter device under the next instruction cycle are predicted;

[0031] Substitute the predicted junction temperature and loss into the multi-objective optimization function;

[0032] Optimizing the multi-objective optimization function to determine a set of current data that minimizes the value of the multi-objective optimization function;

[0033] The current data output by each converter in the modular converter device in the next instruction cycle is determined according to the current data obtained by optimization.

[0034] The present application also proposes a control system for a modular current conversion device, the system comprising: a current converter data acquisition unit, an objective function construction unit and a current data output unit;

[0035] The converter data acquisition unit is used to acquire current data of each converter in the modular converter device under the current instruction cycle; determine the loss of each converter power module according to the current data of each converter; determine the junction temperature of each converter power module according to the loss of each converter power module;

[0036] The objective function construction unit is used to construct a multi-objective optimization function based on the loss and the junction temperature;

[0037] The current data output unit is used to determine the current data output by each converter in the modular current conversion device in the next instruction cycle according to the multi-objective optimization function.

[0038] The present application also proposes a readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the following steps:

[0039] Obtaining current data of each converter in the modular converter device under the current instruction cycle;

[0040] Determine the loss of each converter power module according to the current data of each converter;

[0041] Determining the junction temperature of each converter power module according to the loss of each converter power module;

[0042] Constructing a multi-objective optimization function based on the loss and the junction temperature;

[0043] The current data output by each converter in the modular converter device in the next instruction cycle is determined according to the multi-objective optimization function.

[0044] The present application also proposes a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the following steps of the computer program:

[0045] Obtaining current data of each converter in the modular converter device under the current instruction cycle;

[0046] Determine the loss of each converter power module according to the current data of each converter;

[0047] Determining the junction temperature of each converter power module according to the loss of each converter power module;

[0048] Constructing a multi-objective optimization function based on the loss and the junction temperature;

[0049] The current data output by each converter in the modular converter device in the next instruction cycle is determined according to the multi-objective optimization function.

[0050] The embodiment of the present invention has the following beneficial effects: firstly obtaining the current data of each converter in the modular converter device under the current instruction cycle; determining the loss of each converter power module according to the current data of each converter; determining the junction temperature of each converter power module according to the loss of each converter power module; constructing a multi-objective optimization function based on the loss and the junction temperature; and determining the current data output by each converter in the modular converter device under the next instruction cycle according to the multi-objective optimization function. The present invention collects current data, calculates the loss and junction temperature, and constructs a multi-objective optimization function based on the loss and junction temperature, and uses the optimization algorithm to find the best current distribution scheme, thereby realizing the shunt control of the modular converter device and achieving the purpose of reducing the loss and balancing the junction temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] in:

[0053] Figure 1 A schematic diagram of the structure of a modular current conversion device in one embodiment;

[0054] Figure 2 Based on Figure 1 Schematic diagram of the power module structure of each converter;

[0055] Figure 3 A schematic flow chart of a control method for a modular current conversion device in an embodiment;

[0056] Figure 4 This is a schematic diagram of simulation results of a control method for modular power conversion equipment. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0058] In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present invention; however, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details; in other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described, and it should be understood that the present invention can be implemented in different forms and should not be interpreted as limited to the embodiments presented here; on the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present invention to those skilled in the art.

[0059] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "a", "an" and "said / the" are also intended to include the plural forms, unless the context clearly indicates otherwise, and it should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0060] In the prior art, converter failure is caused by damage to the power module, and the excessive junction temperature of the insulated gate bipolar transistor chip IGBT is one of the main reasons for the damage to the power module; therefore, the development of a control method for a modular converter device is of great significance for improving the reliability and service life of the converter. The present application proposes a control method for a modular converter device, which is used for Figure 1 The modular converter device shown in the figure optimizes and controls the current borne by each converter in the modular converter device by constructing a multi-objective optimization function with loss reduction and junction temperature balance as the goals.

