Power bidirectional switching method, device, converter, controller and storage medium

Abstract

This application relates to a power bidirectional switching method, apparatus, converter, controller, and storage medium. The method includes: responding to a power commutation command from the converter, determining a load switching type based on the magnitude relationship between the load after commutation and the load before commutation, and the direction of the output current; at the end of the current switching cycle of the converter, controlling the state of each switching transistor unit in the converter according to the load switching type and the excitation at both ends of the converter resonant cavity, until the converter re-enters a steady state; wherein the duration between the end of the current switching cycle and the moment when the converter re-enters a steady state is less than or equal to two switching cycles of the converter; thus, reliable bidirectional power switching can be performed.

Description

Technical Field

[0001] This application relates to the field of converter technology, and in particular to a power bidirectional switching method, apparatus, converter, controller and storage medium. Background Technology

[0002] The Dual Bridge Series Resonant Converter (DBSRC) is often used in bidirectional power conversion scenarios because of the symmetrical structure at both ends of the resonant cavity.

[0003] In related technologies, when DBSRC achieves instantaneous power commutation in bidirectional power conversion scenarios, the bandwidth limitation of the closed-loop controller controlling DBSRC means that DBSRC needs a relatively long time to re-enter steady-state. In addition, during the control of DBSRC, there is a problem of zero-voltage turn-on loss of bridge arm switches, which can easily lead to excessive voltage stress on the bridge arm switches in DBSRC, and in severe cases, even damage to DBSRC.

[0004] Therefore, how to reliably perform bidirectional power switching of DBSRC has become an urgent technical problem to be solved. Summary of the Invention

[0005] Therefore, it is necessary to provide a power bidirectional switching method, apparatus, converter, controller, readable storage medium, computer, and computer program product that can reliably perform bidirectional power switching, addressing the aforementioned technical problems.

[0006] In a first aspect, this application provides a power bidirectional switching method, the method comprising:

[0007] In response to the power commutation command of the converter, the load transformation type is determined based on the magnitude relationship between the load after commutation and the load before commutation, as well as the direction of the output current.

[0008] At the end of the current switching cycle of the converter, according to the load transformation type and the excitation at both ends of the converter resonant cavity, the state of each switching transistor unit in the converter is controlled until the converter re-enters a steady state.

[0009] The duration between the end of the current switching cycle and the moment when the converter re-enters a steady state is less than or equal to two switching cycles of the converter.

[0010] In one embodiment, according to the load transformation type, the state of each switching transistor unit in the converter is controlled based on the excitation at both ends of the converter resonant cavity, including:

[0011] The control information of the state of the switching transistor unit in the converter is obtained; wherein, the control information includes the control time of each switching transistor unit in different states under different load transformation types;

[0012] The state of each switching transistor unit in the converter is controlled according to the control information.

[0013] In one embodiment, obtaining control information regarding the state of the switching transistor units in the converter includes:

[0014] Based on the excitation at both ends of the converter resonant cavity, write down the relationship between the resonant capacitor voltage and the resonant inductor current after standardization. The relationship is in the form of a standard equation of a circle.

[0015] Based on the aforementioned relationship, the resonant inductor current value and resonant capacitor voltage value at the first transition moment are determined under different load transformation types.

[0016] Based on the resonant inductor current and resonant capacitor voltage values ​​at the second transition time, and based on the resonant capacitor voltage value at the first transition time, write the time-domain resonant capacitor voltage expression for the first transition time to determine the first control duration;

[0017] Based on the resonant inductor current and resonant capacitor voltage values ​​at the first transition moment, and the resonant capacitor voltage value at the moment when the converter re-enters steady state, the time-domain resonant capacitor voltage expression at the moment when the converter re-enters steady state is written to determine the second control duration.

[0018] In this process, along the time progression, the end time of the current switching cycle of the converter, the second transition time, the first transition time, and the time when the converter re-enters the steady state are sequentially performed.

[0019] The duration between the second transition time and the first transition time is the first control duration; the duration between the first transition time and the moment when the converter re-enters steady state is the second control duration.

[0020] In one embodiment, obtaining control information regarding the state of the switching transistor unit in the converter further includes:

[0021] The third control duration for different load transformation types is determined based on the switching frequency of the converter and the pre-commutation load under different load transformation types.

[0022] The duration between the end of the current switching cycle of the converter and the second transition time is the third control duration.

[0023] In one embodiment, based on the relationship, the resonant inductor current value and resonant capacitor voltage value at the first transition moment are determined under different load transformation types, including:

[0024] Based on the aforementioned relationship, the pre-commutation steady-state trajectory circle formed by the resonant inductor current value and the resonant capacitor voltage value, and the post-commutation steady-state trajectory circle formed by the resonant inductor current value and the resonant capacitor voltage value are determined under different load transformation types.

[0025] Based on the radius of the steady-state trajectory circle before commutation and the radius of the steady-state trajectory circle after commutation, the resonant inductor current value and the resonant capacitor voltage value at the first transition moment are determined.

[0026] In one embodiment, when the load transformation type is heavy load to light load, the second control duration is longer than the first control duration; when the load transformation type is light load to heavy load, the second control duration is shorter than the first control duration; the power corresponding to the heavy load is greater than the power corresponding to the light load, and the positive and negative directions represent different directions of the output current, respectively.

[0027] Controlling the state of each switching transistor unit in the converter according to the control information includes:

[0028] Under different load transformation types, the corresponding switching transistor units of the converter are turned on or off during the first control duration, the second control duration, and the third control duration, respectively.

[0029] In a second aspect, this application also provides a converter, the converter including a controller for performing the power bidirectional switching method as described in the first aspect above;

[0030] The converter further includes: a first switching transistor unit and a third switching transistor unit directly connected to the positive terminal of the first voltage source; a second switching transistor unit and a fourth switching transistor unit directly connected to the negative terminal of the first voltage source; a fifth switching transistor unit and a seventh switching transistor unit directly connected to the positive terminal of the second voltage source; and a sixth switching transistor unit and an eighth switching transistor unit directly connected to the negative terminal of the second voltage source.

[0031] The first voltage source and the second voltage source are located on both sides of the converter resonant cavity;

[0032] Here, the direction of the output current flowing from the first voltage source to the second voltage source is defined as positive, and the direction of the output current flowing from the second voltage source to the first voltage source is defined as negative.

[0033] In one embodiment, when the load transformation type is forward heavy load to reverse light load, the controller is used to control each switching transistor unit in the converter as follows:

[0034] During the time interval between the end of the current switching cycle of the converter and the first transition time, the first and fourth switching units are turned on, and the second and third switching units are turned off.

