Optimization method and device for input voltage of DAB converter topology circuit

Abstract

The invention provides a DAB converter topology circuit input voltage optimization method and device, the method can directly reflect the power condition, the result is closest to the optimization of the highest efficiency, the loss is controlled by controlling the input voltage of the DAB converter topology circuit, and the output voltage of the DAB converter topology circuit can be adjusted under the condition that the voltage at one end is fixed and the voltage at the other end is adjustable. Compared with an existing scheme, the method has the advantages that the lowest-loss input voltage can be found in a short time, so that the problems that the existing scheme is not applicable to the condition that one end of the input and output voltage is uncertain when the phase shift angle is subjected to optimization control, and the existing scheme is mostly manually calibrated, so that the efficiency is low are solved. The method solves the problem that the optimization efficiency of the input voltage of the DAB converter topology circuit is low, and is closer to a simulation model of a wide bandgap device based on a switching device with smaller switching loss.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a method, device, computer-readable storage medium and system for optimizing the input voltage of a DAB converter topology circuit. Background Art

[0002] Due to the characteristics of dual active bridge converters, such as bidirectional energy flow, high power density, easy soft switching characteristics and high efficiency, the exploration of dual active bridge converters is expanding and deepening with the popularization or application of electric vehicle power supplies, charging piles and smart grids. The efficiency of dual active bridge converters includes two aspects: modulation method and optimization control.

[0003] Modulation modes include single phase shift, double phase shift, extended phase shift modulation, and triple phase shift modulation. As the modulation mode changes, the number of controllable phase shift angles changes. The modulation mode is actually the premise for phase shift angle optimization control. The so-called optimization control is also phase shift angle optimization control. Optimization control includes current stress optimization, reflux power stress optimization, soft switching characteristic optimization, etc., that is, by controlling the phase shift angle to control current stress, reflux power, soft switching characteristics, etc., to achieve the purpose of improving efficiency.

[0004] Existing schemes perform optimal control on the phase shift angle, including the selection of modulation mode and the optimization of control objectives. Such methods are generally applied to situations where the input and output voltages of the converter are certain, but are not applicable to situations where one end of the input and output voltages is uncertain. In addition, existing schemes are mostly manually calibrated, resulting in low efficiency in optimizing the input voltage. Summary of the invention

[0005] The main purpose of the present application is to provide a method, device, computer-readable storage medium and system for optimizing the input voltage of a DAB converter topology circuit, so as to at least solve the problem that the optimization control of the phase shift angle performed in the existing scheme is not applicable to the situation where one end of the input and output voltages is uncertain, and the existing schemes are mostly manually calibrated, which leads to the problem of low optimization efficiency of the input voltage of the DAB converter topology circuit.

[0006] In order to achieve the above object, according to one aspect of the present application, a method for optimizing the input voltage of a DAB converter topology circuit is provided, the method comprising:

[0007] Acquire the overall loss of the DAB converter topology circuit according to a predetermined time interval, wherein the overall loss is the sum of the conduction loss of all the switch tubes in the DAB converter topology circuit, the switching loss of all the switch tubes, the iron loss of the transformer in the DAB converter topology circuit, and the copper loss of the transformer in the DAB converter topology circuit;

[0008] Constructing an overall loss function based on the overall loss, wherein the independent variable of the overall loss function is the ratio of the input voltage to the output voltage product of the DAB converter topology circuit, and the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit;

[0009] Compare the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, increase or decrease the independent variable, so as to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit, until the values ​​of the adjacent overall loss functions are the same.

[0010] Optionally, in the process of obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the method further includes:

[0011] According to P cond =I rms 2 R on , determine the conduction loss of the switch tube, where P cond is the conduction loss of the switch tube, I rms is the effective value of the inductor current, R on is the on-resistance of the switch tube.

[0012] Optionally, in the process of obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the method further includes:

[0013] According to P t =(Q oss +Q rr )·V1+V dson ·i Lt0 ·t on ·f+V dsoff ·i Lt2 ·t off f,

[0014] Determine the switching loss of the switch tube, where P t is the switching loss of the switch tube, Q oss is the output charge, Q rr is the reverse recovery charge, V1 is the input voltage of the DAB converter topology circuit, V dson is the voltage before turning on, i Lt0 is the current at the moment of turning on, t on is the opening time, V dsoff is the voltage before shutdown, i Lt2 is the current at the instant of shutoff, t offis the turn-off time, and f is the frequency of the switching tube.

[0015] Optionally, in the process of obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the method further includes:

[0016] according to Determine the transformer iron loss, where P fe is the transformer iron loss, D c is the voltage duty cycle, K, α and β are the corresponding loss coefficients, B m is the maximum magnetic flux density, V ol is the volume of the transformer, and f is the frequency of the switching tube.

[0017] Optionally, in the process of obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the method further includes:

[0018] According to P cu =I rms 2 R cu , determine the transformer copper loss, where P cu is the transformer copper loss, R cu is the winding resistance of the transformer, I rms is the effective value of the inductor current.

