Control method of DAB converter and related equipment

Abstract

The invention relates to the technical field of electronic power, and provides a DAB converter control method and related equipment, and the method comprises the steps: obtaining an input voltage and an output voltage of a DAB converter; determining a phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the expected output voltage; calculating a voltage transmission ratio of the DAB converter according to the input voltage and the output voltage; the phase shift angle and the voltage transmission ratio are input into an optimization control law formula for calculation, a voltage matching coefficient of a clamping capacitor in the DAB converter is obtained, and the duty ratio of the low-voltage side and the duty ratio of the high-voltage side of the DAB converter are calculated based on the voltage matching coefficient and the voltage transmission ratio; and generating a driving signal of each switching tube in the DAB converter according to the duty ratio of the low-voltage side, the duty ratio of the high-voltage side and the phase shift angle, and controlling the on-off of the corresponding switching tube by using each driving signal. According to the method, the efficiency of the DAB converter can be improved.

Description

Technical Field

[0001] This application relates to the technical field of electronic power, and particularly relates to a control method for a DAB converter and related devices. Background Art

[0002] According to the connection mode of the input / output ports, the dual active bridge (DAB) converter can be divided into a voltage type and a current type. Compared with the voltage-type DAB converter, the current-source DAB converter is more suitable for energy storage systems because it has a DC inductor that can suppress high-frequency current ripples. In traditional current-source DAB converters, to ensure equal power sharing among multiple DC inductors, an additional current sampling circuit and current sharing compensation are often required in the control loop. Through the improvement of the circuit structure, the push-pull current-source DAB converter only requires a single DC inductor, which not only reduces the number of magnetic components required but also avoids the problem of current sharing among multiple DC inductors. However, when facing the working requirement of a wide voltage range, the push-pull current-source DAB converter has the problem that it is difficult to improve the efficiency under traditional voltage matching control. Summary of the Invention

[0003] This application provides a control method for a DAB converter and related devices, which can solve the problem that it is difficult to improve the efficiency of the push-pull current-source DAB converter.

[0004] In a first aspect, an embodiment of this application provides a control method for a DAB converter. The control method includes:

[0005] Obtain the input voltage and output voltage of the DAB converter;

[0006] Determine the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the desired output voltage;

[0007] Calculate the voltage transfer ratio of the DAB converter according to the input voltage and output voltage;

[0008] Input the phase shift angle and the voltage transfer ratio into the optimization control law formula for calculation to obtain the voltage matching coefficient of the clamping capacitor in the DAB converter, and deduce the duty ratio of the low-voltage side and the duty ratio of the high-voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio; the optimization control law formula is used to describe the relationship between the phase shift angle, the voltage transfer ratio, and the voltage matching coefficient;

[0009] Generate drive signals for each switch tube in the DAB converter according to the duty ratio of the low-voltage side, the duty ratio of the high-voltage side, and the phase shift angle, and use each drive signal to control the on / off of the corresponding switch tube.

[0010] Optionally, determining the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the desired output voltage includes:

[0011] Calculating the difference between the output voltage and the desired output voltage;

[0012] Processing the difference using a PI regulator to obtain a control quantity;

[0013] Performing a limit processing on the control quantity to obtain the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter.

[0014] Optionally, calculating the voltage transfer ratio of the DAB converter according to the input voltage and the output voltage includes:

[0015] Obtaining the turns ratio of the high-frequency transformer in the DAB converter;

[0016] Calculating the voltage transfer ratio of the DAB converter according to the input voltage, the output voltage, and the turns ratio of the high-frequency transformer.

[0017] Optionally, calculating the voltage transfer ratio of the DAB converter according to the input voltage, the output voltage, and the turns ratio of the high-frequency transformer includes:

[0018] Through the formula:

[0019]

[0020] Calculating the voltage transfer ratio k;

[0021] Wherein, V1 represents the input voltage, V2 represents the output voltage, and n represents the turns ratio of the high-frequency transformer.

[0022] Optionally, the optimized control law formula is:

[0023]

[0024] Wherein, M OptimumLaw represents the voltage matching coefficient of the clamping capacitor in the DAB converter, a Z_1 represents the first coordinate of the Zth intersection point required for designing the linear optimized control law formula when k < 2, b Z_1 represents the second coordinate of the Zth intersection point required for designing the linear optimized control law formula when k < 2, a Z-1_1 represents the first coordinate of the (Z - 1)th intersection point required for designing the linear optimized control law formula when k < 2, b Z-1_1 represents the second coordinate of the (Z - 1)th intersection point required for designing the linear optimized control law formula when k < 2, a Z_2 represents the first coordinate of the Zth intersection point required for designing the linear optimized control law formula when k ≥ 2, b Z_2Denotes the second coordinate of the Z-th intersection point required for designing the linear optimal control law when k ≥ 2, a Z-1_2 Denotes the first coordinate of the (Z - 1)-th intersection point required for designing the linear optimal control law when k ≥ 2, b Z-1_2 Denotes the second coordinate of the (Z - 1)-th intersection point required for designing the linear optimal control law when k ≥ 2 Denotes the phase shift angle, Z = 2, 3, 4:

[0025]

[0026] Wherein, a 1_1 Denotes the first coordinate of the first intersection point when k < 2, b 1_1 Denotes the second coordinate of the first intersection point when k < 2, a 2_1 Denotes the first coordinate of the second intersection point when k < 2, b 2_1 Denotes the second coordinate of the second intersection point when k < 2, a 3_1 Denotes the first coordinate of the third intersection point when k < 2, b 3_1 Denotes the second coordinate of the third intersection point when k < 2, a 4_1 Denotes the first coordinate of the fourth intersection point when k < 2, b 4_1 Denotes the second coordinate of the fourth intersection point when k < 2, a 1_2 Denotes the first coordinate of the first intersection point when k ≥ 2, b 1_2 Denotes the second coordinate of the first intersection point when k ≥ 2, a 2_2 Denotes the first coordinate of the second intersection point when k ≥ 2, b 2_2 Denotes the second coordinate of the second intersection point when k ≥ 2, a 3_2 Denotes the first coordinate of the third intersection point when k ≥ 2, b 3_2 Denotes the second coordinate of the third intersection point when k ≥ 2, a 4_2 Denotes the first coordinate of the fourth intersection point when k ≥ 2, v 4_2 Denotes the second coordinate of the fourth intersection point when k ≥ 2

[0027] Optionally, the duty ratios of the low-voltage side and the high-voltage side of the DAB converter are deduced based on the voltage matching coefficient and the voltage transfer ratio, including:

[0028] By the formula:

[0029]

[0030] Calculate the duty ratio D of the low-voltage side p And the duty ratio D of the high-voltage side s ;

[0031] Wherein, M OptimumLawrepresents the voltage matching coefficient, and k represents the voltage transfer ratio.

