Energy storage bidirectional resonant converter control method

Abstract

The invention discloses a control method of an energy storage bidirectional resonant converter, the bidirectional resonant converter is composed of two direct current power supplies (DC1 and DC2), a transformer (T), a first bridge type switch unit (10), a second bridge type switch unit (30) and a resonant unit (20), the control method can realize wide voltage range adjustment of the converter, and the control method is simple and convenient to operate. By means of the control method, the switches S1-S4 and S5-S8 included in the first bridge type switch unit (10) and the second bridge type switch unit (30) of the converter can achieve uniform distribution of heat respectively, the problem of thermal stress caused by uneven distribution of heat is solved, and the energy can be adjusted in two directions only by adjusting the duty ratio of the bridge type switch units. According to the control method, the resonant converter has wide-range voltage regulation and bidirectional power rapid regulation and control capabilities, meanwhile, uniform heat distribution of the switch tubes of the bridge type switch units can be realized, and the control method is particularly suitable for the technical field of high-performance bidirectional electric energy conversion of energy storage, electric automobiles, new energy and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to a control method of an energy storage bidirectional resonant converter, and belongs to the technical field of power electronic converters, in particular to the technical field of bidirectional DC-DC power conversion. BACKGROUND

[0002] In the field of new energy and power management such as electric vehicles and energy storage systems, bidirectional converters play an indispensable role as the core device for energy interconnection and efficient management. Their application can effectively reduce the overall size, weight, and manufacturing cost of the system, providing key support for the miniaturization and economic improvement of related equipment. At the same time, with the popularization and industrialization of solar photovoltaic power generation systems, DC bidirectional converters have a growing market demand due to their high efficiency, stability, and reliability. They also play an important role in improving the energy conversion efficiency of photovoltaic power generation systems and ensuring system stability and reliability. Currently, how to further improve the power transmission efficiency of bidirectional converters and develop control strategies with superior performance, smooth output, and stable operation has become a core research direction and industry focus in this technical field.

[0003] Traditional LLC variable-frequency resonant converters have the advantages of low switching loss, high efficiency, and high reliability. However, in new energy applications, how to achieve wide-range voltage regulation is a major challenge. To broaden the voltage regulation range, the magnetizing inductance needs to be designed very small, which results in larger reactive circulating current loss in the transformer resonant cavity and lower efficiency. It is difficult to achieve both wide voltage regulation range and high efficiency. Moreover, due to the inconsistent forward and reverse transmission characteristics, it is also difficult to achieve smooth switching of forward and reverse power transmission. In addition, traditional DC bidirectional converters are mainly two-stage architectures. To achieve high-efficiency, high-density, and high-reliability DC bidirectional converters, single-stage architectures have inherent advantages in terms of efficiency and density.

[0004] To enable resonant converters to have wide-range voltage regulation capabilities, reduce the range of frequency variations, and improve efficiency and power density, patent "CN106026645A (publication date: 2016-10-12)" proposes a small bidirectional resonant converter applicable to energy storage systems and photovoltaic power generation. This type of converter utilizes a fixed-frequency pulse width modulation strategy, enabling it to have both boost and buck capabilities, and possessing the same characteristics for forward and reverse transmission. Furthermore, its gain is only related to the duty cycle of the primary and secondary sides, independent of the load, allowing for rapid and smooth switching of power transmission direction. Theoretically, it can achieve a gain range from 0 to infinity. However, this control method, based on PWM modulation, results in different currents at the turn-on, turn-off, and turn-off times for each switch in the voltage regulation side switching bridge. Consequently, the switching and conduction losses of each switch differ. Over long-term operation, the accumulated losses lead to a significant uneven heat distribution, affecting the converter's operational stability and safety, and posing a considerable challenge to heat dissipation design. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a control method for a bidirectional resonant energy storage converter. This control method ensures that the converter always operates near the series resonant point. By adjusting the duty cycle of the bridge switching unit, bidirectional energy regulation is achieved. The voltage gain of the converter is independent of the magnitude and direction of the transmitted power, and it has the ability to smoothly achieve rapid switching of bidirectional power transmission. Furthermore, under the control method of this invention, by rotating the switching sequence of the bridge switching unit on the voltage regulation side in two switching cycles, uniform heat distribution of the switching transistors of the bridge switching unit can be achieved in both boost and buck modes, and local maximum thermal stress can be effectively reduced.