[0035] During the time interval between the first transition moment and the moment when the converter re-enters the steady state, the second and third switching units are both turned on, and the first and fourth switching units are both turned off.

[0036] During the time interval between the end of the current switching cycle of the converter and the second transition time, the sixth and seventh switching units are both turned on, and the fifth and eighth switching units are both turned off.

[0037] During the time interval between the second transition moment and the moment when the converter re-enters steady state, the fifth and eighth switch units are turned on, and the sixth and seventh switch units are turned off.

[0038] In one embodiment, when the load transformation type is forward light load to reverse heavy load, the controller is used to control each switching transistor unit in the converter as follows:

[0039] During the time interval between the end of the current switching cycle of the converter and the first transition time, the first and fourth switching units are turned on, and the second and third switching units are turned off.

[0040] During the time interval between the first transition moment and the moment when the converter re-enters the steady state, the second and third switching units are both turned on, and the first and fourth switching units are both turned off.

[0041] During the time interval between the end of the current switching cycle of the converter and the time when the converter re-enters a steady state, the sixth and seventh switching units are turned on, while the fifth and eighth switching units are turned off.

[0042] In one embodiment, when the load transformation type is reverse heavy load to forward light load, the controller is used to control each switching transistor unit in the converter as follows:

[0043] During the time interval between the end of the current switching cycle of the converter and the first transition time, the fifth and eighth switching units are both turned on, and the sixth and seventh switching units are both turned off.

[0044] During the time interval between the first transition moment and the moment when the converter re-enters steady state, the sixth and seventh switch units are both turned on, and the fifth and eighth switch units are both turned off.

[0045] During the time interval between the end of the current switching cycle of the converter and the second transition time, the second and third switching units are both turned on, while the first and fourth switching units are both turned off.

[0046] During the time interval between the second transition moment and the moment when the converter re-enters steady state, the first and fourth switching units are turned on, while the second and third switching units are turned off.

[0047] In one embodiment, when the load transformation type is reverse light load to forward heavy load, the controller is used to control each switching transistor unit in the converter as follows:

[0048] During the time interval between the end of the current switching cycle of the converter and the first transition time, the fifth and eighth switching units are both turned on, and the sixth and seventh switching units are both turned off.

[0049] During the time interval between the first transition moment and the moment when the converter re-enters steady state, the sixth and seventh switch units are both turned on, and the fifth and eighth switch units are both turned off.

[0050] During the time interval between the end of the current switching cycle of the converter and the time when the converter re-enters a steady state, the second and third switching units are turned on, while the first and fourth switching units are turned off.

[0051] Thirdly, this application also provides a power bidirectional switching device, the device comprising:

[0052] The conversion type module is used to respond to the power commutation command of the converter and determine the load conversion type according to the magnitude relationship between the load after commutation and the load before commutation and the direction of the output current.

[0053] The steady-state switching module is used to control the state of each switching transistor unit in the converter according to the load transformation type and the excitation at both ends of the converter resonant cavity at the end of the current switching cycle of the converter, until the converter re-enters a steady state; wherein the duration between the end of the current switching cycle and the moment when the converter re-enters a steady state is less than or equal to two switching cycles of the converter.

[0054] Fourthly, this application also provides a controller, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the power bidirectional switching method as described in the first aspect above.

[0055] Fifthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the power bidirectional switching method as described in the first aspect above.

[0056] In a sixth aspect, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the power bidirectional switching method as described in the first aspect above.

[0057] The aforementioned power bidirectional switching method, apparatus, converter, controller, readable storage medium, computer, and computer program products, because the positive and negative excitation at both ends of the converter resonant cavity can determine the direction and trajectory of current flow between each switching transistor unit in the converter, can control the state of each switching transistor unit in the converter according to the excitation at both ends of the converter resonant cavity after responding to the power commutation command and determining the load switching type, until the converter re-enters the steady-state operation. This enables zero-voltage turn-on of each switching transistor unit in the converter, thus avoiding excessive voltage stress on the switching transistors and protecting the converter. Furthermore, since the time between the end of the current switching cycle and the time when the converter re-enters the steady-state operation is less than or equal to two switching cycles of the converter, the time for the converter to re-enter the steady-state operation is shortened. In summary, the embodiments of this application achieve reliable power bidirectional switching. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 This is a schematic diagram of the topology of DBSRC in one embodiment;

[0060] Figure 2 This is a flowchart illustrating a bidirectional power switching method in one embodiment;

[0061] Figure 3 This is a flowchart illustrating S204 in one embodiment;

[0062] Figure 4A This is a flowchart illustrating S302 in one embodiment;

[0063] Figure 4B This is the steady-state trajectory circle under forward heavy load and reverse light load in one embodiment;

[0064] Figure 4C This is the steady-state trajectory circle under forward light load and reverse heavy load in one embodiment;

[0065] Figure 5 This is a schematic diagram of the process that S302 further includes in one embodiment;

[0066] Figure 6A This is a flowchart illustrating S304 in one embodiment;

[0067] Figure 6B Here is the time-domain waveform of the resonant inductor current under forward heavy load and reverse light load in one embodiment;

[0068] Figure 6C This is the time-domain waveform of the resonant inductor current under forward light load and reverse heavy load in one embodiment;

[0069] Figure 6D Here is the time-domain waveform of the resonant inductor current under reverse heavy load and forward light load in one embodiment;

[0070] Figure 6E This is the time-domain waveform of the resonant inductor current under reverse light load and forward heavy load in one embodiment;

[0071] Figure 7 This is a structural block diagram of a power bidirectional switching device in one embodiment. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0073] The power bidirectional switching method provided in this application embodiment can be applied to, for example... Figure 1 The DBSRC topology is shown below. There are various DBSRC topologies. Figure 1 The image is merely an example illustrating one of them.

[0074] exist Figure 1In the DBSRC, there are a first and a third switching transistor unit directly connected to the positive terminal of the first voltage source V1, a second and a fourth switching transistor unit directly connected to the negative terminal of the first voltage source V1, a fifth and a seventh switching transistor unit directly connected to the positive terminal of the second voltage source V2, and a sixth and a eighth switching transistor unit directly connected to the negative terminal of the second voltage source V2. The first voltage source V1 and the second voltage source V2 are located on both sides of the converter resonant cavity. The converter resonant cavity includes a resonant capacitor Cr and a resonant inductor Lr. n is the turns ratio of the transformer in the converter, and the gain of the converter is M = n·(V2 / V1).