[0061] In order to thoroughly understand the present invention, a detailed structure will be presented in the following description to illustrate the technical solution proposed by the present invention; optional embodiments of the present invention are described in detail as follows, but in addition to these detailed descriptions, the present invention may also have other implementation methods.

[0062] like Figure 3As shown, in one embodiment, a control method for a modular power conversion device is provided, and the control method for a modular power conversion device includes steps S101 to S105, which are described in detail as follows:

[0063] S101, obtaining current data of each converter in the modular converter device in the current instruction cycle;

[0064] Collecting and obtaining the actual output current value of each converter in the modular converter device under the current instruction cycle is the basis for the subsequent calculation of loss and junction temperature.

[0065] S102, determining the loss of the power module of each converter according to the current data of each converter;

[0066] Using the collected current data, combined with the characteristics and parameters of the power module, the loss of each power module is calculated. The loss usually includes conduction loss and switching loss, which is related to factors such as current value, voltage value, switching frequency, etc. The loss is an important indicator to measure the efficiency of the converter. Through this step, the energy loss of each converter under the current working state can be understood.

[0067] like Figure 2 The figure shows a schematic diagram of the structure of each converter power module. Each converter power module includes an insulated gate bipolar transistor chip IGBT and a freewheeling diode FWD. The loss of each converter power module is determined according to the conduction loss and switching loss of each converter power module.

[0068] Specifically, Figure 1 The six power modules of the first converter in the example generate the same losses. Figure 2 A power module includes an insulated gate bipolar transistor chip IGBT and a freewheeling diode FWD. Taking the power module of the upper bridge arm of phase A as an example, the insulated gate bipolar transistor chip IGBT of the upper bridge arm power module of phase A is denoted as S 1 , the freewheeling diode FWD is D 1 ; The insulated gate bipolar transistor chip IGBT is the core component of the insulated gate bipolar transistor chip IGBT, which is responsible for realizing the conduction and shutdown of the current; The freewheeling diode FWD is an important component in the circuit. In the switching power supply, motor control, inverter and other circuits, when the switching device (such as transistor or insulated gate bipolar transistor chip IGBT) is turned off, the freewheeling diode FWD can provide a path for the current to continue to flow, thereby avoiding voltage spikes and current mutations.

[0069] In some embodiments, determining the loss of each converter power module according to the conduction loss and switching loss of each converter power module specifically includes:

[0070]

[0071] P Tcon (k) = d(k)v ce (k)i a (k)

[0072]

[0073] P Dcon (k) = d(k)v F (k)i a (k)

[0074]

[0075] Where P Tcon (k) is the conduction loss of the insulated gate bipolar transistor chip IGBT, P Tsw (k) is the switching loss of the insulated gate bipolar transistor chip IGBT, P Dcon (k) is the conduction loss of the freewheeling diode FWD, P Dsw (k) is the switching loss of the freewheeling diode FWD, v ce (k) is the on-state voltage drop of the insulated gate bipolar transistor chip IGBT, v F (k) is the conduction voltage drop of the freewheeling diode FWD; E Ton (k) and E Toff (k) are the turn-on energy and turn-off energy of the insulated gate bipolar transistor chip IGBT, E Doff (k) is the turn-off energy of the freewheeling diode FWD; d(k) is the on-duty ratio, v ce_ref and v F_ref is the reference voltage of the insulated gate bipolar transistor chip IGBT, T s is the switching period, P loss (k) is the power module loss.

[0076] S103, determining the junction temperature of each converter power module according to the loss of each converter power module;

[0077] Using loss data and combining it with the thermal network model, the junction temperature of each power module is calculated. Junction temperature is a key factor affecting the life and reliability of the power module. Excessively high junction temperature will accelerate the aging of the power module.