[0019] Optionally, comparing the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, and increasing or decreasing the independent variable, comprises:

[0020] When the value of the overall loss function corresponding to the independent variable collected for the nth time is less than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is greater than the independent variable for the n-1th time, increase the independent variable;

[0021] When the overall loss function corresponding to the independent variable collected for the nth time is smaller than the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is smaller than the independent variable for the n-1th time, reduce the independent variable;

[0022] When the value of the overall loss function corresponding to the independent variable collected for the nth time is greater than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is less than the independent variable for the n-1th time, reduce the independent variable;

[0023] When the value of the overall loss function corresponding to the independent variable collected for the nth time is greater than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is greater than the independent variable for the n-1th time, increase the independent variable.

[0024] Optionally, increasing the independent variable comprises: updating the independent variable of the nth time to the sum of the absolute values ​​of the difference between the independent variable of the n-1th time and the independent variable, the absolute value of the difference between the independent variable of the nth time and the independent variable of the n-1th time;

[0025] Reducing the independent variable includes: updating the independent variable of the nth time to the difference between the independent variable of the n-1th time and the absolute value of the difference of the independent variable.

[0026] According to another aspect of the present application, a device for optimizing the input voltage of a DAB converter topology circuit is provided, the device comprising:

[0027] An acquisition unit, configured to acquire an overall loss of a DAB converter topology circuit according to a predetermined time interval, wherein the overall loss is the sum of conduction losses of all switch tubes in the DAB converter topology circuit, switching losses of all switch tubes, iron losses of transformers in the DAB converter topology circuit, and copper losses of transformers in the DAB converter topology circuit;

[0028] A first processing unit is used to construct an overall loss function based on the overall loss, wherein the independent variable of the overall loss function is a ratio of an input voltage to an output voltage product of the DAB converter topology circuit, and the output voltage product is a product of an output voltage of the DAB converter topology circuit and a transformation ratio of a transformer in the DAB converter topology circuit;

[0029] The second processing unit is used to compare the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, increase or decrease the independent variable, so as to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit until the values ​​of the adjacent overall loss functions are the same.

[0030] According to another aspect of the present application, a computer-readable storage medium is provided, wherein the computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute any one of the methods described.

[0031] According to another aspect of the present application, a system for optimizing the input voltage of a DAB converter topology circuit is provided, the system comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include methods for executing any one of the methods described.

[0032] By applying the technical solution of the present application, an overall loss function is constructed based on the overall loss, wherein the independent variable of the overall loss function is the ratio of the input voltage to the output voltage product of the DAB converter topology circuit, and the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit, and the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently are compared, and the independent variable is increased or decreased to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit, until the adjacent overall loss function is obtained. Until the value of the loss function is the same, the power situation can be directly reflected, and the result is closest to the optimization of the highest efficiency. By controlling the input voltage of the DAB converter topology circuit and then controlling the loss, the loss optimization can be achieved when the voltage at one end is fixed and the voltage at the other end is adjustable, thereby achieving the purpose of improving efficiency. Compared with the existing scheme, the input voltage with the lowest loss can be found in a shorter time, thereby solving the problem of the existing scheme for optimizing the phase shift angle, but it is not applicable to the situation where one end of the input and output voltage is uncertain, and the existing schemes are mostly manually calibrated, which leads to the problem of low optimization efficiency of the input voltage of the DAB converter topology circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0034] Figure 1 A schematic diagram of a DAB converter topology circuit provided according to an embodiment of the present application is shown;

[0035] Figure 2 A schematic flow chart of a method for optimizing the input voltage of a DAB converter topology circuit provided according to an embodiment of the present application is shown;

[0036] Figure 3 A schematic diagram showing a change curve of loss within 0.025 s according to an embodiment of the present application is shown;

[0037] Figure 4A schematic diagram showing a comparison between a simulated loss and an estimated total loss provided according to an embodiment of the present application is shown;

[0038] Figure 5 A schematic flow chart of a method for optimizing the input voltage of a DAB converter topology circuit provided according to an embodiment of the present application is shown;

[0039] Figure 6 The structure block diagram of a device for optimizing input voltage of a DAB converter topology circuit provided according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0041] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] For the convenience of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0044] The DAB converter topology circuit is a circuit used in the digital audio broadcasting (DAB) system to convert analog audio signals into digital signals and perform digital modulation. This circuit usually includes components such as analog-to-digital converters (ADCs), digital signal processors (DSPs), and digital-to-analog converters (DACs) to achieve digital processing and transmission of audio signals. Through the DAB converter topology circuit, high-quality digital processing and transmission of audio signals can be achieved, improving the performance and efficiency of audio broadcasting systems.

[0045] Simulink is an engineering software for simulating, modeling and analyzing multi-domain dynamic systems. It is a graphical programming environment developed by MathWorks that can help engineers and scientists model and simulate various complex systems. Simulink can be used in conjunction with MATLAB, providing powerful tools and functions that enable users to quickly build and analyze dynamic system models. It has a wide range of applications in control systems, signal processing, communication systems, mechanical systems and other fields.

[0046] As introduced in the background technology, modulation modes include single phase shift, double phase shift, extended phase shift modulation, and triple phase shift modulation. As the modulation mode changes, the number of controllable phase shift angles changes. The modulation mode is actually the premise of phase shift angle optimization control, and the so-called optimization control is phase shift angle optimization control. The optimization control includes current stress optimization, reflux power stress optimization, soft switching characteristic optimization, etc., that is, by controlling the phase shift angle to control current stress, reflux power, soft switching characteristics, etc., to achieve the purpose of improving efficiency. In order to solve the problem that the optimization control of the phase shift angle performed by the existing scheme is not applicable to the situation where one end of the input and output voltages is uncertain, and the existing schemes are mostly manually calibrated, resulting in the problem of low optimization efficiency of the input voltage of the DAB converter topology circuit, the embodiments of the present application provide a method, device, computer-readable storage medium and system for optimizing the input voltage of a DAB converter topology circuit.