[0075] Each switching unit may include at least one switching transistor. When a switching unit includes multiple switching transistors, these transistors may be connected in parallel sequentially. For example, as shown... Figure 1 As shown, each switching transistor unit includes one switching transistor, wherein the first switching transistor unit includes a first switching transistor S1, the second switching transistor unit includes a second switching transistor S2, the third switching transistor unit includes a third switching transistor S3, the fourth switching transistor unit includes a fourth switching transistor S4, the fifth switching transistor unit includes a fifth switching transistor S5, the sixth switching transistor unit includes a sixth switching transistor S6, the seventh switching transistor unit includes a seventh switching transistor S7, and the eighth switching transistor unit includes an eighth switching transistor S8.

[0076] For example, the direction of the DBSRC output current flowing from the first voltage source V1 to the second voltage source V2 can be made positive (e.g., Figure 1 (As indicated by the red arrow in the middle), the direction of the DBSRC output current flowing from the second voltage source V2 to the first voltage source V1 is the opposite (to the direction indicated by the red arrow in the middle). Figure 1 (The direction indicated by the red arrow is opposite to the direction of the arrowhead).

[0077] In one exemplary embodiment, such as Figure 2 As shown, a bidirectional power switching method is provided, which can be applied to... Figure 1 Taking the DBSRC topology as an example, this method may include the following steps S202~S204.

[0078] S202, in response to the power commutation command of the converter, determines the load transformation type based on the magnitude relationship between the load after commutation and the load before commutation and the direction of the output current.

[0079] Among them, power commutation commands include power switching commands issued by the user, signals for switching the direction of output current, or signals for switching the direction of output power.

[0080] The magnitude of output power can be understood as the magnitude of the load. In specific numerical calculations, the magnitude of output power can be equal to the magnitude of the load. For example, the magnitude of the load after the converter power commutation can be understood as the magnitude of the output power after the converter power commutation, and the magnitude of the load before the converter power commutation can be understood as the magnitude of the output power before the converter power commutation.

[0081] In response to the power commutation command of the converter, the magnitude of the output power before and after commutation and the direction of the output current before and after commutation can be determined, thereby determining the load transformation type. For example, the direction of the output current of the DBSRC flowing from the first voltage source V1 to the second voltage source V2 can be defined as positive (e.g., ...). Figure 1 (As indicated by the red arrow in the middle), the direction of the DBSRC output current flowing from the second voltage source V2 to the first voltage source V1 is the opposite (to the direction indicated by the red arrow in the middle). Figure 1 (The direction indicated by the red arrow in the middle is opposite to the direction of the load transformation) There are four types of load transformation: forward heavy load to reverse light load, forward light load to reverse heavy load, reverse heavy load to forward light load, and reverse light load to forward heavy load.

[0082] "Forward heavy load switching to reverse light load" means that before power commutation, the output current direction is forward, and after power commutation, the output current direction is reverse, and the load size before power commutation is greater than the load size after power commutation.

[0083] "Forward light load switching to reverse heavy load" means that before power commutation, the output current direction is forward, and after power commutation, the output current direction is reverse, and the load size before power commutation is smaller than the load size after power commutation.

[0084] Reverse heavy load switching to forward light load means that before power commutation, the output current direction is reversed, and after power commutation, the output current direction is forward, and the load size before power commutation is greater than the load size after power commutation.

[0085] Reverse light load to forward heavy load means that before power commutation, the output current direction is reversed, and after power commutation, the output current direction is forward, and the load size before power commutation is smaller than the load size after power commutation.

[0086] S204, at the end of the current switching cycle of the converter, controls the state of each switching transistor unit in the converter according to the load switching type and the excitation at both ends of the converter resonant cavity, until the converter re-enters a steady state.

[0087] The duration between the end of the current switching cycle and the moment when the converter re-enters steady state is less than or equal to two switching cycles of the converter.

[0088] The converter re-entering steady state means that the converter moves from the steady state before power commutation to the steady state after power commutation.

[0089] The excitations at both ends of the converter resonant cavity are V AB and V CD There are four possible cases, namely V AB =V1,V CD =V2;V AB =V1,V CD =-V2;V AB =-V1, V CD =V2;V AB =-V1, V CD =-V2.

[0090] In this embodiment, the positive or negative excitation at both ends of the converter resonant cavity determines the direction and trajectory of current flow among the switching transistors in the converter. Therefore, under different load conversion types, the state of each switching transistor in the converter is controlled according to the excitation at both ends of the converter resonant cavity until the converter re-enters a steady operating state. This enables zero-voltage turn-on of each switching transistor in the converter, meaning that each switching transistor in each switching transistor is turned on with zero voltage. This avoids excessive voltage stress on the switching transistors and protects the converter. Furthermore, since the time between the end of the current switching cycle and the time when the converter re-enters a steady operating state is less than or equal to two switching cycles of the converter, the time for the converter to re-enter a steady operating state is shortened. In summary, this embodiment achieves reliable bidirectional power switching.

[0091] In one exemplary embodiment, such as Figure 3 As shown, in S204, according to the load transformation type, the state of each switching transistor unit in the converter is controlled based on the excitation at both ends of the converter resonant cavity, which may include the following steps S302~S304.

[0092] S302, acquire control information of the state of the switching transistor unit in the converter; wherein, the control information includes the control time of each switching transistor unit in different states under different load conversion types.

[0093] Under different load transformation types, the control time of each switching transistor unit varies in different states. For example, under forward heavy load switching to reverse light load, the on-time of the first switching transistor S1 differs from that of the fifth switching transistor S5; the off-time of the first switching transistor S1 differs from that of the fifth switching transistor S5; the on-time of the first switching transistor S1 differs from that of the first switching transistor S5; and so on. Furthermore, the on-time of the first switching transistor S1 under forward heavy load switching to reverse light load differs from that under forward light load switching to reverse heavy load. Therefore, the acquired control information includes the control time of each switching transistor unit in different states under at least one load transformation type. In other words, the control information includes at least the control time of each switching transistor unit in different states under that load transformation type, determined by the power commutation command in S202.

[0094] S304 controls the state of each switching transistor unit in the converter based on the control information.

[0095] In this embodiment, by turning on or off each switching unit for different durations according to the load switching type during the time between the end of the current switching cycle and the time when the converter re-enters the steady state, zero-voltage turn-on of each switching unit is achieved, and the time for the converter to re-enter the steady state is shortened, thereby realizing reliable bidirectional power switching.