[0006] The objective of this invention is achieved through the following technical solution: the bidirectional resonant converter is composed of a first DC power supply (DC1), a first bridge switching unit (10), a second bridge switching unit (30), a resonant unit (20), a transformer (T), and a second DC power supply (DC2).

[0007] The transformer (T) consists of a primary winding (N) p ) and secondary winding (N s )constitute.

[0008] The first bridge switching unit (10) is composed of switching transistors S1 to S4. The drains of the first switching transistor (S1) and the third switching transistor (S3) are connected to the positive terminal of the first DC power supply (DC1). The sources of the second switching transistor (S2) and the fourth switching transistor (S4) are connected to the negative terminal of the first DC power supply (DC1). The source of the first switching transistor (S1) is connected to the drain of the second switching transistor (S2), and the source of the third switching transistor (S3) is connected to the drain of the fourth switching transistor (S4). The source of the first switching transistor (S1) is connected to the primary winding (N) of the transformer (T). p The source terminal of the third switching transistor (S3) is connected to the primary winding (N) of the transformer (T). p () Non-same-name end.

[0009] The resonant unit (20) consists of a resonant inductor (L r ), resonant capacitor (C) r ) constitutes the resonant inductor (L r One end is connected to the secondary winding (N) of the transformer (T). s One end of the capacitor is connected to the same terminal as the other end of the resonant capacitor (C). r One end of ).

[0010] The second bridge switching unit (30) is composed of switching transistors S5 to S8. The drains of the fifth switching transistor (S5) and the seventh switching transistor (S7) are connected to the positive terminal of the second DC power supply (DC2). The sources of the sixth switching transistor (S6) and the eighth switching transistor (S8) are connected to the negative terminal of the second DC power supply (DC2). The source of the fifth switching transistor (S5) is connected to the drain of the sixth switching transistor (S6), and the source of the seventh switching transistor (S7) is connected to the drain of the eighth switching transistor (S8). The source of the fifth switching transistor (S5) is connected to the resonant capacitor (C) of the resonant unit (20). r At one end of the circuit, the source of the seventh switch (S7) is connected to the secondary winding (N) of the transformer (T). s () Non-same-name end.

[0011] The control method for the switching transistors in the first bridge switching unit (10) is as follows: the first switching transistor (S1) and the second switching transistor (S2) are complementary in conduction, the third switching transistor (S3) and the fourth switching transistor (S4) are complementary in conduction, and the switching frequencies of the first switching transistor (S1), the second switching transistor (S2), the third switching transistor (S3) and the fourth switching transistor (S4) are equal and greater than or equal to the resonant inductor (L) in the resonant unit (20). r ) and resonant capacitor (C r The resonant frequency of ).

[0012] The control method for the switching transistors in the second bridge switching unit (30) is as follows: the fifth switching transistor (S5) and the sixth switching transistor (S6) are complementary in conduction, the seventh switching transistor (S7) and the eighth switching transistor (S8) are complementary in conduction, and the switching frequencies of the fifth switching transistor (S5), the sixth switching transistor (S6), the seventh switching transistor (S7) and the eighth switching transistor (S8) are equal and greater than or equal to the resonant inductor (L) in the resonant unit (20). r ) and resonant capacitor (C r The resonant frequency of ).

