Optimization method, device and equipment of bidirectional active full-bridge transformer and storage medium

Abstract

The application discloses a bidirectional active full-bridge transformer optimization method, device, equipment and storage medium, and the method comprises the following steps: dividing the running state of the transformer into boost, buck and matching states; in the boost state, determining a plurality of first modes according to the phase shift time, the dead time, the off time of the secondary side and primary side devices, the inductor current zero-crossing time and the inductor current direction at the off time of the primary side devices, obtaining characteristic data in each first mode; different from the boost state, in the buck state, a plurality of second modes are determined according to the inductor current direction at the off time of the secondary side devices, and characteristic data in each second mode is obtained; in the matching state, a plurality of third modes are determined according to the inductor current direction at the off time of the secondary side devices, the off time of the primary side devices and the inductor current zero-crossing time, and characteristic data in each third mode is obtained; and the leakage inductance parameters of the transformer are optimized according to the characteristic data. The application can optimize the leakage inductance parameters of the transformer and improve the power transmission performance.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and in particular to a method, apparatus, equipment, and storage medium for optimizing bidirectional active full-bridge transformers. Background Technology

[0002] Transformers are essential devices for converting electrical energy and are a key component of power systems. Large-capacity medium-frequency isolation transformers are crucial for achieving grid interconnection, high-voltage electrical isolation, and high-power transmission in DC transmission and distribution systems, and are an effective means of improving the overall power density of the system.

[0003] Unlike traditional power frequency isolation transformers in power systems, large-capacity intermediate frequency isolation transformers, as the core basic components of power electronic transformers (PETs), often exhibit characteristics such as high operating frequency, high voltage change rate (dv / dt), high current change rate (di / dt), high power density, high integration, and high loss density. Large-capacity intermediate frequency isolation transformers face challenges such as enhanced skin and proximity effects, significantly increased core and winding losses, severe temperature rise, and large leakage flux losses. Simultaneously, complex high-frequency port modes of power electronic transformers, such as voltage polarity reversal, phase drift, transient bias, and AC link oscillation, also affect the transformer body.

[0004] In practical operation, to prevent bridge arm shoot-through, dead time must be added to the switching transistors of a transformer. However, increasing the dead time will change the switching characteristics of the converter; especially under high frequency and light load conditions, the larger the proportion of dead time in the switching cycle, the more obvious the impact on the switching characteristics, causing AC port waveform distortion, which in turn leads to inaccurate design of power electronic transformer parameters. Summary of the Invention

[0005] The purpose of this invention is to provide a method, apparatus, device, and storage medium for optimizing bidirectional active full-bridge transformers, in order to solve the technical problem in the prior art that the impact of the difference between dead time and phase shift time on transformer characteristics is not evaluated, resulting in inaccurate transformer parameter design.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] Option 1: This invention provides an optimization method for bidirectional active full-bridge transformers, including:

[0008] Based on the voltage transformation ratio, the operating states of bidirectional active full-bridge transformers are divided into step-up state, step-down state, and matching state.

[0009] For the boost state, several first modes are determined based on the phase shift time, dead time, turn-off time of the secondary device, turn-off time of the primary device, zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the primary device. Characteristic data of the transformer in each first mode are obtained. The characteristic data includes inductor voltage and inductor current data when the transformer experiences voltage polarity reversal and / or phase drift. The inductor voltage is determined based on the primary side voltage and secondary side voltage of the transformer.

[0010] For the step-down state, several second modes are determined based on the phase shift time, the dead time, the turn-off time of the secondary device, the turn-off time of the primary device, the zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the secondary device, and the characteristic data of the transformer in each second mode are obtained.

[0011] For the matching state, several third modes are determined based on the direction of the inductor current at the turn-off time of the secondary device, the turn-off time of the primary device, and the zero-crossing time of the inductor current, and the characteristic data of the transformer in each of the third modes are obtained.

[0012] The leakage inductance parameters of the transformer are optimized based on the aforementioned characteristic data to improve the power transmission and leakage flux loss performance of the transformer.

[0013] Optionally, the turn-off time of the primary-side device includes the turn-off time of the first primary-side device and the turn-off time of the second primary-side device, and the turn-off time of the secondary-side device includes the turn-off time of the first secondary-side device and the turn-off time of the second secondary-side device. The step of determining several first modes for the boost state based on the phase shift time, dead time, turn-off time of the secondary-side device, turn-off time of the primary-side device, inductor current zero-crossing time, and the inductor current direction at the turn-off or turn-on time of the primary-side device includes:

[0014] When the phase shift time is greater than or equal to the dead time, and the inductor current direction at the turn-off time of the primary-side first device is positive, and the first time difference is greater than or equal to the dead time, the first first mode is obtained.

[0015] When the phase shift time is greater than or equal to the dead time, and the inductor current direction at the turn-off time of the primary-side first device is positive, and the first time difference is less than the dead time, a second first mode is obtained.

[0016] When the phase shift time is greater than or equal to the dead time, and the direction of the inductor current at the moment the primary-side first device is turned off is negative, the third first mode is obtained;

[0017] When the phase shift time is less than the dead time, and the inductor current direction at the turn-off time of the primary-side first device is positive, and the second time difference is greater than or equal to the dead time, the fourth first mode is obtained.

[0018] When the phase shift time is less than the dead time, and the inductor current direction at the turn-off time of the primary-side first device is positive, and the second time difference is less than the dead time, the fifth first mode is obtained;

[0019] When the phase shift time is less than the dead time and the direction of the inductor current at the moment the primary-side first device is turned off is negative, the sixth first mode is obtained;

[0020] Wherein, the first time difference is the time difference between the zero-crossing moment of the inductor current and the turn-off moment of the first device on the primary side; the second time difference is the time difference between the zero-crossing moment of the inductor current and the turn-off moment of the second device on the secondary side.

[0021] Optionally, the turn-off time of the primary-side device includes the turn-off time of the first primary-side device and the turn-off time of the second primary-side device, and the turn-off time of the secondary-side device includes the turn-off time of the first secondary-side device and the turn-off time of the second secondary-side device. For the buck state, the step of determining several second modes based on the phase shift time, the dead time, the turn-off time of the secondary-side device, the turn-off time of the primary-side device, the zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the secondary-side device includes:

[0022] When the phase shift time is greater than or equal to the dead time, and the inductor current direction at the turn-off time of the secondary side second device is positive, and the first time difference is greater than or equal to the dead time, the first second mode is obtained;

[0023] When the phase shift time is greater than or equal to the dead time, and the inductor current direction at the turn-off time of the second secondary device is positive, and the first time difference is less than the dead time, a second second mode is obtained.

[0024] When the phase shift time is less than the dead time, and the inductor current direction at the turn-off time of the second secondary device is positive, and the third time difference is less than or equal to the phase shift time, the third second mode is obtained.

[0025] When the phase shift time is less than the dead time, the inductor current direction at the turn-off time of the second secondary device is positive, and the third time difference is greater than or equal to the phase shift time, a fourth second mode is obtained.