[0032] Optionally, drive signals for each switching tube in the DAB converter are generated based on the duty cycle of the low-voltage side, the duty cycle of the high-voltage side, and the phase shift angle, including:

[0033] Generate drive signals for each switching tube on the low-voltage side of the DAB converter using the duty cycle of the low-voltage side and the phase shift angle;

[0034] Generate drive signals for each switching tube on the high-voltage side of the DAB converter using the duty cycle of the high-voltage side and the phase shift angle.

[0035] In a second aspect, an embodiment of the present application provides a control device for a DAB converter, including:

[0036] An acquisition module for acquiring the input voltage and output voltage of the DAB converter;

[0037] A determination module for determining the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the desired output voltage;

[0038] A calculation module for calculating the voltage transfer ratio of the DAB converter according to the input voltage and the output voltage;

[0039] An extrapolation module for inputting the phase shift angle and the voltage transfer ratio into the optimization control law formula for calculation to obtain the voltage matching coefficient of the clamping capacitor in the DAB converter, and extrapolating the duty cycle of the low-voltage side and the duty cycle of the high-voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio; the optimization control law formula is used to describe the relationship between the phase shift angle, the voltage transfer ratio, and the voltage matching coefficient;

[0040] A control module for generating drive signals for each switching tube in the DAB converter according to the duty cycle of the low-voltage side, the duty cycle of the high-voltage side, and the phase shift angle, and controlling the on / off of the corresponding switching tube using each drive signal.

[0041] In a third aspect, an embodiment of the present application provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the control method of the above-mentioned DAB converter is implemented.

[0042] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the control method of the above-mentioned DAB converter is implemented.

[0043] The above solution of the present application has the following beneficial effects:

[0044] In an embodiment of the present application, by obtaining the input voltage and output voltage of the DAB converter, then determining the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the desired output voltage, calculating the voltage transfer ratio of the DAB converter based on the input voltage and output voltage, then inputting the phase shift angle and the voltage transfer ratio into the optimization control law formula for calculation to obtain the voltage matching coefficient of the clamping capacitor in the DAB converter, and inferring the duty ratio of the low-voltage side and the duty ratio of the high-voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio, and finally generating drive signals for each switching tube in the DAB converter according to the duty ratio of the low-voltage side, the duty ratio of the high-voltage side, and the phase shift angle, and controlling the on-off of the corresponding switching tube by using each drive signal. Among them, by using an optimization control law formula that is easy to implement by a digital signal processor and has a low effective current value to calculate the voltage matching coefficient, the accuracy of the voltage matching coefficient can be improved. Generating drive signals for the switching tubes according to the accurate voltage matching coefficient and using the drive signals to control the on-off of the switching tubes in the DAB converter can ensure zero-voltage turn-on in a wide voltage range while effectively reducing the conduction loss of the devices and improving the overall efficiency performance.

[0045] Other beneficial effects of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0047] Figure 1 It is a flowchart of the control method of the DAB converter provided by an embodiment of the present application;

[0048] Figure 2 It is a schematic structural diagram of a push-pull current source DAB converter provided by an embodiment of the present application;

[0049] Figure 3 It is a schematic diagram of working mode one provided by an embodiment of the present application;

[0050] Figure 4 It is a schematic diagram of working mode two provided by an embodiment of the present application;

[0051] Figure 5 It is a schematic diagram of working mode three provided by an embodiment of the present application;

[0052] Figure 6 It is a schematic diagram of working mode four provided by an embodiment of the present application;

[0053] Figure 7 Schematic diagram of the first optimized control law curve provided by an embodiment of the present application;

[0054] Figure 8 Schematic diagram of the second optimized control law curve provided by an embodiment of the present application;

[0055] Figure 9 Schematic diagram of the structure of the control device of the DAB converter provided by an embodiment of the present application;

[0056] Figure 10 Schematic diagram of the structure of the terminal device provided by an embodiment of the present application. Detailed implementation manners

[0057] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0058] It should be understood that when used in the specification and appended claims of the present application, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0059] It should also be understood that the term " / and / " as used in the specification and appended claims of the present application refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0060] As used in the specification and appended claims of the present application, the term "if" can be interpreted as "when...", "once", "in response to determining", or "in response to detecting" according to the context. Similarly, the phrase "if determined" or "if [the described condition or event] is detected" can be interpreted as meaning "once determined", "in response to determining", "once [the described condition or event] is detected", or "in response to detecting [the described condition or event]" according to the context.

[0061] In addition, in the description of the specification and appended claims of the present application, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0062] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized.

[0063] Aiming at the problem that it is difficult to improve the efficiency of the existing push - pull current - source DAB converter, an embodiment of this application provides a control method for a DAB converter. This control method obtains the input voltage and output voltage of the DAB converter, then determines the phase - shift angle between the low - voltage side and the high - voltage side of the DAB converter according to the output voltage and the desired output voltage, calculates the voltage transfer ratio of the DAB converter based on the input voltage and output voltage, then inputs the phase - shift angle and the voltage transfer ratio into the optimization control law formula for calculation to obtain the voltage matching coefficient of the clamping capacitor in the DAB converter, and calculates the duty ratio of the low - voltage side and the duty ratio of the high - voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio. Finally, drive signals for each switching tube in the DAB converter are generated according to the duty ratio of the low - voltage side, the duty ratio of the high - voltage side, and the phase - shift angle, and the on - off of the corresponding switching tube is controlled by using each drive signal. Among them, by using an optimization control law formula that is easy to implement through a digital signal processor and has a low effective current value to calculate the voltage matching coefficient, the accuracy of the voltage matching coefficient can be improved. Generating drive signals for switching tubes according to the accurate voltage matching coefficient and controlling the on - off of switching tubes in the DAB converter by using the drive signals can effectively reduce the conduction loss of devices while ensuring zero - voltage turn - on in a wide voltage range and improve the overall efficiency performance.

[0064] Next, an exemplary description is given of the control method for the DAB converter provided in this application.