[0013] The drive signals for all the switching transistors in the first bridge switching unit (10) and the second bridge switching unit (30) are implemented in the following way: the drive signals for the first switching transistor (S1), the fourth switching transistor (S4), the fifth switching transistor (S5), and the eighth switching transistor (S8) are driven by the first modulation wave (V m1 ), second modulation wave (V m2 ), third modulation wave (V m3 ), fourth modulation wave (V m4 ) and carrier (V c The carrier (V) is obtained by intersection. c The modulating wave is a centrally symmetric triangular wave, and the amplitude range of both the modulating wave and the carrier wave is 0 to V. cpk First modulated wave (V m1 ) and the second modulated wave (V m2 The sum of the carrier waves (V) and the carrier wave (V) c The peak values ​​of (V) are equal. m1 +V m2 =V cpk ), third modulation wave (V m3 ) and the fourth modulation wave (V m4 The sum of the carrier waves (V) and the carrier wave (V) c The peak values ​​of (V) are equal. m3 +V m4 =V cpk The drive signal of the second switch (S2) is generated by complementing the drive signal of the first switch (S1), the drive signal of the third switch (S3) is generated by complementing the drive signal of the fourth switch (S4), the drive signal of the sixth switch (S6) is generated by complementing the drive signal of the fifth switch (S5), and the drive signal of the seventh switch (S7) is generated by complementing the drive signal of the eighth switch (S8).

[0014] The control method for the bidirectional resonant converter operating in buck mode is as follows: by adjusting the first modulation wave (V... m1 ) and the second modulated wave (V m2 The third modulation wave (V) is used to adjust the output power of the bidirectional resonant converter. m3 ) and the fourth modulation wave (V m4Equal to and equal to the triangular carrier wave (V) c The duty cycle of the fifth switch (S5) is half the peak value, determined by the third modulation wave (V). m3 The duty cycle of the eighth switch (S8) is generated by the intersection of the fourth modulating wave (V) and the carrier wave. m4 ) and carrier (V c Intersection generation.

[0015] In any two adjacent switching cycles, during one of the switching cycles, the duty cycle of the first switch (S1) of the first bridge switching unit (10) is determined by the first modulation wave (V). m1 ) and triangular carrier (V c The duty cycle of the fourth switch (S4) is generated by the intersection of the second modulation wave (V). m2 ) and triangular carrier (V c Intersection generation, in another switching cycle, the duty cycle of the first switch (S1) of the first bridge switching unit (10) is generated by the second modulation wave (V). m2 ) and triangular carrier (V c The duty cycle of the fourth switch (S4) is generated by the intersection of the first modulation wave (V). m1 ) and triangular carrier (V c Intersection generation.

[0016] The control method for the bidirectional resonant converter operating in boost mode is as follows: by adjusting the third modulation wave (V... m3 ) and the fourth modulation wave (V m4 The output power of the bidirectional resonant converter is adjusted by the first modulation wave (V). m1 ) and the second modulated wave (V m2 Equal to and equal to the triangular carrier wave (V) c The duty cycle of the first switching transistor (S1) is half of the peak value, determined by the first modulated wave (V). m1 ) and carrier (V c The duty cycle of the fourth switch (S4) is generated by the intersection of the second modulation wave (V). m2 ) and carrier (V c Intersection generation.

[0017] In any two adjacent switching cycles, during one of the switching cycles, the duty cycle of the fifth switch (S5) of the second bridge switching unit (30) is determined by the third modulation wave (V). m3 ) and triangular carrier (V c The duty cycle of the eighth switch (S8) is generated by the intersection of the fourth modulation wave (V). m4 ) and triangular carrier (V c Intersection generation, in another switching cycle, the duty cycle of the fifth switch (S5) of the second bridge switching unit (30) is generated by the fourth modulation wave (Vm4 ) and triangular carrier (V c The duty cycle of the eighth switch (S8) is generated by the intersection of the three modulation waves (V). m3 ) and triangular carrier (V c Intersection generation.