[0096] In one exemplary embodiment, such as Figure 4A As shown, the control information for obtaining the state of the switching transistor unit in the converter in S302 may include the following steps S402~S408.

[0097] S402, based on the excitation at both ends of the converter resonant cavity, write the relationship between the resonant capacitor voltage and the resonant inductor current after standardization. The relationship is in the form of a standard circle equation.

[0098] For example, the excitation at both ends of the converter resonant cavity is V AB =V1,V CD When V2 = 1, the per-unit relationship between the resonant capacitor voltage and the resonant inductor current is as follows:

[0099] .

[0100] For example, the excitation at both ends of the converter resonant cavity is V AB =V1,V CD When V = -V2, the per-unit relationship between the resonant capacitor voltage and the resonant inductor current is as follows:

[0101] .

[0102] For example, the excitation at both ends of the converter resonant cavity is V AB =-V1, V CD When V2 = 1, the per-unit relationship between the resonant capacitor voltage and the resonant inductor current is as follows:

[0103] .

[0104] For example, the excitation at both ends of the converter resonant cavity is V AB =-V1, V CD When V = -V2, the per-unit relationship between the resonant capacitor voltage and the resonant inductor current is as follows:

[0105] .

[0106] Among them, V cn For the resonant capacitor voltage, i pn For the resonant inductor current, V 2n =V2' / V1, V2'=n·V2, V c0n =V c0 / V1,i p0n =i p0 / I b I b =V1 / sqrt(Lr / Cr), V c0 and i p0 These are the initial values ​​of the resonant capacitor voltage and the resonant inductor current, respectively.

[0107] S404, based on the relationship, determines the resonant inductor current value and resonant capacitor voltage value at the first transition moment under different load transformation types.

[0108] In this process, along the time progression, the current switching cycle end time t1, the second transition time t2, the first transition time t3, and the time when the converter re-enters steady state t1' are sequentially performed.

[0109] Optionally, based on the relationship satisfied by the per-unit resonant capacitor voltage and resonant inductor current, the pre-commutation steady-state trajectory circle formed by the resonant inductor current value and the post-commutation steady-state trajectory circle formed by the resonant inductor current value and the resonant capacitor voltage value are determined under different load transformation types; according to the radius of the pre-commutation steady-state trajectory circle and the radius of the post-commutation steady-state trajectory circle, the resonant inductor current value and the resonant capacitor voltage value at the first transition time t3 are determined.

[0110] For example, when switching from a heavy load in the forward direction to a light load in the reverse direction, or vice versa, the direction before the switch is heavy load, and the direction after the switch is light load, such as... Figure 4B As shown, the ring with the larger enclosing area (i.e., the red circle) is the steady-state trajectory circle before commutation, and the ring with the smaller enclosing area (i.e., the blue circle) is the steady-state trajectory circle after commutation. The orange segment between the first transition time t3 and the time when the converter re-enters steady state t1' is the power commutation trajectory line from heavy load to light load. Each ring consists of four segments, and each segment is a partial arc of a certain circle. Figure 4B O1, O2, O3 and O4 in the diagram are all centers of circles, and the corresponding radii are indicated by dotted lines.

[0111] The coordinates of O1 are (-(1+V) 2n The radius of the steady-state trajectory circle before commutation corresponding to O1 is R1, which can be determined based on the converter gain M and the output power before commutation. The radius of the steady-state trajectory circle after commutation corresponding to O1 is R2, which can be determined based on the converter gain M and the output power after commutation.

[0112] The coordinates of O2 are (1-V) 2n The radius of the steady-state trajectory circle before commutation corresponding to O2 is r1, which can be determined based on the converter gain M and the output power before commutation. The radius of the steady-state trajectory circle after commutation corresponding to O2 is r2, which can be determined based on the converter gain M and the output power after commutation.

[0113] The coordinates of O3 are (-(1-V) 2n The radius of the steady-state trajectory circle before the commutation of O3 is r1, and the radius of the steady-state trajectory circle after the commutation of O3 is r2.

[0114] The coordinates of O4 are (1+V) 2n The radius of the steady-state trajectory circle before the commutation of O4 is R1, and the radius of the steady-state trajectory circle after the commutation of O4 is R2.

[0115] like Figure 4B As shown, the area of ​​the shaded region of the triangle can be calculated using Heron's formula, resulting in:

[0116] ;

[0117] ;

[0118] Among them, I Lt3 and V crt3 These represent the resonant inductor current and resonant capacitor voltage values ​​at the first transition time t3, respectively, under either forward heavy load switching to reverse light load or reverse heavy load switching to forward light load.

[0119] For example, when switching from a light load in the forward direction to a heavy load in the reverse direction, or vice versa, the load before the switch is light, and the load after the switch is heavy. Figure 4CAs shown, the ring with the larger enclosing area (i.e., the blue circle) is the steady-state trajectory circle after commutation, and the ring with the smaller enclosing area (i.e., the red circle) is the steady-state trajectory circle before commutation. The orange segment between the second transition time t2 and the first transition time t3 is the power commutation trajectory line from light load to heavy load. Each ring consists of four segments, and each segment is a part of the arc of a certain circle. Figure 4C O1, O2, O3 and O4 in the diagram are all centers of circles, and the corresponding radii are indicated by dotted lines.

[0120] The coordinates of O1 are (-(1+V) 2n The radius of the steady-state trajectory circle after commutation corresponding to O1 is R1, which can be determined based on the converter gain M and the output power after commutation. The radius of the steady-state trajectory circle before commutation corresponding to O1 is R2, which can be determined based on the converter gain M and the output power before commutation.

[0121] The coordinates of O2 are (1-V) 2n The radius of the steady-state trajectory circle after commutation corresponding to O2 is r1, which can be determined based on the converter gain M and the output power after commutation. The radius of the steady-state trajectory circle before commutation corresponding to O2 is r2, which can be determined based on the converter gain M and the output power before commutation.

[0122] The coordinates of O3 are (-(1-V) 2n The radius of the steady-state trajectory circle after commutation is r1, and the radius of the steady-state trajectory circle before commutation is r2.

[0123] The coordinates of O4 are (1+V) 2n The radius of the steady-state trajectory circle after commutation is R1, and the radius of the steady-state trajectory circle before commutation is R2.

[0124] like Figure 4C As shown, the area of ​​the shaded region of the triangle can be calculated using Heron's formula, resulting in:

[0125] ;

[0126] ;

[0127] Among them, I Lt3 and V crt3 These represent the resonant inductor current and resonant capacitor voltage values ​​at the first transition time t3, respectively, under either a forward light load switching to a reverse heavy load or a reverse light load switching to a forward heavy load.