[0065] As Figure 1 shown, the control method for the DAB converter provided in this application includes the following steps:

[0066] Step 11, obtain the input voltage and output voltage of the DAB converter.

[0067] The above - mentioned DAB converter is a push - pull current - source DAB converter, and the structure of this DAB converter is as Figure 2 shown, including a low - voltage side, a high - voltage side, and a high - frequency transformer. The low - voltage side includes a first switching tube ( Figure 2 S1 inFigure 2 S2) in, the third switching transistor ( Figure 2 S3) in, the fourth switching transistor ( Figure 2 S4) in, the input power supply ( Figure 2 V1) in, the DC inductor ( Figure 2 L) in, the clamping capacitor ( Figure 2 C in S , the voltage across the clamping capacitor is V C ); the first end of the clamping capacitor is respectively connected to the drain of the first switching transistor and the drain of the third switching transistor, the second end of the clamping capacitor is respectively connected to the negative pole of the input power supply, the source of the second switching transistor, and the source of the fourth switching transistor, the source of the first switching transistor is respectively connected to the same-named end of the first winding ( Figure 2 N1) in of the high-frequency transformer and the drain of the second switching transistor, the source of the third switching transistor is respectively connected to the different-named end of the second winding ( Figure 2 N2) in of the high-frequency transformer and the drain of the fourth switching transistor, the positive pole of the input power supply is connected to the first end of the DC inductor, and the second end of the DC inductor is connected to the different-named end of the first winding and the same-named end of the second winding of the high-frequency transformer.

[0068] The high-voltage side includes a fifth switching transistor ( Figure 2 Q1) in, a sixth switching transistor ( Figure 2 Q2) in, a seventh switching transistor ( Figure 2 Q3) in, an eighth switching transistor ( Figure 2 Q4) in, a filter capacitor ( Figure 2 C2) in, a leakage inductance ( Figure 2 L in k ); the same-named end of the third winding ( Figure 2 N3) in of the high-frequency transformer is connected to the first end of the leakage inductance, the drain of the fifth switching transistor is respectively connected to the drain of the seventh switching transistor and the first end of the filter capacitor, the source of the fifth switching transistor is respectively connected to the second end of the leakage inductance and the drain of the sixth switching transistor, the source of the sixth switching transistor is respectively connected to the source of the eighth switching transistor and the second end of the filter capacitor, the source of the seventh switching transistor is respectively connected to the drain of the eighth switching transistor and the different-named end of the third winding of the high-frequency transformer, and the voltage across the filter capacitor is the output voltage ( Figure 2 V2) in.

[0069] Figure 2 i in L represents the current of the DC inductor, i1 represents the current of the same-named end of the first winding, there are a first point A and a second point B in the low-voltage side to determine its voltage, and the voltage in the middle is the low-voltage side voltage v ab , there are a third point C and a fourth point D in the high-voltage side to determine its voltage, and the voltage in the middle is the high-voltage side voltage v cd, i2 represents the current at the opposite name terminal of the second winding, and i s represents the current at the same name terminal of the third winding. The turns ratio of the high-frequency transformer is: the first winding N1: the second winding N2: the third winding N3 = 1:1:n.

[0070] In some embodiments of the present application, the input voltage and the output voltage can be obtained by using a voltage sensor or the like.

[0071] Step 12: Determine the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the desired output voltage.

[0072] Specifically, calculate the difference between the output voltage and the desired output voltage, then use a PI regulator to process the difference to obtain a control quantity, and finally perform a limiting process on the control quantity to obtain the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter.

[0073] Exemplarily, a limiter can be used to perform a limiting process on the control quantity.

[0074] Step 13: Calculate the voltage transfer ratio of the DAB converter according to the input voltage and the output voltage.

[0075] In some embodiments of the present application, the step of calculating the voltage transfer ratio of the DAB converter according to the input voltage and the output voltage includes:

[0076] The first step: Obtain the turns ratio of the high-frequency transformer in the DAB converter.

[0077] Exemplarily, the turns ratio can be obtained according to the production information of the high-frequency transformer itself or the like.

[0078] The second step: Calculate the voltage transfer ratio of the DAB converter according to the input voltage, the output voltage, and the turns ratio of the high-frequency transformer.

[0079] Specifically, through the formula:

[0080]

[0081] Calculate the voltage transfer ratio k.

[0082] Among them, V1 represents the input voltage, V2 represents the output voltage, and n represents the turns ratio of the high-frequency transformer.

[0083] Step 14: Input the phase shift angle and the voltage transfer ratio into the optimal control law formula for calculation to obtain the voltage matching coefficient of the clamping capacitor in the DAB converter, and deduce the duty cycle of the low-voltage side and the duty cycle of the high-voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio.

[0084] The above optimization control law formula is used to describe the relationship between the phase-shifting angle, the voltage transfer ratio, and the voltage matching coefficient, where the voltage matching coefficient is the voltage matching coefficient of the clamping capacitor.

[0085] Specifically, the optimization control law formula is:

[0086]

[0087] Among them, M OptimumLaw represents the voltage matching coefficient of the clamping capacitor in the DAB converter, and a Z_1 represents the first coordinate of the Z-th intersection point required for designing the linear optimization control law formula when k < 2, where k is the voltage transfer ratio, and b Z_1 represents the second coordinate of the Z-th intersection point required for designing the linear optimization control law formula when k < 2, and a Z-1_1 represents the first coordinate of the (Z - 1)-th intersection point required for designing the linear optimization control law formula when k < 2, and b Z-1_1 represents the second coordinate of the (Z - 1)-th intersection point required for designing the linear optimization control law formula when k < 2, and a Z_2 represents the first coordinate of the Z-th intersection point required for designing the linear optimization control law formula when k ≥ 2, and b Z_2 represents the second coordinate of the Z-th intersection point required for designing the linear optimization control law formula when k ≥ 2, and a Z-1_2 represents the first coordinate of the (Z - 1)-th intersection point required for designing the linear optimization control law formula when k ≥ 2, and b Z-1_2 represents the second coordinate of the (Z - 1)-th intersection point required for designing the linear optimization control law formula when k ≥ 2, represents the phase-shifting angle, and Z = 2, 3, 4:

[0088]