[0047] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0048] In this embodiment, a method for optimizing the input voltage of a DAB converter topology circuit is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical sequence is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0049] like Figure 1 As shown, the structure of the DAB converter topology circuit is demonstrated, which will not be described in detail here.

[0050] Figure 2 FIG. 1 is a flow chart of a method for optimizing the input voltage of a DAB converter topology circuit provided according to an embodiment of the present application. Figure 2 As shown, the method comprises the following steps:

[0051] Step S201, obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, wherein the overall loss is the sum of the conduction loss of all the switch tubes in the DAB converter topology circuit, the switching loss of all the switch tubes, the iron loss of the transformer in the DAB converter topology circuit, and the copper loss of the transformer in the DAB converter topology circuit;

[0052] In one embodiment of the present application, in the process of obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the method further includes:

[0053] According to P cond =I rms 2 R on , determine the conduction loss of the above switch tube, where P cond is the conduction loss of the above switch tube, I rms is the effective value of the inductor current, R on is the on-resistance of the switch tube.

[0054] Specifically, compared to IGBT and MOSFET, GaN has a shorter switching characteristic and there is no need to consider the anti-parallel diode. Therefore, only the loss caused by the on-resistance of the switch tube and the effective value of the inductor current need to be considered. The on-state loss of the switch tube is proportional to the square of the effective value of the inductor current.

[0055] In one embodiment of the present application, in the process of obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the method further includes:

[0056] According to P t =(Q oss +Q rr )·V1+V dson ·i Lt0 ·t on ·f+V dsoff ·i Lt2 ·t off f,

[0057] Determine the switching loss of the above switch tube, where P t is the switching loss of the above switch tube, Q oss is the output charge, Q rr is the reverse recovery charge, V1 is the input voltage of the above DAB converter topology circuit, V dson is the voltage before turning on, i Lt0 is the current at the moment of turning on, t on is the opening time, V dsoff is the voltage before shutdown, i Lt2 is the current at the instant of shutoff, t offis the turn-off time, and f is the frequency of the above-mentioned switching tube.

[0058] Specifically, although the switching loss of GaN switch tubes will not account for more than 50% of the loss like IGBT, due to the ultra-high switching frequency, the switching loss still accounts for a certain proportion and cannot be ignored. The switching loss consists of two parts, the capacitance loss that is independent of the current and the loss that is related to the current. The output charge and reverse recovery charge are obtained from the corresponding mapping table. The switching loss of the switch tube is proportional to the input voltage.

[0059] In one embodiment of the present application, in the process of obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the method further includes:

[0060] according to Determine the iron loss of the above transformer, where P fe is the iron loss of the above transformer, D c is the voltage duty cycle, K, α and β are the corresponding loss coefficients, B m is the maximum magnetic flux density, V ol is the volume of the above transformer, and f is the frequency of the above switching tube.

[0061] Specifically, the transformer iron loss can be calculated by the Steinmetz formula (SE formula), but since the primary side of the transformer is not subjected to sinusoidal excitation, the modified SE formula should be used:

[0062] P e is the loss per unit volume of the core;

[0063] V ol =4.44fNφ m ;

[0064] φ m =BS;

[0065] φ m is the magnetic flux, B is the maximum magnetic flux density, S is the magnetic flux area, and N is the transformer ratio;

[0066] The transformer iron loss is the volume of the transformer and P e The product of .

[0067] In one embodiment of the present application, in the process of obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the method further includes:

[0068] According to P cu =I rms 2 R cu , determine the above transformer copper loss, where P cuis the copper loss of the above transformer, R cu is the winding resistance of the transformer, I rms is the effective value of the inductor current.

[0069] Step S202, constructing an overall loss function based on the overall loss, wherein the independent variable of the overall loss function is the ratio of the input voltage to the output voltage product of the DAB converter topology circuit, and the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit;

[0070] Specifically, the overall loss function is: P all (k) = P cond (k)+P t (k)+P fe (k)+P cu (k);

[0071] P all (k) is the value of the overall loss function, and k is the independent variable.

[0072] Step S203, comparing the values ​​of the above-mentioned overall loss function corresponding to the above-mentioned independent variables collected twice adjacently, increasing or decreasing the above-mentioned independent variables to increase or decrease the input voltage of the above-mentioned DAB converter topology circuit and optimize the input voltage of the above-mentioned DAB converter topology circuit until the values ​​of the above-mentioned adjacent overall loss functions are the same.

[0073] In the above steps, a total loss function is constructed based on the total loss, the independent variable of the total loss function is the ratio of the input voltage to the product of the output voltage of the DAB converter topology circuit, the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit, and the values ​​of the total loss function corresponding to the independent variables collected twice adjacently are compared, and the independent variables are increased or decreased to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit, until the values ​​of the adjacent total loss functions are the same, so that It directly reflects the power situation, and the result is closest to the optimization of the highest efficiency. By controlling the input voltage of the DAB converter topology circuit and then controlling the loss, the loss optimization can be achieved when the voltage at one end is fixed and the voltage at the other end is adjustable, thereby achieving the purpose of improving efficiency. Compared with the existing scheme, it can find the input voltage with the lowest loss in a shorter time, thereby solving the optimization control of the phase shift angle in the existing scheme, but it is not applicable to the situation where one end of the input and output voltage is uncertain, and the existing schemes are mostly manually calibrated, which leads to the problem of low optimization efficiency of the input voltage of the DAB converter topology circuit. It is based on switching devices with smaller switching losses and is closer to the simulation model of wide bandgap devices.