[0018] The present invention has the following beneficial effects: (1) By redistributing the modulation waves corresponding to different switching tubes in adjacent switching cycles, the heat distribution of the first bridge switching unit (10) and the second bridge switching unit (30) is uniformly distributed, effectively reducing the local maximum thermal stress. (2) The converter operates at the resonant frequency of the series resonant circuit and has the ability to achieve soft switching under a wide voltage regulation range and a wide load range. (3) The voltage gain of the converter is independent of the transmission power and transmission direction. It has smooth and symmetrical dynamic characteristics of forward and reverse power transmission. The voltage and current of the DC bidirectional converter can be adjusted by simply adjusting the duty cycle of the switching transistor. Attached Figure Description

[0019] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the embodiments will be briefly described below; Appendix Figure 1 This is a schematic diagram of the bidirectional resonant converter upon which the present invention is based; Appendix Figure 2 The generation strategy diagram for the switching transistor drive signal of the first bridge switching unit (10) in buck mode; Appendix Figure 3 The generation strategy diagram for the switching transistor drive signal of the second bridge switching unit (30) in boost mode; Appendix Figure 4 The waveform diagram shows the drive waveforms of all switching transistors in buck mode. Appendix Figure 5 The waveform diagram shows the drive waveforms of all switching transistors in boost mode. Appendix Figure 6 This is a thermal distribution diagram of the first bridge switching unit (10) under the energy storage bidirectional resonant converter control method described in this invention; Appendix Figure 7 The heat distribution diagram of the first bridge switching unit (10) using the control method described in patent "CN106026645A (publication date: 2016-10-12)" is shown. Appendix Figure 8 The thermal distribution diagram of the second bridge switching unit (30) under the energy storage bidirectional resonant converter control method described in this invention is shown. Appendix Figure 9The heat distribution diagram of the second bridge switching unit (30) using the control method described in patent "CN106026645A (publication date: 2016-10-12)" is shown. Detailed Implementation

[0020] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] like Figure 1 As shown, the bidirectional resonant converter consists of a first DC power supply (DC1), a first bridge switching unit (10), a second bridge switching unit (30), a resonant unit (20), a transformer (T), and a second DC power supply (DC2).

[0022] The transformer (T) consists of a primary winding (N) p ) and secondary winding (N s )constitute.

[0023] The first bridge switching unit (10) is composed of switching transistors S1 to S4. The drains of the first switching transistor (S1) and the third switching transistor (S3) are connected to the positive terminal of the first DC power supply (DC1). The sources of the second switching transistor (S2) and the fourth switching transistor (S4) are connected to the negative terminal of the first DC power supply (DC1). The source of the first switching transistor (S1) is connected to the drain of the second switching transistor (S2), and the source of the third switching transistor (S3) is connected to the drain of the fourth switching transistor (S4). The source of the first switching transistor (S1) is connected to the primary winding (N) of the transformer (T). p The source terminal of the third switching transistor (S3) is connected to the primary winding (N) of the transformer (T). p () Non-same-name end.

[0024] The resonant unit (20) consists of a resonant inductor (L r ), resonant capacitor (C) r ) constitutes the resonant inductor (L r One end is connected to the secondary winding (N) of the transformer (T). s One end of the capacitor is connected to the same terminal as the other end of the resonant capacitor (C). r One end of ).

[0025] The second bridge switching unit (30) is composed of switching transistors S5 to S8. The drains of the fifth switching transistor (S5) and the seventh switching transistor (S7) are connected to the positive terminal of the second DC power supply (DC2). The sources of the sixth switching transistor (S6) and the eighth switching transistor (S8) are connected to the negative terminal of the second DC power supply (DC2). The source of the fifth switching transistor (S5) is connected to the drain of the sixth switching transistor (S6), and the source of the seventh switching transistor (S7) is connected to the drain of the eighth switching transistor (S8). The source of the fifth switching transistor (S5) is connected to the resonant capacitor (C) of the resonant unit (20). rAt one end of the transformer (T), the source of the seventh switch (S7) is connected to the secondary winding (N) of the transformer (T). s () Non-same-name end.