[0089] Among them, a 1_1 represents the first coordinate of the first intersection point when k < 2, and b 1_1 represents the second coordinate of the first intersection point when k < 2, and a 2_1 represents the first coordinate of the second intersection point when k < 2, and b 2_1 represents the second coordinate of the second intersection point when k < 2, and a 3_1 represents the first coordinate of the third intersection point when k < 2, and b 3_1 represents the second coordinate of the third intersection point when k < 2, and a 4_1 represents the first coordinate of the fourth intersection point when k < 2, and b 4_1 represents the second coordinate of the fourth intersection point when k < 2, and a 1_2 represents the first coordinate of the first intersection point when k ≥ 2, and b 1_2 represents the second coordinate of the first intersection point when k ≥ 2,2_2 Represents the first coordinate of the second intersection point when k ≥ 2, b 2_2 Represents the second coordinate of the second intersection point when k ≥ 2, a 3_2 Represents the first coordinate of the third intersection point when k ≥ 2, b 3_2 Represents the second coordinate of the third intersection point when k ≥ 2, a 4_2 Represents the first coordinate of the fourth intersection point when k ≥ 2, b 4_2 Represents the second coordinate of the fourth intersection point when k ≥ 2.

[0090] It should be noted that the value of Z in the above optimized control law formula depends on the relationship between the phase shift angle obtained in step 12 and the first coordinate of the intersection point. For example, when k < 2, the phase shift angle is less than the first coordinate of the second intersection point (a 2_1 ), then the value of Z in the optimized control law formula is 2, and the first intersection point (a 1_1, b 1_1, ) and the second intersection point (a 2_1, b 2_1, ) are used to calculate the voltage matching coefficient of the clamping capacitor. The coordinates of the above intersection points are in a three-dimensional coordinate system. The horizontal axis of this three-dimensional coordinate system is the phase shift angle The vertical axis is the voltage matching coefficient M, and the vertical axis is the per-unit value of the transmission power P _pu , and the intersection points are all on the initial plane of the three-dimensional coordinate system. Since the per-unit value of the transmission power is determined by the phase shift angle and the voltage matching coefficient, only two coordinate values are required on the transmission power surface to determine the power information transmitted by the current DAB converter.

[0091] Exemplarily, the four working modes are respectively: as Figure 3 shown, when D p < 0.5, the first working mode of the DAB converter, Figure 4 shown, D p < 0.5, the second working mode of the DAB converter, Figure 5 shown, D p > 0.5, the third working mode of the DAB converter, Figure 6 shown, D p > 0.5, the fourth working mode of the DAB converter. In Figures 3 to 6 , t0 to t 16 are all time points on a switching cycle, D p *T s is the conduction duration of the second switch tube S2, (1 - D p )*T sis the conduction duration of the first switching transistor S1. The conduction and disconnection conditions of the third switching transistor S3, the fourth switching transistor S4, the fifth switching transistor Q1, the sixth switching transistor Q2, the seventh switching transistor Q3, and the eighth switching transistor Q4 are also shown in the figure. v ab (t) is the curve of the voltage between point A and point B changing with time. v cd (t) is the curve of the voltage between point C and point D changing with time. i L (t) is the curve of the current of the DC inductor changing with time. i s (t) is the curve of the current of the same-named terminal of the third winding changing with time. V2 is the output voltage. V C is the voltage of the clamping capacitor. D p represents the duty cycle of the low-voltage side circuit and is also the duty cycle of the driving signal of the second switching transistor S2.

[0092] It should be noted that Figures 3 to 6 the four operating modes are defined and divided based on the duty cycle of the low-voltage side circuit and the position of the voltage falling edge on both sides of the leakage inductance.

[0093] The steps of calculating the duty cycle of the low-voltage side and the duty cycle of the high-voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio are as follows:

[0094] Through the formula:

[0095]

[0096] Calculate the duty cycle D of the low-voltage side p and the duty cycle D of the high-voltage side s ;

[0097] Among them, M OptimumLaw represents the voltage matching coefficient, and k represents the voltage transfer ratio.

[0098] The following is an exemplary description of the derivation process of the above optimization control law.

[0099] The per-unit value expression of the effective value of the leakage inductance current of the push-pull current source DAB converter in operating mode 1 is:

[0100]

[0101] Among them, I s(rms)case1_pu represents the per-unit value of the effective value of the leakage inductance current of the push-pull current source DAB converter in operating mode 1. I base represents the current reference value. M represents the voltage matching coefficient of the clamping capacitor voltage, k represents the voltage transfer ratio, represents the phase shift angle between the low-voltage side and the high-voltage side.

[0102] Similarly, the per-unit value expression of the leakage inductance current effective value of the converter in operating mode 2 can be obtained as follows:

[0103]

[0104] The per-unit value expression of the leakage inductance current effective value of the converter in operating mode 3 is:

[0105]

[0106] The per-unit value expression of the leakage inductance current effective value of the converter in operating mode 4 is:

[0107]

[0108] Among them, I s(rms)case2_pu , I s(rms)case3_pu and I s(rms)case4_pu represent the per-unit values of the leakage inductance current effective values of the push-pull current source DAB converter under different operating modes.

[0109] Taking the leakage inductance current effective value as the optimization objective to ensure that the converter can maintain a low current effective value within a wide voltage range. However, from the per-unit value expressions of the leakage inductance current effective values under the above different operating modes, it is difficult to directly solve the analytical expression of the lowest current effective value. At the same time, in order to achieve fast operation on a digital signal processor, a multi-segment linear fitting method for the lowest current effective value curve is adopted to design the optimization control law formula. For the two cases of voltage transfer ratio k < 2 and k ≥ 2, a three-segment linear fitting method is adopted, that is, four intersection coordinates are required respectively to determine the control law expressions of the three-segment linear fitting.

[0110] Based on the lowest current effective value curve, the derivation process of the four intersection coordinates required for designing the linear optimization control law formula is as follows.

[0111] In the case of voltage transfer ratio k < 2, four endpoints are required respectively for linear fitting of the optimization control law curve, which are: the first intersection coordinate (a 1_1 , b 1_1 ), the second intersection coordinate (a 2_1 , b 2_1 ), the third intersection coordinate (a 3_1 , b 3_1 ) and the fourth intersection coordinate (a 4_1 , b 4_1 ).

