Control optimization method and system for dual-active-bridge direct-current transformer, medium and terminal

Abstract

The invention discloses a double-active-bridge direct-current transformer control optimization method and system, a medium and a terminal, and the method comprises the steps: controlling a double-active-bridge direct-current transformer which comprises a primary side active full bridge, a secondary side active full bridge and a high-frequency transformer to be in a single-phase-shift control mode, and then obtaining the transmission power and the backflow power of the double-active-bridge direct-current transformer in real time; controlling and adjusting the phase shift duty ratio of the dual-active-bridge direct-current transformer so as to enable the backflow power of the dual-active-bridge direct-current transformer to be greater than or equal to a first preset value and the backflow power and transmission power of the dual-active-bridge direct-current transformer to be greater than a second preset value, and then performing a high-power test on the dual-active-bridge direct-current transformer so as to evaluate the performance of the dual-active-bridge direct-current transformer during operation under a high-power condition; wherein the second preset value is greater than zero; and optimizing a control strategy or a topological structure of the dual-active-bridge direct-current transformer according to a performance evaluation result. According to the invention, the large-power test based on open-loop control is carried out on the dual-active-bridge direct-current transformer by using relatively small active transmission power, so that the requirements on the active power of a power supply and a load are reduced.

Description

Technical Field

[0001] The present invention relates to the field of dual active bridge DC transformer optimization, and in particular to a dual active bridge DC transformer control optimization method, system, medium and terminal. Background Art

[0002] Power electronic circuits play a key role in modern power systems and are widely used in power transmission, power conversion, motor drive, renewable energy access, electric vehicles and other fields. These circuits achieve reliable transmission and efficient use of electric energy through efficient power conversion and control. High-power power electronic circuits usually involve high voltage, high current and high power application scenarios. Their design and manufacturing face many challenges such as high voltage and high current processing, electromagnetic compatibility, reliability and safety. In the process of R&D, production and delivery of high-power power electronic circuits, continuous power testing under full load is a key step to verify its performance and reliability. Through rigorous testing and data analysis, the stability and reliability of the circuit under high load conditions can be ensured, the design can be optimized, and industry standards and user needs can be met, thereby improving the quality and market competitiveness of the product. Among them, the dual active bridge DC transformer (Dual Active Bridge, DAB) is a highly efficient power electronic transformer, which is widely used in modern DC power grids, distributed energy systems, electric vehicle charging piles, data center power supplies and other scenarios that require efficient DC conversion. At present, for dual-active bridge DC transformers, one power test method is to build a test circuit of power supply-dual-active bridge DC transformer-load. At this time, the power supply and load provide all the power required by the dual-active bridge DC transformer. However, the power level of the power supply and load required by this method is relatively high, the equipment is expensive, and it is difficult to meet various application scenarios; another power test method is to power-drag two completely identical dual-active bridge DC transformers. At this time, the power circulates between the two dual-active bridge DC transformers, and the external power supply only needs to provide dissipated power. However, this test method has high requirements on closed-loop control performance, and when implementing a power test of a dual-active bridge DC transformer, two dual-active bridge DC transformers are required. Summary of the invention

[0003] The embodiments of the present invention provide a dual-active bridge DC transformer control optimization method, system, medium and terminal, which ignore reactive return power and only use a smaller active transmission power to perform a high-power test on the dual-active bridge DC transformer based on open-loop control, so as to solve the problem that the power test has a large demand for active power of the power supply and the load, and improve the timeliness and accuracy of performance evaluation and control optimization.

[0004] In order to solve the above technical problems, an embodiment of the present invention provides a dual active bridge DC transformer control optimization method, comprising:

[0005] Controlling the dual active bridge DC transformer to be in a single phase shift control mode, and acquiring the transmission power and return power of the dual active bridge DC transformer in the single phase shift control mode in real time;

[0006] Controlling and adjusting the phase shift duty cycle of the dual active bridge DC transformer so that the return power of the dual active bridge DC transformer is greater than or equal to a first preset value and the return power of the dual active bridge DC transformer and the transmission power of the dual active bridge DC transformer are greater than a second preset value, and then performing a high-power test on the dual active bridge DC transformer to evaluate the performance of the dual active bridge DC transformer when operating under high-power conditions; wherein the second preset value is greater than zero;

[0007] According to the performance evaluation result, the control strategy or topology of the dual active bridge DC transformer is optimized.