[0026] The control method for the switching transistors in the first bridge switching unit (10) is as follows: the first switching transistor (S1) and the second switching transistor (S2) are complementary in conduction, the third switching transistor (S3) and the fourth switching transistor (S4) are complementary in conduction, and the switching frequencies of the first switching transistor (S1), the second switching transistor (S2), the third switching transistor (S3) and the fourth switching transistor (S4) are equal and greater than or equal to the resonant inductor (L) in the resonant unit (20). r ) and resonant capacitor (C r The resonant frequency of ).

[0027] The control method for the switching transistors in the second bridge switching unit (30) is as follows: the fifth switching transistor (S5) and the sixth switching transistor (S6) are complementary in conduction, the seventh switching transistor (S7) and the eighth switching transistor (S8) are complementary in conduction, and the switching frequencies of the fifth switching transistor (S5), the sixth switching transistor (S6), the seventh switching transistor (S7) and the eighth switching transistor (S8) are equal and greater than or equal to the resonant inductor (L) in the resonant unit (20). r ) and resonant capacitor (C r The resonant frequency of ).

[0028] like Figure 2 , Figure 3 As shown, the drive signals for all switches in the first bridge switching unit (10) and the second bridge switching unit (30) are implemented in the following way: the drive signals for the first switch (S1), the fourth switch (S4), the fifth switch (S5), and the eighth switch (S8) are driven by a first modulation wave (V m1 ), second modulation wave (V m2 ), third modulation wave (V m3 ), fourth modulation wave (V m4 ) and carrier (V c The carrier (V) is obtained by intersection. c The modulating wave is a centrally symmetric triangular wave, and the amplitude range of both the modulating wave and the carrier wave is 0 to V. cpk First modulated wave (V m1 ) and the second modulated wave (V m2 The sum of the carrier waves (V) and the carrier wave (V) c The peak values ​​of (V) are equal. m1 +V m2 =V cpk ), third modulation wave (V m3 ) and the fourth modulation wave (V m4 The sum of the carrier waves (V) and the carrier wave (V) c The peak values ​​of (V) are equal. m3 +V m4=V cpk The drive signal of the second switch (S2) is generated by complementing the drive signal of the first switch (S1), the drive signal of the third switch (S3) is generated by complementing the drive signal of the fourth switch (S4), the drive signal of the sixth switch (S6) is generated by complementing the drive signal of the fifth switch (S5), and the drive signal of the seventh switch (S7) is generated by complementing the drive signal of the eighth switch (S8).

[0029] like Figure 4 As shown, the control method for the bidirectional resonant converter operating in buck mode is as follows: by adjusting the first modulation wave (V... m1 ) and the second modulated wave (V m2 The third modulation wave (V) is used to adjust the output power of the bidirectional resonant converter. m3 ) and the fourth modulation wave (V m4 Equal to and equal to the triangular carrier wave (V) c The duty cycle of the fifth switch (S5) is half the peak value, determined by the third modulation wave (V). m3 The duty cycle of the eighth switch (S8) is generated by the intersection of the fourth modulating wave (V) and the carrier wave. m4 ) and carrier (V c The resonant current is generated by the intersection, and due to the odd symmetry of the resonant current, the conduction, turn-on and turn-off losses of the fifth switch (S5), the sixth switch (S6), the seventh switch (S7) and the eighth switch (S8) are equal. Therefore, the heat of the second bridge switch unit (30) is uniformly distributed.

