Control method and device of DAB converter, switching power supply and storage medium

Abstract

This invention discloses a control method, device, switching power supply, and storage medium for a DAB converter. The method includes: obtaining the per-unit values ​​of the voltage transfer ratio and actual transmitted power of the DAB converter using a virtual current power control method based on the input and output voltages of the DAB converter; obtaining the outer phase shift angle, inner phase shift angle, and pulse width control quantity of the DAB converter using a return current power control method based on the per-unit values ​​of the voltage transfer ratio and actual transmitted power of the DAB converter; determining the primary-side drive signal and secondary-side drive signal of the transformer in the DAB converter based on the outer phase shift angle, inner phase shift angle, and pulse width control quantity; and controlling the operation of the switching transistors in the corresponding bridge circuits of the transformer according to the corresponding drive signals. This scheme improves the dynamic response performance and efficiency of the DAB converter by performing virtual current power control based on return current power optimization.

Description

Technical Field

[0001] This invention belongs to the field of switching power supply technology, specifically relating to a control method, device, switching power supply and storage medium for a DAB converter, and particularly to a virtual current power control method, device, switching power supply and storage medium for a hybrid three-level DAB converter. Background Technology

[0002] With the escalating global energy crisis and environmental pollution, the trend towards new energy sources is growing, and bidirectional DC-DC converter technology is receiving increasing attention. Bidirectional DC-DC converters are widely used in distributed generation systems, DC distribution networks, and electric vehicles. Among them, the Dual Active Bridge Converter (DAB) can perform voltage level transformation and electrical insulation, allows bidirectional power flow, boasts high power density and efficiency, provides electrical isolation between input and output terminals, and facilitates soft switching, thus attracting considerable attention and research from numerous researchers.

[0003] The presence of return power requires the converter to have a larger input voltage or current to transmit the same power, which significantly increases the converter's losses and reduces the efficiency of the battery formation system. Reducing return power is an important research topic in DAB control, and researchers have proposed various control methods, including Single Phase-Shift (SPS), Extended Phase-Shift (EPS), Dual Phase-Shift (DPS), and Triple Phase-Shift (TPS).

[0004] DAB converters exhibit varying power conversion performance depending on the control strategy employed. When there is voltage mismatch in the DAB converter, both current stress and return power increase significantly. Higher current stress leads to increased peak and RMS current in the line, resulting in increased line losses and reduced DAB converter efficiency. Increased return power causes continuous power transfer between the power supply and load sides, with some power loss occurring in the loop resistance, further reducing DAB converter efficiency. When the DAB converter operates in a mismatched state (where the primary and secondary bridge arm voltages of the transformer are mismatched), it causes the loss of soft-switching behavior of the switching transistors, increasing turn-on and turn-off losses, hindering DAB converter efficiency and output voltage stability, and increasing power transmission losses.

[0005] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0006] The purpose of this invention is to provide a control method, device, switching power supply, and storage medium for a DAB converter, in order to solve the problem that the dynamic performance of the DAB converter is poor and its efficiency is affected when the voltage of the DAB converter is mismatched under varying operating conditions. The invention achieves the effect of improving the dynamic response performance and efficiency of the DAB converter by performing virtual current power control based on return power optimization.

[0007] This invention provides a control method for a DAB converter, comprising: acquiring the input voltage of the DAB converter and acquiring the output voltage of the DAB converter; based on the input voltage and the output voltage of the DAB converter, using a virtual current power control method to obtain the voltage transfer ratio and the per-unit value of the actual power transferred by the DAB converter; based on the voltage transfer ratio and the per-unit value of the actual power transferred by the DAB converter, using a return current power control method to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter; based on the voltage transfer ratio and the per-unit value of the actual power transferred by the DAB converter, using a return current power control method to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter; and based on the DAB converter... The external phase shift angle of the DAB converter, the internal phase shift angle of the DAB converter, and the pulse width control quantity are used to determine the driving signal of the switching transistor in the primary bridge circuit of the transformer in the DAB converter, denoted as the primary-side driving signal of the transformer in the DAB converter; and the driving signal of the switching transistor in the secondary bridge circuit of the transformer in the DAB converter is also determined, denoted as the secondary-side driving signal of the transformer in the DAB converter; the operation of the switching transistor in the primary bridge circuit of the transformer in the DAB converter is controlled according to the primary-side driving signal of the transformer in the DAB converter; and the operation of the switching transistor in the secondary bridge circuit of the transformer in the DAB converter is controlled according to the secondary-side driving signal of the transformer in the DAB converter.

[0008] In some implementations, the voltage transfer ratio and the per-unit value of the actual transmission power of the DAB converter are obtained using a virtual current power control method based on the input voltage and the output voltage of the DAB converter. This includes: determining the actual transmission power of the DAB converter using a virtual current power control method based on the output voltage of the DAB converter; and obtaining the per-unit value of the voltage transfer ratio and the actual transmission power of the DAB converter using a transmission power estimation method based on the input voltage, the output voltage, and the actual transmission power of the DAB converter.

[0009] In some implementations, the actual transmission power of the DAB converter is determined using a virtual current power control method based on the output voltage of the DAB converter. This includes: comparing the output voltage of the DAB converter with a preset reference voltage to obtain a comparison result; performing PI control on the comparison result to obtain a virtual output current; determining the output power of the DAB converter as the product of the virtual output current and the set reference voltage; and determining the actual transmission power of the DAB converter as the ratio of the output power of the DAB converter to the transmission efficiency of the DAB converter.

[0010] In some implementations, the voltage transfer ratio and the per-unit value of the actual transmission power of the DAB converter are obtained by using a transmission power estimation method based on the input voltage, output voltage, and actual transmission power of the DAB converter. This includes: determining the reference power of the DAB converter based on the input voltage and output voltage; determining the error of the output voltage of the DAB converter based on the output voltage; determining the per-unit value of the actual transmission power of the DAB converter as the ratio of the actual transmission power to the reference power of the DAB converter; and determining the voltage transfer ratio of the DAB converter based on the error of the output voltage.

[0011] In some implementations, based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmitted power of the DAB converter, a return power control method is used to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter. This includes: under the given power condition of the DAB converter, based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmitted power of the DAB converter, using the KKT algorithm to optimize the return power of the DAB converter, thereby obtaining the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter.