[0008] In the implementation of the embodiment of the present invention, the dual active bridge DC transformer is controlled to be in a single phase shift control mode, and the transmission power and return power of the dual active bridge DC transformer in the single phase shift control mode are obtained in real time, and then the phase shift duty cycle of the dual active bridge DC transformer is controlled to adjust so that the return power of the dual active bridge DC transformer is greater than or equal to a first preset value and the return power of the dual active bridge DC transformer and the transmission power of the dual active bridge DC transformer are greater than a second preset value, wherein the second preset value is greater than zero, and by setting a larger second preset value according to actual conditions, it is possible to achieve that the return power is much greater than the active power, and because for circuit components such as the active full bridge and high frequency transformer in the dual active bridge DC transformer, the effects of the transmission power and the return power are equivalent, and the return power is only The return power is transmitted between the primary and secondary sides. For the power supply, the return power is reactive power. Therefore, the power that the power supply and the load need to process at this time is only a small transmission power. The low-power power supply can be used to carry out a high-power test on the dual-active bridge DC transformer to evaluate the stability and reliability of the dual-active bridge DC transformer when operating under high-power conditions, thereby solving the problem of large active power requirements for the power supply and load in the power test. Finally, according to the performance evaluation results, the control strategy or topology of the dual-active bridge DC transformer is optimized to adapt to different application scenarios and load requirements, improve the adaptability and flexibility of the system, and through reasonable power management and optimized control, the stress of the equipment under high load can be reduced, the service life of the equipment can be extended, and the frequency of equipment replacement and maintenance can be reduced. In addition, by controlling the dual active bridge DC transformer in a single phase shift control mode to generate reactive power, and controlling and adjusting the phase shift duty ratio of the dual active bridge DC transformer to control the flow size and direction of power, bidirectional controllable power flow is achieved. This process is open-loop control. The high-power test method based on open-loop control is not affected by the feedback of the output quantity, and will not have stability problems due to feedback delays, thereby improving the timeliness and accuracy of the performance evaluation and control optimization of the dual active bridge DC transformer. In addition, through the parallel design of the input side power supply and the input side capacitor, and the parallel design of the output side load and the output side capacitor, stable power transmission between the power supply and the load is guaranteed, energy loss is reduced, and the conversion efficiency of the system is improved.

[0009] As a preferred solution, the dual active bridge DC transformer further comprises: a primary active full bridge, a secondary active full bridge, a high frequency transformer, an input side power supply, an input side capacitor, an inductor, an output side capacitor and an output side load;

[0010] Wherein, the input side power supply is connected in parallel with the input side capacitor, and the input side capacitor is connected in series with the primary side active full bridge;

[0011] The primary active full bridge is connected to the secondary active full bridge through the high frequency transformer;

[0012] The first end of the inductor is connected to the primary active full bridge, and the second end of the inductor is connected to the first end of the primary coil of the high-frequency transformer;

[0013] A series branch consisting of the output-side load and the output-side power supply is connected in parallel with the output-side capacitor, and the output-side capacitor is connected in series with the secondary-side active full-bridge.

[0014] In the preferred embodiment of the present invention, the primary active full bridge and the secondary active full bridge are connected through a high-frequency transformer, so that the dual active bridge DC transformer can flexibly control power transmission, adapt to different load requirements and input voltage fluctuations, and realize electrical isolation and voltage conversion between the primary and secondary sides through the high-frequency transformer, so that the system can work under high-frequency conditions, reduce the volume and weight of the transformer, and improve the integration and efficiency of the system. In addition, the first end of the inductor is connected to the primary active full bridge, and the second end is connected to the first end of the primary coil of the high-frequency transformer. Such a design helps to filter and stabilize the current, reduce harmonics and electromagnetic interference in the system, and improve the electromagnetic compatibility of the system.

[0015] As a preferred solution, the dual active bridge DC transformer control optimization method further includes:

[0016] The primary side active full bridge comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; wherein the drain of the first switch tube is respectively connected to the first end of the input side capacitor and the drain of the second switch tube, the gate of the first switch tube is respectively connected to the drain of the third switch tube and the first end of the inductor, the gate of the third switch tube is respectively connected to the second end of the input side capacitor and the gate of the fourth switch tube, and the drain of the fourth switch tube is respectively connected to the gate of the second switch tube and the second end of the primary coil of the high-frequency transformer;

[0017] The secondary side active full bridge includes a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube; wherein the drain of the fifth switch tube is respectively connected to the first end of the output side capacitor and the drain of the sixth switch tube, the gate of the fifth switch tube is respectively connected to the drain of the seventh switch tube and the first end of the secondary coil of the high-frequency transformer, the gate of the seventh switch tube is respectively connected to the second end of the output side capacitor and the gate of the eighth switch tube, and the drain of the eighth switch tube is respectively connected to the gate of the sixth switch tube and the second end of the secondary coil of the high-frequency transformer.

[0018] By implementing the preferred scheme of the embodiment of the present invention, the voltage and current stress on each switch tube can be effectively reduced, the service life of the switch tube can be extended, and the reliability of the system can be improved through a reasonable layout and connection method of the switch tubes. In addition, based on the design of an active full bridge composed of multiple switch tubes, the dual active bridge DC transformer can operate under high frequency conditions, reduce the volume and weight of the magnetic components, and improve the integration and response speed of the dual active bridge DC transformer.

[0019] As a preferred solution, the dual active bridge DC transformer is controlled in a single phase shift control mode, and the transmission power of the dual active bridge DC transformer in the single phase shift control mode is obtained in real time, specifically:

[0020] Controlling the switch states of the first switch tube and the fourth switch tube in the primary active full bridge to be the same, the switch states of the second switch tube and the third switch tube to be the same, and the switch states of the first switch tube and the third switch tube to be different, and controlling the switch states of the fifth switch tube and the eighth switch tube in the secondary active full bridge to be the same, the switch states of the sixth switch tube and the seventh switch tube to be the same, and the switch states of the fifth switch tube and the seventh switch tube to be different, so that the dual active bridge DC transformer is in a single phase shift control mode;

[0021] The primary DC side voltage, the secondary DC side voltage and the leakage inductance of the high-frequency transformer are collected in real time, and the turns ratio of the high-frequency transformer, the switching frequency of the switch tube and the phase-shift duty cycle of the dual-active bridge DC transformer are obtained in real time. According to a preset transmission power algorithm, the transmission power of the dual-active bridge DC transformer in single phase-shift control mode is obtained by combining the primary DC side voltage, the secondary DC side voltage, the leakage inductance of the high-frequency transformer, the switching frequency of the switch tube and the phase-shift duty cycle of the dual-active bridge DC transformer.