[0128] In this embodiment of the application, for example, determining the radius of the corresponding steady-state trajectory circle based on the converter's gain M and output power can be achieved by looking up the radius of the steady-state trajectory circle corresponding to the converter's gain M and output power in a pre-stored pre-defined correspondence table. This pre-defined correspondence table can be obtained based on empirical values ​​from actual applications and stored in advance. Alternatively, a pre-established radius calculation model can be used, inputting the converter's gain M and output power into the radius calculation model to calculate the radius of the steady-state trajectory circle corresponding to the gain M and output power.

[0129] S406. Based on the resonant inductor current value and resonant capacitor voltage value at the second transition time, and based on the resonant capacitor voltage value at the first transition time, write the time-domain resonant capacitor voltage expression for the first transition time to determine the first control duration.

[0130] For example, under either a forward heavy load switching to a reverse light load or a reverse heavy load switching to a forward light load, the expression for the time-domain resonant capacitor voltage at the first transition time t3 is:

[0131] ;

[0132] Among them, V AB =V1,V CD =V2. i p (t2) and V c (t2) represents the resonant inductor current and resonant capacitor voltage at the second transition time t2, respectively, which can be determined based on the load size before commutation. ΔT1 is the first control duration, Zr=sqrt(Lr / Cr), fs is the switching frequency of the converter, F=fs / fr, fr=1 / (2π*sqrt(Lr*Cr)).

[0133] For example, under forward light load switching to reverse heavy load or reverse light load switching to forward heavy load, the expression for the time-domain resonant capacitor voltage at the first transition time t3 is:

[0134] = ;

[0135] Among them, V AB =V1,V CD =-V2. i p (t2) and V c (t2) represents the resonant inductor current and resonant capacitor voltage at the second transition time t2, respectively, which can be determined by the load size before commutation. ΔT1 is the first control duration, Zr=sqrt(Lr / Cr), fs is the switching frequency of the converter, F=fs / fr, fr=1 / (2π*sqrt(Lr*Cr)).

[0136] S408, based on the resonant inductor current value and resonant capacitor voltage value at the first transition moment, and based on the resonant capacitor voltage value at the moment when the converter re-enters steady state, write the time-domain resonant capacitor voltage expression at the moment when the converter re-enters steady state, so as to determine the second control duration.

[0137] The duration between the second transition time t2 and the first transition time t3 is the first control duration ΔT1; the duration between the first transition time t3 and the time t1' when the converter re-enters steady state is the second control duration ΔT2.

[0138] For example, under either forward heavy load switching to reverse light load or reverse heavy load switching to forward light load, the expression for the time-domain resonant capacitor voltage at the moment t1' when the converter re-enters steady state is:

[0139] ;

[0140] Among them, V AB =-V1, V CD =V2,V c (t1') can be determined by the load size after commutation, and ΔT2 is the second control duration.

[0141] ;

[0142] .

[0143] For example, under forward light load switching to reverse heavy load or reverse light load switching to forward heavy load, the expression for the time-domain resonant capacitor voltage at the moment t1' when the converter re-enters steady state is:

[0144] = ;

[0145] Among them, V AB =-V1, V CD =-V2,V c (t1') can be determined by the load size after commutation, and ΔT2 is the second control duration.

[0146] ;

[0147] .

[0148] In one exemplary embodiment, such as Figure 5 As shown, the control information for obtaining the state of the switching transistor unit in the converter in S302 may also include the following step S502.

[0149] S502 determines the third control duration for different load transformation types based on the switching frequency of the converter and the pre-commutation load under different load transformation types.

[0150] ;

[0151] The duration between the end time t1 of the current switching cycle of the converter and the second transition time t2 is the third control duration t2-t1. ɸ can be determined based on the load size of the pre-commutation load. After determining the third control duration t2-t1, the end time t1 of the current switching cycle of the converter can be obtained, and then the second transition time t2 can be determined.

[0152] For example, the relationship between ɸ and the output power Po corresponding to the pre-commutation load can be expressed as follows:

[0153] Where π is the ratio of a circle's diameter to its circumference.

[0154] In an exemplary embodiment, t1, t2, t3, t1' under forward heavy load and reverse light load and t1, t2, t3, t1' under reverse heavy load and forward light load are all equal; t1, t2, t3, t1' under forward light load and reverse heavy load and t1, t2, t3, t1' under reverse light load and forward heavy load are all equal.

[0155] In an exemplary embodiment, when the load change type is heavy load to light load, the second control duration ΔT2 is greater than the first control duration ΔT1; when the load change type is light load to heavy load, the second control duration ΔT2 is less than the first control duration ΔT1. Herein, heavy load to light load includes forward heavy load to reverse light load and reverse heavy load to forward light load, and light load to heavy load includes forward light load to reverse heavy load and reverse light load to forward heavy load.

[0156] In one exemplary embodiment, such as Figure 6A As shown, controlling the state of each switching transistor unit in the converter according to the control information in S304 may include the following step S602.

[0157] S602 controls the corresponding switching transistor unit of the converter to turn on or off during the first control duration, the second control duration, and the third control duration, respectively, under different load transformation types.

[0158] For example, under forward heavy load and reverse light load, combined Figure 1 and Figure 6B During the time interval between the end of the current switching cycle of the converter, t1, and the first transition time, t3, the first switch S1 and the fourth switch S4 are both turned on, while the second switch S2 and the third switch S3 are both turned off.

[0159] During the time interval between the first transition time t3 and the time when the converter re-enters the steady state t1', the second switch S2 and the third switch S3 are both turned on, while the first switch S1 and the fourth switch S4 are both turned off.

[0160] During the time interval between the end of the current switching cycle of the converter t1 and the second transition time t2, the sixth switch S6 and the seventh switch S7 are both turned on, and the fifth switch S5 and the eighth switch S8 are both turned off.

[0161] During the time interval between the second transition time t2 and the time when the converter re-enters steady state t1', the fifth switch S5 and the eighth switch S8 are both turned on, while the sixth switch S6 and the seventh switch S7 are both turned off.

[0162] Thus, the turn-on of the first switch S1, the fourth switch S4, the second switch S2, the third switch S3, the sixth switch S6, the seventh switch S7, the fifth switch S5, and the eighth switch S8 all achieve zero-voltage turn-on; zero-voltage turn-on means that, just before a switch is turned on, the current first flows through the parallel diode of the switch. Furthermore, refer to... Figure 6B The time between t1 and t1' is around half a switching cycle, which shortens the time it takes for the converter to re-enter a steady operating state.