[0026] When the inductor current direction is negative at the time the second device on the secondary side is turned off, and the dead time is greater than or equal to the time difference between the initial dead time and the phase shift time, the fifth second mode is obtained.

[0027] When the inductor current direction is negative at the time the second device on the secondary side is turned off, and the dead time is less than the time difference between the initial dead time and the phase shift time, the sixth second mode is obtained.

[0028] Wherein, the first time difference is the time difference between the zero-crossing moment of the inductor current and the turn-off moment of the first device on the primary side; the second time difference is the time difference between the zero-crossing moment of the inductor current and the turn-off moment of the second device on the secondary side; the third time difference is the time difference between the turn-off moment of the first device on the secondary side and the zero-crossing moment of the inductor current; and the initial dead time is the dead time that makes the inductor current zero at the turn-off moment of the first device on the secondary side.

[0029] Optionally, the turn-off time of the primary-side device includes the turn-off time of the first primary-side device and the turn-off time of the second primary-side device, and the turn-off time of the secondary-side device includes the turn-off time of the first secondary-side device and the turn-off time of the second secondary-side device. For the matched state, the step of determining several third modes based on the inductor current direction at the turn-off time of the secondary-side device, the turn-off time of the primary-side device, and the zero-crossing time of the inductor current includes:

[0030] When the inductor current direction is positive at the time the second device on the secondary side is turned off, and the first time difference is greater than or equal to the dead time, the first third mode is obtained.

[0031] When the inductor current direction is positive at the time the second device on the secondary side is turned off, and the first time difference is less than the dead time, the second third mode is obtained.

[0032] When the direction of the inductor current is negative at the moment the second device on the secondary side is turned off, the third mode is obtained.

[0033] Optionally, obtaining the characteristic data of the transformer in each of the first modes includes:

[0034] Obtain the inductor voltage and inductor current data of the transformer in each of the first modes;

[0035] Based on the inductor voltage and inductor current data of the first mode, determine whether the transformer exhibits voltage polarity reversal and / or phase drift in different transient states of each of the first modes;

[0036] If the voltage polarity reversal and / or phase drift phenomenon exists in the first mode, the corresponding inductor voltage and inductor current data will be used as characteristic data.

[0037] Optionally, obtaining the characteristic data of the transformer in each of the second modes includes:

[0038] Acquire the inductor voltage and inductor current data of the transformer in each of the second modes;

[0039] Based on the inductor voltage and inductor current data of the second mode, determine whether the transformer exhibits voltage polarity reversal and / or phase drift in different transient states of each of the second modes;

[0040] If the voltage polarity reversal and / or phase drift phenomenon exists in the second mode, the corresponding inductor voltage and inductor current data will be used as characteristic data.

[0041] Optionally, obtaining the characteristic data of the transformer in each of the third modes includes:

[0042] Obtain the inductor voltage and inductor current data of the transformer in each of the third modes;

[0043] Based on the inductor voltage and inductor current data of the third mode, determine whether the transformer exhibits voltage polarity reversal and / or phase drift in different transient states of each of the third modes;

[0044] If the voltage polarity reversal and / or phase drift phenomenon exists in the third mode, the corresponding inductor voltage and inductor current data will be used as characteristic data.

[0045] Option 2: This invention also provides a bidirectional active full-bridge transformer optimization device, comprising:

[0046] The status judgment module is used to classify the operating status of the bidirectional active full-bridge transformer into step-up state, step-down state, and matching state according to the voltage transformation ratio.

[0047] The boost state data acquisition module is used to determine several first modes for the boost state based on phase shift time, dead time, turn-off time of secondary-side devices, turn-off time of primary-side devices, zero-crossing time of inductor current, and the direction of inductor current at the turn-off or turn-on time of the primary-side devices, and to acquire characteristic data of the transformer in each of the first modes; the characteristic data includes inductor voltage and inductor current data when the transformer experiences voltage polarity reversal and / or phase drift, and the inductor voltage is determined based on the primary side voltage and secondary side voltage of the transformer;

[0048] A step-down state data acquisition module is used to determine several second modes for the step-down state based on the phase shift time, the dead time, the turn-off time of the secondary device, the turn-off time of the primary device, the zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the secondary device, and to acquire the characteristic data of the transformer in each of the second modes.

[0049] The matching state data acquisition module is used to determine several third modes based on the inductor current direction at the turn-off time of the secondary device, the turn-off time of the primary device, and the zero-crossing time of the inductor current for the matching state, and to acquire the characteristic data of the transformer in each of the third modes.

[0050] The leakage inductance parameter optimization module is used to optimize the leakage inductance parameters of the transformer based on the characteristic data, so as to improve the power transmission and leakage flux loss performance of the transformer.

[0051] Option 3: The present invention provides a computer device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the bidirectional active full-bridge transformer optimization method described in Option 1.

[0052] Option 4: The present invention provides a computer-readable storage medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the bidirectional active full-bridge transformer optimization method described in Option 1.

[0053] This invention provides a method, apparatus, device, and storage medium for optimizing a bidirectional active full-bridge transformer. The optimization method includes: classifying the operating state of the bidirectional active full-bridge transformer into a step-up state, a step-down state, and a matching state based on the voltage transformation ratio; for the step-up state, determining several first modes based on phase shift time, dead time, secondary-side device turn-off time, primary-side device turn-off time, inductor current zero-crossing time, and the inductor current direction at the primary-side device turn-off or turn-on time, and acquiring characteristic data of the transformer in each of the first modes; the characteristic data includes inductor voltage and inductor current data when the transformer experiences voltage polarity reversal and / or phase drift, wherein the inductor voltage is based on the primary side voltage and... The secondary side voltage is determined; for the step-down state, several second modes are determined based on the phase shift time, the dead time, the turn-off time of the secondary-side device, the turn-off time of the primary-side device, the zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the secondary-side device, and the characteristic data of the transformer in each of the second modes are obtained; for the matched state, several third modes are determined based on the direction of the inductor current at the turn-off time of the secondary-side device, the turn-off time of the primary-side device, and the zero-crossing time of the inductor current, and the characteristic data of the transformer in each of the third modes are obtained; the leakage inductance parameters of the transformer are optimized based on the characteristic data to improve the power transmission and leakage flux loss performance of the transformer.