[0012] In conjunction with the above method, another aspect of the present invention provides a control device for a DAB converter, comprising: an acquisition unit configured to acquire the input voltage of the DAB converter and the output voltage of the DAB converter; a control unit configured to, based on the input voltage and the output voltage of the DAB converter, use a virtual current power control method to obtain the voltage transfer ratio and the per-unit value of the actual power transferred by the DAB converter; the control unit is further configured to, based on the voltage transfer ratio and the per-unit value of the actual power transferred by the DAB converter, use a return current power control method to obtain the outer phase shift angle and the inner phase shift angle and pulse width modulation of the DAB converter. The control unit is further configured to determine, based on the external phase shift angle, the internal phase shift angle, and the pulse width control quantity of the DAB converter, the driving signal of the switching transistor in the primary bridge circuit of the transformer in the DAB converter, denoted as the primary-side driving signal of the DAB converter; and to determine, based on the external phase shift angle, the internal phase shift angle, and the pulse width control quantity of the DAB converter, the driving signal of the switching transistor in the secondary bridge circuit of the transformer in the DAB converter, denoted as the secondary-side driving signal of the DAB converter; the control unit is further configured to control the operation of the switching transistor in the primary bridge circuit of the transformer in the DAB converter based on the primary-side driving signal of the transformer in the DAB converter; and to control the operation of the switching transistor in the secondary bridge circuit of the transformer in the DAB converter based on the secondary-side driving signal of the transformer in the DAB converter.

[0013] In some embodiments, the control unit obtains the voltage transfer ratio and the per-unit value of the actual transmission power of the DAB converter using a virtual current power control method based on the input voltage and output voltage of the DAB converter. This includes: determining the actual transmission power of the DAB converter using a virtual current power control method based on the output voltage of the DAB converter; and obtaining the per-unit value of the voltage transfer ratio and the actual transmission power of the DAB converter using a transmission power estimation method based on the input voltage, output voltage, and actual transmission power of the DAB converter.

[0014] In some embodiments, the control unit determines the actual transmission power of the DAB converter using a virtual current power control method based on the output voltage of the DAB converter. This includes: comparing the output voltage of the DAB converter with a preset reference voltage to obtain a comparison result; performing PI control on the comparison result to obtain a virtual output current; determining the output power of the DAB converter as the product of the virtual output current and the set reference voltage; and determining the actual transmission power of the DAB converter as the ratio of the output power of the DAB converter to the transmission efficiency of the DAB converter.

[0015] In some embodiments, the control unit obtains the voltage transfer ratio and the per-unit value of the actual transmission power of the DAB converter by using a transmission power estimation method based on the input voltage of the DAB converter, the output voltage of the DAB converter, and the actual transmission power of the DAB converter. This includes: determining the reference power of the DAB converter based on the input voltage and the output voltage of the DAB converter; determining the error of the output voltage of the DAB converter based on the output voltage of the DAB converter; determining the ratio of the actual transmission power of the DAB converter to the reference power of the DAB converter as the per-unit value of the actual transmission power of the DAB converter; and determining the voltage transfer ratio of the DAB converter based on the error of the output voltage of the DAB converter.

[0016] In some embodiments, the control unit, based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, uses a return power control method to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter. This includes: under the given power condition of the DAB converter, optimizing the return power of the DAB converter using the KKT algorithm based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter.

[0017] In conjunction with the above-described device, the present invention further provides a switching power supply, comprising: a control device for the DAB converter described above.

[0018] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located executes the control method for the DAB converter described above.

[0019] Therefore, the solution of this invention detects the input and output voltages of the DAB converter, obtains the virtual output current based on the output voltage and reference voltage of the DAB converter, obtains the output power based on the virtual output current and reference voltage, and obtains the efficiency of the DAB converter based on the output power. Furthermore, based on the input voltage, output voltage, and efficiency of the DAB converter, the voltage transfer ratio and transmission power during DAB converter operation are obtained. The voltage transfer ratio and transmission power during DAB converter operation are then input into a return current power optimization algorithm to obtain the outer phase shift angle, inner phase shift angle, and pulse width control quantity of the DAB converter. Based on the outer phase shift angle, inner phase shift angle, and pulse width control quantity of the DAB converter, the drive signals of the switching transistors in the bridges on both sides of the transformer in the DAB converter are obtained. Thus, by performing virtual current power control based on return current power optimization, the dynamic response performance of the DAB converter is improved, and the efficiency of the DAB converter is increased.

[0020] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the main circuit of a hybrid three-level dual active bridge converter (i.e., hybrid three-level DAB converter) according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the control flow of an embodiment of the optimized power control method in the relevant scheme;

[0024] Figure 3 A schematic diagram of the control flow of an embodiment of the power control method for optimizing dummy variables in a related scheme;

[0025] Figure 4 This is a flowchart illustrating an embodiment of the control method for the DAB converter of the present invention;

[0026] Figure 5 This is a flowchart illustrating an embodiment of the method of the present invention for determining the per-unit value of the voltage transfer ratio and the actual transmission power of the DAB converter based on the input voltage and output voltage of the DAB converter.

[0027] Figure 6 This is a flowchart illustrating an embodiment of the method of the present invention for determining the actual transmission power of a DAB converter based on the output voltage of the DAB converter.

[0028] Figure 7This is a flowchart illustrating an embodiment of the method of the present invention that uses a transmission power estimation method to determine the per-unit value of the voltage transfer ratio and the actual transmission power of the DAB converter.

[0029] Figure 8 This is a schematic diagram of the structure of a control device for the DAB converter of the present invention;

[0030] Figure 9 A schematic diagram of the control flow of an embodiment of a power control method optimized for virtual current;

[0031] Figure 10 The diagram shows the dynamic response curve of the DAB converter when the input voltage fluctuates. (a) is the dynamic response curve of the DAB converter when the input voltage fluctuates under power control in the relevant scheme, and (b) is the dynamic response curve of the DAB converter when the input voltage fluctuates under the virtual current power control of the present invention.

[0032] Figure 11 The diagram shows the dynamic response characteristics of the DAB converter under load resistance fluctuations; where (a) is the dynamic response characteristics of the DAB converter under load resistance fluctuations in the power control scheme of the relevant scheme, and (b) is the dynamic response characteristics of the DAB converter under load resistance fluctuations in the virtual current power control scheme of the present invention.

[0033] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0034] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] Figure 1 This is a schematic diagram of the main circuit of an embodiment of a hybrid three-level dual active bridge converter (i.e., a hybrid three-level DAB converter). Figure 1 In the main circuit of the hybrid three-level DAB converter shown, and This indicates the input and output voltages of the DAB converter. , and These represent the equalizing capacitor and the supporting capacitor on both sides of the DAB converter, respectively. This indicates the midpoint clamping diode of the side arm of a three-level full-bridge circuit; This refers to the switching transistor on the three-level inverter side. This refers to the parasitic diodes across the switching transistors on the three-level inverter side; This refers to the switching transistor on the two-level rectifier side. This refers to the parasitic diodes across the switching transistors on the two-level rectifier side; the transformer turns ratio is... , , These represent the output voltage and input voltage of the two bridge sides of the transformer, respectively. This represents the transmission inductance after considering the transformer's leakage inductance and auxiliary inductance. This represents the current flowing through the inductor. This indicates the output current.