[0163] For example, under forward light load and reverse heavy load, combined Figure 1 and Figure 6C During the time interval between the end of the current switching cycle of the converter, t1, and the first transition time, t3, the first switch S1 and the fourth switch S4 are both turned on, while the second switch S2 and the third switch S3 are both turned off.

[0164] During the time interval between the first transition time t3 and the time when the converter re-enters the steady state t1', the second switch S2 and the third switch S3 are both turned on, while the first switch S1 and the fourth switch S4 are both turned off.

[0165] During the time interval between the end of the current switching cycle of the converter at time t1 and the time when the converter re-enters steady state at time t1', the sixth switch S6 and the seventh switch S7 are both turned on, while the fifth switch S5 and the eighth switch S8 are both turned off.

[0166] Thus, the switching of the first switch S1, the fourth switch S4, the second switch S2, the third switch S3, the sixth switch S6, and the seventh switch S7 all achieved zero-voltage turn-on. Furthermore, referring to... Figure 6C The time between t1 and t1' is around half a switching cycle, which shortens the time it takes for the converter to re-enter a steady operating state.

[0167] For example, under reverse heavy load and forward light load, combined Figure 1 and Figure 6D During the time interval between the end of the current switching cycle of the converter, t1, and the first transition time, t3, the fifth switch S5 and the eighth switch S8 are turned on, while the sixth switch S6 and the seventh switch S7 are turned off.

[0168] During the time interval between the first transition time t3 and the time when the converter re-enters the steady state t1', the sixth switch S6 and the seventh switch S7 are both turned on, while the fifth switch S5 and the eighth switch S8 are both turned off.

[0169] During the time interval between the end of the current switching cycle of the converter, t1, and the second transition time, t2, the second switch S2 and the third switch S3 are both turned on, while the first switch S1 and the fourth switch S4 are both turned off.

[0170] During the time interval between the second transition time t2 and the time when the converter re-enters steady state t1', the first switch S1 and the fourth switch S4 are both turned on, while the second switch S2 and the third switch S3 are both turned off.

[0171] Thus, the switching of the first switch S1, the fourth switch S4, the second switch S2, the third switch S3, the sixth switch S6, the seventh switch S7, the fifth switch S5, and the eighth switch S8 all achieved zero-voltage turn-on. Furthermore, referring to... Figure 6D The time between t1 and t1' is around half a switching cycle, which shortens the time it takes for the converter to re-enter a steady operating state.

[0172] For example, under reverse light load and forward heavy load, combined Figure 1 and Figure 6E During the time interval between the end of the current switching cycle of the converter, t1, and the first transition time, t3, the fifth switch S5 and the eighth switch S8 are turned on, while the sixth switch S6 and the seventh switch S7 are turned off.

[0173] During the time interval between the first transition time t3 and the time when the converter re-enters the steady state t1', the sixth switch S6 and the seventh switch S7 are both turned on, while the fifth switch S5 and the eighth switch S8 are both turned off.

[0174] During the time interval between the end of the current switching cycle of the converter at time t1 and the time when the converter re-enters steady state at time t1', the second switch S2 and the third switch S3 are both turned on, while the first switch S1 and the fourth switch S4 are both turned off.

[0175] Thus, the turn-on of the second switch S2, the third switch S3, the sixth switch S6, the seventh switch S7, the fifth switch S5, and the eighth switch S8 all achieved zero-voltage turn-on. Furthermore, refer to... Figure 6E The time between t1 and t1' is around half a switching cycle, which shortens the time it takes for the converter to re-enter a steady operating state.

[0176] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0177] This application embodiment also provides a converter, the converter including a controller for executing the power bidirectional switching method as described in any of the above embodiments; the converter further includes: a first switching transistor unit and a third switching transistor unit directly connected to the positive terminal of a first voltage source, a second switching transistor unit and a fourth switching transistor unit directly connected to the negative terminal of the first voltage source, a fifth switching transistor unit and a seventh switching transistor unit directly connected to the positive terminal of a second voltage source, and a sixth switching transistor unit and an eighth switching transistor unit directly connected to the negative terminal of the second voltage source; the first voltage source and the second voltage source are respectively located on both sides of the converter resonant cavity; wherein, the direction of the output current flowing from the first voltage source to the second voltage source is defined as positive, and the direction of the output current flowing from the second voltage source to the first voltage source is defined as negative.

[0178] The converter and power bidirectional switching method provided in the embodiments of this application belong to the same inventive concept, can solve the same technical problems, and thus achieve the same technical effects. Repeated content will not be repeated here.

[0179] In an exemplary embodiment, when the load transformation type is forward heavy load to reverse light load, the controller is used to control each switching transistor unit in the converter as follows:

[0180] During the time interval between the end of the current switching cycle of the converter and the first transition time, the first and fourth switching units are turned on, and the second and third switching units are turned off.

[0181] During the time interval between the first transition moment and the moment when the converter re-enters the steady state, the second and third switching units are both turned on, and the first and fourth switching units are both turned off.

[0182] During the time interval between the end of the current switching cycle of the converter and the second transition time, the sixth and seventh switching units are both turned on, and the fifth and eighth switching units are both turned off.

[0183] During the time interval between the second transition moment and the moment when the converter re-enters steady state, the fifth and eighth switch units are turned on, and the sixth and seventh switch units are turned off.

[0184] In an exemplary embodiment, when the load transformation type is forward light load to reverse heavy load, the controller is used to control each switching transistor unit in the converter as follows:

[0185] During the time interval between the end of the current switching cycle of the converter and the first transition time, the first and fourth switching units are turned on, and the second and third switching units are turned off.

[0186] During the time interval between the first transition moment and the moment when the converter re-enters the steady state, the second and third switching units are both turned on, and the first and fourth switching units are both turned off.

[0187] During the time interval between the end of the current switching cycle of the converter and the time when the converter re-enters a steady state, the sixth and seventh switching units are turned on, while the fifth and eighth switching units are turned off.

[0188] In an exemplary embodiment, when the load transformation type is reverse heavy load to forward light load, the controller is used to control each switching unit in the converter as follows:

[0189] During the time interval between the end of the current switching cycle of the converter and the first transition time, the fifth and eighth switching units are both turned on, and the sixth and seventh switching units are both turned off.