[0022] The preferred scheme of the embodiment of the present invention is implemented to control the switching states of the diagonal switches in the primary active full bridge to be the same and the switching states of the upper and lower switches to be complementary, and to control the switching states of the diagonal switches in the secondary active full bridge to be the same and the switching states of the upper and lower switches to be complementary, so that the dual active bridge DC transformer is in a single phase shift control mode, and then the primary DC side voltage, the secondary DC side voltage and the leakage inductance of the high-frequency transformer are collected in real time, and the turns ratio of the high-frequency transformer, the switching frequency of the switch tube and the phase shift duty cycle of the dual active bridge DC transformer are obtained in real time, and the transmission power of the dual active bridge DC transformer in the single phase shift control mode is obtained by combining the real-time collected data, and the real-time monitoring and adjustment mechanism is established through the above means, so that the dual active bridge DC transformer can respond quickly to load changes and maintain the stability of the output voltage, so as to improve the dynamic performance of the dual active bridge DC transformer and enhance the application scope of the dual active bridge DC transformer.

[0023] As a preferred solution, the reflux power of the dual active bridge DC transformer in the single phase shift control mode is obtained as follows:

[0024] Controlling the switch states of the first switch tube and the fourth switch tube in the primary active full bridge to be the same, the switch states of the second switch tube and the third switch tube to be the same, and the switch states of the first switch tube and the third switch tube to be different, and controlling the switch states of the fifth switch tube and the eighth switch tube in the secondary active full bridge to be the same, the switch states of the sixth switch tube and the seventh switch tube to be the same, and the switch states of the fifth switch tube and the seventh switch tube to be different, so that the dual active bridge DC transformer is in a single phase shift control mode;

[0025] The primary DC side voltage, the secondary DC side voltage and the leakage inductance of the high-frequency transformer are collected in real time, and the phase-shift duty cycle of the dual-active bridge DC transformer, the turns ratio of the high-frequency transformer and the switching frequency of the switch tube are obtained in real time. According to a preset reflux power algorithm, the reflux power of the dual-active bridge DC transformer in single phase-shift control mode is obtained by combining the primary DC side voltage, the secondary DC side voltage, the leakage inductance of the high-frequency transformer, the phase-shift duty cycle of the dual-active bridge DC transformer, the turns ratio of the high-frequency transformer and the switching frequency of the switch tube.

[0026] A preferred scheme for implementing the embodiment of the present invention is to control the switching states of the diagonal switches in the primary active full bridge to be the same and the switching states of the upper and lower switches to be complementary, and to control the switching states of the diagonal switches in the secondary active full bridge to be the same and the switching states of the upper and lower switches to be complementary, so that the dual active bridge DC transformer is in a single phase shift control mode, and then the primary DC side voltage, the secondary DC side voltage and the leakage inductance of the high-frequency transformer are collected in real time, and the phase shift duty cycle of the dual active bridge DC transformer, the turns ratio of the high-frequency transformer and the switching frequency of the switch tube are obtained in real time, and combined with the real-time collected data, high-precision and real-time reflux power measurement is achieved, thereby reducing the energy loss of the dual active bridge DC transformer during operation, improving the overall conversion efficiency and reducing energy consumption.

[0027] As a preferred solution, the phase shift duty ratio of the dual active bridge DC transformer is obtained as follows:

[0028] When the dual active bridge DC transformer is in a single phase shift control mode, the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge is collected in real time, and the switching period of the dual active bridge DC transformer is obtained;

[0029] According to a preset phase-shift duty cycle algorithm, based on the time that the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge, and the switching period of the dual active bridge DC transformer, the phase-shift duty cycle of the dual active bridge DC transformer is analyzed and obtained.

[0030] The preferred scheme of implementing the embodiment of the present invention collects in real time the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge, and combines the switching cycle of the dual active bridge DC transformer to accurately calculate the phase shift duty cycle of the dual active bridge DC transformer, which helps to achieve precise phase shift control and optimize power transmission efficiency.

[0031] In order to solve the same technical problem, an embodiment of the present invention further provides a dual active bridge DC transformer control optimization system, comprising:

[0032] A control acquisition module, used to control the dual active bridge DC transformer to be in a single phase shift control mode, and to acquire the transmission power and return power of the dual active bridge DC transformer in the single phase shift control mode in real time; wherein the dual active bridge DC transformer comprises a primary side active full bridge, a secondary side active full bridge and a high frequency transformer;

[0033] A control and analysis module, used for controlling and adjusting the phase shift duty ratio of the dual active bridge DC transformer, so that the return power of the dual active bridge DC transformer is greater than or equal to a first preset value and the return power of the dual active bridge DC transformer and the transmission power of the dual active bridge DC transformer are greater than a second preset value, and then performing a high-power test on the dual active bridge DC transformer to evaluate the performance of the dual active bridge DC transformer when operating under high-power conditions; wherein the second preset value is greater than zero;

[0034] The optimization module is used to optimize the control strategy or topology structure of the dual active bridge DC transformer according to the performance evaluation result.