[0030] The control method of the first bridge switching unit (10) is as follows: In any two adjacent switching cycles, during one of the switching cycles, the duty cycle of the first switching transistor (S1) of the first bridge switching unit (10) is controlled by the first modulation wave (V). m1 ) and triangular carrier (V c Intersection generated, at t It will be available immediately. t At time 2, the fourth switch (S4) is turned off, and its duty cycle is determined by the second modulation wave (V). m2 ) and triangular carrier (V c Intersection generated, at t Open at 0:00 t At time 3, the circuit is turned off. In another switching cycle, the duty cycle of the first switch (S1) of the first bridge switching unit (10) is controlled by the second modulation wave (V). m2 ) and triangular carrier (V c Intersection generated, at t It will be available at 4 o'clock. t At time 7, the fourth switch (S4) is turned off, and its duty cycle is determined by the first modulation wave (V). m1) and triangular carrier (V c Intersection generated, at t It will be available at 5 o'clock. t Turn off at 6 o'clock.

[0031] The turn-on, turn-off currents of the first switch (S1) in one switching cycle are the same as those of the fourth switch (S4) in another switching cycle. Therefore, the total losses of the first switch (S1) and the fourth switch (S4) are the same in the two switching cycles. Since the second switch (S2) and the first switch (S1) are complementary in conduction, and the third switch (S3) and the fourth switch (S4) are complementary in conduction, the heat of the switch in the first bridge switching unit (10) is also uniformly distributed in buck mode.

[0032] like Figure 5 As shown, the control method for the bidirectional resonant converter operating in boost mode is as follows: by adjusting the third modulation wave (V... m3 ) and the fourth modulation wave (V m4 The output power of the bidirectional resonant converter is adjusted by the first modulation wave (V). m1 ) and the second modulated wave (V m2 Equal to and equal to the triangular carrier wave (V) c The duty cycle of the first switching transistor (S1) is half of the peak value, determined by the first modulated wave (V). m1 ) and carrier (V c The duty cycle of the fourth switch (S4) is generated by the intersection of the second modulation wave (V). m2 ) and carrier (V c The resonant current is generated by the intersection, and due to the odd symmetry of the resonant current, the conduction, turn-on and turn-off losses of the first switch (S1), the second switch (S2), the third switch (S3) and the fourth switch (S4) are equal. Therefore, the heat of the first bridge switch unit (10) is uniformly distributed.

[0033] The control method of the second bridge switching unit (30) is as follows: In any two adjacent switching cycles, during one of the switching cycles, the duty cycle of the fifth switching transistor (S5) of the second bridge switching unit (30) is controlled by the third modulation wave (V). m3 ) and triangular carrier (V c Intersection generated, at t It will be available immediately. t At time 2, the switch is turned off, and the duty cycle of the eighth switch (S8) is determined by the fourth modulation wave (V). m4 ) and triangular carrier (V c Intersection generated, at t Open at 0:00 tAt time 3, the circuit is turned off. In another switching cycle, the duty cycle of the fifth switch (S5) of the second bridge switching unit (30) is controlled by the fourth modulation wave (V). m4 ) and triangular carrier (V c Intersection generated, at t It will be available at 4 o'clock. t At time 7, the switch is turned off, and the duty cycle of the eighth switch (S8) is determined by the third modulation wave (V). m3 ) and triangular carrier (V c Intersection generated, at t It will be available at 5 o'clock. t Turn off at 6 o'clock.

[0034] The turn-on, turn-off currents of the fifth switch (S5) in one switching cycle are the same as those of the eighth switch (S8) in another switching cycle. Therefore, the total losses of the fifth switch (S5) and the eighth switch (S8) are the same in the two switching cycles. Since the sixth switch (S6) and the fifth switch (S5) are complementary in conduction, and the seventh switch (S7) and the eighth switch (S8) are complementary in conduction, the heat of the switches in the second bridge switching unit (30) is also uniformly distributed in the boost mode.

[0035] like Figure 6 , Figure 7 The figures show the heat distribution of the first bridge switching unit (10) under the step-down mode using the energy storage bidirectional resonant converter control method of the present invention and the control method of the patent "CN106026645A (publication date: 2016-10-12)". It can be seen that the energy storage bidirectional resonant converter control method of the present invention effectively reduces thermal stress and makes the heat distribution more uniform.