[0074] In one embodiment of the present application, comparing the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, and increasing or decreasing the independent variables, includes:

[0075] When the value of the overall loss function corresponding to the independent variable collected for the nth time is less than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is greater than the independent variable for the n-1th time, increase the independent variable;

[0076] When the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the nth time is smaller than the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the n-1th time, and the above-mentioned independent variable for the nth time is smaller than the above-mentioned independent variable for the n-1th time, reduce the above-mentioned independent variable;

[0077] When the value of the overall loss function corresponding to the independent variable collected for the nth time is greater than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is less than the independent variable for the n-1th time, reduce the independent variable;

[0078] When the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the nth time is greater than the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the n-1th time, and the above-mentioned independent variable for the nth time is greater than the above-mentioned independent variable for the n-1th time, increase the above-mentioned independent variable.

[0079] Specifically, when the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the nth time is equal to the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the n-1th time, the input voltage is obtained according to the current independent variable, and the input voltage is the optimal input voltage. Since the output voltage and the transformation ratio are fixed, the input voltage can be directly obtained from the independent variable.

[0080] By comparing the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the nth time with the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the n-1th time, and also comparing the above-mentioned independent variable for the nth time with the above-mentioned independent variable for the n-1th time, the adjustment of the independent variable can be made more in line with the actual working conditions.

[0081] In one embodiment of the present application, increasing the independent variable includes: updating the independent variable of the nth time to the sum of the absolute value of the difference between the independent variable of the n-1th time and the independent variable, the absolute value of the difference between the independent variable is the absolute value of the difference between the independent variable of the nth time and the independent variable of the n-1th time;

[0082] Reducing the independent variable includes: updating the independent variable of the nth time to the difference between the independent variable of the n-1th time and the absolute value of the difference between the independent variable.

[0083] Specifically, when increasing the above-mentioned independent variable, the above-mentioned independent variable of the nth time is updated to the sum of the absolute values ​​of the above-mentioned independent variable and the difference between the independent variables of the n-1th time; when decreasing the above-mentioned independent variable, the above-mentioned independent variable of the nth time is updated to the difference between the absolute values ​​of the above-mentioned independent variable and the difference between the independent variables of the n-1th time, thereby making the optimization process of the input voltage more in line with the actual working conditions.

[0084] The important nodes in the charging process of the charging pile are simulated and analyzed on Simulink, and the main circuit parameters are shown in Table 1.

[0085] Table 1

[0086]

[0087]

[0088] In the above loss comparison process, the loss is compared with the loss after the last stabilization, and the comparison result is used as the basis for voltage change, that is, the basis for the change of the independent variable. In order to find the stabilization time, the voltage is first kept unchanged for simulation, such as Figure 3 As shown, the power reaches stability at 0.025s when the single power is detected, so 0.025s is used as the loss selection point for the above loss comparison.

[0089] Figure 4 The polyline Figure 3 The points correspond to the constant current stage, constant voltage stage, and trickle current stage of the three-stage charging. It can be seen that the simulated loss almost coincides with the expected loss, verifying the correctness of the calculation.

[0090] The power corresponding to the power consumption point in each stage is calculated and represented as the power of the entire stage, as shown in Table 2.

[0091] Table 2

[0092] <![CDATA[K0]]> <![CDATA[P0]]> <![CDATA[K1]]> <![CDATA[P1]]> Constant current stage 1.26 843.5 1 1053.9 Constant pressure stage 1.12 584.5 1 628.9 Trickle stage 0.98 27.2 1 27.9

[0093] Among them, K0 represents the optimized voltage ratio, K1 represents the unoptimized voltage ratio, and it is fixed to 1. Taking a 60Kwh battery as an example, the state of charge (SOC) between 0 and 75% represents the constant current stage, 75% to 98% represents the constant voltage stage, 98% to 100% represents the trickle stage, P0 is the optimized power loss, and P1 is the power loss when the voltage ratio is constant at 1.

[0094] SOC=SOC0+(∫E·Idt) / W;

[0095] Among them, SOC0 is the initial SOC value, t is the time, W is the battery capacity, E and I represent the output voltage effective value and current effective value respectively. According to the expression of SOC and the power of each stage, the duration of each state can be calculated: the constant current stage 18000w lasts for 9000s, the constant voltage stage 17500w lasts for 2838s, and the trickle stage 1800w lasts for 2880s. Finally, the optimized power loss is 2.59Kwh, accounting for 4.32% of the total power, and the unoptimized power loss is 3.15Kwh, accounting for 5.26%. It can be seen that the optimized power loss is reduced by 17.8%.

[0096] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the method for optimizing the input voltage of the DAB converter topology circuit of the present application will be described in detail below in conjunction with specific embodiments.