[0035] As a preferred solution, the dual active bridge DC transformer control optimization system further includes:

[0036] The acquisition and analysis module is used to collect in real time the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge when the dual active bridge DC transformer is in a single phase shift control mode, and obtain the switching period of the dual active bridge DC transformer; according to a preset phase shift duty cycle algorithm, based on the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge, and the switching period of the dual active bridge DC transformer, analyze and obtain the phase shift duty cycle of the dual active bridge DC transformer.

[0037] In order to solve the same technical problem, the present invention also provides a computer-readable storage medium, which includes a stored computer program; wherein, when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the dual active bridge DC transformer control optimization method.

[0038] In order to solve the same technical problem, the present invention also provides a terminal, including a processor, a memory and a computer program stored in the memory; wherein the computer program can be executed by the processor to implement the dual active bridge DC transformer control optimization method. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 : A flow chart of a dual active bridge DC transformer control optimization method provided in Embodiment 1 of the present invention;

[0040] Figure 2 : A topological diagram of a dual active bridge DC transformer provided in Embodiment 1 of the present invention;

[0041] Figure 3 : A topological current and voltage waveform diagram of a dual active bridge DC transformer provided in the first embodiment of the present invention;

[0042] Figure 4 : A structural schematic diagram of a dual active bridge DC transformer control optimization system provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Embodiment one:

[0045] Please refer to Figure 1 , is a dual active bridge DC transformer control optimization method provided by an embodiment of the present invention, the method includes steps S1 to S3, each step is specifically as follows:

[0046] Step S1, controlling the dual active bridge DC transformer to be in a single phase shift control mode, and acquiring the transmission power and return power of the dual active bridge DC transformer in the single phase shift control mode in real time.

[0047] Please refer to Figure 2, a dual active bridge DC transformer, including a primary side active full bridge, a secondary side active full bridge and a high frequency transformer.

[0048] As a preferred option, please refer to Figure 2 , dual active bridge DC transformer, also includes: input side power supply V i , input side capacitor C in 、Inductance L k , output side capacitor C and output side load R.

[0049] Among them, the input side power supply V i With the input side capacitor C in In parallel, input side capacitor C in Connected in series with the primary side active full bridge.

[0050] The primary active full bridge is connected through a leakage inductance value L k A high-frequency transformer is connected to the secondary side active full bridge.

[0051] The first end of the inductor is connected to the primary active full bridge, and the second end of the inductor is connected to the first end of the primary coil of the high-frequency transformer.

[0052] A series branch consisting of an output side load and an output side power supply is connected in parallel with an output side capacitor C, and the output side capacitor is connected in series with the secondary side active full bridge.

[0053] In this embodiment, the primary active full bridge and the secondary active full bridge each include four switch tubes, and the switch tubes of the active full bridge on each side operate with a high-frequency square wave with a duty cycle of 50% and a voltage equal to the DC bus voltage. Based on the existence of the high-frequency transformer leakage inductance Lk, the flow size and direction of power can be controlled by controlling the phase shift of the active bridges on both sides, thereby realizing a bidirectional controllable flow of power, and the power flows from the side generating the leading square wave to the side generating the lagging square wave.

[0054] As a preferred option, please refer to Figure 2 , the composition of the primary side active full bridge and the secondary side active full bridge is as follows:

[0055] The primary side active full bridge includes the first switch tube S 1 , the second switch tube S 2 , the third switch tube S 3 and the fourth switch tube S 4 ; Among them, the drain of the first switching tube is respectively connected to the first end of the input side capacitor and the drain of the second switching tube, the gate of the first switching tube is respectively connected to the drain of the third switching tube and the first end of the inductor, the gate of the third switching tube is respectively connected to the second end of the input side capacitor and the gate of the fourth switching tube, and the drain of the fourth switching tube is respectively connected to the gate of the second switching tube and the second end of the primary coil of the high-frequency transformer.

[0056] The secondary side active full bridge includes the fifth switch tube S 5 , the sixth switch tube S 6 , the seventh switch tube S 7 and the eighth switch tube S 8 ; Among them, the drain of the fifth switch tube is respectively connected to the first end of the output side capacitor and the drain of the sixth switch tube, the gate of the fifth switch tube is respectively connected to the drain of the seventh switch tube and the first end of the secondary coil of the high-frequency transformer, the gate of the seventh switch tube is respectively connected to the second end of the output side capacitor and the gate of the eighth switch tube, and the drain of the eighth switch tube is respectively connected to the gate of the sixth switch tube and the second end of the secondary coil of the high-frequency transformer.

[0057] As a preferred solution, step S1 includes steps S11 to S13, and each step is specifically as follows:

[0058] Step S11, control the switching states of the first switch tube and the fourth switch tube in the primary active full bridge to be the same, the switching states of the second switch tube and the third switch tube to be the same, and the switching states of the first switch tube and the third switch tube to be different, and control the switching states of the fifth switch tube and the eighth switch tube in the secondary active full bridge to be the same, the switching states of the sixth switch tube and the seventh switch tube to be the same, and the switching states of the fifth switch tube and the seventh switch tube to be different, that is, the switching states of the diagonal switch tubes in the primary active full bridge are the same, and the switching states of the upper and lower switch tubes are complementary, and the switching states of the diagonal switch tubes in the secondary active full bridge are the same, and the switching states of the upper and lower switch tubes are complementary, so that the dual active bridge DC transformer is in a single phase shift control mode.