[0054] In view of this, the beneficial effects of this invention are:

[0055] This invention addresses the voltage polarity reversal and phase drift phenomena that occur in transformers under boost, buck, and matched conditions. These differences, caused by the difference between phase shift time and dead time, affect the transformer's power transmission efficiency and leakage flux loss. Starting with the transformer's dead time and phase shift time, the invention analyzes the voltage, current, and power transmission direction based on these factors and the turn-off times of the primary and secondary devices. Characteristic data related to voltage polarity reversal and phase drift are obtained, revealing the impact of dead time on voltage, current, and phase shift time. Furthermore, by optimizing the transformer's leakage inductance parameters based on this characteristic data, the accuracy of power electronic transformer parameter design is improved, thereby reducing leakage flux loss and enhancing the transformer's power transmission performance. Attached Figure Description

[0056] Figure 1 This is a flowchart illustrating an embodiment of the optimized method of the present invention;

[0057] Figure 2 A schematic diagram illustrating the voltage polarity reversal phenomenon in a transformer;

[0058] Figure 3 A schematic diagram illustrating the phase drift phenomenon present in a transformer;

[0059] Figure 4 This is a schematic diagram of the working waveform of the first mode of the boost state in an embodiment of the optimization method of the present invention;

[0060] Figure 5 This is a schematic diagram of the working waveform of the second first mode in the boost state of an embodiment of the optimization method of the present invention;

[0061] Figure 6 This is a schematic diagram of the working waveform of the third first mode in the boost state of an embodiment of the optimization method of the present invention;

[0062] Figure 7 This is a schematic diagram of the working waveform of the fourth first mode in the boost state of an embodiment of the optimization method of the present invention;

[0063] Figure 8 This is a schematic diagram of the working waveform of the fifth first mode in the boost state of an embodiment of the optimized method of the present invention;

[0064] Figure 9 This is a schematic diagram of the working waveform of the sixth first mode in the boost state of an embodiment of the optimization method of the present invention;

[0065] Figure 10 This is a schematic diagram of the equivalent circuit of the transformer during transient t0 to t1 in the first mode of the boost state in an embodiment of the optimization method of the present invention.

[0066] Figure 11 This is a schematic diagram of the equivalent circuit of the transformer in the first mode of the boost state in an embodiment of the optimization method of the present invention, under transient t1 to t2.

[0067] Figure 12 This is a schematic diagram of the equivalent circuit of the transformer during transient t2 to t3 in the first mode of the boost state in an embodiment of the optimization method of the present invention.

[0068] Figure 13 This is a schematic diagram of the equivalent circuit of the transformer before transient t2 in the second first mode of the boost state in an embodiment of the optimization method of the present invention.

[0069] Figure 14 This is a schematic diagram of the equivalent circuit of the transformer during transient t2 to t3 in the fifth first mode of the boost state in an embodiment of the optimization method of the present invention.

[0070] Figure 15 This is a schematic diagram of the equivalent circuit of the transformer in the transient t1 to t2 during the sixth first mode of the boost state in an embodiment of the optimization method of the present invention.

[0071] Figure 16 This is a schematic diagram of the equivalent circuit of the transformer under transient t2 to t3 in the second second mode of the step-down state in an embodiment of the optimization method of the present invention.

[0072] Figure 17 This is a schematic diagram of the working waveform of the first second mode of the voltage reduction state in an embodiment of the optimized method of the present invention;

[0073] Figure 18 This is a schematic diagram of the working waveform of the second mode of the voltage reduction state in an embodiment of the optimized method of the present invention;

[0074] Figure 19 This is a schematic diagram of the working waveform of the third second mode of the voltage reduction state in an embodiment of the optimization method of the present invention;

[0075] Figure 20 This is a schematic diagram of the working waveform of the fourth second mode of the voltage reduction state in an embodiment of the optimized method of the present invention;

[0076] Figure 21 This is a schematic diagram of the working waveform of the fifth second mode in the step-down state of the embodiment of the optimization method of the present invention;

[0077] Figure 22 This is a schematic diagram of the working waveform of the sixth second mode in the step-down state of an embodiment of the optimized method of the present invention;

[0078] Figure 23 This is a schematic diagram of the working waveform of the first third mode of the matching pressure state in an embodiment of the optimization method of the present invention;

[0079] Figure 24 This is a schematic diagram of the working waveform of the second and third modes of the matching pressure state in an embodiment of the optimization method of the present invention;

[0080] Figure 25 This is a schematic diagram of the working waveform of the third mode of the matching pressure state in an embodiment of the optimization method of the present invention;

[0081] Figure 26 This is a schematic diagram of an embodiment of the optimized device of the present invention. Detailed Implementation

[0082] Terminology Explanation:

[0083] Dead time: Dead time is a protection period set in PWM (Pulse Width Modulation) output to prevent the upper and lower bridge arm switches from turning on simultaneously due to switching speed issues. It usually refers to the PWM response time. In other words, after one switch turns on and off, another switch can only turn on after a certain dead time.

[0084] Dead ratio: The dead ratio is the equivalent duty cycle of the dead time within half a switching cycle.

[0085] Phase shift: Phase shift refers to the phase difference between two signals. In electronics, phase shift is often used to describe phase delay or advance. When two signals have similar waveforms but a certain time offset, the phase shift can be obtained by calculating the phase difference between them.

[0086] Phase shift time: The phase shift time is the product of the phase shift and half a switching cycle.

[0087] This invention provides a method, apparatus, device, and storage medium for optimizing bidirectional active full-bridge transformers, in order to solve the technical problem in the prior art that the impact of the difference between dead time and phase shift time on transformer characteristics is not evaluated, resulting in inaccurate transformer parameter design.

[0088] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0089] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0090] Firstly, please refer to Figure 1 The bidirectional active full-bridge transformer optimization method provided in this embodiment of the invention includes:

[0091] S100: The operating state of the bidirectional active full-bridge transformer is divided into step-up state, step-down state and matching state according to the voltage transformation ratio;

[0092] S200: For the boost state, several first modes are determined based on the phase shift time, dead time, turn-off time of the secondary device, turn-off time of the primary device, zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the primary device, and characteristic data of the transformer in each first mode are obtained; the characteristic data includes inductor voltage and inductor current data when the transformer experiences voltage polarity reversal and / or phase drift, and the inductor voltage is determined based on the primary side voltage and secondary side voltage of the transformer;

[0093] S300: For the step-down state, several second modes are determined based on the phase shift time, the dead time, the turn-off time of the secondary device, the turn-off time of the primary device, the zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the secondary device, and the characteristic data of the transformer in each second mode are obtained.

[0094] S400: For the matching state, several third modes are determined based on the direction of the inductor current at the turn-off time of the secondary device, the turn-off time of the primary device, and the zero-crossing time of the inductor current, and the characteristic data of the transformer in each of the third modes are obtained.

[0095] S500: Optimize the leakage inductance parameters of the transformer based on the aforementioned characteristic data to improve the power transmission and leakage flux loss performance of the transformer.

[0096] The difference between phase shift time and dead time can lead to varying degrees of voltage polarity reversal and phase drift at the port voltage of a bidirectional active full-bridge transformer (DAB transformer) under different dead times, affecting the power transmission efficiency and leakage flux loss of the DAB transformer. Therefore, this invention compares and analyzes the dead time and phase shift time, and optimizes the leakage inductance parameters of the transformer based on the analysis results, thereby improving the current freewheeling time and current change rate (di / dt) and enhancing the working performance of the power electronic transformer.

[0097] This invention starts with the dead time and phase shift time of power electronic transformers, and studies the voltage, current and power flow of power electronic transformers based on the dead time and phase shift time. It analyzes the impact of different dead times and phase shift times on voltage, current and phase shift time, thereby proposing new requirements for the parameters of power electronic transformers and improving the accuracy of power electronic transformer parameter design, so as to reduce the leakage flux loss of transformers and improve the power transmission performance of transformers.