[0036] like Figure 8 , Figure 9 The figures show the heat distribution of the second bridge switching unit (30) under boost mode using the energy storage bidirectional resonant converter control method of the present invention and the control method of the patent "CN106026645A (publication date: 2016-10-12)". It can be seen that the energy storage bidirectional resonant converter control method of the present invention also effectively reduces the thermal stress of the second bridge switching unit (30) and makes the heat distribution more uniform.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various improvements and modifications can be made without fundamentally departing from the principles of the present invention, and all such improvements and modifications should be considered within the scope of protection of the present invention.

Claims

1. A control method for an energy storage bidirectional resonant converter, characterized in that: The bidirectional resonant converter consists of a first DC power supply (DC1), a first bridge switching unit (10), a second bridge switching unit (30), a resonant unit (20), a transformer (T), and a second DC power supply (DC2). The transformer (T) consists of a primary winding (N) p ) and secondary winding (N s )constitute; The first bridge switching unit (10) is composed of switching transistors S1 to S4. The drains of the first switching transistor (S1) and the third switching transistor (S3) are connected to the positive terminal of the first DC power supply (DC1). The sources of the second switching transistor (S2) and the fourth switching transistor (S4) are connected to the negative terminal of the first DC power supply (DC1). The source of the first switching transistor (S1) is connected to the drain of the second switching transistor (S2), and the source of the third switching transistor (S3) is connected to the drain of the fourth switching transistor (S4). The source of the first switching transistor (S1) is connected to the primary winding (N) of the transformer (T). p The source of the third switching transistor (S3) is connected to the primary winding (N) of the transformer (T), at the same terminal as the source of the third switching transistor (S3). p () non-same-name end; The resonant unit (20) consists of a resonant inductor (L r ), resonant capacitor (C) r ) constitutes the resonant inductor (L r One end is connected to the secondary winding (N) of the transformer (T). s One end of the capacitor is connected to the same terminal as the other end of the resonant capacitor (C). r one end; The second bridge switching unit (30) is composed of switching transistors S5 to S8. The drains of the fifth switching transistor (S5) and the seventh switching transistor (S7) are connected to the positive terminal of the second DC power supply (DC2). The sources of the sixth switching transistor (S6) and the eighth switching transistor (S8) are connected to the negative terminal of the second DC power supply (DC2). The source of the fifth switching transistor (S5) is connected to the drain of the sixth switching transistor (S6), and the source of the seventh switching transistor (S7) is connected to the drain of the eighth switching transistor (S8). The source of the fifth switching transistor (S5) is connected to the resonant capacitor (C) of the resonant unit (20). r At one end of the circuit, the source of the seventh switch (S7) is connected to the secondary winding (N) of the transformer (T). s () non-same-name end; The control method for the switching transistor in the first bridge switching unit (10) is as follows: The first switch (S1) and the second switch (S2) are complementary in conduction, and the third switch (S3) and the fourth switch (S4) are complementary in conduction. The switching frequencies of the first switch (S1), the second switch (S2), the third switch (S3), and the fourth switch (S4) are equal and greater than or equal to the resonant inductance (L) in the resonant unit (20). r ) and resonant capacitor (C r The resonant frequency of ). The control method for the switching transistor in the second bridge switching unit (30) is as follows: The fifth switch (S5) and the sixth switch (S6) are complementary in conduction, and the seventh switch (S7) and the eighth switch (S8) are complementary in conduction. The switching frequencies of the fifth switch (S5), the sixth switch (S6), the seventh switch (S7), and the eighth switch (S8) are equal and greater than or equal to the resonant inductance (L) in the resonant unit (20). r ) and resonant capacitor (C r The resonant frequency of ). The drive signals for all switching transistors in the first bridge switching unit (10) and the second bridge switching unit (30) are implemented using the following method: The drive signals of the first switch (S1), the fourth switch (S4), the fifth switch (S5), and the eighth switch (S8) are transmitted through the first modulation wave (V). m1 ), second modulation wave (V m2 ), third modulation wave (V m3 ), fourth modulation wave (V m4 ) and carrier (V c The carrier (V) is obtained by intersection. c The modulating wave is a centrally symmetric triangular wave, and the amplitude range of both the modulating wave and the carrier wave is 0 to V. cpk First modulated wave (V m1 ) and the second modulated wave (V m2 The sum of the carrier waves (V) and the carrier wave (V) c The peak values ​​of (V) are equal. m1 +V m2 =V cpk ), third modulation wave (V m3 ) and the fourth modulation wave (V m4 The sum of the carrier waves (V) and the carrier wave (V) c The peak values ​​of (V) are equal. m3 +V m4 =V cpk The drive signal of the second switch (S2) is generated by complementing the drive signal of the first switch (S1), the drive signal of the third switch (S3) is generated by complementing the drive signal of the fourth switch (S4), the drive signal of the sixth switch (S6) is generated by complementing the drive signal of the fifth switch (S5), and the drive signal of the seventh switch (S7) is generated by complementing the drive signal of the eighth switch (S8).