[0037] To ensure the reliable operation of DAB converters under varying operating conditions, improving their dynamic performance is of paramount importance. The optimization control strategies employed in relevant schemes typically employ two methods: optimized power control methods and virtual optimized power control methods.

[0038] Figure 2 This is a schematic diagram of the control flow of an embodiment of the optimized power control method in a related scheme. For example... Figure 2 As shown, the outer phase shift angle The calculation formula is combined with a PI controller for the output voltage. This PI controller maintains a stable output voltage, enhancing the robustness of the DAB converter system. The internal phase shift angle and pulse width control parameters... The drive pulses for the switching transistors are obtained through optimization algorithms, thereby achieving closed-loop control of the converter. However, this control method has poor suppression of input voltage ripples and poor dynamic adaptability under conditions such as load and input voltage changes.

[0039] Figure 3 This is a schematic diagram of the control flow of an embodiment of the power control method for optimizing dummy variables in a related scheme. For example... Figure 3 As shown, the original mathematical model of the converter is made more accurate by introducing capacitor current. Then, the transmission power expression is transformed to incorporate virtual control quantities such as capacitor current or virtual voltage. The output voltage is processed by a PI regulator to obtain the virtual control quantity. Then, the per-unit value of transmission power and voltage transmission ratio are obtained through transmission power estimation, and the outer phase shift angle is directly calculated. and internal phase shift angle Ultimately, the control of the switching transistor's drive pulse is achieved, thus realizing closed-loop control of the converter. However, due to the presence of multiple variables, the control difficulty and complexity are greatly increased, making the implementation of this optimized modulation strategy relatively complex.

[0040] Specifically, the original mathematical model of the converter is made more accurate by introducing capacitor current. Then, the power transmission expression is transformed to introduce virtual control quantities such as capacitor current or virtual voltage. In particular, the capacitor current is introduced into the mathematical model of the converter to obtain a more accurate mathematical model. Then, the power expression of the DAB converter can be transformed to obtain the required virtual control quantity, so as to control the output of the converter more accurately.

[0041] The per-unit value of transmission power and the voltage transmission ratio are obtained through transmission power estimation. Specifically, this means that the transmission power P of the DAB converter under control is calculated using the power expression of the DAB converter:

[0042] .

[0043] The actual transmission power P of the DAB converter is normalized to obtain the normalized transmission power of the DAB converter under control. As shown in the following formula:

[0044] .

[0045] The outer phase angle is obtained by direct calculation. and internal phase shift angle and pulse width control quantity Specifically, it refers to: such as Figure 3 As shown, the voltage transfer ratio is calculated from the transmission power. and per-unit value of transmission power Substituting this into the return power optimization, we obtain the outer phase shift angle. and internal phase shift angle The control switch drive pulse refers to: such as Figure 3 As shown, the external phase shift angle is obtained by optimizing the return power. and internal phase shift angle The software program outputs high and low levels to control the conduction of each switching transistor. Specifically, This refers to the turns ratio of transformer T in the DAB converter. For frequency, The transmission inductance is the sum of the leakage inductance and auxiliary inductance of the transformer T in the DAB converter. The input voltage of the DAB converter. This is the output voltage of the DAB converter.

[0046] To enable DAB converters to operate reliably under varying operating conditions and improve their dynamic performance, this invention combines two approaches to optimized power control (i.e., optimized power control method and virtual variable optimized power control method). Based on return power optimization, it proposes a virtual current power control method for hybrid three-level DAB converters to improve their dynamic response performance and efficiency.

[0047] According to an embodiment of the present invention, a control method for a DAB converter is provided, such as... Figure 4 The diagram shows a flowchart of an embodiment of the method of the present invention. The control method of the DAB converter may include steps S110 to S150.

[0048] At step S110, the input voltage of the DAB converter is obtained (e.g., DAB converter input voltage). ), and obtain the output voltage of the DAB converter (such as the DAB converter output voltage). ).

[0049] In step S120, based on the input voltage and output voltage of the DAB converter, a virtual current power control method is used to obtain the voltage transfer ratio and the per-unit value of the actual power transferred by the DAB converter. The voltage transfer ratio of the DAB converter is the voltage transfer ratio during DAB converter operation. The per-unit value of the actual transmission power of the DAB converter is the same as the per-unit value of the transmission power when the DAB converter is running. .

[0050] In some embodiments, the specific process of obtaining the voltage transfer ratio and the per-unit value of the actual transmission power of the DAB converter by adopting a virtual current power control method based on the input voltage and the output voltage of the DAB converter in step S120 is described in the following exemplary description.

[0051] The following is combined with Figure 5 The schematic diagram shows an embodiment of the method of the present invention for determining the per-unit value of the voltage transfer ratio and the actual transmission power of the DAB converter based on the input voltage and output voltage of the DAB converter. The specific process of determining the per-unit value of the voltage transfer ratio and the actual transmission power of the DAB converter based on the input voltage and output voltage of the DAB converter in step S120 is further explained, including steps S210 to S220.

[0052] Step S210: Based on the output voltage of the DAB converter, determine the actual transmission power of the DAB converter using a virtual current power control method. The actual transmission power of the DAB converter may be more accurately determined by the actual transmission power of the system in which the DAB converter is located. .

[0053] In some implementations, the specific process of determining the actual transmission power of the DAB converter in step S210 using a virtual current power control method based on the output voltage of the DAB converter is described in the following exemplary description.

[0054] The following is combined with Figure 6 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention for determining the actual transmission power of the DAB converter based on the output voltage of the DAB converter. The specific process of determining the actual transmission power of the DAB converter based on the output voltage of the DAB converter in step S210 is further explained, including steps S310 to S340.

[0055] Step S310: Compare the output voltage of the DAB converter with a preset reference voltage to obtain a comparison result.

[0056] Step S320: Perform PI control on the comparison result to obtain the virtual output current.

[0057] Step S330: The product of the virtual output current and the set reference voltage is determined as the output power of the DAB converter.

[0058] Step S340: The ratio of the output power of the DAB converter to the transmission efficiency of the DAB converter is determined as the actual transmission power of the DAB converter.

[0059] The virtual current power control method involves sampling the input and output voltages, comparing the output voltage with a reference output voltage, obtaining a virtual output current via a PI controller, and then multiplying the virtual output current by the reference output voltage to obtain the output power. To obtain more accurate power transmission, the efficiency of the DAB converter is introduced here. The voltage transfer ratio of the DAB converter during operation was calculated. and per-unit value of transmission power The voltage transfer ratio of the DAB converter during operation and transmission power By incorporating the return power optimization algorithm, the optimal control combination is obtained, aiming to reduce system cost and improve the efficiency and dynamic performance of the DAB converter.