[0059] Step S12, real-time acquisition of the primary DC side voltage, the secondary DC side voltage and the leakage inductance of the high-frequency transformer, and real-time acquisition of the turns ratio of the high-frequency transformer, the switching frequency of the switch tube and the phase-shift duty cycle of the dual active bridge DC transformer, and according to a preset transmission power algorithm, combined with the primary DC side voltage, the secondary DC side voltage, the leakage inductance of the high-frequency transformer, the switching frequency of the switch tube, and the phase-shift duty cycle of the dual active bridge DC transformer, the transmission power of the dual active bridge DC transformer in the single phase-shift control mode is analyzed.

[0060] As a preferred solution, the process of obtaining the phase shift duty ratio of the dual active bridge DC transformer includes steps S01 to S02, and each step is specifically as follows:

[0061] Step S01, when the dual active bridge DC transformer is in a single phase shift (SPS) control mode, the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge is collected in real time, and the switching period of the dual active bridge DC transformer is obtained.

[0062] Step S02, according to a preset phase-shift duty cycle algorithm, based on the time that the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge, and the switching cycle of the dual active bridge DC transformer, the phase-shift duty cycle of the dual active bridge DC transformer is analyzed and obtained. For the preset phase-shift duty cycle algorithm, please refer to formula (1) for details.

[0063]

[0064] In the formula, Indicates the phase shift duty cycle of the dual active bridge DC transformer; please refer to Figure 3 , t 0 Indicates the first switch tube S 1 and the fourth switch tube S 4 The second switch tube S is turned on and 2 and the third switch tube S 3 The moment of shutting down is also t 0 The start time of the switching cycle, t 2 Indicates the fifth switch tube S 5 and the eighth switch tube S 8 The sixth switch tube S is turned on and 6 and the seventh switch tube S 7 The moment of shut-off, therefore (t 2 -t 0 ) represents the time that the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge; t 1 The current i flowing through the inductor Lk The moment when t is equal to 0; 3 Indicates the second switch tube S 2 and the third switch tube S 3 The first switch tube S is turned on and 1 and the fourth switch tube S 4 Turn off time; t 4 The current i flowing through the inductor Lk The moment when it is equal to 0 again; t 5 Indicates the sixth switch tube S 6 and the seventh switch tube S 7 The fifth switch tube S is turned on and 5 and the eighth switch tube S 8 The time of shut-off, t 0 ,t 1 ,t 2 ,t 3 ,t 4 With t 5 In the same switching cycle; and t 6 Indicates the start time of the next switching cycle, that is, the first switch tube S in the next switching cycle 1 and the fourth switch tube S4 The second switch tube S is turned on and 2 and the third switch tube S 3 Turn off time; T hs Represents half a switching cycle of the dual active bridge DC transformer.

[0065] The preset transmission power algorithm is specifically shown in formula (2).

[0066]

[0067] Where P O represents the transmission power of the dual active bridge DC transformer in single phase shift control mode; T hs represents half a switching cycle of the dual active bridge DC transformer; t 0 represents the time when the first switch tube and the fourth switch tube are turned on and the second switch tube and the third switch tube are turned off, which is also t 0 The start time of the switching cycle; t 3 represents the time when the second switch tube and the third switch tube are turned on and the first switch tube and the fourth switch tube are turned off, t 0 With t 3 In the same switching cycle; V 1 Represents the AC voltage of the primary active full bridge; i Lk represents the current flowing through the inductor; n represents the turns ratio of the high-frequency transformer; t 6 Indicates t 0 The end time of the switching cycle; V 2 Represents the AC voltage of the secondary active full bridge; v i Represents the primary DC side voltage; i ia Represents the primary DC side current; v o Indicates the secondary DC side voltage; L k Represents the leakage inductance of the high-frequency transformer; represents the phase shift duty cycle of the dual active bridge DC transformer; f sw Indicates the switching frequency of the switch tube.

[0068] Step S13, real-time acquisition of the primary DC side voltage, the secondary DC side voltage and the leakage inductance of the high-frequency transformer, and real-time acquisition of the phase-shift duty cycle of the dual-active bridge DC transformer, the turns ratio of the high-frequency transformer and the switching frequency of the switch tube, and according to a preset reflux power algorithm, combined with the primary DC side voltage, the secondary DC side voltage, the leakage inductance of the high-frequency transformer, the phase-shift duty cycle of the dual-active bridge DC transformer, the turns ratio of the high-frequency transformer, and the switching frequency of the switch tube, the reflux power of the dual-active bridge DC transformer in the single phase-shift control mode is analyzed.

[0069] Please note that, please refer to Figure 3 , in one switching cycle, at t0 to 1 Time period and t 3 to 4 During this period, the current i flowing through the inductor Lk The AC voltage V of the primary active full bridge 1 The direction is opposite to that at t 1 to 2 Time period and t 4 to 5 During this period, the current i flowing through the inductor Lk The AC voltage V of the secondary active full bridge 2 The direction of the inductor is opposite to that of the input power supply, that is, in these two periods, the inductor energy is transmitted back to the input power supply in the opposite direction, which is called the return power. According to the symmetry of the waveform, the return power in the two periods is equal. Therefore, the preset return power algorithm, please refer to formula (3) for details.