[0098] It should be noted that the leakage inductance parameter of a transformer is the leakage inductance value of the magnetic circuit during the transformer's manufacturing process, and it is determined at the time of manufacture. di / dt is the rate of change of current, which can be understood as the degree of drastic change of current over time.

[0099] Figure 2 and Figure 3 This paper presents phenomena observed in the practical operation of power electronic transformers with a double active bridge (DAB) topology. From... Figure 2 As can be seen from the waveform, for the switching waveform, the polarity of the primary voltage of the transformer suddenly changes, and returns to normal after a period of time. In this state, the voltage and current polarities are opposite, which is called the voltage polarity reversal phenomenon; from Figure 3 As can be seen, for transmitted power, when the phase shift D = 0, the transmitted power P of the power electronic transformer is < 0 and remains constant within a certain range; this phenomenon is called phase drift. Both voltage polarity reversal and phase drift differ from the pure mathematical model. In fact, voltage polarity reversal will increase return power, reduce volt-second time, and affect the operating characteristics of the isolation transformer, while phase drift will reduce the accuracy of power calculation for DAB transformers, further affecting the parameter design of DAB transformers.

[0100] Based on the voltage transformation ratio of the DAB transformer, its operating state can be divided into three states: (1) step-up state (k<1); (2) step-down state (k>1); (3) matching state (k=1); where k=V1 / nV2, V1 is the input voltage of the DAB transformer, V2 is the output voltage of the DAB transformer, and k represents the voltage transformation ratio. Under different operating states, the switching characteristics of the DAB transformer differ.

[0101] In step S200, for the boost state, several first modes are determined based on the phase shift time, dead time, turn-off time of the secondary device, turn-off time of the primary device, zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the primary device, and characteristic data of the transformer in each first mode are obtained; the characteristic data includes the inductor voltage and inductor current data when the transformer experiences voltage polarity reversal and / or phase drift, wherein the inductor voltage includes the primary side voltage and the secondary side voltage.

[0102] Please see Figure 4 Taking the first half of the switching cycle as an example, the turn-off time of the primary-side devices of the DAB transformer includes the turn-off of the first primary-side device (denoted by S). 1,4 (off indicates) the time when the primary-side second device is turned off (using S) 2,3 (represented by "off") The turn-off time of the secondary device includes the turn-off time of the first secondary device (represented by Q). 1,4 (off indicates) the time when the second secondary device is turned off (using Q). 2,3 (off indicates the time)

[0103] Similarly, the turn-on timing of the primary-side devices of a DAB transformer includes the turn-on of the first primary-side device (denoted by S). 1,4 (on indicates) the time and the primary-side second device being turned on (using S) 2,3 (indicated by on) the time when the secondary device is turned on, including the time when the first secondary device is turned on (indicated by Q). 1,4 (on indicates) the time and the second secondary device being turned on (using Q). 2,3 (on indicates time)

[0104] exist Figure 4 In this context, M represents the equivalent duty cycle of the dead time within half a switching cycle (i.e., the dead ratio within half a switching cycle), D represents the shift ratio, and T represents the dead time. hs For half a switching cycle time, MT hs Dead time, DT hs For phase shift time, i L The current on the auxiliary inductor of the DAB transformer is the inductor current (also called winding current). t0 is the turn-off time of the second device on the secondary side, t1 is the turn-off time of the first device on the primary side, and t2 is the inductor current i. L At the zero-crossing moment (when the inductor current i) L The size is reduced to zero), t3 is the turn-off time of the first device on the secondary side, v h1 V is the primary voltage of the DAB transformer. h2 This is the secondary voltage of the DAB transformer.

[0105] from Figure 4As can be seen, the turn-on time of the first device on the secondary side is equal to the turn-off time of the second device on the secondary side plus the dead time, and the turn-on time of the second device on the primary side is equal to the turn-off time of the first device on the primary side plus the dead time; the time difference between the turn-off time of the first device on the primary side and the turn-off time of the first device on the secondary side is the phase shift time. At time t3, the inductor current i L It reaches the minimum value.

[0106] It should be noted that, Figure 4 t0 in the equation is also the phase shift start time, which is the moment when v / i begins to decrease, that is, the moment when the phase begins to change. In other words, v / i begins to decrease from the moment t0. Therefore, t0 is taken as a characteristic point.

[0107] In one embodiment of the present invention, when the phase shift time is greater than or equal to the dead time, and the direction of the inductor current at the moment the primary side first device is turned off is positive, and the first time difference is greater than or equal to the dead time, the first mode is obtained.

[0108] When the phase shift time is greater than or equal to the dead time, and the direction of the inductor current at the moment the first device on the primary side is turned off is positive, and the first time difference is less than the dead time, the second first mode is obtained.

[0109] When the phase shift time is greater than or equal to the dead time and the direction of the inductor current at the moment the first device on the primary side is turned off is negative, the third first mode is obtained.

[0110] When the phase shift time is less than the dead time, the inductor current direction at the moment the first device on the primary side is turned off is positive, and the second time difference is greater than or equal to the dead time, the fourth first mode is obtained.

[0111] When the phase shift time is less than the dead time, the inductor current direction at the moment the first device on the primary side is turned off is positive, and the second time difference is less than the dead time, the fifth first mode is obtained.

[0112] When the phase shift time is less than the dead time and the direction of the inductor current at the moment the first device on the primary side is turned off is negative, the sixth first mode is obtained.

[0113] The first time difference is the time difference between the moment when the inductor current crosses zero and the moment when the first device on the primary side turns off; the second time difference is the time difference between the moment when the inductor current crosses zero and the moment when the second device on the secondary side turns off.

[0114] In one embodiment, obtaining the characteristic data of the transformer in each first mode includes:

[0115] Acquire the inductor voltage and inductor current data of the transformer in each first mode;

[0116] Based on the inductor voltage and inductor current data of the first mode, determine whether the transformer exhibits voltage polarity reversal and / or phase drift in different transient states of each first mode;

[0117] If voltage polarity reversal and / or phase drift occurs in the first mode, the corresponding inductor voltage and inductor current data will be used as characteristic data.

[0118] Specifically, in the first first mode (where D≥M, i) L (t1)≥0 and t2-t1≥MT hs In the above, before time t0, the first set of switches S1 and S4 on the primary side are turned on, i.e., S1 and S4 are turned on. 1,4 on( Figure 4 (Not shown in the image), inductor current i L The direction is positive. At time t0, the second set of switches Q2 and Q3 on the secondary side are turned off, i.e., Q... 2,3 Because of the dead time, the first set of switches Q1 and Q4 on the secondary side are not turned on. Therefore, on the input voltage side (V1 side) of the DAB transformer, the inductor current i L The inductor current i flows through the first set of switches S1 and S4 on the primary side; on the output voltage side of the DAB transformer, i.e., the V2 side, the inductor current i L The current flows through M1 and M4. The voltage across inductor L1 (i.e., the inductor voltage) is V1 - nV2 < 0, and the inductor current i L The transient decreases linearly. This transient ends when the first set of primary-side switches S1 and S4 are turned off, and during this transient, the first set of secondary-side switches Q1 and Q4 are turned on. During the transient t0~t1, the equivalent circuit of the DAB transformer is as follows: Figure 10 As shown.