[0097] This embodiment relates to a specific method for optimizing the input voltage of a DAB converter topology circuit. Figure 5 As shown, including:

[0098] Obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the overall loss being the sum of the conduction loss of all switch tubes in the DAB converter topology circuit, the switching loss of all switch tubes, the iron loss of the transformer in the DAB converter topology circuit, and the copper loss of the transformer in the DAB converter topology circuit;

[0099] A total loss function is constructed based on the total loss, wherein the independent variable of the total loss function is the ratio of the input voltage to the output voltage product of the DAB converter topology circuit, and the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit;

[0100] When the value of the overall loss function corresponding to the independent variable collected for the nth time is less than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is greater than the independent variable for the n-1th time, increase the independent variable;

[0101] When the overall loss function corresponding to the independent variable collected for the nth time is smaller than the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is smaller than the independent variable for the n-1th time, reduce the independent variable;

[0102] When the value of the overall loss function corresponding to the independent variable collected for the nth time is greater than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is less than the independent variable for the n-1th time, reduce the independent variable;

[0103] When the value of the overall loss function corresponding to the independent variable collected for the nth time is greater than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is greater than the independent variable for the n-1th time, increase the independent variable;

[0104] When the value of the overall loss function corresponding to the independent variable collected for the nth time is equal to the value of the overall loss function corresponding to the independent variable collected for the (n-1)th time, the input voltage is obtained according to the current independent variable, and the input voltage is the optimal input voltage.

[0105] Wherein, increasing the independent variable includes: updating the n-th independent variable to the sum of the absolute values ​​of the difference between the n-1-th independent variable and the independent variable, the absolute value of the difference between the independent variable is the absolute value of the difference between the n-th independent variable and the n-1-th independent variable;

[0106] Reducing the independent variable includes: updating the n-th independent variable to the difference between the n-1-th independent variable and the absolute value of the difference between the independent variables.

[0107] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0108] The embodiment of the present application also provides an input voltage optimization device for a DAB converter topology circuit. It should be noted that the input voltage optimization device for a DAB converter topology circuit of the embodiment of the present application can be used to execute the input voltage optimization method for a DAB converter topology circuit provided by the embodiment of the present application. The device is used to implement the above-mentioned embodiments and preferred implementation modes, and those that have been described will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware of a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0109] The following is an introduction to the device for optimizing the input voltage of the DAB converter topology circuit provided in the embodiment of the present application.

[0110] Figure 6 1 is a structural block diagram of an input voltage optimization device for a DAB converter topology circuit provided according to an embodiment of the present application. Figure 6 As shown, the device comprises:

[0111] An acquisition unit 41 is used to acquire the overall loss of the DAB converter topology circuit according to a predetermined time interval, wherein the overall loss is the sum of the conduction loss of all the switch tubes in the DAB converter topology circuit, the switching loss of all the switch tubes, the iron loss of the transformer in the DAB converter topology circuit, and the copper loss of the transformer in the DAB converter topology circuit;

[0112] A first processing unit 42 is used to construct an overall loss function based on the overall loss, wherein the independent variable of the overall loss function is the ratio of the input voltage to the output voltage product of the DAB converter topology circuit, and the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit;

[0113] The second processing unit 43 is used to compare the values ​​of the above-mentioned overall loss function corresponding to the above-mentioned independent variables collected twice adjacently, increase or decrease the above-mentioned independent variables, so as to increase or decrease the input voltage of the above-mentioned DAB converter topology circuit and optimize the input voltage of the above-mentioned DAB converter topology circuit until the values ​​of the above-mentioned adjacent overall loss functions are the same.

[0114] In the above device, a total loss function is constructed based on the above total loss, the independent variable of the above total loss function is the ratio of the input voltage of the above DAB converter topology circuit to the product of the output voltage, the above output voltage product is the product of the output voltage of the above DAB converter topology circuit and the transformation ratio of the transformer in the above DAB converter topology circuit, and the values ​​of the above total loss function corresponding to the above independent variables collected twice adjacently are compared, and the above independent variables are increased or decreased to increase or decrease the input voltage of the above DAB converter topology circuit and optimize the input voltage of the above DAB converter topology circuit until the values ​​of the above adjacent total loss functions are the same, so that It directly reflects the power situation, and the result is closest to the optimization of the highest efficiency. By controlling the input voltage of the DAB converter topology circuit and then controlling the loss, the loss optimization can be achieved when the voltage at one end is fixed and the voltage at the other end is adjustable, thereby achieving the purpose of improving efficiency. Compared with the existing scheme, it can find the input voltage with the lowest loss in a shorter time, thereby solving the optimization control of the phase shift angle in the existing scheme, but it is not applicable to the situation where one end of the input and output voltage is uncertain, and the existing schemes are mostly manually calibrated, which leads to the problem of low optimization efficiency of the input voltage of the DAB converter topology circuit. It is based on switching devices with smaller switching losses and is closer to the simulation model of wide bandgap devices.

[0115] In one embodiment of the present application, the acquisition unit includes a first determination module, and in the process of acquiring the overall loss of the DAB converter topology circuit according to the predetermined time interval, the method further includes:

[0116] The first determination module is used to determine the cond =I rms 2 R on , determine the conduction loss of the above switch tube, where P cond is the conduction loss of the above switch tube, I rms is the effective value of the inductor current, R on is the on-resistance of the switch tube.