[0060] Step S220: Based on the input voltage of the DAB converter, the output voltage of the DAB converter, and the actual transmission power of the DAB converter, the voltage transmission ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter are obtained by using a transmission power estimation method.

[0061] In some embodiments, the specific process of obtaining the voltage transfer ratio and the per-unit value of the actual transmission power of the DAB converter by using a transmission power estimation method based on the input voltage of the DAB converter, the output voltage of the DAB converter, and the actual transmission power of the DAB converter in step S220 is described in the following exemplary description.

[0062] The following is combined with Figure 7 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention that uses a transmission power estimation method to determine the per-unit value of the voltage transmission ratio and the actual transmission power of the DAB converter. It further illustrates the specific process of determining the per-unit value of the voltage transmission ratio and the actual transmission power of the DAB converter using the transmission power estimation method in step S220, including steps S410 to S430.

[0063] Step S410: Determine the reference power of the DAB converter based on its input voltage and output voltage. Also, determine the output voltage error of the DAB converter based on its output voltage.

[0064] Step S420: The ratio of the actual transmission power of the DAB converter to the reference power of the DAB converter is determined as the per-unit value of the actual transmission power of the DAB converter.

[0065] Step S430: Determine the voltage transfer ratio of the DAB converter based on the error of the output voltage of the DAB converter.

[0066] Figure 9 A schematic diagram of the control flow of an embodiment of the power control method optimized for virtual current. See also: Figure 9 In the example shown, the output power of the DAB converter is:

[0067] (1).

[0068] in, The output power of the DAB converter, The output voltage of the DAB converter. The output current is used to generate heat for the DAB converter.

[0069] Considering the transmission loss in the main circuit of the hybrid three-level dual active bridge converter, the transmission efficiency of the DAB converter... The transmission efficiency of the DAB converter is related to both the control method and the main circuit hardware design of the hybrid three-level dual active bridge converter. This allows for a more accurate determination of the actual transmission power of the system containing the DAB converter. :

[0070] (2).

[0071] in, The output power of the DAB converter, This represents the actual transmission power of the DAB converter. This refers to the transmission efficiency of the DAB converter.

[0072] Normalizing formula (2) yields:

[0073] (3).

[0074] in, The actual transmission power of the DAB converter per-unit value, This represents the actual transmission power of the DAB converter. This is the reference power for the DAB converter. For frequency, The transmission inductance is the sum of the leakage inductance and auxiliary inductance of the transformer T in the DAB converter. The output voltage of the DAB converter. This refers to the output current of the DAB converter. This refers to the turns ratio of transformer T in the DAB converter. For the transmission efficiency of DAB converters, This is the input voltage of the DAB converter.

[0075] Because of the virtual current in formula (3) Through the output voltage of the DAB converter The frequency of the DAB converter in formula (3) is obtained from the PI controller, therefore, it can be compensated by an integrator. The transmission inductance of the transformer T in the DAB converter after considering the leakage inductance and auxiliary inductance. The turns ratio of transformer T in a DAB converter Constant terms are omitted, but this allows for more accurate adjustment of the actual transmission power of the DAB converter. The transmission efficiency of DAB converters This part cannot be omitted; therefore, the actual transmission power of the DAB converter... It can be further simplified to formula (4):

[0076] (4).

[0077] in, This represents the per-unit value of the actual transmission power P of the DAB converter. This represents the actual transmission power of the DAB converter. This is the reference power for the DAB converter. The output reference voltage of the DAB converter. The virtual current is obtained by passing the output voltage of the DAB converter through a PI controller. For the transmission efficiency of DAB converters, The input voltage of the DAB converter. This is the output voltage of the DAB converter.

[0078] Based on the above analysis, the overall scheme for virtual current power control is as follows: Figure 9 As shown in the figure, the analysis reveals that, compared to the optimization method that includes a current sensor in related schemes, this method eliminates the current sampling part and directly calculates the current using the output voltage error. The per-unit value of the actual transmission power P of the DAB converter Adjust the drive signal, k is and The difference is obtained by subtracting the two values, which simplifies the procedure, can further accelerate the dynamic response speed, and reduce the design cost.

[0079] In step S130, based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmitted power of the DAB converter, a return power control method is used to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control value of the DAB converter. The outer phase shift angle of the DAB converter is as follows: The internal phase shift angle and pulse width control quantity of the DAB converter are as follows: .

[0080] In some implementations, step S130, based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, uses a return power control method to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter. This includes: under the given power condition of the DAB converter, using the KKT algorithm to optimize the return power of the DAB converter based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter.

[0081] Return power refers to the power flowing back to the power source during the control of a DAB converter, where there is inter-bridge phase shift. The output voltage of the primary H-bridge in the DAB converter cannot be in the same direction as the inductor current in real time, resulting in a period where the transmitted power is negative. This means that within a switching cycle, there exists a situation where the input power is negative, indicating power flowing back to the power source. Return power optimization refers to optimizing the return power of the DAB converter while still satisfying the transmitted power requirements. Therefore, the return power optimization problem can be transformed into a mathematical extremum problem of finding the optimal control combination that minimizes the return power of the DAB converter under given power conditions. For extremum optimization problems containing equality constraints, the KKT (Karush-Kuhn-Tucke) algorithm is the most effective method for solving optimal solutions under mixed conditions of equality and inequality.

[0082] In step S140, based on the outer phase shift angle, the inner phase shift angle, and the pulse width control value of the DAB converter, the drive signal for the switching transistor in the primary bridge circuit of the transformer in the DAB converter is determined and denoted as the primary-side drive signal of the transformer in the DAB converter. The drive signal for the switching transistor in the secondary bridge circuit of the transformer in the DAB converter is also determined and denoted as the secondary-side drive signal of the transformer in the DAB converter.

[0083] In step S150, the operation of the switching transistors in the primary bridge circuit of the transformer in the DAB converter is controlled according to the primary-side drive signal of the transformer in the DAB converter. Similarly, the operation of the switching transistors in the secondary bridge circuit of the transformer in the DAB converter is controlled according to the secondary-side drive signal of the transformer in the DAB converter.

[0084] The present invention proposes a virtual current power control method for a hybrid three-level DAB converter. Based on return power optimization, it combines two optimized power control methods (i.e., optimized power control method and virtual variable optimized power control method). Based on return power optimization, a virtual current power control scheme is proposed, which eliminates the need for a current sensor, reduces the design cost of the system containing the DAB converter, and has better dynamic performance and faster response speed under input voltage fluctuations or load jumps. This enables the DAB converter to work reliably in environments with changing operating conditions and improves the dynamic response performance of the DAB converter.

[0085] To further analyze its dynamic characteristics, the following simulation compares and analyzes its power control with that of related schemes under the same voltage fluctuations and load jumps.