[0119] At time t1, the first set of switches S1 and S4 on the primary side are turned off. Due to the inductor current i L The direction is positive, on the V1 side, the inductor current i L The current flows from inductor L1 through D2 and D3 to V1; on the V2 side, the circuit operates the same as during the transient t0~t1. The voltage across inductor L1 is -V1-nV2, and the inductor current i L It continues to decrease linearly. When the inductor current i L When t2 = 0, this transient ends; since t2 - t1 ≥ MT hs During this transient state, the second set of primary-side switches S2 and S3 are turned on. During transient states t1 to t2, the equivalent circuit of the DAB transformer is as follows: Figure 11 As shown in the diagram. Based on the preceding analysis, during the transient period t1 to t2, the DAB transformer primarily experiences return power, leading to higher current stress and lower efficiency. Therefore, to address this issue, the leakage inductance of the DAB transformer can be appropriately increased to reduce the current i. L The rate of decrease di / dt decreases, thereby reducing current stress and improving power transmission efficiency.

[0120] It should be noted that the first group of switches on the primary side is the first device on the primary side, the second group of switches on the primary side is the second device on the primary side, the first group of switches on the secondary side is the first device on the secondary side, and the second group of switches on the secondary side is the second device on the secondary side.

[0121] At time t2, the inductor current i L The value drops to zero, and then the inductor current i... L The direction changes from positive to negative. On the V1 side, the inductor current i L The current flows from V1 through S2 and S3 to inductor L1; on the V2 side, the inductor current i L The current flows through Q1 and Q4. The voltage across inductor L1 remains -V1 - nV2, but the inductor current i L The change from a positive decrease to a negative increase occurs. This transient ends when the first set of switches Q1 and Q4 on the secondary side are turned off. During transients t2 to t3, the equivalent circuit of the DAB transformer is as follows: Figure 12 As shown.

[0122] It should be noted that the above analysis mainly focuses on the operation of the DAB transformer in the first half of the first switching cycle of the first mode. The circuit analysis in the second half of the switching cycle is similar and will not be repeated here.

[0123] Specifically, in the second first mode (where D≥M, i) L (t1)≥0 and t2-t1 <MT hs In the diagram, the operating waveform of the DAB transformer is as follows: Figure 5 As shown.

[0124] Before time t2, the circuit operates in the same manner as in the first mode. Since t2-t1 <MT hs The second set of switches S2 and S3 on the secondary side are not turned on at time t2. Therefore, from t2 to t5, on the V1 side, the inductor current i L The current flows from inductor L1 through D1 and D4 to V1; on the V2 side, the inductor current i L The current flows from V2 through the first set of primary-side switches Q1 and Q4 to inductor L1. The voltage across inductor L1 is V1 - nV2. Since k < 1, the inductor current i L It increases linearly in the opposite direction. This transient ends when the second set of switches S2 and S3 on the primary side are turned on. During the transient t2 to t5, the equivalent circuit of the DAB transformer is as follows: Figure 13 As shown. During the transient period t2 to t5, there is still return power in the DAB transformer. It can be understood that t5 is the turn-on time of the second device on the primary side, that is, t5 corresponds to S. 2,3 on, t5 = t1 + MT hs .

[0125] t4 represents the inductor current i when phase drift occurs.L The moment when the value drops to the minimum; since the second set of switches S2 and S3 on the primary side are turned on, the circuit operation at this time is similar to the transient state t2~t3 in the first mode.

[0126] from Figure 5 As can be seen, due to the existence of dead time, voltage polarity reversal occurs in the working waveform of the DAB transformer.

[0127] Specifically, in the third first mode (where D≥M and i L In (t1)<0), the operating waveform of the DAB transformer is as follows: Figure 6 As shown.

[0128] During the transient state t0~t2, due to i L (t)>0, the circuit operation is the same as in the second first mode from t0 to t1. In the transient states from t2 to t3, since i L (t)<0, the circuit operation is the same as t2~t5 in the second first mode, and the first set of primary side switches S1 and S4 are turned off between t2 and t5.

[0129] It should be noted that the above i L (t)>0 indicates that the inductor current i during the time period from t0 to t2 is... L For positive direction, i L In (t), t is the independent variable. Since the transient state t0~t2 corresponds to the time period t0~t2, i L The t in (t) changes during the time interval t0 to t2.

[0130] Specifically, in the fourth first mode (where D≥M, i) L (t6)≥0 and t2-t0≥MT hs In the diagram, the operating waveform of the DAB transformer is as follows: Figure 7 As shown.

[0131] During the transient states t0 to t6, due to i L (t6)≥0, the first set of primary-side switches S1 and S4 are not conducting, and the circuit operation is the same as in the first and second first modes from t1 to t2. In the transient states t6 to t3, since the first set of primary-side switches S1 and S4 are conducting, the circuit operation is the same as in the third first mode from t0 to t5. Furthermore, since t2-t0≥MT hs The first set of switches Q1 and Q4 on the secondary side are turned off between t6 and t2, and the first set of switches S1 and S4 on the primary side are turned off between t2 and t3.

[0132] Specifically, in the fifth first mode (at this time D) <M、i L(t6)≥0 and t2-t0<MT hs ), the operating waveforms of the DAB transformer are as shown in Figure 8 below.

[0133] In the transient state t0 to t2, the circuit operation is the same as that of t0 to t2 in the fourth first mode. However, since t2-t0<MT hs , the first set of switches Q1 and Q4 on the secondary side are not turned on at time t2. Therefore, on the V1 side, the primary full bridge H1 operates in an unloaded inversion state; on the V2 side, the secondary full bridge H2 stops working. The voltage of the inductor L1 is 0, and the inductor current i L is also 0. This transient state ends when Q1 and Q4 are turned on. The equivalent circuit of the DAB transformer under the transient state t2 to t7 is as shown in Figure 14 below. Herein, t6 is the turn-on time of the first primary-side device, and t6 corresponds to S 1,4 on; t7 is the turn-on time of the first secondary-side device, and t7 corresponds to Q 1,4 on.

[0134] In the transient state t7 to t3, since Q1 and Q4 are turned on, the operation is the same as that of t2 to t3 in the fourth first mode.

[0135] It can be seen from Figure 8 that, since V1<nV2, the high-frequency AC voltage v h2 exhibits a voltage sag phenomenon during t2 to t7.

[0136] Specifically, in the sixth first mode (at this time D<M and i L (t6)<0), the operating waveforms of the DAB transformer are as shown in Figure 9 below.

[0137] In the transient state t0 to t6, the circuit operation is the same as that of t0 to t6 in the fifth first mode. However, since t6-t0<(M-D)T hs , S1 and S4 are not turned on at time t6. Therefore, both the primary full bridge H1 and the secondary full bridge H2 stop working. The voltage of the inductor L1 is 0, and the inductor current i L is also 0. This transient state ends when S1 and S4 are turned on. The equivalent circuit of DAB under the transient state t6 to t2 is as shown in Figure 15 below.