[0117] In one embodiment of the present application, the acquisition unit includes a second determination module, in the process of acquiring the overall loss of the DAB converter topology circuit according to a predetermined time interval,

[0118] The second determination module is used to determine the t =(Q oss +Q rr )·V1+V dson ·i Lt0 ·t on ·f+V dsoff ·i Lt2 ·t off f,

[0119] Determine the switching loss of the above switch tube, where P t is the switching loss of the above switch tube, Q oss is the output charge, Q rr is the reverse recovery charge, V1 is the input voltage of the above DAB converter topology circuit, V dson is the voltage before turning on, i Lt0 is the current at the moment of turning on, t on is the opening time, V dsoff is the voltage before shutdown, i Lt2 is the current at the instant of shutoff, t off is the turn-off time, and f is the frequency of the above-mentioned switching tube.

[0120] In one embodiment of the present application, the acquisition unit includes a third determination module, in the process of acquiring the overall loss of the DAB converter topology circuit according to the predetermined time interval,

[0121] The third determination module is used to Determine the iron loss of the above transformer, where P fe is the iron loss of the above transformer, D c is the voltage duty cycle, K, α and β are the corresponding loss coefficients, B m is the maximum magnetic flux density, V ol is the volume of the above transformer, and f is the frequency of the above switching tube.

[0122] In one embodiment of the present application, the acquisition unit includes a fourth determination module, in the process of acquiring the overall loss of the DAB converter topology circuit according to the predetermined time interval,

[0123] The fourth determination module is used to determine the cu =I rms 2 R cu , determine the above transformer copper loss, where P cu is the copper loss of the above transformer, R cu is the winding resistance of the transformer, I rms is the effective value of the inductor current.

[0124] In one embodiment of the present application, the acquisition unit includes a second determination module, in the process of acquiring the overall loss of the DAB converter topology circuit according to a predetermined time interval,

[0125] The second determination module is used to determine the t =(Q oss +Q rr )·V1+V dson ·i Lt0 ·t on·f+V dsoff ·i Lt2 ·t off f,

[0126] Determine the switching loss of the above switch tube, where P t is the switching loss of the above switch tube, Q oss is the output charge, Q rr is the reverse recovery charge, V1 is the input voltage of the above DAB converter topology circuit, V dson is the voltage before turning on, i Lt0 is the current at the moment of turning on, t on is the opening time, V dsoff is the voltage before shutdown, i Lt2 is the current at the instant of shutoff, t off is the turn-off time, and f is the frequency of the above-mentioned switching tube.

[0127] In one embodiment of the present application, the acquisition unit includes a third determination module, in the process of acquiring the overall loss of the DAB converter topology circuit according to the predetermined time interval,

[0128] The third determination module is used to Determine the iron loss of the above transformer, where P fe is the iron loss of the above transformer, D c is the voltage duty cycle, K, α and β are the corresponding loss coefficients, B m is the maximum magnetic flux density, V ol is the volume of the above transformer, and f is the frequency of the above switching tube.

[0129] In one embodiment of the present application, the acquisition unit includes a fourth determination module, in the process of acquiring the overall loss of the DAB converter topology circuit according to the predetermined time interval,

[0130] The fourth determination module is used to determine the cu =I rms 2 R cu , determine the above transformer copper loss, where P cu is the copper loss of the above transformer, R cu is the winding resistance of the transformer, I rms is the effective value of the inductor current.

[0131] In one embodiment of the present application, the second processing unit includes a first processing module, a second processing module, a third processing module and a fourth processing module.

[0132] The first processing module is used to increase the above-mentioned independent variable when the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the nth time is less than the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the n-1th time, and the above-mentioned independent variable for the nth time is greater than the above-mentioned independent variable for the n-1th time;

[0133] The second processing module is used to reduce the independent variable when the overall loss function corresponding to the independent variable collected for the nth time is less than the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is less than the independent variable for the n-1th time;

[0134] The third processing module is used to reduce the above-mentioned independent variable when the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the nth time is greater than the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the n-1th time, and the above-mentioned independent variable for the nth time is less than the above-mentioned independent variable for the n-1th time;

[0135] The fourth processing module is used to increase the above-mentioned independent variable when the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the nth time is greater than the value of the above-mentioned overall loss function corresponding to the above-mentioned independent variable collected for the n-1th time, and the above-mentioned independent variable for the nth time is greater than the above-mentioned independent variable for the n-1th time.

[0136] In one embodiment of the present application, the second processing unit includes a fifth processing module and a sixth processing module, and the fifth processing module is used to update the above-mentioned independent variable for the nth time to the sum of the absolute values ​​of the difference between the above-mentioned independent variable for the n-1th time and the independent variable, and the absolute value of the difference between the above-mentioned independent variable is the absolute value of the difference between the above-mentioned independent variable for the nth time and the above-mentioned independent variable for the n-1th time;

[0137] The sixth processing module is used to update the n-th independent variable to the difference between the independent variable at the (n-1)th time and the absolute value of the difference of the independent variable.

[0138] The above-mentioned device for optimizing the input voltage of the DAB converter topology circuit includes a processor and a memory. The above-mentioned acquisition unit, the first processing unit, the second processing unit, etc. are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize corresponding functions. The above-mentioned modules are all located in the same processor; or, the above-mentioned modules are located in different processors in any combination.