[0078] In some embodiments, determining the junction temperature of each converter power module according to the loss of each converter power module specifically includes:

[0079]

[0080] Where P loss (k) is the power module loss, Z Ti(T s ) is the equivalent thermal impedance of the fourth-order junction-shell thermal network model and shell-heat sink thermal network model, ΔT i (k-1) is the temperature difference between the two ends of the equivalent thermal impedance in the previous switching cycle, T a is the ambient temperature, DT i (k) is the junction temperature of the converter power module.

[0081] S104, constructing a multi-objective optimization function based on loss and junction temperature;

[0082] This step is the key to transforming the problem into a mathematical optimization problem. By constructing a multi-objective optimization function that includes both loss and junction temperature, we can comprehensively consider the two factors and find an optimal solution so that both loss and junction temperature can reach a better level under certain conditions.

[0083] In some embodiments, a multi-objective optimization function is constructed based on the loss and the junction temperature, specifically including:

[0084]

[0085] Where P lossi (t+1) is the loss of the i-th converter power module in the next instruction cycle predicted by the optimization algorithm, x(t+1) is the maximum value of the junction temperature difference of the insulated gate bipolar transistor chip IGBT of all converter power modules in the next instruction cycle predicted by the optimization algorithm, λ is the weight coefficient, T jm (t) and T jq (t) are the junction temperature differences of the insulated gate bipolar transistor chip IGBT of the mth converter and the qth converter power modules in the current instruction cycle, respectively; x(t) is the maximum junction temperature difference of the insulated gate bipolar transistor chip IGBT of all converter power modules in the current instruction cycle.

[0086] Specifically, since the junction temperature difference of the freewheeling diode FWD in the power module is negligible, only the junction temperature difference of the insulated gate bipolar transistor chip IGBT of the power module is considered to construct the multi-objective optimization function.

[0087] In some embodiments, the method further includes: determining a weight coefficient λ according to the following formula:

[0088]

[0089] Where, T min and T max are the minimum and maximum allowable junction temperature differences, T d is the junction temperature difference when the junction temperature and loss weight ratio is 50, and a, b, and c are known coefficients.

[0090] S105 . Determine the current data output by each converter in the modular converter device in the next instruction cycle according to the multi-objective optimization function.

[0091] According to the results of the multi-objective optimization function, the current output of each converter in the modular converter device in the next instruction cycle is adjusted. By optimizing the current distribution, the loss of the power module and the junction temperature can be reduced while ensuring the overall performance of the system, thereby improving the efficiency and reliability of the system. The optimization algorithm is used to find a set of current data that can minimize the value of the multi-objective optimization function. This set of data is the current value that each converter of the modular converter device should output in the next instruction cycle, which can achieve balanced control of loss and junction temperature.

[0092] Preferably, when x(t) <T min When , the weight coefficient λ is set to 1. At this time, priority is given to reducing the loss of the power module, and the next instruction cycle is controlled to reduce the loss of the power module while maintaining the junction temperature balance;

[0093] When T min ≤x(t) <T max When the weight coefficient λ is set to a quadratic function about x(t), the value of λ increases exponentially with the increase of the junction temperature difference x(t). At this time, consider strengthening the control of junction temperature balance, thereby strengthening the control of junction temperature balance;

[0094] When x ≥ T max When the weight coefficient λ is set to 100, the next instruction cycle is controlled to control the junction temperature balance as the main control to ensure that the junction temperature of the insulated gate bipolar transistor chip IGBT does not exceed the maximum allowable value, giving priority to controlling the junction temperature balance to prevent the insulated gate bipolar transistor chip IGBT from overheating.

[0095] It can be seen that by controlling the current borne by each converter according to the junction temperature and loss of each converter in the modular converter device, the junction temperature of each converter in the modular converter device can be balanced while the loss is effectively reduced, and the converter reliability can be improved while the converter efficiency is improved.