[0138] In the transient state t2 to t4, since S1 and S4 are turned on, the circuit operation is the same as that of t2 to t4 in the fifth first mode.

[0139] It can be seen from Figure 9 that both the high-frequency AC voltages v h1 and v h2 drop to 0 during t6 to t2.

[0140] Based on the above analysis, due to the dead zone effect, phenomena such as voltage polarity reversal and phase drift may also occur in DAB transformers.

[0141] In one embodiment, for the buck state, the steps of determining several second modes based on the phase shift time, dead time, secondary-side device turn-off time, primary-side device turn-off time, inductor current zero-crossing time, and inductor current direction at the secondary-side device turn-off or turn-on time include:

[0142] In the depressurization state, the state where k>1 is analyzed. Figures 17 to 22 The working waveforms under the condition k>1 are given.

[0143] The first second mode is obtained when the phase shift time is greater than or equal to the dead time, the inductor current direction at the turn-off time of the second device on the secondary side is positive, and the first time difference is greater than or equal to the dead time.

[0144] When the phase shift time is greater than or equal to the dead time, and the direction of the inductor current at the moment the second device on the secondary side is turned off is positive, and the first time difference is less than the dead time, the second second mode is obtained.

[0145] When the phase shift time is less than the dead time, the inductor current direction at the turn-off time of the second device on the secondary side is positive, and the third time difference is less than or equal to the phase shift time, the third second mode is obtained.

[0146] When the phase shift time is less than the dead time, the inductor current direction at the turn-off time of the second device on the secondary side is positive, and the third time difference is greater than or equal to the phase shift time, the fourth second mode is obtained.

[0147] When the inductor current direction is negative at the moment the second device on the secondary side is turned off, and the dead time is greater than or equal to the time difference between the initial dead time and the phase shift time, the fifth second mode is obtained.

[0148] When the inductor current direction is negative at the moment the second device on the secondary side is turned off, and the dead time is less than the time difference between the initial dead time and the phase shift time, the sixth second mode is obtained.

[0149] Wherein, the first time difference is the time difference between the moment when the inductor current crosses zero and the moment when the first device on the primary side turns off; the second time difference is the time difference between the moment when the inductor current crosses zero and the moment when the second device on the secondary side turns off; the third time difference is the time difference between the moment when the first device on the secondary side turns off and the moment when the inductor current crosses zero; and the initial dead time is the dead time that makes the inductor current zero at the moment when the first device on the secondary side turns off.

[0150] In one embodiment, obtaining the characteristic data of the transformer in each of the second modes includes:

[0151] Acquire the inductor voltage and inductor current data of the transformer in each second mode;

[0152] Determine whether voltage polarity reversal and / or phase drift phenomena exist in different transients of each second mode of the transformer according to the inductor voltage and inductor current data of the second mode;

[0153] If voltage polarity reversal and / or phase drift phenomena exist in the second mode, the corresponding inductor voltage and the inductor current data are taken as characteristic data.

[0154] Specifically, in the first second mode (at this time D≥M, i L (t0)≥0 and t2-t1≥MT hs ), the operating waveforms of the DAB transformer are as shown in Figure 17 shown in the figure.

[0155] As the voltage conversion ratio k changes, in the transient state t0 to t1, the inductor current i L changes from decreasing linearly to increasing linearly. However, the commutation behavior does not change, which is the same as the first first mode in the boost state.

[0156] Specifically, in the second second mode (at this time D≥M, i L (t0)≥0 and t2-t1<MT hs ), the operating waveforms of the DAB transformer are as shown in Figure 18 shown in the figure.

[0157] In the transient state t2 to t5, since V1>nV2, D1 and D2 are turned off. On the primary side of the transformer T, the primary full bridge H1 stops working, and the secondary full bridge H2 operates in an unloaded inversion state. The voltage of the inductor L1 is 0, and the inductor current i L =0, and the equivalent circuit is as shown in Figure 16 shown in the figure. It can be seen that this transient state will reduce the volt-second product, but will not generate backflow power. In addition, since nV2<V1, v between t2 and t5 h1 has a phase drift phenomenon.

[0158] In the transient states t0 to t2 and t5 to t4, the circuit commutation behavior is the same as that of the second first mode in the boost state.

[0159] Specifically, in the third second mode (at this time D<M, i L (t0)≥0 and t2-t1≤DT hs ), the operating waveforms of the DAB transformer are as shown in Figure 19 shown in the figure, at this time i L (t0)=0.

[0160] Before t0, the inductor current i Lhas decreased to 0, the primary side full bridge H1 stops working, the secondary side full bridge H2 operates in an no-load inverter state, and Q2 and Q3 are turned on. At time t0, Q2 and Q3 are turned off, and both full bridges stop working. The equivalent circuit is as Figure 15 shown.

[0161] In the transient state, since S1 and S4 are turned on, the circuit has the same operating state as that of t0 to t5 in the second second mode.

[0162] Specifically, in the fourth second mode (at this time, D<M, i L (t0)≥0 and t3-t1>DT hs ), the operating waveforms of the DAB transformer are as Figure 20 shown.

[0163] In fact, when t3-t1=DT hs , the transient state t2 to t4 in the third second mode will disappear. And since the inductor current i L >0 in the transient state t1 to t3, the commutation behavior of the DAB transformer will not change regardless of whether Q1 and Q4 are turned off. Therefore, in the fourth second mode, the commutation behavior will be the same as that when t2-t1=DT hs in the third second mode.

[0164] Specifically, the fifth second mode:

[0165] In fact, the second, third and fourth second modes only exist when i L (t0)≥0 in the first second mode. When i L (t0)<0 in the first second mode, the operating waveforms of the DAB transformer are as Figure 21 shown. The fifth second mode only exists when D≥D0-M, where D0 makes i L (t0)=0.

[0166] When D=D0, the transient state t2 to t3 in the first second mode will disappear. When D<D0 and D≥D0-M, since Q1 and Q4 are turned off when the inductor current i L >0 (before t9), the commutation behavior will not change in the transient state t9 to t1. In addition, in the transient state t1 to t2, since Q2 and Q3 are turned off when the inductor current i L >0 (before t2), the commutation behavior will not change either. Therefore, in the fifth second mode, the commutation behavior of the circuit will be the same as that when D=D0 in the first second mode. It should be noted that t9 is within the dead time between Q 2,3 off and Q 1,4 on, the inductor current i Lthe moment when it is zero.

[0167] Specifically, in the sixth second mode (at this time D<D0-M and i L (t0)<0), the operating waveforms of the DAB transformer are as shown in Figure 22 the figure.

[0168] Since when the inductor current i L <0, Q1 and Q4 are turned on, therefore in the transient state t7 to t2, the inductor current flows from the inductor L1 to V1 through D1 and D4, and the inductor current flows from V2 to V1 through Q1 and Q4, the equivalent circuit is as shown in Figure 13 the figure. It can be seen therefrom that this transient state will generate backflow power.