2. The control method for the energy storage bidirectional resonant converter according to claim 1, characterized in that: The control method for the bidirectional resonant converter operating in buck mode is as follows: By adjusting the first modulation wave (V) m1 ) and the second modulated wave (V m2 The third modulation wave (V) is used to adjust the output power of the bidirectional resonant converter. m3 ) and the fourth modulation wave (V m4 Equal to and equal to the triangular carrier wave (V) c The duty cycle of the fifth switch (S5) is half the peak value, determined by the third modulation wave (V). m3 The duty cycle of the eighth switch (S8) is generated by the intersection of the fourth modulating wave (V) and the carrier wave. m4 ) and carrier (V c Intersection generation; In any two adjacent switching cycles, during one of the switching cycles, the duty cycle of the first switch (S1) of the first bridge switching unit (10) is determined by the first modulation wave (V). m1 ) and triangular carrier (V c The duty cycle of the fourth switch (S4) is generated by the intersection of the second modulation wave (V). m2 ) and triangular carrier (V c Intersection generation, in another switching cycle, the duty cycle of the first switch (S1) of the first bridge switching unit (10) is generated by the second modulation wave (V). m2 ) and triangular carrier (V c The duty cycle of the fourth switch (S4) is generated by the intersection of the first modulation wave (V). m1 ) and triangular carrier (V c Intersection generation; The control method for the bidirectional resonant converter operating in boost mode is as follows: By adjusting the third modulation wave (V) m3 ) and the fourth modulation wave (V m4 The output power of the bidirectional resonant converter is adjusted by the first modulation wave (V). m1 ) and the second modulated wave (V m2 Equal to and equal to the triangular carrier wave (V) c The duty cycle of the first switching transistor (S1) is half of the peak value, determined by the first modulated wave (V). m1 ) and carrier (V c The duty cycle of the fourth switch (S4) is generated by the intersection of the second modulation wave (V). m2 ) and carrier (V c Intersection generation; In any two adjacent switching cycles, during one of the switching cycles, the duty cycle of the fifth switch (S5) of the second bridge switching unit (30) is determined by the third modulation wave (V). m3 ) and triangular carrier (V c The duty cycle of the eighth switch (S8) is generated by the intersection of the fourth modulation wave (V). m4 ) and triangular carrier (V c Intersection generation, in another switching cycle, the duty cycle of the fifth switch (S5) of the second bridge switching unit (30) is generated by the fourth modulation wave (V m4 ) and triangular carrier (V c The duty cycle of the eighth switch (S8) is generated by the intersection of the three modulation waves (V). m3 ) and triangular carrier (V c Intersection generation.

Images