[0096] In some embodiments, determining the current data output by each converter in the modular converter device in the next instruction cycle according to the multi-objective optimization function specifically includes:

[0097] Using the current data of each converter in the modular converter device under the current instruction cycle, the junction temperature and loss of the insulated gate bipolar transistor chip IGBT of each converter power module in the modular converter device under the next instruction cycle are predicted;

[0098] Substitute the predicted junction temperature and loss into the multi-objective optimization function;

[0099] Optimizing the multi-objective optimization function to determine a set of current data that minimizes the value of the multi-objective optimization function;

[0100] The current data output by each converter in the modular converter device in the next instruction cycle is determined according to the current data obtained by optimization.

[0101] Preferably, optimizing the multi-objective optimization function and determining a set of current data that minimizes the value of the multi-objective optimization function mainly comprises the following steps:

[0102] (1) Define the number of converters in the modular converter device as n, the number of particles as N, each particle contains the current values ​​of n converters, the number of iterations as M, and the optimal solution set f of the jth particle as jb , the current value set i corresponding to the optimal solution set of individual particles jb (n), particle swarm optimal solution f b , the optimal current value i of the converter b (n);

[0103] (2) Calculate the average loss and steady-state junction temperature of the n converters under the j-th particle current value, and use the average loss and steady-state junction temperature to calculate the multi-objective optimization function value g under the j-th particle. j；

[0104] (3) Calculate the sum of the current values ​​of the n converters under the jth particle, and judge whether the combination of the output current values ​​of the n converters of the jth particle is feasible based on the sum of the current values. If it is not feasible, punish the particle so that its multi-objective optimization function value is infinite, that is, the particle is considered invalid. If it is feasible, keep the calculated multi-objective optimization function value.

[0105] (4) The multi-objective optimization function value g j With f jb Compare; if g j Less than f jb This indicates that the output current values ​​of the n converters contained in the jth particle in the current cycle are closer to the optimal solution than those in the previous cycle. Therefore, update f jb and i jb (n) value; if g j Greater than f jb , then keep f jb and i jb The value of (n) remains unchanged;

[0106] (5) Determine N f jb Is the minimum value in less than f? b ; If min[f Nb ] is less than f bThis means that in the current cycle, the N particles contain a set that is closest to the optimal solution of the multi-objective optimization function in the previous cycle, so update f b and i b (n) value; if min[f Nb ] is greater than f b , then keep f b and i b The value of (n) remains unchanged;

[0107] (6) Calculate the inertia weight of each particle and update the particle's velocity and current value. The calculation formula is as follows:

[0108]

[0109] v ij m+1 =ω j v ij m +c 1 r 1 [i b m (i)-i ij m ]+c 2 r 2 [i jb m (i)-i ij m ]

[0110] i ij m+1 =i ij m +v ij m+1

[0111] In the formula, ω j is the inertia weight coefficient; ω max is the maximum value of the inertia weight coefficient; ω min is the minimum value of the inertia weight coefficient; g min and g avg are the minimum and average fitness values ​​of N particles respectively; v ij is the velocity of the jth particle of the ith converter; c 1 is the social learning coefficient, c 2 is the individual learning coefficient; r 1 and r 2 is a random number between 0 and 1; m represents the mth cycle;

[0112] (7) To prevent the obtained current value from exceeding the reference current value limit of the converter, the speed and current values ​​of the particles exceeding the speed limit and the current reference value limit are set to be close to the boundary values ​​of their values;

[0113] (8) Continue to search for the optimal solution until the number of cycles reaches the specified value M, and output the optimal solution current value i for each converter b (n) and acts on the converter control system.

[0114] like Figure 4 As shown, in some embodiments, the number of converters in the modular converter device is 3, and the traditional current balancing control strategy is adopted from 0 to 5s, that is, the output currents of the three converters in the modular converter device are the same; at the 5th second, the controller switches to the current sharing control strategy of each converter in the modular converter device based on junction temperature balancing.