[0190] During the time interval between the first transition moment and the moment when the converter re-enters steady state, the sixth and seventh switch units are both turned on, and the fifth and eighth switch units are both turned off.

[0191] During the time interval between the end of the current switching cycle of the converter and the second transition time, the second and third switching units are both turned on, while the first and fourth switching units are both turned off.

[0192] During the time interval between the second transition moment and the moment when the converter re-enters steady state, the first and fourth switching units are turned on, while the second and third switching units are turned off.

[0193] In an exemplary embodiment, when the load transformation type is reverse light load to forward heavy load, the controller is used to control each switching unit in the converter as follows:

[0194] During the time interval between the end of the current switching cycle of the converter and the first transition time, the fifth and eighth switching units are both turned on, and the sixth and seventh switching units are both turned off.

[0195] During the time interval between the first transition moment and the moment when the converter re-enters steady state, the sixth and seventh switch units are both turned on, and the fifth and eighth switch units are both turned off.

[0196] During the time interval between the end of the current switching cycle of the converter and the time when the converter re-enters a steady state, the second and third switching units are turned on, while the first and fourth switching units are turned off.

[0197] Based on the same inventive concept, this application also provides a power bidirectional switching device for implementing the power bidirectional switching method described above. The solution provided by this device is similar to the implementation described in the above method; therefore, the specific limitations in one or more power bidirectional switching device embodiments provided below can be found in the limitations of the power bidirectional switching method described above, and will not be repeated here.

[0198] In one exemplary embodiment, such as Figure 7 As shown, a bidirectional power switching device is provided, comprising:

[0199] The conversion type module 710 is used to respond to the power commutation command of the converter and determine the load conversion type according to the magnitude relationship between the load after commutation and the load before commutation and the direction of the output current.

[0200] The steady-state switching module 720 is used to control the state of each switching transistor unit in the converter according to the load transformation type and the excitation at both ends of the converter resonant cavity at the end of the current switching cycle of the converter, until the converter re-enters a steady state; wherein the duration between the end of the current switching cycle and the moment when the converter re-enters a steady state is less than or equal to two switching cycles of the converter.

[0201] In an exemplary embodiment, the steady-state switching module 720 is further configured to acquire control information of the state of the switching transistor unit in the converter; wherein, the control information includes the control time of each switching transistor unit in different states under different load transformation types;

[0202] The state of each switching transistor unit in the converter is controlled according to the control information.

[0203] In an exemplary embodiment, the steady-state switching module 720 is further configured to write, based on the excitation at both ends of the converter resonant cavity, a per-unit relationship between the resonant capacitor voltage and the resonant inductor current, wherein the relationship is in the form of a standard circular equation.

[0204] Based on the aforementioned relationship, the resonant inductor current value and resonant capacitor voltage value at the first transition moment are determined under different load transformation types.

[0205] Based on the resonant inductor current and resonant capacitor voltage values ​​at the second transition time, and based on the resonant capacitor voltage value at the first transition time, write the time-domain resonant capacitor voltage expression for the first transition time to determine the first control duration;

[0206] Based on the resonant inductor current and resonant capacitor voltage values ​​at the first transition moment, and the resonant capacitor voltage value at the moment when the converter re-enters steady state, the time-domain resonant capacitor voltage expression at the moment when the converter re-enters steady state is written to determine the second control duration.

[0207] In this process, along the time progression, the end time of the current switching cycle of the converter, the second transition time, the first transition time, and the time when the converter re-enters the steady state are sequentially performed.

[0208] The duration between the second transition time and the first transition time is the first control duration; the duration between the first transition time and the moment when the converter re-enters steady state is the second control duration.

[0209] In an exemplary embodiment, the steady-state switching module 720 is further configured to determine the third control duration under different load transformation types based on the switching frequency of the converter and the pre-commutation load under different load transformation types.

[0210] The duration between the end of the current switching cycle of the converter and the second transition time is the third control duration.

[0211] In an exemplary embodiment, the steady-state switching module 720 is further configured to determine, based on the relationship, the pre-commutation steady-state trajectory circle composed of the resonant inductor current value and the resonant capacitor voltage value, and the post-commutation steady-state trajectory circle composed of the resonant inductor current value and the resonant capacitor voltage value under different load transformation types.

[0212] Based on the radius of the steady-state trajectory circle before commutation and the radius of the steady-state trajectory circle after commutation, the resonant inductor current value and the resonant capacitor voltage value at the first transition moment are determined.

[0213] In an exemplary embodiment, when the load transformation type is from heavy load to light load, the second control duration is longer than the first control duration; when the load transformation type is from light load to heavy load, the second control duration is shorter than the first control duration; the power corresponding to the heavy load is greater than the power corresponding to the light load, and the positive and negative directions represent different directions of the output current, respectively.

[0214] The steady-state switching module 720 is also used to control the corresponding switching transistor unit of the converter to turn on or off during the first control duration, the second control duration, and the third control duration, respectively, under different load transformation types.

[0215] Each module in the aforementioned bidirectional power switching device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0216] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the power bidirectional switching method described in any of the above embodiments.

[0217] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the power bidirectional switching method described in any of the above embodiments.

[0218] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the power bidirectional switching method described in any of the above embodiments.

[0219] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0220] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0221] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for bidirectional power switching, characterized in that, The method includes: In response to the power commutation command of the converter, the load transformation type is determined based on the magnitude relationship between the load after commutation and the load before commutation, as well as the direction of the output current. At the end of the current switching cycle of the converter, according to the load transformation type and the excitation at both ends of the converter resonant cavity, the state of each switching transistor unit in the converter is controlled until the converter re-enters a steady state. The duration between the end of the current switching cycle and the moment when the converter re-enters a steady state is less than or equal to two switching cycles of the converter.

2. The method according to claim 1, characterized in that, According to the load transformation type, and based on the excitation at both ends of the converter resonant cavity, the state of each switching transistor unit in the converter is controlled, including: The control information of the state of the switching transistor unit in the converter is obtained; wherein, the control information includes the control time of each switching transistor unit in different states under different load transformation types; The state of each switching transistor unit in the converter is controlled according to the control information.