[0169] In the transient state t2 to t8, since the inductor current i L >0 and Q2 and Q3 are turned off, the circuit operating state is the same as that of t9 to t2 in the fifth second mode. Wherein, t8 is the turn-on moment of the secondary side second device, and t8 corresponds to Q 2,3 on.

[0170] In one embodiment of the present invention, for the matching state, the step of determining a plurality of third modes according to the inductor current direction at the turn-off moment of the secondary side device, the turn-off moment of the primary side device, and the zero-crossing moment of the inductor current comprises:

[0171] when the inductor current direction at the turn-off moment of the secondary side second device is positive and the first time difference is greater than or equal to the dead time, a first third mode is obtained;

[0172] when the inductor current direction at the turn-off moment of the secondary side second device is positive and the first time difference is less than the dead time, a second third mode is obtained;

[0173] when the inductor current direction at the turn-off moment of the secondary side second device is negative, a third third mode is obtained.

[0174] It should be noted that between t0 and t1, if it is in the step-up state, the inductor current i L decreases, and zero-voltage turn-on is more likely to be lost at moment t1 than at moment t0, resulting in voltage polarity reversal. Therefore, in the step-up state, the inductor current direction at the turn-off moment of the primary side first device is considered; if it is in the step-down state, the inductor current i L increases, and the zero-voltage turn-on characteristic is more likely to be lost at moment t0 than at moment t1, resulting in voltage polarity reversal. Therefore, in the step-down state, the inductor current direction at the turn-off moment of the secondary side second device is considered. That is to say, in different operating states of the transformer, the inductor current directions at different moments are selected as the basis for dividing different modes.

[0175] In one embodiment, acquiring the characteristic data of the transformer in each third mode comprises:

[0176] Acquire the inductor voltage and inductor current data of the transformer in each third mode;

[0177] Based on the inductor voltage and inductor current data of the third mode, determine whether there is voltage polarity reversal and / or phase drift phenomenon in the different transient states of each third mode of the transformer;

[0178] If voltage polarity reversal and / or phase drift occur in the third mode, the corresponding inductor voltage and inductor current data will be used as characteristic data.

[0179] In the matching state, the state where k=1 is analyzed. Figures 23 to 25 The operating waveforms under the k=1 state are given.

[0180] Specifically, in the first third mode (at this time i) L (t0)≥0 and t2-t1≥MT hs In the diagram, the operating waveform of the DAB transformer is as follows: Figure 23 As shown. Since k=1, the inductor current i L It remains constant between t0 and t1. The commutation behavior is the same as the first mode under boost condition and the first mode under buck condition.

[0181] Specifically, in the second and third modes (where i... L (t0)≥0 and t2-t1≥MT hs In the diagram, the operating waveform of the DAB transformer is as follows: Figure 24 As shown, the commutation behavior is still the same as the first second mode under the buck condition. However, since k=1, no phase drift phenomenon occurs between t2 and t5.

[0182] Specifically, in the third third mode (at this time i) L In (t0)<0), the operating waveform of the DAB transformer is as follows: Figure 25 As shown, the commutation behavior is still the same as the second second mode under the buck condition. However, since k=1, no phase drift phenomenon occurs between t2 and t1.

[0183] During the transient states t0 to t2, since Q1 and Q4 are turned off, the circuit operates in the same manner as during the sixth first mode t6 to t7 under boost conditions. However, since k = 1, there is no phase drift during the transient states t6 to t2.

[0184] At time t2, Q1 and Q4 are turned on. Since k = 1, the voltage across inductor L1 is still 0, and the inductor current i L =0, equivalent current as Figure 7 As shown.

[0185] During transient states t1 to t3, since S1 and S4 are turned off, the circuit operates in the same manner as during the third second mode t2 to t4 under the buck condition. However, since k = 1, there is no phase drift phenomenon during transient states t6 to t2.

[0186] The bidirectional active full-bridge transformer optimization method provided in this invention considers the voltage polarity reversal and phase drift phenomena caused by the difference between phase shift time and dead time in the transformer's step-up, step-down, and matched states, which affect the transformer's power transmission efficiency and leakage flux loss. Starting from the transformer's dead time and phase shift time, the method analyzes the transformer's voltage, current, and power transmission direction based on the dead time, phase shift time, and the turn-off times of the primary and secondary devices. It obtains characteristic data related to the voltage polarity reversal and phase drift phenomena, and derives the impact of dead time on voltage, current, and phase shift time. Then, based on the obtained characteristic data, the method optimizes the transformer's leakage inductance parameters, improving the accuracy of power electronic transformer parameter design to reduce leakage flux loss and enhance the transformer's power transmission performance.

[0187] Please see Figure 26 This invention provides an embodiment of a bidirectional active full-bridge transformer optimization device, comprising:

[0188] The status judgment module 11 is used to classify the operating status of the bidirectional active full-bridge transformer into step-up state, step-down state and matching state according to the voltage transformation ratio.

[0189] The boost state data acquisition module 22 is used to determine several first modes for the boost state based on the phase shift time, dead time, turn-off time of the secondary device, turn-off time of the primary device, zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the primary device, and to acquire characteristic data of the transformer in each of the first modes; the characteristic data includes inductor voltage and inductor current data when the transformer experiences voltage polarity reversal and / or phase drift, and the inductor voltage is determined based on the primary side voltage and secondary side voltage of the transformer;

[0190] The step-down state data acquisition module 33 is used to determine several second modes for the step-down state based on the phase shift time, the dead time, the turn-off time of the secondary device, the turn-off time of the primary device, the zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off or turn-on time of the secondary device, and to acquire the characteristic data of the transformer in each of the second modes.

[0191] The matching state data acquisition module 44 is used to determine several third modes based on the inductor current direction at the turn-off time of the secondary device, the turn-off time of the primary device, and the zero-crossing time of the inductor current for the matching state, and to acquire the characteristic data of the transformer in each of the third modes.

[0192] The leakage inductance parameter optimization module is used to optimize the leakage inductance parameters of the transformer based on the characteristic data, so as to improve the power transmission and leakage flux loss performance of the transformer.

[0193] The bidirectional active full-bridge transformer optimization device provided in this invention optimizes the transformer in three states: step-up, step-down, and matched states. Considering that the difference between phase-shift time and dead time can cause voltage polarity reversal and phase drift, thus affecting the transformer's power transmission efficiency and leakage flux loss, the device analyzes the transformer's voltage, current, and power transmission direction based on the dead time, phase-shift time, and the turn-off times of the primary and secondary devices. It obtains characteristic data related to voltage polarity reversal and phase drift, and derives the impact of dead time on voltage, current, and phase-shift time. Then, based on the obtained characteristic data, it optimizes the transformer's leakage inductance parameters, improving the accuracy of power electronic transformer parameter design to reduce leakage flux loss and enhance the transformer's power transmission performance.

[0194] Furthermore, the present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the bidirectional active full-bridge transformer optimization method.

[0195] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the bidirectional active full-bridge transformer optimization method.

[0196] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0197] In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, indirect coupling or communication connection between apparatuses or units, and may be electrical, mechanical, or other forms.