[0115] When the junction temperature reaches a steady state under the traditional current sharing control strategy, the average junction temperature of the insulated gate bipolar transistor chip IGBT of the first converter power module in the modular converter device is 57.11°C; the average junction temperature of the insulated gate bipolar transistor chip IGBT of the second converter power module is 63.39°C; the average junction temperature of the insulated gate bipolar transistor chip IGBT of the third converter power module is 50.79°C; the maximum average junction temperature difference of the insulated gate bipolar transistor chip IGBT of each converter power module in the modular converter device is 12.6°C; at this time, the total loss of the power module is 102.1W.

[0116] After switching the control strategy at the 5th second, the average junction temperature of the insulated gate bipolar transistor chip IGBT of the first converter power module was 56.36°C; the average junction temperature of the insulated gate bipolar transistor chip IGBT of the second converter power module was 56.44°C; the average junction temperature of the insulated gate bipolar transistor chip IGBT of the third converter power module was 56.48°C; the maximum average junction temperature difference of the insulated gate bipolar transistor chip IGBT of each converter power module in the modular converter equipment was 0.12°C; at this time, the average total loss of the power module was 90.77W.

[0117] Compared with the traditional current sharing control strategy, after adopting the shunt control strategy of each converter in the modular converter device based on junction temperature balancing, the average junction temperature difference of the insulated gate bipolar transistor chip IGBT of each converter power module in the modular converter device was reduced by 98.1%, the junction temperature balancing effect was significant, and the power module loss was reduced by 11.1%.

[0118] The present application also proposes a control system for a modular current conversion device, the system comprising: a current converter data acquisition unit, an objective function construction unit and a current data output unit;

[0119] The converter data acquisition unit is used to acquire the current data of each converter in the modular converter device under the current instruction cycle; determine the loss of each converter power module according to the current data of each converter; determine the junction temperature of each converter power module according to the loss of each converter power module;

[0120] An objective function building unit, used to build a multi-objective optimization function based on loss and junction temperature;

[0121] The current data output unit is used to determine the current data output by each converter in the modular current conversion device in the next instruction cycle according to the multi-objective optimization function.

[0122] The present application also proposes a readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the following steps:

[0123] Obtaining current data of each converter in the modular converter device under the current instruction cycle;

[0124] Determine the loss of each converter power module according to the current data of each converter;

[0125] Determining the junction temperature of each converter power module according to the loss of each converter power module;

[0126] Construct a multi-objective optimization function based on loss and junction temperature;

[0127] The current data output by each converter in the modular converter device under the next instruction cycle is determined according to the multi-objective optimization function.

[0128] The present application also proposes a computer device, including a memory and a processor, wherein the memory stores a computer program, and the computer program is executed by the processor to perform the following steps:

[0129] Obtaining current data of each converter in the modular converter device under the current instruction cycle;

[0130] Determine the loss of each converter power module according to the current data of each converter;

[0131] Determining the junction temperature of each converter power module according to the loss of each converter power module;

[0132] Construct a multi-objective optimization function based on loss and junction temperature;

[0133] The current data output by each converter in the modular converter device under the next instruction cycle is determined according to the multi-objective optimization function.

[0134] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0135] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present application. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. The above disclosure is only a preferred embodiment of the present invention, and of course it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A control method for a modular current conversion device, characterized in that: The method comprises: Obtaining current data of each converter in the modular converter device under the current instruction cycle; Determine the loss of each converter power module according to the current data of each converter; Determining the junction temperature of each converter power module according to the loss of each converter power module; Constructing a multi-objective optimization function based on the loss and the junction temperature; The current data output by each converter in the modular converter device in the next instruction cycle is determined according to the multi-objective optimization function.

2. A control method for a modular power conversion device according to claim 1, characterized in that: Each of the converter power modules includes an insulated gate bipolar transistor chip IGBT and a freewheeling diode FWD, and the loss of each of the converter power modules is determined according to the conduction loss and switching loss of each of the converter power modules.