3. The method according to claim 2, characterized in that, The control information for obtaining the state of the switching transistor units in the converter includes: Based on the excitation at both ends of the converter resonant cavity, write down the relationship between the resonant capacitor voltage and the resonant inductor current after standardization. The relationship is in the form of a standard equation of a circle. Based on the aforementioned relationship, the resonant inductor current value and resonant capacitor voltage value at the first transition moment are determined under different load transformation types. Based on the resonant inductor current and resonant capacitor voltage values ​​at the second transition time, and based on the resonant capacitor voltage value at the first transition time, write the time-domain resonant capacitor voltage expression for the first transition time to determine the first control duration; Based on the resonant inductor current and resonant capacitor voltage values ​​at the first transition moment, and the resonant capacitor voltage value at the moment when the converter re-enters steady state, the time-domain resonant capacitor voltage expression at the moment when the converter re-enters steady state is written to determine the second control duration. In this process, along the time progression, the end time of the current switching cycle of the converter, the second transition time, the first transition time, and the time when the converter re-enters the steady state are sequentially performed. The duration between the second transition time and the first transition time is the first control duration; the duration between the first transition time and the moment when the converter re-enters steady state is the second control duration.

4. The method according to claim 3, characterized in that, The control information for obtaining the state of the switching transistor unit in the converter also includes: The third control duration for different load transformation types is determined based on the switching frequency of the converter and the pre-commutation load under different load transformation types. The duration between the end of the current switching cycle of the converter and the second transition time is the third control duration.

5. The method according to claim 3, characterized in that, Based on the aforementioned relationship, the resonant inductor current and resonant capacitor voltage values ​​at the first transition moment are determined under different load transformation types, including: Based on the aforementioned relationship, the pre-commutation steady-state trajectory circle formed by the resonant inductor current value and the resonant capacitor voltage value, and the post-commutation steady-state trajectory circle formed by the resonant inductor current value and the resonant capacitor voltage value are determined under different load transformation types. Based on the radius of the steady-state trajectory circle before commutation and the radius of the steady-state trajectory circle after commutation, the resonant inductor current value and the resonant capacitor voltage value at the first transition moment are determined.

6. The method according to any one of claims 3-5, characterized in that, When the load switching type is from heavy load to light load, the second control duration is longer than the first control duration; when the load switching type is from light load to heavy load, the second control duration is shorter than the first control duration; the power corresponding to the heavy load is greater than the power corresponding to the light load, and the forward and reverse directions represent different directions of the output current, respectively. Controlling the state of each switching transistor unit in the converter according to the control information includes: Under different load transformation types, the corresponding switching transistor units of the converter are turned on or off during the first control duration, the second control duration, and the third control duration, respectively.

7. A converter, characterized in that, The converter includes a controller for performing the power bidirectional switching method as described in any one of claims 1-6; The converter further includes: a first switching transistor unit and a third switching transistor unit directly connected to the positive terminal of the first voltage source; a second switching transistor unit and a fourth switching transistor unit directly connected to the negative terminal of the first voltage source; a fifth switching transistor unit and a seventh switching transistor unit directly connected to the positive terminal of the second voltage source; and a sixth switching transistor unit and an eighth switching transistor unit directly connected to the negative terminal of the second voltage source. The first voltage source and the second voltage source are located on both sides of the converter resonant cavity; Here, the direction of the output current flowing from the first voltage source to the second voltage source is defined as positive, and the direction of the output current flowing from the second voltage source to the first voltage source is defined as negative.

8. The converter according to claim 7, characterized in that, When the load transformation type is forward heavy load to reverse light load, the controller is used to control each switching transistor unit in the converter as follows: During the time interval between the end of the current switching cycle of the converter and the first transition time, the first and fourth switching units are turned on, and the second and third switching units are turned off. During the time interval between the first transition moment and the moment when the converter re-enters the steady state, the second and third switching units are both turned on, and the first and fourth switching units are both turned off. During the time interval between the end of the current switching cycle of the converter and the second transition time, the sixth and seventh switching units are both turned on, and the fifth and eighth switching units are both turned off. During the time interval between the second transition moment and the moment when the converter re-enters steady state, the fifth and eighth switch units are turned on, and the sixth and seventh switch units are turned off.

9. The converter according to claim 7, characterized in that, When the load transformation type is forward light load to reverse heavy load, the controller is used to control each switching transistor unit in the converter as follows: During the time interval between the end of the current switching cycle of the converter and the first transition time, the first and fourth switching units are turned on, and the second and third switching units are turned off. During the time interval between the first transition moment and the moment when the converter re-enters the steady state, the second and third switching units are both turned on, and the first and fourth switching units are both turned off. During the time interval between the end of the current switching cycle of the converter and the time when the converter re-enters a steady state, the sixth and seventh switching units are turned on, while the fifth and eighth switching units are turned off.

10. The converter according to claim 7, characterized in that, When the load transformation type is reverse heavy load to forward light load, the controller is used to control each switching transistor unit in the converter as follows: During the time interval between the end of the current switching cycle of the converter and the first transition time, the fifth and eighth switching units are both turned on, and the sixth and seventh switching units are both turned off. During the time interval between the first transition moment and the moment when the converter re-enters steady state, the sixth and seventh switch units are both turned on, and the fifth and eighth switch units are both turned off. During the time interval between the end of the current switching cycle of the converter and the second transition time, the second and third switching units are both turned on, while the first and fourth switching units are both turned off. During the time interval between the second transition moment and the moment when the converter re-enters steady state, the first and fourth switching units are turned on, while the second and third switching units are turned off.

11. The converter according to any one of claims 7-10, characterized in that, When the load transformation type is reverse light load to forward heavy load, the controller is used to control each switching transistor unit in the converter as follows: During the time interval between the end of the current switching cycle of the converter and the first transition time, the fifth and eighth switching units are both turned on, and the sixth and seventh switching units are both turned off. During the time interval between the first transition moment and the moment when the converter re-enters steady state, the sixth and seventh switch units are both turned on, and the fifth and eighth switch units are both turned off. During the time interval between the end of the current switching cycle of the converter and the time when the converter re-enters a steady state, the second and third switching units are turned on, while the first and fourth switching units are turned off.

12. A power bidirectional switching device, characterized in that, The device includes: The conversion type module is used to respond to the power commutation command of the converter and determine the load conversion type according to the magnitude relationship between the load after commutation and the load before commutation and the direction of the output current. The steady-state switching module is used to control the state of each switching transistor unit in the converter according to the load transformation type and the excitation at both ends of the converter resonant cavity at the end of the current switching cycle of the converter, until the converter re-enters a steady state; wherein the duration between the end of the current switching cycle and the moment when the converter re-enters a steady state is less than or equal to two switching cycles of the converter.

13. A controller comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the power bidirectional switching method according to any one of claims 1 to 6.

14. 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 power bidirectional switching method according to any one of claims 1 to 6.

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