[0112] The first intersection point (a 1_1 , b 1_1 ) represents the operating condition of the converter under no-load conditions, so it is selected as the starting point of the lowest current effective value curve, that is:

[0113]

[0114] The second intersection point (a 2_1 , b 2_1 ) is selected as the intersection point when the curve of the lowest effective current value passes through the boundary line between operating mode 1 and operating mode 2. In order to derive the relationship between the voltage matching coefficient M and the minimum effective current value at this time, it is necessary to substitute the control freedom in the expression (2) of the effective current value in operating mode 2. It can be deduced that the relationship between the per-unit value of the output power and the phase-shift angle and the voltage matching coefficient M of the push-pull current source DAB converter in operating mode 2 is as follows:

[0115]

[0116] where P _pu represents the per-unit value of the output power of the push-pull current source DAB converter.

[0117] Substitute equation (6) into equation (2) to eliminate the phase-shift angle The following expression can be obtained:

[0118]

[0119] where A Eq = (8Mk - 8P _pu Mk 2 - M 2 k 2 - 8) 0.5 .

[0120] Since the second intersection point is located on the boundary line between operating mode 1 and operating mode 2, the following constraint relation is satisfied:

[0121]

[0122] The lowest effective current value must be a stationary point of equation (8). Therefore, the stationary point can be solved, and the per-unit value of the output power term in the stationary point is replaced by the phase-shift angle , and at the same time, equation (9) is used to further replace the phase-shift angle Furthermore, the following expression can be obtained:

[0123]

[0124] It can be seen that it is challenging to solve the analytical formula of the voltage matching coefficient from equation (10). Considering the actual value ranges of M and k, the numerical solution is fitted with a second-order polynomial to obtain the following expression:

[0125] M = 0.529k 2 - 2.234k + 3.355 (11)

[0126] According to Equation (9) and Equation (11), the coordinates of the second intersection point can be obtained as follows:

[0127]

[0128] The third intersection point (a 3_1 , b 3_1 ) is selected as the intersection point when the curve of the minimum effective current passes through the boundary between operating mode 2 and operating mode 4. To derive the relationship between the voltage matching coefficient M and the minimum effective current at this time, it is necessary to replace the control degree of freedom in the expression of the effective current in operating mode 4 (Equation (4)). The per-unit value expression of the transmission power of the above converter in operating mode 4 is:

[0129]

[0130] Substitute Equation (13) into Equation (4) to eliminate the phase-shift angle The following expression can be obtained:

[0131]

[0132] Since the third intersection point is located on the boundary between operating mode 2 and operating mode 4, the following constraint relation is satisfied:

[0133] M = 2 / k (15)

[0134] By solving the stationary point of Equation (14), and using the phase-shift angle to replace the per-unit value term of the output power in the stationary point, and at the same time, using Equation (15) to further replace the voltage matching coefficient M, the following expression can be obtained:

[0135]

[0136] It can be seen that it is difficult to solve the analytical expression of Equation (16). Therefore, the numerical solution is fitted with a second-order polynomial to obtain the following expression:

[0137]

[0138] According to Equation (15) and Equation (17), the coordinates of the third intersection point can be obtained as follows:

[0139]

[0140] The fourth intersection point (a 4_1 , b 4_1) represents the operating condition of the maximum transmission power designed for the converter. Therefore, it is selected as the coordinate point of the lowest root-mean-square current curve at the designed maximum transmission power. Considering comprehensively, the maximum per-unit value of the transmission power is designed as 0.105, that is:

[0141]

[0142] Since the fourth intersection point is located in operating mode four, the root-mean-square current expression (14) of operating mode four can be used to solve for the stationary point. By using the per-unit value term of the power transmission and the phase-shift angle term in the stationary point formula mentioned in Equation (19), the following expression can be obtained:

[0143]

[0144] where B Eq =(200Mk - 21Mk 2 - 25M 2 k 2 - 200) 0.5 .

[0145] It can be seen that there are challenges in solving the analytical expression of Equation (20). Therefore, using polynomial fitting for the numerical solution, the following expression is obtained:

[0146] M = -0.234k + 1.664 (21)

[0147] Substitute Equation (21) into Equation (19), and use polynomial fitting again to obtain the relationship of the phase-shift angle:

[0148]

[0149] According to Equation (21) and Equation (22), the coordinates of the fourth intersection point can be obtained as:

[0150]

[0151] According to the coordinates of the first intersection point (a 1_1 , b 1_1 ), the coordinates of the second intersection point (a 2_1 , b 2_1 ), the coordinates of the third intersection point (a 3_1 , b 3_1 ) and the coordinates of the fourth intersection point (a 4_1 , b 4_1 ), the optimized control law formula after multi-segment linear fitting of the lowest root-mean-square current curve can be obtained:

[0152]

[0153] where M OptimumLaw represents the voltage matching coefficient of the clamped capacitor voltage. represents the phase shift angle between the low-voltage side circuit and the high-voltage side circuit. Z can be selected as 2, 3, or 4, and a Z and b Z respectively represent the coordinates of different linear fitting endpoints.

[0154] When the voltage transfer ratio k≥2, four endpoints are also used to fit the optimal control law curve, which are: the coordinates of the fifth intersection point (a 1_2 , b 1_2 ), the coordinates of the sixth intersection point (a 2_2 , b 2_2 ), the coordinates of the seventh intersection point (a 3_2 , b 3_2 ), and the coordinates of the eighth intersection point (a 4_2 , b 4_2 ).

[0155] The coordinates of the fifth intersection point (a 1_2 , b 1_2 ) represent the no-load condition, so it is selected as the starting point of the lowest effective current curve, that is:

[0156]

[0157] The sixth intersection point (a 2_2 , b 2_2 ) is selected as the intersection point when the lowest effective current curve passes through the boundary between operating mode three and operating mode four. Therefore, it satisfies the following constraint relation:

[0158]

[0159] The effective value of the leakage inductance current at the sixth intersection point satisfies the constraint relation of Equation (14). Therefore, the stationary point can be solved, and at the same time, Equation (26) is used to replace the phase shift angle Furthermore, the following expression can be obtained:

[0160]

[0161] It can be seen that it is challenging to solve the analytical formula of the voltage matching coefficient from Equation (27). Using a second-order polynomial to fit the numerical solution, the following expression is obtained:

[0162] M = -0.135k 2 + 0.55k + 0.439 (28)

[0163] According to Equation (26) and Equation (28), the coordinates of the sixth intersection point can be obtained as:

[0164]

[0165] The seventh intersection point is selected as the midpoint between the sixth and eighth intersection points. Therefore, after obtaining the coordinate information of the sixth and eighth intersection points, the coordinate information of the seventh intersection point can be deduced.