3. A control method for a modular converter device according to claim 2, characterized in that: Determining the loss of each converter power module according to the conduction loss and switching loss of each converter power module specifically includes: P Tcon (k)=d(k)v ce (k)i a (k) P Dcon (k)=d(k)v F (k)i a (k) Where P Tcon (k) is the conduction loss of the insulated gate bipolar transistor chip IGBT, P Tsw (k) is the switching loss of the insulated gate bipolar transistor chip IGBT, P Dcon (k) is the conduction loss of the freewheeling diode FWD, P Dsw (k) is the switching loss of the freewheeling diode FWD, v ce (k) is the on-state voltage drop of the insulated gate bipolar transistor chip IGBT, v F (k) is the conduction voltage drop of the freewheeling diode FWD; E Ton (k) and E Toff (k) are the turn-on energy and turn-off energy of the insulated gate bipolar transistor chip IGBT, E Doff (k) is the turn-off energy of the freewheeling diode FWD; d(k) is the on-duty ratio, v ce_ref and v F_ref is the reference voltage of the insulated gate bipolar transistor chip IGBT, T s is the switching period, P loss (k) is the power module loss.

4. The control method of a modular converter device according to claim 1, characterized in that: Determining the junction temperature of each converter power module according to the loss of each converter power module specifically includes: Where P loss (k) is the power module loss, Z Ti (T s ) is the equivalent thermal impedance of the fourth-order junction-shell thermal network model and shell-heat sink thermal network model, ΔT i (k-1) is the temperature difference between the two ends of the equivalent thermal impedance in the previous switching cycle, T a is the ambient temperature, DT i (k) is the junction temperature of the converter power module.

5. The control method of a modular converter device according to claim 1, characterized in that: The constructing of a multi-objective optimization function based on the loss and the junction temperature specifically includes: Where P lossi (t+1) is the loss of the i-th converter power module in the next instruction cycle predicted by the optimization algorithm, x(t+1) is the maximum value of the junction temperature difference of the insulated gate bipolar transistor chip IGBT of all converter power modules in the next instruction cycle predicted by the optimization algorithm, λ is the weight coefficient, T jm (t) and T jq (t) are the junction temperature differences of the insulated gate bipolar transistor chip IGBT of the mth converter and the qth converter power modules in the current instruction cycle, respectively; x(t) is the maximum junction temperature difference of the insulated gate bipolar transistor chip IGBT of all converter power modules in the current instruction cycle.

6. A control method for a modular converter device according to claim 5, characterized in that: Also includes: The weight coefficient λ is determined according to the following formula: Where, T min and T max are the minimum and maximum allowable junction temperature differences, T d is the junction temperature difference when the junction temperature and loss weight ratio is 50, and a, b, and c are known coefficients.

7. A control method for a modular converter device according to claim 1, characterized in that: Determining the current data output by each converter in the modular converter device in the next instruction cycle according to the multi-objective optimization function specifically includes: Using the current data of each converter in the modular converter device under the current instruction cycle, the junction temperature and loss of the insulated gate bipolar transistor chip IGBT of each converter power module in the modular converter device under the next instruction cycle are predicted; Substitute the predicted junction temperature and loss into the multi-objective optimization function; Optimizing the multi-objective optimization function to determine a set of current data that minimizes the value of the multi-objective optimization function; The current data output by each converter in the modular converter device in the next instruction cycle is determined according to the current data obtained by optimization.

8. A control system for a modular power conversion device, characterized in that: The system comprises: a converter data acquisition unit, an objective function construction unit and a current data output unit; The converter data acquisition unit is used to acquire current data of each converter in the modular converter device under the current instruction cycle; determine the loss of each converter power module according to the current data of each converter; determine the junction temperature of each converter power module according to the loss of each converter power module; The objective function construction unit is used to construct a multi-objective optimization function based on the loss and the junction temperature; The current data output unit is used to determine the current data output by each converter in the modular current conversion device in the next instruction cycle according to the multi-objective optimization function.

9. A readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to execute the steps of the method according to any one of claims 1 to 7.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 7.

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