[0086] Figure 10 The diagram shows the dynamic response curves of the DAB converter when the input voltage fluctuates. (a) is a diagram showing the dynamic response curve of the DAB converter when the input voltage fluctuates under power control in the relevant scheme, and (b) is a diagram showing the dynamic response curve of the DAB converter when the input voltage fluctuates under virtual current power control in this invention. Figure 10 The output voltage and current response curves of the DAB converter are given when the input voltage jumps from 480V to 432V with an output voltage of 15V and constant transmission power. Figure 10 It is known that when the DAB converter encounters the same input voltage fluctuation, compared with the power control in related schemes, the virtual current control proposed in this invention has better robustness, and its recovery time is close to zero.

[0087] Figure 11 This is a schematic diagram of the dynamic response characteristics of the DAB converter when the load resistance fluctuates. Figure 11 The following data is provided: with an input voltage of 480V and an output voltage of 15V, the load changes from the original 0.7... Jump to 0.6372 The output voltage and current response curves of the DAB converter are shown. (a) is a schematic diagram of the dynamic response characteristics of the DAB converter under load resistance fluctuations in the power control scheme of the relevant scheme, and (b) is a schematic diagram of the dynamic response characteristics of the DAB converter under load resistance fluctuations in the virtual current power control of the present invention. Figure 11 It is known that when the DAB converter encounters the same load change, compared with the power control in related schemes, the virtual current control proposed in this invention has better robustness, and its recovery time is close to zero.

[0088] The present invention combines two optimized power control methods (i.e., optimized power control method and virtual variable optimized power control method) and proposes a virtual current power control method, which eliminates the need for a current sensor. By sampling the input and output voltages, the output voltage is compared with a reference output voltage, and a virtual output current is obtained through a PI controller. The virtual output current is then multiplied by the reference output voltage to obtain the output power. To obtain more accurate transmission power, converter efficiency is introduced here. The voltage transfer ratio of the DAB converter during operation was calculated. and transmission power The voltage transfer ratio of the DAB converter during operation and transmission power By incorporating the return current power optimization algorithm, the optimal control combination is obtained to reduce system cost and improve the efficiency and dynamic performance of the DAB converter. As a result, it has better dynamic performance under input voltage fluctuations or load jumps, enabling the DAB converter to work reliably in environments with varying operating conditions and improving the dynamic response performance of the DAB converter.

[0089] In this invention, based on the optimization of return current power, a virtual current power control method is proposed, which eliminates the need for a current sensor. By sampling the input voltage and output voltage, the output voltage is compared with a reference output voltage, and a virtual output current is obtained through a PI controller. The virtual output current is then multiplied by the reference output voltage to obtain the output power. To obtain more accurate transmission power, the transmission power is incorporated into the return current power optimization algorithm to obtain the optimal control combination. This results in better dynamic performance under input voltage fluctuations or load changes, aiming to reduce the cost of the DAB converter system, improve the efficiency and dynamic performance of the DAB converter, and ultimately enhance the efficiency of the DAB converter.

[0090] The technical solution of this embodiment detects the input and output voltages of the DAB converter, obtains the virtual output current based on the output voltage and reference voltage, calculates the output power based on the virtual output current and reference voltage, and then calculates the efficiency of the DAB converter based on the output power. Furthermore, based on the input voltage, output voltage, and efficiency of the DAB converter, the voltage transfer ratio during DAB converter operation is obtained. and transmission power The voltage transfer ratio during DAB converter operation and transmission power By incorporating the return power optimization algorithm, the external phase shift angle of the DAB converter is obtained. and internal phase shift angle and pulse width control quantity According to the external phase shift angle of the DAB converter and internal phase shift angle and pulse width control quantity The drive signals of the switching transistors in the bridges on both sides of the transformer in the DAB converter are obtained. Thus, by performing virtual current power control based on return power optimization, the dynamic response performance of the DAB converter is improved, and the efficiency of the DAB converter is increased.

[0091] According to an embodiment of the present invention, a control device for a DAB converter corresponding to a control method for a DAB converter is also provided. See also Figure 8 The diagram shows a structural schematic of an embodiment of the device of the present invention. The control device of the DAB converter may include: an acquisition unit 102 and a control unit 104.

[0092] The acquisition unit 102 is configured to acquire the input voltage of the DAB converter (e.g., the DAB converter input voltage). ), and obtain the output voltage of the DAB converter (such as the DAB converter output voltage). For the specific functions and processing of the acquisition unit 102, please refer to step S110.

[0093] Control unit 104 is configured to obtain the voltage transfer ratio and the per-unit value of the actual power transfer of the DAB converter using a virtual current power control method, based on the input voltage and output voltage of the DAB converter. The voltage transfer ratio of the DAB converter is the voltage transfer ratio during DAB converter operation. The per-unit value of the actual transmission power of the DAB converter is the same as the per-unit value of the transmission power when the DAB converter is running. The specific functions and processing of the control unit 104 are described in step S120.

[0094] In some embodiments, the control unit 104, based on the input voltage and output voltage of the DAB converter, uses a virtual current power control method to obtain the voltage transfer ratio and the per-unit value of the actual transfer power of the DAB converter, including:

[0095] The control unit 104 is further configured to determine the actual transmission power of the DAB converter based on the output voltage of the DAB converter using a virtual current power control method. The actual transmission power of the DAB converter may be more accurately determined by the actual transmission power of the system in which the DAB converter is located. For details on the specific functions and processing of the control unit 104, please refer to step S210.

[0096] In some embodiments, the control unit 104 determines the actual transmission power of the DAB converter based on the output voltage of the DAB converter using a virtual current power control method, including:

[0097] The control unit 104 is further configured to compare the output voltage of the DAB converter with a preset reference voltage to obtain a comparison result. The specific functions and processing of the control unit 104 are further described in step S310.

[0098] The control unit 104 is further configured to perform PI control on the comparison result to obtain a virtual output current. The specific functions and processing of the control unit 104 are further described in step S320.

[0099] The control unit 104 is further configured to determine the output power of the DAB converter by multiplying the virtual output current by a set reference voltage. The specific functions and processing of the control unit 104 are further described in step S330.

[0100] The control unit 104 is further configured to determine the ratio of the output power of the DAB converter to the transmission efficiency of the DAB converter as the actual transmission power of the DAB converter. The specific functions and processing of the control unit 104 are further described in step S340.

[0101] The virtual current power control method, also known as the virtual current power control device, involves sampling the input and output voltages, comparing the output voltage with a reference output voltage, obtaining a virtual output current via a PI controller, and then multiplying the virtual output current by the reference output voltage to obtain the output power. To obtain more accurate power transmission, the efficiency of the DAB converter is introduced here. The voltage transfer ratio of the DAB converter during operation was calculated. and per-unit value of transmission power The voltage transfer ratio of the DAB converter during operation and transmission power By incorporating the return power optimization algorithm, the optimal control combination is obtained, aiming to reduce system cost and improve the efficiency and dynamic performance of the DAB converter.