[0139] The processor includes a kernel, and the kernel retrieves the corresponding program unit from the memory. One or more kernels can be set, and the optimization control of the phase shift angle by adjusting the kernel parameters is solved in the existing scheme, but it is not applicable to the case where one end of the input and output voltage is uncertain, and the existing schemes are mostly manually calibrated, which leads to the problem of low optimization efficiency of the input voltage of the DAB converter topology circuit.

[0140] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0141] An embodiment of the present invention provides a computer-readable storage medium, which includes a stored program. When the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method for optimizing the input voltage of the DAB converter topology circuit.

[0142] An embodiment of the present invention provides a processor, and the processor is used to run a program, wherein the program executes the method for optimizing the input voltage of the DAB converter topology circuit when running.

[0143] The embodiment of the present invention provides a device, the device includes a processor, a memory and a program stored in the memory and can be run on the processor, and the processor implements at least the following steps when executing the program: obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the overall loss is the sum of the conduction loss of all the switch tubes in the DAB converter topology circuit, the switching loss of all the switch tubes, the iron loss of the transformer in the DAB converter topology circuit, and the copper loss of the transformer in the DAB converter topology circuit; constructing an overall loss function based on the overall loss, the independent variable of the overall loss function is the ratio of the input voltage of the DAB converter topology circuit to the product of the output voltage, and the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit; comparing the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, increasing or decreasing the independent variables, so as to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit, until the values ​​of the adjacent overall loss functions are the same. The device in this article can be a server, a PC, a PAD, a mobile phone, etc.

[0144] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program that is initialized with at least the following method steps: obtaining the overall loss of the DAB converter topology circuit according to a predetermined time interval, the overall loss being the sum of the conduction loss of all the switch tubes in the DAB converter topology circuit, the switching loss of all the switch tubes, the iron loss of the transformer in the DAB converter topology circuit, and the copper loss of the transformer in the DAB converter topology circuit; constructing an overall loss function based on the overall loss, the independent variable of the overall loss function being the ratio of the product of the input voltage and the output voltage of the DAB converter topology circuit, the output voltage product being the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit; comparing the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, increasing or decreasing the independent variables, so as to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit, until the values ​​of the adjacent overall loss functions are the same.

[0145] According to another aspect of the present application, a system for optimizing the input voltage of a DAB converter topology circuit is provided, the system comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include methods for executing any of the above methods. By constructing an overall loss function based on the overall loss, the independent variable of the overall loss function is the ratio of the product of the input voltage and the output voltage of the DAB converter topology circuit, the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit, and comparing the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, increasing or decreasing the independent variables to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit, until the values ​​of the adjacent overall loss functions are the same, so that the above loss function can be directly reversed. The output power situation is the closest to the optimization of the highest efficiency. By controlling the input voltage of the DAB converter topology circuit and then controlling the loss, the loss optimization can be achieved when the voltage at one end is fixed and the voltage at the other end is adjustable, thereby achieving the purpose of improving efficiency. Compared with the existing scheme, the input voltage with the lowest loss can be found in a shorter time, thereby solving the optimization control of the phase shift angle by the existing scheme, but it is not applicable to the situation where one end of the input and output voltage is uncertain, and the existing schemes are mostly manually calibrated, which leads to the problem of low optimization efficiency of the input voltage of the DAB converter topology circuit. The simulation model is closer to the wide bandgap device based on the switching device with smaller switching loss.

[0146] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0147] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0148] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0149] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0150] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0151] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0152] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0153] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0154] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0155] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0156] 1) The method for optimizing the input voltage of the DAB converter topology circuit of the present application is to construct an overall loss function based on the overall loss, wherein the independent variable of the overall loss function is the ratio of the input voltage to the output voltage product of the DAB converter topology circuit, and the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit, and compare the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, increase or decrease the independent variables, so as to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit, until the adjacent overall loss function is obtained. Until the values ​​are the same, the power situation can be directly reflected, and the result is closest to the optimization of the highest efficiency. By controlling the input voltage of the DAB converter topology circuit and then controlling the loss, the loss optimization can be achieved when the voltage at one end is fixed and the voltage at the other end is adjustable, thereby achieving the purpose of improving efficiency. Compared with the existing scheme, the input voltage with the lowest loss can be found in a shorter time, thereby solving the optimization control of the phase shift angle by the existing scheme, but it is not applicable to the situation where one end of the input and output voltage is uncertain, and the existing schemes are mostly manually calibrated, which leads to the problem of low optimization efficiency of the input voltage of the DAB converter topology circuit. The simulation model is closer to the wide bandgap device based on the switching device with smaller switching loss.

[0157] 2) The device for optimizing the input voltage of the DAB converter topology circuit of the present application constructs an overall loss function based on the overall loss, wherein the independent variable of the overall loss function is the ratio of the input voltage to the product of the output voltage of the DAB converter topology circuit, and the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit, and compares the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, increases or decreases the independent variables, so as to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit, until the adjacent overall loss function is obtained. Until the values ​​are the same, the power situation can be directly reflected, and the result is closest to the optimization of the highest efficiency. By controlling the input voltage of the DAB converter topology circuit and then controlling the loss, the loss optimization can be achieved when the voltage at one end is fixed and the voltage at the other end is adjustable, thereby achieving the purpose of improving efficiency. Compared with the existing scheme, the input voltage with the lowest loss can be found in a shorter time, thereby solving the optimization control of the phase shift angle by the existing scheme, but it is not applicable to the situation where one end of the input and output voltage is uncertain, and the existing schemes are mostly manually calibrated, which leads to the problem of low optimization efficiency of the input voltage of the DAB converter topology circuit. The simulation model is closer to the wide bandgap device based on the switching device with smaller switching loss.