[0198] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0199] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0200] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0201] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optimization method for bidirectional active full-bridge transformers, characterized in that, include: Based on the voltage transformation ratio, the operating states of bidirectional active full-bridge transformers are divided into step-up state, step-down state, and matching state. For the boost state, several first modes are determined based on the phase shift time, dead time, turn-off time of the secondary device, turn-off time of the primary device, zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off time of the primary device. Characteristic data of the transformer in each first mode are obtained. The characteristic data includes inductor voltage and inductor current data when the transformer experiences voltage polarity reversal and / or phase drift. The inductor voltage is determined based on the primary side voltage and secondary side voltage of the transformer. For the step-down state, several second modes are determined based on the phase shift time, the dead time, the turn-off time of the secondary device, the turn-off time of the primary device, the zero-crossing time of the inductor current, and the direction of the inductor current at the turn-off time of the secondary device, and the characteristic data of the transformer in each second mode are obtained. For the matching state, several third modes are determined based on the direction of the inductor current at the turn-off time of the secondary device, the turn-off time of the primary device, and the zero-crossing time of the inductor current, and the characteristic data of the transformer in each of the third modes are obtained. The leakage inductance parameters of the transformer are optimized based on the aforementioned characteristic data to improve the power transmission and leakage flux loss performance of the transformer.

2. The optimization method for bidirectional active full-bridge transformers according to claim 1, characterized in that, The primary-side device turn-off time includes the turn-off time of the first primary-side device and the turn-off time of the second primary-side device. The secondary-side device turn-off time includes the turn-off time of the first secondary-side device and the turn-off time of the second secondary-side device. The step of determining several first modes for the boost state based on the phase shift time, dead time, secondary-side device turn-off time, primary-side device turn-off time, inductor current zero-crossing time, and the inductor current direction at the primary-side device turn-off time includes: When the phase shift time is greater than or equal to the dead time, and the inductor current direction at the turn-off time of the primary-side first device is positive, and the first time difference is greater than or equal to the dead time, the first first mode is obtained. When the phase shift time is greater than or equal to the dead time, and the inductor current direction at the turn-off time of the primary-side first device is positive, and the first time difference is less than the dead time, a second first mode is obtained. When the phase shift time is greater than or equal to the dead time, and the direction of the inductor current at the moment the primary-side first device is turned off is negative, the third first mode is obtained; When the phase shift time is less than the dead time, and the inductor current direction at the turn-off time of the primary-side first device is positive, and the second time difference is greater than or equal to the dead time, the fourth first mode is obtained. When the phase shift time is less than the dead time, and the inductor current direction at the turn-off time of the primary-side first device is positive, and the second time difference is less than the dead time, the fifth first mode is obtained; When the phase shift time is less than the dead time and the direction of the inductor current at the moment the primary-side first device is turned off is negative, the sixth first mode is obtained; Wherein, the first time difference is the time difference between the zero-crossing moment of the inductor current and the turn-off moment of the first device on the primary side; the second time difference is the time difference between the zero-crossing moment of the inductor current and the turn-off moment of the second device on the secondary side.

3. The optimization method for bidirectional active full-bridge transformer according to claim 2, characterized in that, The primary-side device turn-off time includes the turn-off time of the first primary-side device and the turn-off time of the second primary-side device. The secondary-side device turn-off time includes the turn-off time of the first secondary-side device and the turn-off time of the second secondary-side device. For the matched state, the step of determining several third modes based on the inductor current direction at the turn-off time of the secondary-side device, the turn-off time of the primary-side device, and the zero-crossing time of the inductor current includes: When the inductor current direction is positive at the time the second device on the secondary side is turned off, and the first time difference is greater than or equal to the dead time, the first third mode is obtained. When the inductor current direction is positive at the time the second device on the secondary side is turned off, and the first time difference is less than the dead time, the second third mode is obtained. When the direction of the inductor current is negative at the moment the second device on the secondary side is turned off, the third mode is obtained.

4. The optimization method for bidirectional active full-bridge transformer according to claim 1, characterized in that, The process of obtaining the characteristic data of the transformer in each of the first modes includes: Obtain the inductor voltage and inductor current data of the transformer in each of the first modes; Based on the inductor voltage and inductor current data of the first mode, determine whether the transformer exhibits voltage polarity reversal and / or phase drift in different transient states of each of the first modes; If the voltage polarity reversal and / or phase drift phenomenon exists in the first mode, the corresponding inductor voltage and inductor current data will be used as characteristic data.

5. The optimization method for bidirectional active full-bridge transformers according to claim 1, characterized in that, The step of obtaining the characteristic data of the transformer in each of the second modes includes: Acquire the inductor voltage and inductor current data of the transformer in each of the second modes; Based on the inductor voltage and inductor current data of the second mode, determine whether the transformer exhibits voltage polarity reversal and / or phase drift in different transient states of each of the second modes; If the voltage polarity reversal and / or phase drift phenomenon exists in the second mode, the corresponding inductor voltage and inductor current data will be used as characteristic data.

6. The optimization method for bidirectional active full-bridge transformer according to claim 1, characterized in that, The acquisition of the characteristic data of the transformer in each of the third modes includes: Obtain the inductor voltage and inductor current data of the transformer in each of the third modes; Based on the inductor voltage and inductor current data of the third mode, determine whether the transformer exhibits voltage polarity reversal and / or phase drift in different transient states of each of the third modes; If the voltage polarity reversal and / or phase drift phenomenon exists in the third mode, the corresponding inductor voltage and inductor current data will be used as characteristic data.

7. A bidirectional active full-bridge transformer optimization device, characterized in that, include: The status judgment module is used to classify the operating status of the bidirectional active full-bridge transformer into step-up state, step-down state, and matching state according to the voltage transformation ratio. The boost state data acquisition module is used to determine several first modes for the boost state based on phase shift time, dead time, turn-off time of secondary-side devices, turn-off time of primary-side devices, zero-crossing time of inductor current, and the direction of inductor current at the turn-off time of primary-side devices, and to acquire characteristic data of the transformer in each of the first modes; the characteristic data includes inductor voltage and inductor current data when the transformer experiences voltage polarity reversal and / or phase drift, and the inductor voltage is determined based on the primary side voltage and secondary side voltage of the transformer; A step-down state data acquisition module is used to determine several second modes for the step-down state based on the phase shift time, the dead time, the turn-off time of the secondary-side device, the turn-off time of the primary-side device, the zero-crossing time of the inductor current, and the inductor current direction at the turn-off time of the secondary-side device, and to acquire the characteristic data of the transformer in each of the second modes. The matching state data acquisition module is used to determine several third modes based on the inductor current direction at the turn-off time of the secondary device, the turn-off time of the primary device, and the zero-crossing time of the inductor current for the matching state, and to acquire the characteristic data of the transformer in each of the third modes. The leakage inductance parameter optimization module is used to optimize the leakage inductance parameters of the transformer based on the characteristic data, so as to improve the power transmission and leakage flux loss performance of the transformer.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the bidirectional active full-bridge transformer optimization method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the bidirectional active full-bridge transformer optimization method according to any one of claims 1 to 6.

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