[0102] The control unit 104 is further configured to obtain the voltage transfer ratio and the per-unit value of the actual transmission power of the DAB converter by using a transmission power estimation method based on the input voltage of the DAB converter, the output voltage of the DAB converter, and the actual transmission power of the DAB converter. The specific functions and processing of this control unit 104 are further described in step S220.

[0103] In some embodiments, the control unit 104, based on the input voltage of the DAB converter, the output voltage of the DAB converter, and the actual transmission power of the DAB converter, uses a transmission power estimation method to obtain the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, including:

[0104] The control unit 104 is further configured to determine the reference power of the DAB converter based on the input voltage and the output voltage of the DAB converter, and to determine the error of the output voltage of the DAB converter based on the output voltage of the DAB converter. The specific functions and processing of this control unit 104 are further described in step S410.

[0105] The control unit 104 is further configured to determine the ratio of the actual transmission power of the DAB converter to the reference power of the DAB converter as the per-unit value of the actual transmission power of the DAB converter. The specific functions and processing of the control unit 104 are further described in step S420.

[0106] The control unit 104 is further configured to determine the voltage transfer ratio of the DAB converter based on the error of the output voltage of the DAB converter. The specific functions and processing of the control unit 104 are further described in step S430.

[0107] Figure 9 A schematic diagram of the control flow of an embodiment of the power control method optimized for virtual current. See also: Figure 9 In the example shown, the output power of the DAB converter is:

[0108] (1).

[0109] in, The output power of the DAB converter, The output voltage of the DAB converter. The output current is used to generate heat for the DAB converter.

[0110] Considering the transmission loss in the main circuit of the hybrid three-level dual active bridge converter, the transmission efficiency of the DAB converter... The transmission efficiency of the DAB converter is related to both the control method and the main circuit hardware design of the hybrid three-level dual active bridge converter. This allows for a more accurate determination of the actual transmission power of the system containing the DAB converter. :

[0111] (2).

[0112] in, The output power of the DAB converter, This represents the actual transmission power of the DAB converter. This refers to the transmission efficiency of the DAB converter.

[0113] Normalizing formula (2) yields:

[0114] (3).

[0115] in, The actual transmission power of the DAB converter per-unit value, This represents the actual transmission power of the DAB converter. This is the reference power for the DAB converter. For frequency, The transmission inductance is the sum of the leakage inductance and auxiliary inductance of the transformer T in the DAB converter. The output voltage of the DAB converter. This refers to the output current of the DAB converter. This refers to the turns ratio of transformer T in the DAB converter. For the transmission efficiency of DAB converters, This is the input voltage of the DAB converter.

[0116] Because of the virtual current in formula (3) Through the output voltage of the DAB converter The frequency of the DAB converter in formula (3) is obtained from the PI controller, therefore, it can be compensated by an integrator. The transmission inductance of the transformer T in the DAB converter after considering the leakage inductance and auxiliary inductance. The turns ratio of transformer T in a DAB converter Constant terms are omitted, but this allows for more accurate adjustment of the actual transmission power of the DAB converter. The transmission efficiency of DAB converters This part cannot be omitted; therefore, the actual transmission power of the DAB converter... It can be further simplified to formula (4):

[0117] (4).

[0118] in, This represents the per-unit value of the actual transmission power P of the DAB converter. This represents the actual transmission power of the DAB converter. This is the reference power for the DAB converter. The output reference voltage of the DAB converter. The virtual current is obtained by passing the output voltage of the DAB converter through a PI controller. For the transmission efficiency of DAB converters, The input voltage of the DAB converter. This is the output voltage of the DAB converter.

[0119] Based on the above analysis, the overall scheme for virtual current power control is as follows: Figure 9 As shown in the figure, the analysis reveals that, compared to the optimized devices with current sensors in related schemes, this device eliminates the current sampling part and directly calculates the current through the output voltage error. The per-unit value of the actual transmission power P of the DAB converter Adjusting the drive signal simplifies the program, further accelerating dynamic response speed and reducing design costs.

[0120] The control unit 104 is further configured to obtain the outer phase shift angle, inner phase shift angle, and pulse width control value of the DAB converter based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, using a return power control method. The outer phase shift angle of the DAB converter is as follows: The internal phase shift angle and pulse width control quantity of the DAB converter are as follows: For details on the specific functions and processing of the control unit 104, please refer to step S130.

[0121] In some embodiments, the control unit 104, based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, uses a return power control method to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter. Specifically, the control unit 104 is further configured to, under a given power condition of the DAB converter, optimize the return power of the DAB converter using the KKT algorithm based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter.

[0122] Return power refers to the power flowing back to the power source during the control of a DAB converter, where there is inter-bridge phase shift. The output voltage of the primary H-bridge in the DAB converter cannot be in the same direction as the inductor current in real time, resulting in a period where the transmitted power is negative. This means that within a switching cycle, there exists a situation where the input power is negative, indicating power flowing back to the power source. Return power optimization refers to optimizing the return power of the DAB converter while still satisfying the transmitted power requirements. Therefore, the return power optimization problem can be transformed into a mathematical extremum problem of finding the optimal control combination that minimizes the return power of the DAB converter under given power conditions. For extremum optimization problems containing equality constraints, the KKT (Karush-Kuhn-Tucke) algorithm is the most efficient device for solving optimal solutions under mixed conditions of equality and inequality.

[0123] The control unit 104 is further configured to determine, based on the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter, the drive signal of the switching transistor in the primary bridge circuit of the transformer in the DAB converter, denoted as the primary-side drive signal of the DAB converter. It also determines the drive signal of the switching transistor in the secondary bridge circuit of the transformer in the DAB converter, denoted as the secondary-side drive signal of the DAB converter. The specific functions and processing of this control unit 104 are further described in step S140.

[0124] The control unit 104 is further configured to control the operation of the switching transistors in the primary bridge circuit of the transformer in the DAB converter according to the primary-side drive signal of the transformer in the DAB converter, and to control the operation of the switching transistors in the secondary bridge circuit of the transformer in the DAB converter according to the secondary-side drive signal of the transformer in the DAB converter. The specific functions and processing of this control unit 104 are further described in step S150.

[0125] The present invention proposes a virtual current power control device for a hybrid three-level DAB converter. Based on return power optimization, it combines two types of optimized power control (i.e., optimized power control device and virtual variable optimized power control device). Based on return power optimization, a virtual current power control scheme is proposed, which eliminates the need for a current sensor, reduces the design cost of the system containing the DAB converter, and has better dynamic performance and faster response speed under input voltage fluctuations or load jumps. This enables the DAB converter to work reliably in environments with changing operating conditions and improves the dynamic response performance of the DAB converter.