[0166] The eighth intersection point (a 4_2 , b 4_2 ) represents the operating condition of the maximum transmission power designed for the converter. To ensure smooth switching of the optimal control law at different voltage transfer ratios, the per-unit value of the transmission power at the eighth intersection point is designed to be 0.105.

[0167] Meanwhile, the eighth intersection point is also within the region of operating mode four. Therefore, the coordinates of the eighth intersection point can be expressed as:

[0168]

[0169] The seventh intersection point (a 3_2 , b 3_2 ) is selected as the midpoint between the sixth and eighth intersection points and satisfies the following constraint relations:

[0170]

[0171] The seventh intersection point is within the region of operating mode four, so the effective value of its leakage inductance current satisfies the constraint relation of Equation (14). Therefore, by solving the stationary point of Equation (14), substituting it into Equation (31) to replace the voltage matching coefficient M term, and finally using polynomial fitting for the numerical solution, the following expression can be obtained:

[0172]

[0173] According to Equation (31) and Equation (32), the coordinates of the seventh intersection point can be obtained as:

[0174]

[0175] Based on the coordinates of the fifth intersection point (a 1_2 , b 1_2 ), the sixth intersection point (a 2_2 , b 2_2 ), the seventh intersection point (a 3_2 , b 3_2 ) and the eighth intersection point (a 4_2 , b 4_2 ), the optimized control law formula for linear fitting can be obtained when the voltage transfer ratio k≥2:

[0176]

[0177] Combining the above expressions, the optimized linear control law expression based on the curve of the lowest effective current value can be obtained as:

[0178]

[0179] Among them, M OptimumLaw represents the voltage matching coefficient of the clamped capacitor voltage, represents the phase shift angle between the low-voltage side circuit and the high-voltage side circuit. Z can be selected as 2, 3, or 4. a Z and b Z respectively represent the expressions of different intersection points, as follows:

[0180]

[0181] Selecting Equation (35) as the control curve of the push-pull current source DAB converter can achieve the effect of low effective current within a wide voltage range. At the same time, this control curve is easy to implement through a digital signal processor.

[0182] When the voltage transfer ratio k < 2, according to the first intersection point coordinates (a 1_1 , b 1_1 ), the second intersection point coordinates (a 2_1 , b 2_1 ), the third intersection point coordinates (a 3_1 , b 3_1 ), and the fourth intersection point coordinates (a 4_1 , b 4_1 ), the optimized control law curve obtained by multi-segment linear fitting is as shown in Figure 7 . When the voltage transfer ratio k ≥ 2, according to the fifth intersection point coordinates (a 1_2 , b 1_2 ), the sixth intersection point coordinates (a 2_2 , b 2_2 ), the seventh intersection point coordinates (a 3_2 , b 3_2 ), and the eighth intersection point coordinates (a 4_2 , b 4_2 ), the optimized control law curve obtained by multi-segment linear fitting is as shown in Figure 8 . Figure 7 and Figure 8 The three axes in represent the phase shift angle between the low-voltage side circuit and the high-voltage side circuit, the voltage matching coefficient M, and the per-unit value P _pu of the transmission power. ① represents operating mode 1, ② represents operating mode 2, ③ represents operating mode 3, and ④ represents operating mode 4.

[0183] Step 15: Generate drive signals for each switch tube in the DAB converter according to the duty ratio of the low-voltage side, the duty ratio of the high-voltage side, and the phase shift angle, and use each drive signal to control the on and off of the corresponding switch tube.

[0184] Specifically, the duty cycle and phase shift angle on the low-voltage side are used to generate the drive signals for each switch tube on the low-voltage side of the DAB converter (i.e., Figure 2 S1, S2, S3, and S4 in Figure 2 ), and the duty cycle and phase shift angle on the high-voltage side are used to generate the drive signals for each switch tube on the high-voltage side of the DAB converter (i.e.,

[0185] Q1, Q2, Q3, and Q4 in

[0186] ). Finally, for each switch tube respectively, the on / off of the switch tube is controlled using the drive signal corresponding to the switch tube. Figures 3 to 6 It can be seen that in the DAB converter as shown in Figure 2 , the drive signals of the first switch tube S1 and the second switch tube S2 are complementary, the drive signals of the third switch tube S3 and the fourth switch tube S4 are complementary, the drive signals of the fifth switch tube Q1 and the sixth switch tube Q2 are complementary, and the drive signals of the seventh switch tube Q3 and the eighth switch tube Q4 are complementary; the duty cycle of the drive signals of the first switch tube S1, the second switch tube S2, the third switch tube S3, and the fourth switch tube S4 is determined by the duty cycle of the low-voltage side circuit. At the same time, the drive signal of the first switch tube S1 leads the drive signal of the third switch tube S3 by half a switching cycle time, and the drive signal of the second switch tube S2 leads the drive signal of the fourth switch tube S4 by half a switching cycle time; the drive signals of the fifth switch tube Q1, the sixth switch tube Q2, the seventh switch tube Q3, and the eighth switch tube Q4 are all 50% square wave signals; the lead of the drive signal of the second switch tube S2 over the drive signal of the seventh switch tube Q3 is controlled by both the phase shift angle and the duty cycle of the low-voltage side circuit; the lead of the drive signal of the sixth switch tube Q2 over the drive signal of the seventh switch tube Q3 is controlled by the duty cycle of the high-voltage side circuit.

[0187] Therefore, after obtaining the duty cycle of the low-voltage side circuit, a driving signal for controlling the second switch tube S2 can be generated through a unipolar carrier modulation method and a PWM generation circuit. According to the relationship that the driving signal of the second switch tube S2 leads the driving signal of the fourth switch tube S4 by half a switching cycle time, a driving signal for the fourth switch tube S4 is generated. Then, according to the complementary relationship between the driving signal of the first switch tube S1 and the driving signal of the second switch tube S2, and the complementary relationship between the driving signal of the third switch tube S3 and the driving signal of the fourth switch tube S4, driving signals for the first switch tube S1 and the third switch tube S3 are generated. According to the driving signal of the second switch tube S2, the duty cycle of the low-voltage side circuit, and the phase shift angle between the driving signal of the second switch tube S2 and the driving signal of the seventh switch tube Q3, a driving signal for the seventh switch tube Q3 is generated. According to the duty cycle of the high-voltage side circuit and the driving signal of the seventh switch tube Q3, a driving signal for the sixth switch tube Q2 can be generated. Then, according to the complementary relationship between the driving signal of the fifth switch tube Q1 and the driving signal of the sixth switch tube Q2, and the complementary relationship between the driving signal of the eighth switch tube Q4 and the driving signal of the seventh switch tube Q3, driving signals for the fifth switch tube Q1 and the eighth switch tube Q4 are generated.