[0070]

[0071] Where P reac,SPS represents the reflux power of the dual active bridge DC transformer in single phase shift control mode; P reac,SPS,o It means (t 1 -t 2 ) period or (t 4 -t 5 ) period of reflux power; P reac,SPS,i It means (t 0 -t 1 ) period or (t 3 -t 4 ) period of return power; t 0 represents the time when the first switch tube and the fourth switch tube are turned on and the second switch tube and the third switch tube are turned off, which is also t 0 The start time of the switching cycle; t 1 Indicates the moment when the current flowing through the inductor is equal to 0; t 2 represents the time when the fifth switch tube and the eighth switch tube are turned on and the sixth switch tube and the seventh switch tube are turned off; t 3 represents the time when the second switch tube and the third switch tube are turned on and the first switch tube and the fourth switch tube are turned off; t 4 Indicates the moment when the current flowing through the inductor equals 0 again; t 5 represents the time when the sixth switch tube and the seventh switch tube are turned on and the fifth switch tube and the eighth switch tube are turned off, t 0 ,t 1 ,t 2 ,t 3 ,t 4 With t 5 In the same switching cycle; T hsRepresents half a switching cycle of the dual active bridge DC transformer; V 2 Represents the AC voltage of the secondary active full bridge; i Lk Represents the current flowing through the inductor; V 1 Represents the AC voltage of the primary active full bridge; v i Indicates the primary DC side voltage; v o Indicates the secondary DC side voltage; represents the phase shift duty cycle of the dual active bridge DC transformer; M represents a constant; n represents the turns ratio of the high frequency transformer; f sw Indicates the switching frequency of the switch tube; L k Represents the leakage inductance of the high-frequency transformer.

[0072] Step S2, controlling and adjusting the phase shift duty cycle of the dual active bridge DC transformer so that the return power of the dual active bridge DC transformer is greater than or equal to a first preset value and the return power of the dual active bridge DC transformer and the transmission power of the dual active bridge DC transformer are greater than a second preset value, and then performing a high-power test on the dual active bridge DC transformer to evaluate the stability and reliability of the dual active bridge DC transformer when operating under high-power conditions.

[0073] Wherein, the second preset value is greater than zero.

[0074] In this embodiment, according to actual needs, the second preset value is set to be as large as possible so that in the process of controlling and adjusting the phase shift duty cycle of the dual active bridge DC transformer, the transmission power of the dual active bridge DC transformer can be much smaller than the return power. At this time, the power that the power supply and the load need to process is only the transmission power, thereby achieving active power optimization.

[0075] It should be noted that, by observing equations (2) and (3), the transmission power P O Phase shift duty cycle A quadratic relationship, when It reaches its maximum value when or 1:P O =0. When M=1, the reflux power P reac,SPS along with As the power increases, the transmission power P O and return power P reac,SPS The effects produced are equivalent. Therefore, controlling the phase shift duty cycle Exceeding 0.5 and approaching 1, the reflux power P reac,SPS is greater than or equal to the first preset value, that is, the power test requirement is met, and the transmission power P O Much smaller than the return power P reac,SPSSince the reflux power is only transferred between the primary and secondary sides, it is reactive power for the power supply. Therefore, a high-power test is performed on the dual active bridge DC transformer at this time. The power that the power supply and load need to handle is only a small active transmission power P O In the process of realizing high-power testing of power electronic circuits using a small power supply, if the device temperature reaches thermal equilibrium after a certain period of time (such as 1 hour) and no longer rises, it indicates that the stability requirement has been met; if the device temperature still rises or thermal damage occurs after a certain period of time (such as 1 hour), it indicates that the stability requirement has not been met.

[0076] Step S3, optimizing the control strategy or topology of the dual active bridge DC transformer according to the performance evaluation result.

[0077] Please refer to Figure 4 , is a structural diagram of a dual active bridge DC transformer control optimization system provided by an embodiment of the present invention, the system includes a control acquisition module M1, a control analysis module M2 and an optimization module M3, and each module is specifically as follows:

[0078] The control acquisition module M1 is used to control the dual active bridge DC transformer to be in a single phase shift control mode, and to acquire the transmission power and return power of the dual active bridge DC transformer in the single phase shift control mode in real time;

[0079] The control and analysis module M2 is used to control and adjust the phase shift duty cycle of the dual active bridge DC transformer so that the return power of the dual active bridge DC transformer is greater than or equal to a first preset value and the return power of the dual active bridge DC transformer and the transmission power of the dual active bridge DC transformer are greater than a second preset value, and then a high-power test is performed on the dual active bridge DC transformer to evaluate the performance of the dual active bridge DC transformer when operating under high-power conditions; wherein the second preset value is greater than zero;

[0080] The optimization module M3 is used to optimize the control strategy or topology structure of the dual active bridge DC transformer according to the performance evaluation result.

[0081] As a preferred option, please refer to Figure 4 The dual active bridge DC transformer control optimization system provided by the embodiment of the present invention further includes a collection and analysis module M4, which is specifically as follows:

[0082] The acquisition and analysis module M4 is used to collect the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge in real time when the dual active bridge DC transformer is in the single phase shift control mode, and obtain the switching period of the dual active bridge DC transformer; according to the preset phase shift duty cycle algorithm, based on the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge, and the switching period of the dual active bridge DC transformer, the phase shift duty cycle of the dual active bridge DC transformer is analyzed and obtained.

[0083] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0084] An embodiment of the present invention also provides a computer-readable storage medium, which includes a stored computer program; wherein, when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute a dual active bridge DC transformer control optimization method described in Example 1.

[0085] An embodiment of the present invention also provides a terminal, including a processor, a memory, and a computer program stored in the memory; wherein the computer program can be executed by the processor to implement a dual active bridge DC transformer control optimization method described in Example 1.