[0126] To further analyze its dynamic characteristics, the following simulation compares and analyzes its power control with that of related schemes under the same voltage fluctuations and load jumps.

[0127] Figure 10The diagram shows the dynamic response curves of the DAB converter when the input voltage fluctuates. (a) is a diagram showing the dynamic response curve of the DAB converter when the input voltage fluctuates under power control in the relevant scheme, and (b) is a diagram showing the dynamic response curve of the DAB converter when the input voltage fluctuates under virtual current power control in this invention. Figure 10 The output voltage and current response curves of the DAB converter are given when the input voltage jumps from 480V to 432V with an output voltage of 15V and constant transmission power. Figure 10 It is known that when the DAB converter encounters the same input voltage fluctuation, compared with the power control in related schemes, the virtual current control proposed in this invention has better robustness, and its recovery time is close to zero.

[0128] Figure 11 This is a schematic diagram of the dynamic response characteristics of the DAB converter when the load resistance fluctuates. Figure 11 The following data is provided: with an input voltage of 480V and an output voltage of 15V, the load changes from the original 0.7... Jump to 0.6372 The output voltage and current response curves of the DAB converter are shown. (a) is a schematic diagram of the dynamic response characteristics of the DAB converter under load resistance fluctuations in the power control scheme of the relevant scheme, and (b) is a schematic diagram of the dynamic response characteristics of the DAB converter under load resistance fluctuations in the virtual current power control of the present invention. Figure 11 It is known that when the DAB converter encounters the same load change, compared with the power control in related schemes, the virtual current control proposed in this invention has better robustness, and its recovery time is close to zero.

[0129] The present invention combines two optimized power control methods (i.e., optimized power control device and virtual variable optimized power control device) and proposes a virtual current power control device, eliminating the need for a current sensor. By sampling the input and output voltages, the output voltage is compared with a reference output voltage, and a PI controller is used to obtain the virtual output current. The virtual output current is then multiplied by the reference output voltage to obtain the output power. To obtain more accurate transmission power, converter efficiency is introduced here. The voltage transfer ratio of the DAB converter during operation was calculated. and transmission power The voltage transfer ratio of the DAB converter during operation and transmission power By incorporating the return current power optimization algorithm, the optimal control combination is obtained to reduce system cost and improve the efficiency and dynamic performance of the DAB converter. As a result, it has better dynamic performance under input voltage fluctuations or load jumps, enabling the DAB converter to work reliably in environments with varying operating conditions and improving the dynamic response performance of the DAB converter.

[0130] In the present invention, based on the optimization of return current power, a virtual current power control device is proposed, which eliminates the need for a current sensor. By sampling the input voltage and output voltage, the output voltage is compared with a reference output voltage, and a virtual output current is obtained through a PI controller. The virtual output current is then multiplied by the reference output voltage to obtain the output power. To obtain more accurate transmission power, the transmission power is incorporated into the return current power optimization algorithm to obtain the optimal control combination. This results in better dynamic performance under input voltage fluctuations or load jumps, aiming to reduce the cost of the DAB converter system, improve the efficiency and dynamic performance of the DAB converter, and ultimately increase the efficiency of the DAB converter.

[0131] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0132] By employing the technical solution of this invention, the input and output voltages of the DAB converter are detected, a virtual output current is obtained based on the output voltage and reference voltage of the DAB converter, the output power is obtained based on the virtual output current and reference voltage, and the efficiency of the DAB converter is obtained based on the output power; furthermore, the voltage transfer ratio of the DAB converter during operation is obtained based on the input voltage, output voltage, and efficiency of the DAB converter. and transmission power The voltage transfer ratio during DAB converter operation and transmission power By incorporating the return power optimization algorithm, the external phase shift angle of the DAB converter is obtained. and internal phase shift angle and pulse width control quantity According to the external phase shift angle of the DAB converter and internal phase shift angle and pulse width control quantity This allows us to obtain the drive signals for the switching transistors in the bridges on both sides of the transformer in the DAB converter, thereby reducing the cost of the system containing the DAB converter and improving its efficiency and dynamic performance.

[0133] According to an embodiment of the present invention, a switching power supply corresponding to a control device for a DAB converter is also provided. This switching power supply may include the control device for the DAB converter described above.

[0134] Since the processing and functions implemented by the switching power supply in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned device, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0135] By employing the technical solution of this invention, the input and output voltages of the DAB converter are detected, a virtual output current is obtained based on the output voltage and reference voltage of the DAB converter, the output power is obtained based on the virtual output current and reference voltage, and the efficiency of the DAB converter is obtained based on the output power; furthermore, the voltage transfer ratio of the DAB converter during operation is obtained based on the input voltage, output voltage, and efficiency of the DAB converter. and transmission power The voltage transfer ratio during DAB converter operation and transmission power By incorporating the return power optimization algorithm, the external phase shift angle of the DAB converter is obtained. and internal phase shift angle and pulse width control quantity According to the external phase shift angle of the DAB converter and internal phase shift angle and pulse width control quantity This allows the DAB converter to obtain the drive signals of the switching transistors in the bridges on both sides of the transformer, enabling the DAB converter to operate reliably under varying operating conditions and improving its dynamic response performance.

[0136] According to an embodiment of the present invention, a storage medium corresponding to a control method for a DAB converter is also provided, the storage medium including a stored program, wherein the program controls the device where the storage medium is located to execute the control method for the DAB converter described above when the program is executed.

[0137] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0138] By employing the technical solution of this invention, the input and output voltages of the DAB converter are detected, a virtual output current is obtained based on the output voltage and reference voltage of the DAB converter, the output power is obtained based on the virtual output current and reference voltage, and the efficiency of the DAB converter is obtained based on the output power; furthermore, the voltage transfer ratio of the DAB converter during operation is obtained based on the input voltage, output voltage, and efficiency of the DAB converter. and transmission power The voltage transfer ratio during DAB converter operation and transmission power By incorporating the return power optimization algorithm, the external phase shift angle of the DAB converter is obtained. and internal phase shift angle and pulse width control quantity According to the external phase shift angle of the DAB converter and internal phase shift angle and pulse width control quantity This allows the DAB converter to obtain the drive signals of the switching transistors in the bridges on both sides of the transformer, enabling the DAB converter to have better dynamic performance and faster response speed under input voltage fluctuations or load jumps.