[0158] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for optimizing the input voltage of a DAB converter topology circuit, characterized in that: include: Acquire the overall loss of the DAB converter topology circuit according to a predetermined time interval, wherein the overall loss is the sum of the conduction loss of all the switch tubes in the DAB converter topology circuit, the switching loss of all the switch tubes, the iron loss of the transformer in the DAB converter topology circuit, and the copper loss of the transformer in the DAB converter topology circuit; Constructing an overall loss function based on the overall loss, wherein the independent variable of the overall loss function is the ratio of the input voltage to the output voltage product of the DAB converter topology circuit, and the output voltage product is the product of the output voltage of the DAB converter topology circuit and the transformation ratio of the transformer in the DAB converter topology circuit; Compare the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, increase or decrease the independent variable, so as to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit, until the values ​​of the adjacent overall loss functions are the same.

2. The method according to claim 1, characterized in that In the process of obtaining the overall loss of the DAB converter topology circuit according to the predetermined time interval, the method further includes: According to P cond =I rms 2 R on , determine the conduction loss of the switch tube, where P cond is the conduction loss of the switch tube, I rms is the effective value of the inductor current, R on is the on-resistance of the switch tube.

3. The method according to claim 1, characterized in that In the process of obtaining the overall loss of the DAB converter topology circuit according to the predetermined time interval, the method further includes: According to P t =(Q oss +Q rr )·V1+V dson ·i Lt0 ·t on ·f+V dsoff ·i Lt2 ·t off f, Determine the switching loss of the switch tube, where P t is the switching loss of the switch tube, Q oss is the output charge, Q rr is the reverse recovery charge, V1 is the input voltage of the DAB converter topology circuit, V dson is the voltage before turning on, i Lt0 is the current at the moment of turning on, t on is the opening time, V dsoff is the voltage before shutdown, i Lt2 is the current at the instant of shutoff, t off is the turn-off time, and f is the frequency of the switching tube.

4. The method according to claim 1, characterized in that: In the process of obtaining the overall loss of the DAB converter topology circuit according to the predetermined time interval, the method further includes: according to Determine the transformer iron loss, where P fe is the transformer iron loss, D c is the voltage duty cycle, K, α and β are the corresponding loss coefficients, B m is the maximum magnetic flux density, V ol is the volume of the transformer, and f is the frequency of the switching tube.

5. The method according to claim 1, characterized in that In the process of obtaining the overall loss of the DAB converter topology circuit according to the predetermined time interval, the method further includes: According to P cu =I rms 2 R cu , determine the transformer copper loss, where P cu is the transformer copper loss, R cu is the winding resistance of the transformer, I rms is the effective value of the inductor current.

6. The method according to claim 1, characterized in that Comparing the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, and increasing or decreasing the independent variables, comprises: When the value of the overall loss function corresponding to the independent variable collected for the nth time is less than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is greater than the independent variable for the n-1th time, increase the independent variable; When the overall loss function corresponding to the independent variable collected for the nth time is smaller than the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is smaller than the independent variable for the n-1th time, reduce the independent variable; When the value of the overall loss function corresponding to the independent variable collected for the nth time is greater than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is less than the independent variable for the n-1th time, reduce the independent variable; When the value of the overall loss function corresponding to the independent variable collected for the nth time is greater than the value of the overall loss function corresponding to the independent variable collected for the n-1th time, and the independent variable for the nth time is greater than the independent variable for the n-1th time, increase the independent variable.

7. The method according to any one of claims 1 to 6, characterized in that Increasing the independent variable comprises: updating the n-th independent variable to the sum of the absolute values ​​of the independent variable and the independent variable difference at the n-1th time, wherein the absolute value of the independent variable difference is the absolute value of the difference between the n-th independent variable and the n-1th independent variable; Reducing the independent variable includes: updating the independent variable of the nth time to the difference between the independent variable of the n-1th time and the absolute value of the difference of the independent variable.

8. A device for optimizing input voltage of a DAB converter topology circuit, characterized in that: include: An acquisition unit, configured to acquire an overall loss of a DAB converter topology circuit according to a predetermined time interval, wherein the overall loss is the sum of conduction losses of all switch tubes in the DAB converter topology circuit, switching losses of all switch tubes, iron losses of transformers in the DAB converter topology circuit, and copper losses of transformers in the DAB converter topology circuit; A first processing unit is used to construct an overall loss function based on the overall loss, wherein the independent variable of the overall loss function is a ratio of an input voltage to an output voltage product of the DAB converter topology circuit, and the output voltage product is a product of an output voltage of the DAB converter topology circuit and a transformation ratio of a transformer in the DAB converter topology circuit; The second processing unit is used to compare the values ​​of the overall loss function corresponding to the independent variables collected twice adjacently, increase or decrease the independent variable, so as to increase or decrease the input voltage of the DAB converter topology circuit and optimize the input voltage of the DAB converter topology circuit until the values ​​of the adjacent overall loss functions are the same.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method according to any one of claims 1 to 7.

10. A system for optimizing input voltage of a DAB converter topology circuit, characterized in that: include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include methods for executing any one of claims 1 to 7.

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