[0086] Preferably, the computer program can be divided into one or more modules / units (such as computer program, computer program), one or more modules / units are stored in the memory and executed by the processor to complete the present invention. One or more modules / units can be a series of computer program instruction segments that can complete specific functions, and the instruction segments are used to describe the execution process of the computer program in the terminal.

[0087] The processor can 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. The general-purpose processor can be a microprocessor, or the processor can also be any conventional processor. The processor is the control center of the terminal, and various parts of the terminal are connected using various interfaces and lines.

[0088] The memory mainly includes a program storage area and a data storage area, wherein the program storage area can store an operating system, an application required for at least one function, etc., and the data storage area can store related data, etc. In addition, the memory can be a high-speed random access memory, or a non-volatile memory, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, and a flash card (Flash Card), etc., or the memory can also be other volatile solid-state storage devices.

[0089] It should be noted that the above-mentioned terminal may include, but is not limited to, a processor and a memory. Those skilled in the art will understand that the above-mentioned terminal is merely an example and does not constitute a limitation on the terminal. It may include more or fewer components, or a combination of certain components, or different components.

[0090] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0091] The present invention provides a dual-active bridge DC transformer control optimization method, system, medium and terminal, which control the dual-active bridge DC transformer to be in a single-phase shift control mode, and obtain the transmission power and return power of the dual-active bridge DC transformer in the single-phase shift control mode in real time, and then control and adjust the phase shift duty ratio of the dual-active bridge DC transformer to make the return power of the dual-active bridge DC transformer greater than or equal to a first preset value and the return power of the dual-active bridge DC transformer and the transmission power of the dual-active bridge DC transformer greater than a second preset value, wherein the second preset value is greater than zero, and by setting a larger second preset value according to actual conditions, it is possible to achieve that the return power is much greater than the active power, and because for circuit components such as an active full bridge and a high-frequency transformer in the dual-active bridge DC transformer, the effect of the transmission power and the return power are equivalent, and the return power is only transmitted between the original and secondary sides. For the power supply, the return power is reactive power. Therefore, the power that the power supply and the load need to process at this time is only a small transmission power. The low-power power supply can be used to carry out a high-power test on the dual-active bridge DC transformer to evaluate the stability and reliability of the dual-active bridge DC transformer when running under high-power conditions, thereby solving the problem of large active power requirements for the power supply and load in the power test. Finally, according to the performance evaluation results, the control strategy or topology of the dual-active bridge DC transformer is optimized to adapt to different application scenarios and load requirements, improve the adaptability and flexibility of the system, and through reasonable power management and optimized control, the stress of the equipment under high load can be reduced, the service life of the equipment can be extended, and the frequency of equipment replacement and maintenance can be reduced. In addition, by controlling the dual active bridge DC transformer in a single phase shift control mode to generate reactive power, and controlling and adjusting the phase shift duty cycle of the dual active bridge DC transformer to control the size and direction of power flow, bidirectional controllable power flow is achieved. This process is open-loop control. The high-power test method based on open-loop control is not affected by the feedback of the output quantity, and will not have stability problems due to feedback delays, thereby improving the timeliness and accuracy of performance evaluation and dual active bridge DC transformer control optimization.

[0092] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dual active bridge DC transformer control optimization method, characterized in that: include: Controlling the dual active bridge DC transformer to be in a single phase shift control mode, and acquiring the transmission power and return power of the dual active bridge DC transformer in the single phase shift control mode in real time; Controlling and adjusting the phase shift duty ratio of the dual active bridge DC transformer so that the return power of the dual active bridge DC transformer is greater than or equal to a first preset value and the return power of the dual active bridge DC transformer and the transmission power of the dual active bridge DC transformer are greater than a second preset value, performing a high power test on the dual active bridge DC transformer to evaluate the performance of the dual active bridge DC transformer when operating under high power conditions; wherein the second preset value is greater than zero; According to the performance evaluation result, the control strategy or topology of the dual active bridge DC transformer is optimized.

2. A dual active bridge DC transformer control optimization method as claimed in claim 1, characterized in that: The dual active bridge DC transformer also includes: a primary active full bridge, a secondary active full bridge, a high frequency transformer, an input side power supply, an input side capacitor, an inductor, an output side capacitor and an output side load; Wherein, the input side power supply is connected in parallel with the input side capacitor, and the input side capacitor is connected in series with the primary side active full bridge; The primary active full bridge is connected to the secondary active full bridge through the high frequency transformer; The first end of the inductor is connected to the primary active full bridge, and the second end of the inductor is connected to the first end of the primary coil of the high-frequency transformer; A series branch consisting of the output-side load and the output-side power supply is connected in parallel with the output-side capacitor, and the output-side capacitor is connected in series with the secondary-side active full-bridge.

3. A dual active bridge DC transformer control optimization method as claimed in claim 2, characterized in that: The primary side active full bridge comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; wherein the drain of the first switch tube is respectively connected to the first end of the input side capacitor and the drain of the second switch tube, the gate of the first switch tube is respectively connected to the drain of the third switch tube and the first end of the inductor, the gate of the third switch tube is respectively connected to the second end of the input side capacitor and the gate of the fourth switch tube, and the drain of the fourth switch tube is respectively connected to the gate of the second switch tube and the second end of the primary coil of the high-frequency transformer; The secondary side active full bridge includes a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube; wherein the drain of the fifth switch tube is respectively connected to the first end of the output side capacitor and the drain of the sixth switch tube, the gate of the fifth switch tube is respectively connected to the drain of the seventh switch tube and the first end of the secondary coil of the high-frequency transformer, the gate of the seventh switch tube is respectively connected to the second end of the output side capacitor and the gate of the eighth switch tube, and the drain of the eighth switch tube is respectively connected to the gate of the sixth switch tube and the second end of the secondary coil of the high-frequency transformer.