[0188] In some embodiments of the present application, since the driving signal of the second switch tube S2 leads the driving signal of the fourth switch tube S4 by half a switching cycle time, after obtaining the driving signal of the second switch tube S2, the driving signal of the fourth switch tube S4 can be obtained. At the same time, since the driving signals of the first switch tube S1 and the second switch tube S2 are complementary, and the driving signals of the third switch tube S3 and the fourth switch tube S4 are complementary, the driving signals of the first switch tube S1 and the third switch tube S3 can be obtained.

[0189] In some embodiments of the present application, since the driving signal of the fifth switch tube Q1 and the driving signal of the sixth switch tube Q2 are complementary, and the driving signal of the eighth switch tube Q4 and the driving signal of the seventh switch tube Q3 are complementary, after obtaining the driving signals of the sixth switch tube Q2 and the seventh switch tube Q3, based on the complementary relationship, the driving signals of the fifth switch tube Q1 and the eighth switch tube Q4 can be obtained. The driving signal of the sixth switch tube Q2 is generated according to the duty cycle of the high-voltage side circuit and the driving signal of the seventh switch tube Q3. The driving signal of the seventh switch tube Q3 is generated according to the driving signal of the second switch tube S2, the duty cycle of the low-voltage side circuit, and the phase shift angle between the driving signal of the second switch tube S2 and the driving signal of the seventh switch tube Q3.

[0190] It is worth mentioning that by optimizing the control law formula to calculate the voltage matching coefficient, the accuracy of the voltage matching coefficient can be improved. Generating the driving signal of the switch according to the accurate voltage matching coefficient and using the driving signal to control the on / off of the switch tube in the DAB converter can effectively reduce the conduction loss of the device and improve the overall efficiency performance.

[0191] An exemplary description of the control device for the DAB converter provided by the present application will be given below.

[0192] As Figure 9 shown, an embodiment of the present application provides a control device for a DAB converter. The control device 900 includes:

[0193] An acquisition module 901, configured to acquire the input voltage and output voltage of the DAB converter;

[0194] A determination module 902, configured to determine the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the desired output voltage;

[0195] A calculation module 903, configured to calculate the voltage transfer ratio of the DAB converter according to the input voltage and the output voltage;

[0196] An extrapolation module 904, configured to input the phase shift angle and the voltage transfer ratio into an optimal control law formula for calculation to obtain the voltage matching coefficient of the clamping capacitor in the DAB converter, and extrapolate the duty cycle of the low-voltage side and the duty cycle of the high-voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio; the optimal control law formula is used to describe the relationship between the phase shift angle, the voltage transfer ratio and the voltage matching coefficient;

[0197] A control module 905, configured to generate drive signals for each switch tube in the DAB converter according to the duty cycle of the low-voltage side, the duty cycle of the high-voltage side, and the phase shift angle, and control the on / off of the corresponding switch tube by using each drive signal.

[0198] It should be noted that for the information interaction, execution process, etc. between the above-mentioned device / units, since they are based on the same concept as the method embodiment of the present application, the specific functions and the technical effects brought thereby can be specifically referred to the method embodiment part, and will not be elaborated here.

[0199] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the above-mentioned division of each functional unit and module is used for illustration. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiment and will not be elaborated here.

[0200] like Figure 10 As shown, an embodiment of the present application provides a terminal device. The terminal device D10 of this embodiment includes: at least one processor D100 ( Figure 10 Only one processor is shown in the figure), a memory D101, and a computer program D102 stored in the memory D101 and executable on the at least one processor D100, wherein the processor D100 implements the steps of any of the above-mentioned method embodiments when executing the computer program D102.

[0201] Specifically, when the processor D100 executes the computer program D102, the input voltage and output voltage of the DAB converter are obtained, and then the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter is determined according to the output voltage and the expected output voltage, and then the voltage transfer ratio of the DAB converter is calculated according to the input voltage and the output voltage, and then the phase shift angle and the voltage transfer ratio are input into the optimization control law for calculation to obtain the voltage matching coefficient of the clamping capacitor in the DAB converter, and the duty cycle of the low-voltage side and the duty cycle of the high-voltage side of the DAB converter are calculated based on the voltage matching coefficient and the voltage transfer ratio, and finally the driving signal of each switch tube in the DAB converter is generated according to the duty cycle of the low-voltage side, the duty cycle of the high-voltage side, and the phase shift angle, and each driving signal is used to control the on and off of the corresponding switch tube. Among them, by calculating the voltage matching coefficient using an optimized control law that is easy to implement through a digital signal processor and has a low current effective value, the accuracy of the voltage matching coefficient can be improved, and a driving signal of the switching tube is generated according to the accurate voltage matching coefficient. The driving signal is used to control the on and off of the switching tube in the DAB converter, which can effectively reduce the device conduction loss while ensuring zero voltage turn-on in a wide voltage range, thereby improving the overall efficiency performance.

[0202] The processor D100 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0203] In some embodiments, the memory D101 may be an internal storage unit of the terminal device D10, such as the hard disk or memory of the terminal device D10. In some other embodiments, the memory D101 may also be an external storage device of the terminal device D10, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the terminal device D10. Further, the memory D101 may also include both the internal storage unit and the external storage device of the terminal device D10. The memory D101 is used to store an operating system, application programs, a boot loader (BootLoader), data, and other programs, such as the program code of the computer program. The memory D101 may also be used to temporarily store data that has been output or is to be output.

[0204] An embodiment of the present application also provides a computer-readable storage medium storing a computer program, which when executed by a processor, can implement the steps in the above-mentioned method embodiments.

[0205] An embodiment of the present application provides a computer program product, which when running on a terminal device, enables the terminal device to implement the steps in the above-mentioned method embodiments.

[0206] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-mentioned method embodiments of the present application, a computer program can be used to instruct relevant hardware to complete. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium may at least include: any entity or device that can carry the computer program code to the control method device / terminal device of the DAB converter, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk, or an optical disc, etc. In some jurisdictions, according to legislation and patent practice, the computer-readable medium may not be an electrical carrier signal and a telecommunication signal.