[0139] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0140] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A control method for a DAB converter, characterized in that, include: Obtain the input voltage of the DAB converter and the output voltage of the DAB converter; Based on the input voltage and output voltage of the DAB converter, a virtual current power control method is used to obtain the voltage transfer ratio and the per-unit value of the actual power transferred by the DAB converter. The output voltage is compared with a reference output voltage, and a virtual output current is obtained through a PI controller. The virtual output current is then multiplied by the reference output voltage to obtain the output power. Based on the efficiency of the DAB converter... The per-unit value of the actual transmission power of the DAB converter is calculated. ; Based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, the external phase shift angle, the internal phase shift angle, and the pulse width control amount of the DAB converter are obtained by using the return power control method. Based on the external phase shift angle, the internal phase shift angle, and the pulse width control value of the DAB converter, the driving signal of the switching transistor in the primary bridge circuit of the transformer in the DAB converter is determined and denoted as the primary driving signal of the transformer in the DAB converter; and the driving signal of the switching transistor in the secondary bridge circuit of the transformer in the DAB converter is determined and denoted as the secondary driving signal of the transformer in the DAB converter. The operation of the switching transistors in the primary bridge circuit of the transformer in the DAB converter is controlled according to the primary drive signal of the transformer in the DAB converter; and the operation of the switching transistors in the secondary bridge circuit of the transformer in the DAB converter is controlled according to the secondary drive signal of the transformer in the DAB converter.

2. The control method for the DAB converter according to claim 1, characterized in that, Based on the input voltage and output voltage of the DAB converter, a virtual current power control method is used to obtain the voltage transfer ratio and the per-unit value of the actual power transferred by the DAB converter, including: Based on the output voltage of the DAB converter, the actual transmission power of the DAB converter is determined using a virtual current power control method. Based on the input voltage of the DAB converter, the output voltage of the DAB converter, and the actual transmission power of the DAB converter, the voltage transmission ratio and the per-unit value of the actual transmission power of the DAB converter are obtained by using a transmission power estimation method.

3. The control method for the DAB converter according to claim 2, characterized in that, Based on the output voltage of the DAB converter, the actual transmission power of the DAB converter is determined using a virtual current power control method, including: The output voltage of the DAB converter is compared with a preset reference voltage to obtain a comparison result; The comparison result is subjected to PI control to obtain the virtual output current; The product of the virtual output current and the set reference voltage is determined as the output power of the DAB converter; The ratio of the output power of the DAB converter to the transmission efficiency of the DAB converter is determined as the actual transmission power of the DAB converter.

4. The control method for the DAB converter according to claim 2, characterized in that, Based on the input voltage, output voltage, and actual transmission power of the DAB converter, a transmission power estimation method is used to obtain the voltage transfer ratio and per-unit value of the actual transmission power of the DAB converter, including: The reference power of the DAB converter is determined based on its input voltage and output voltage; and the error of its output voltage is determined based on its output voltage. The ratio of the actual transmission power of the DAB converter to the reference power of the DAB converter is determined as the per-unit value of the actual transmission power of the DAB converter. The voltage transfer ratio of the DAB converter is determined based on the error of the output voltage of the DAB converter.

5. The control method for the DAB converter according to any one of claims 1 to 4, characterized in that, Based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmitted power of the DAB converter, a return power control method is used to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter, including: Under the given power conditions of the DAB converter, based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, the KKT algorithm is used to optimize the return power of the DAB converter, thereby obtaining the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter.

6. A control device for a DAB converter, characterized in that, include: The acquisition unit is configured to acquire the input voltage of the DAB converter and the output voltage of the DAB converter; The control unit is configured to, based on the input voltage and output voltage of the DAB converter, use a virtual current power control method to obtain the voltage transfer ratio and the per-unit value of the actual power transferred by the DAB converter; compare the output voltage with a reference output voltage, obtain the virtual output current through a PI controller, and multiply the virtual output current by the reference output voltage to obtain the output power. Based on the efficiency of the DAB converter, the per-unit value of the actual transmission power of the DAB converter is calculated. ; The control unit is further configured to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control amount of the DAB converter by using a return power control method based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter. The control unit is further configured to determine, based on the outer phase shift angle of the DAB converter, the inner phase shift angle of the DAB converter, and the pulse width control quantity, the driving signal of the switching transistor in the primary bridge circuit of the transformer in the DAB converter, denoted as the primary driving signal of the transformer in the DAB converter; and to determine, based on the outer phase shift angle of the DAB converter, the inner phase shift angle of the DAB converter, and the pulse width control quantity, denoted as the secondary driving signal of the transformer in the DAB converter; The control unit is further configured to control the operation of the switching transistors in the primary bridge circuit of the transformer in the DAB converter according to the primary drive signal of the transformer in the DAB converter; and to control the operation of the switching transistors in the secondary bridge circuit of the transformer in the DAB converter according to the secondary drive signal of the transformer in the DAB converter.

7. The control device for the DAB converter according to claim 6, characterized in that, The control unit, based on the input voltage and output voltage of the DAB converter, uses a virtual current power control method to obtain the voltage transfer ratio and the per-unit value of the actual transfer power of the DAB converter, including: Based on the output voltage of the DAB converter, the actual transmission power of the DAB converter is determined using a virtual current power control method. Based on the input voltage of the DAB converter, the output voltage of the DAB converter, and the actual transmission power of the DAB converter, the voltage transmission ratio and the per-unit value of the actual transmission power of the DAB converter are obtained by using a transmission power estimation method.

8. The control device for the DAB converter according to claim 7, characterized in that, The control unit determines the actual transmission power of the DAB converter based on the output voltage of the DAB converter using a virtual current power control method, including: The output voltage of the DAB converter is compared with a preset reference voltage to obtain a comparison result; The comparison result is subjected to PI control to obtain the virtual output current; The product of the virtual output current and the set reference voltage is determined as the output power of the DAB converter; The ratio of the output power of the DAB converter to the transmission efficiency of the DAB converter is determined as the actual transmission power of the DAB converter.

9. The control device for the DAB converter according to claim 7, characterized in that, The control unit, based on the input voltage of the DAB converter, the output voltage of the DAB converter, and the actual transmission power of the DAB converter, uses a transmission power estimation method to obtain the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, including: The reference power of the DAB converter is determined based on its input voltage and output voltage; and the error of its output voltage is determined based on its output voltage. The ratio of the actual transmission power of the DAB converter to the reference power of the DAB converter is determined as the per-unit value of the actual transmission power of the DAB converter. The voltage transfer ratio of the DAB converter is determined based on the error of the output voltage of the DAB converter.

10. The control device for the DAB converter according to any one of claims 6 to 9, characterized in that, The control unit, based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, uses a return power control method to obtain the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter, including: Under the given power conditions of the DAB converter, based on the voltage transfer ratio of the DAB converter and the per-unit value of the actual transmission power of the DAB converter, the KKT algorithm is used to optimize the return power of the DAB converter, thereby obtaining the outer phase shift angle, the inner phase shift angle, and the pulse width control quantity of the DAB converter.

11. A switching power supply, characterized in that, include: The control device for the DAB converter as described in any one of claims 6 to 10.

12. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the control method of the DAB converter as described in any one of claims 1 to 5.

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