4. A dual active bridge DC transformer control optimization method as claimed in claim 3, characterized in that: The controlling the dual active bridge DC transformer to be in a single phase shift control mode and obtaining the transmission power of the dual active bridge DC transformer in the single phase shift control mode in real time is specifically as follows: Controlling the switch states of the first switch tube and the fourth switch tube in the primary active full bridge to be the same, the switch states of the second switch tube and the third switch tube to be the same, and the switch states of the first switch tube and the third switch tube to be different, and controlling the switch states of the fifth switch tube and the eighth switch tube in the secondary active full bridge to be the same, the switch states of the sixth switch tube and the seventh switch tube to be the same, and the switch states of the fifth switch tube and the seventh switch tube to be different, so that the dual active bridge DC transformer is in a single phase shift control mode; The primary DC side voltage, the secondary DC side voltage and the leakage inductance of the high-frequency transformer are collected in real time, and the turns ratio of the high-frequency transformer, the switching frequency of the switch tube and the phase-shift duty cycle of the dual-active bridge DC transformer are obtained in real time. According to a preset transmission power algorithm, the transmission power of the dual-active bridge DC transformer in single phase-shift control mode is obtained by combining the primary DC side voltage, the secondary DC side voltage, the leakage inductance of the high-frequency transformer, the switching frequency of the switch tube and the phase-shift duty cycle of the dual-active bridge DC transformer.

5. A dual active bridge DC transformer control optimization method as claimed in claim 3, characterized in that: The acquisition of the reflux power of the dual active bridge DC transformer in the single phase shift control mode is specifically as follows: Controlling the switch states of the first switch tube and the fourth switch tube in the primary active full bridge to be the same, the switch states of the second switch tube and the third switch tube to be the same, and the switch states of the first switch tube and the third switch tube to be different, and controlling the switch states of the fifth switch tube and the eighth switch tube in the secondary active full bridge to be the same, the switch states of the sixth switch tube and the seventh switch tube to be the same, and the switch states of the fifth switch tube and the seventh switch tube to be different, so that the dual active bridge DC transformer is in a single phase shift control mode; The primary DC side voltage, the secondary DC side voltage and the leakage inductance of the high-frequency transformer are collected in real time, and the phase-shift duty cycle of the dual-active bridge DC transformer, the turns ratio of the high-frequency transformer and the switching frequency of the switch tube are obtained in real time. According to a preset reflux power algorithm, the reflux power of the dual-active bridge DC transformer in single phase-shift control mode is obtained by combining the primary DC side voltage, the secondary DC side voltage, the leakage inductance of the high-frequency transformer, the phase-shift duty cycle of the dual-active bridge DC transformer, the turns ratio of the high-frequency transformer and the switching frequency of the switch tube.

6. A dual active bridge DC transformer control optimization method as claimed in claim 3, characterized in that: The acquisition of the phase shift duty ratio of the dual active bridge DC transformer is specifically as follows: When the dual active bridge DC transformer is in a single phase shift control mode, the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge is collected in real time, and the switching period of the dual active bridge DC transformer is obtained; According to a preset phase-shift duty cycle algorithm, based on the time that the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge, and the switching period of the dual active bridge DC transformer, the phase-shift duty cycle of the dual active bridge DC transformer is analyzed and obtained.

7. A dual active bridge DC transformer control optimization system, characterized in that: include: A control acquisition module, used to control the dual active bridge DC transformer to be in a single phase shift control mode, and to acquire the transmission power and return power of the dual active bridge DC transformer in the single phase shift control mode in real time; A control and analysis module, used for controlling and adjusting the phase shift duty ratio of the dual active bridge DC transformer, so that the return power of the dual active bridge DC transformer is greater than or equal to a first preset value and the return power of the dual active bridge DC transformer and the transmission power of the dual active bridge DC transformer are greater than a second preset value, and then performing a high-power test on the dual active bridge DC transformer to evaluate the performance of the dual active bridge DC transformer when operating under high-power conditions; wherein the second preset value is greater than zero; The optimization module is used to optimize the control strategy or topology structure of the dual active bridge DC transformer according to the performance evaluation result.

8. A dual active bridge DC transformer control optimization system as claimed in claim 7, characterized in that: Also includes: The acquisition and analysis module is used to collect in real time the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge when the dual active bridge DC transformer is in a single phase shift control mode, and obtain the switching period of the dual active bridge DC transformer; according to a preset phase shift duty cycle algorithm, based on the time when the action of the switch tube in the secondary active full bridge lags behind the action of the switch tube in the primary active full bridge, and the switching period of the dual active bridge DC transformer, analyze and obtain the phase shift duty cycle of the dual active bridge DC transformer.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored computer program; wherein, when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute a dual active bridge DC transformer control optimization method as described in any one of claims 1 to 6.

10. A terminal, characterized in that: It comprises a processor, a memory and a computer program stored in the memory; wherein the computer program can be executed by the processor to implement a dual active bridge DC transformer control optimization method as described in any one of claims 1 to 6.

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