[0207] In the above embodiments, the descriptions of the respective embodiments each have their own emphasis. For parts not detailed or recorded in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0208] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0209] The above is the preferred embodiment of this application. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle described in this application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of this application.

Claims

1. A control method for a DAB converter, characterized in that Including: Obtain the input voltage and output voltage of the DAB converter; Determine the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the desired output voltage; Calculate the voltage transfer ratio of the DAB converter according to the input voltage and the output voltage; Input the phase shift angle and the voltage transfer ratio into the optimization control law formula for calculation to obtain the voltage matching coefficient of the clamping capacitor in the DAB converter, and deduce the duty cycle of the low-voltage side and the duty cycle of the high-voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio; The optimization control law formula is used to describe the relationship between the phase shift angle, the voltage transfer ratio and the voltage matching coefficient; Generate the drive signals of each switch tube in the DAB converter according to the duty cycle of the low-voltage side, the duty cycle of the high-voltage side, and the phase shift angle, and use each drive signal to control the on-off of the corresponding switch tube.

2. The control method according to claim 1, characterized in that, The determining the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the desired output voltage includes: Calculate the difference between the output voltage and the desired output voltage; Process the difference by using a PI regulator to obtain a control quantity; Perform a limiting process on the control quantity to obtain the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter.

3. The control method according to claim 1, wherein The calculating the voltage transfer ratio of the DAB converter according to the input voltage and the output voltage includes: Obtain the turns ratio of the high-frequency transformer in the DAB converter; Calculate the voltage transfer ratio of the DAB converter according to the input voltage, the output voltage, and the turns ratio of the high-frequency transformer.

4. The control method according to claim 2, wherein The calculating the voltage transfer ratio of the DAB converter according to the input voltage, the output voltage, and the turns ratio of the high-frequency transformer includes: Through the formula: Calculate the voltage transfer ratio k; Where, V1 represents the input voltage, V2 represents the output voltage, and n represents the turns ratio of the high-frequency transformer.

5. The control method according to claim 4, characterized in that The optimization control law formula is: Among them, M OptimumLaw represents the voltage matching coefficient of the clamping capacitor in the DAB converter, a Z_1 represents the first coordinate of the Z-th intersection point required for designing the linear optimization control law formula when k < 2, b Z_1 represents the second coordinate of the Z-th intersection point required for designing the linear optimization control law formula when k < 2, a Z-1_1 represents the first coordinate of the (Z - 1)-th intersection point required for designing the linear optimization control law formula when k < 2, b Z-1_1 represents the second coordinate of the (Z - 1)-th intersection point required for designing the linear optimization control law formula when k < 2, a Z_2 represents the first coordinate of the Z-th intersection point required for designing the linear optimization control law formula when k ≥ 2, b Z_2 represents the second coordinate of the Z-th intersection point required for designing the linear optimization control law formula when k ≥ 2, a Z-1_2 represents the first coordinate of the (Z - 1)-th intersection point required for designing the linear optimization control law formula when k ≥ 2, b Z-1_2 represents the second coordinate of the (Z - 1)-th intersection point required for designing the linear optimization control law formula when k ≥ 2, represents the phase shift angle, Z = 2, 3, 4: where a 1_1 represents the first coordinate of the first intersection point when k < 2, and b 1_1 represents the second coordinate of the first intersection point when k < 2, a 2_1 represents the first coordinate of the second intersection point when k < 2, and b 2_1 represents the second coordinate of the second intersection point when k < 2, a 3_1 represents the first coordinate of the third intersection point when k < 2, and b 3_1 represents the second coordinate of the third intersection point when k < 2, a 4_1 represents the first coordinate of the fourth intersection point when k < 2, and b 4_1 represents the second coordinate of the fourth intersection point when k < 2, a 1_2 represents the first coordinate of the first intersection point when k ≥ 2, and b 1_2 represents the second coordinate of the first intersection point when k ≥ 2, a 2_2 represents the first coordinate of the second intersection point when k ≥ 2, and b 2_2 represents the second coordinate of the second intersection point when k ≥ 2, a 3_2 represents the first coordinate of the third intersection point when k ≥ 2, and b 3_2 represents the second coordinate of the third intersection point when k ≥ 2, a 4_2 represents the first coordinate of the fourth intersection point when k ≥ 2, and b 4_2 represents the second coordinate of the fourth intersection point when k ≥ 2.

6. The control method according to claim 1, wherein The deducing the duty cycle of the low-voltage side and the duty cycle of the high-voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio includes: Through the formula: Calculate the duty cycle D of the low-voltage side p and the duty cycle D of the high-voltage side s ; Among them, M OptimumLaw represents the voltage matching coefficient, and k represents the voltage transfer ratio.

7. The control method according to claim 6, characterized in that, The generating the drive signals of each switch tube in the DAB converter according to the duty cycle of the low-voltage side, the duty cycle of the high-voltage side, and the phase shift angle includes: Generate the drive signals of each switch tube on the low-voltage side in the DAB converter by using the duty cycle of the low-voltage side and the phase shift angle; Generate the drive signals of each switch tube on the high-voltage side in the DAB converter by using the duty cycle of the high-voltage side and the phase shift angle.

8. A control device for a DAB converter, characterized in that, Including: An acquisition module, configured to acquire the input voltage and output voltage of the DAB converter; A determination module, configured to determine the phase shift angle between the low-voltage side and the high-voltage side of the DAB converter according to the output voltage and the desired output voltage; A calculation module, configured to calculate the voltage transfer ratio of the DAB converter according to the input voltage and the output voltage; A calculation module, configured to input the phase-shift angle and the voltage transfer ratio into an optimization control law formula for calculation, so as to obtain a voltage matching coefficient of the clamping capacitor in the DAB converter, and calculate the duty ratio of the low-voltage side and the duty ratio of the high-voltage side of the DAB converter based on the voltage matching coefficient and the voltage transfer ratio; The optimization control law formula is used to describe the relationship between the phase-shift angle, the voltage transfer ratio and the voltage matching coefficient; A control module, configured to generate drive signals for each switching tube in the DAB converter according to the duty ratio of the low-voltage side, the duty ratio of the high-voltage side, and the phase-shift angle, and control the on / off of the corresponding switching tube by using each drive signal.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the control method of the DAB converter according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the control method of the DAB converter according to any one of claims 1 to 7.

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