Current balancing method, device, parallel H-bridge circuit and energy storage system

Abstract

The present application relates to a current balancing method, device, parallel H-bridge circuit and energy storage system, which are applied to the parallel H-bridge circuit, wherein the parallel H-bridge circuit includes a plurality of mutually parallel monomer H-bridge units, wherein the monomer H-bridge unit includes a plurality of switch elements, and the method includes: determining the expected state of the parallel H-bridge circuit at the next moment, and determining the target state of each monomer H-bridge unit at the next moment according to the bridge arm current of the parallel H-bridge circuit, the average current of each monomer H-bridge unit at the current moment, and the rated current of the switch element, so as to control the working state of each switch element in each monomer H-bridge unit according to the expected state and each target state, so that the difference between the average currents of each monomer H-bridge unit at the next moment is less than the preset difference. The use of this method can reduce costs.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a current balancing method, device, parallel H-bridge circuit and energy storage system. Background Art

[0002] With the continuous improvement of new energy technologies, energy storage systems are developing towards larger capacity and higher power. At present, high-voltage and high-current energy storage systems can be realized through low-voltage and low-current switching elements. Among them, the switching elements may include but are not limited to insulated gate bipolar transistors (IGBT) and metal-oxide-semiconductor field-effect transistors (MOSFET).

[0003] Due to the inconsistency of the on-resistance between the switch elements, there is an imbalance in the current flowing through each switch element in the energy storage system, which leads to overheating and aging of some switch elements, affecting the overall performance. To address the above problems, related technologies usually design corresponding auxiliary capacitors, inductors or on-time sensors and other additional hardware for each single switch to achieve current balancing.

[0004] However, the current current balancing method has the problem of high cost. Summary of the invention

[0005] Based on this, it is necessary to provide a current balancing method, device, parallel H-bridge circuit and energy storage system that can reduce costs in response to the above technical problems.

[0006] In a first aspect, the present application provides a current balancing method, which is applied to a parallel H-bridge circuit, wherein the parallel H-bridge circuit includes a plurality of mutually parallel single H-bridge units, each of which includes a plurality of switch elements, and the method includes:

[0007] Determine the desired state of the parallel H-bridge circuit at the next moment;

[0008] Determine the target state of each H-bridge unit at the next moment according to the bridge arm current of the parallel H-bridge circuit, the average current of each H-bridge unit at the current moment, and the rated current of the switch element;

[0009] According to the expected state and each target state, the working state of each switch element in each single H-bridge unit is controlled so that the difference between the average currents of each single H-bridge unit at the next moment is less than the preset difference.

[0010] In one embodiment, the target state of each single H-bridge unit at the next moment is determined according to the bridge arm current of the parallel H-bridge circuit, the average current of each single H-bridge unit at the current moment, and the rated current of the switch element, including:

[0011] Determine the target number of single H-bridge units in a first state in the parallel H-bridge circuit according to the bridge arm current and the rated current; the first state indicates that the single H-bridge unit is turned on and current exists;

[0012] Each target state is determined according to the target quantity and the average current of each single H-bridge unit at the current moment.

[0013] In one embodiment, each target state is determined according to the target quantity and the average current of each single H-bridge unit at the current moment, including:

[0014] Each target state is determined according to the target quantity and the priority order of each monomer H-bridge unit; each priority order is related to the average current of each monomer H-bridge unit at the current moment.

[0015] In one embodiment, each target state is determined according to the target quantity and the priority order of each monomer H-bridge unit, including:

[0016] Determine the priority order according to the average current of each H-bridge unit at the current moment;

[0017] For each monomer H-bridge unit, determining a difference between the target quantity and the priority order of the monomer H-bridge unit;

[0018] Based on the difference and sign function, the target state of the monomer H-bridge unit is determined.

[0019] In one embodiment, determining a target number of single H-bridge units in a first state in a parallel H-bridge circuit according to a bridge arm current and a rated current includes:

[0020] Determine the quotient between the bridge arm current and the rated current;

[0021] Round the quotient upward to get the target quantity.

[0022] In one embodiment, according to the desired state and each target state, the working state of each switch element in each single H-bridge unit is controlled, including:

[0023] When the stop condition is not met, the working state of each switch element in the single-unit H-bridge unit is determined according to the expected state and the target state of the single-unit H-bridge unit; the stop condition is used to determine whether all single-unit H-bridge units in the parallel H-bridge circuit have been traversed;

[0024] When the stop condition is met, each switch element is controlled according to the working state of each switch element in each single H-bridge unit.

[0025] In one embodiment, determining the working state of each switch element in the single-unit H-bridge unit according to the desired state and the target state of the single-unit H-bridge unit includes:

[0026] If the desired state is a positive voltage state, and the target state of the single H-bridge unit is a first state, then the working state of the switch elements located at the upper left bridge arm and the lower right bridge arm in the single H-bridge unit is determined to be an off state, and the working state of the switch elements located at the lower left bridge arm and the upper right bridge arm in the single H-bridge unit is determined to be an on state;

[0027] If the expected state is a positive voltage state, and the target state of the monomer H-bridge unit is the second state or the third state, it is determined that the working state of each switch element in the monomer H-bridge unit is the cut-off state; the second state indicates that the monomer H-bridge unit is not turned on or is turned on but there is no current; the third state indicates that the monomer H-bridge unit is not turned on.

[0028] In one embodiment, determining the working state of each switch element in the single-unit H-bridge unit according to the desired state and the target state of the single-unit H-bridge unit includes:

[0029] If the desired state is a negative voltage state, and the target state of the single H-bridge unit is the first state, then the working state of the switch elements located at the lower left bridge arm and the upper right bridge arm in the single H-bridge unit is determined to be the cut-off state, and the working state of the switch elements located at the upper left bridge arm and the lower right bridge arm in the single H-bridge unit is determined to be the on state;

[0030] If the desired state is a negative voltage state, and the target state of the single H-bridge unit is the second state or the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0031] In one embodiment, the left bridge arm of any one of the monomer H-bridge units is connected to the first energy storage unit, and the right bridge arm of any one of the monomer H-bridge units is connected to the second energy storage unit; according to the expected state and the target state of the monomer H-bridge unit, the working state of each switch element in the monomer H-bridge unit is determined, including:

[0032] If the desired state is a zero voltage state, obtaining a first voltage of the first energy storage unit and a second voltage of the second energy storage unit;

[0033] The working state of each switch element in the single H-bridge unit is determined according to the bridge arm current, the first voltage, the second voltage and the target state of the single H-bridge unit of the parallel H-bridge circuit.

[0034] In one embodiment, determining the working state of each switch element in the single H-bridge unit according to the bridge arm current, the first voltage, the second voltage and the target state of the single H-bridge unit of the parallel H-bridge circuit includes:

[0035] If the bridge arm current is greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the first state, it is determined that the working state of the switch element located in the upper left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the upper left bridge arm is the off state;

[0036] If the bridge arm current is greater than zero, and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the second state, the working state of the switch element located in the lower right bridge arm in the single H-bridge unit is determined to be the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower right bridge arm is the off state;

[0037] If the bridge arm current is greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0038] In one embodiment, determining the working state of each switch element in the single H-bridge unit according to the bridge arm current, the first voltage, the second voltage and the target state of the single H-bridge unit of the parallel H-bridge circuit includes:

[0039] If the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the first state, the working state of the switch element located in the lower right bridge arm in the single H-bridge unit is determined to be the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower right bridge arm is the off state;

[0040] If the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the second state, the working state of the switch element located in the upper left bridge arm in the single H-bridge unit is determined to be the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the upper left bridge arm is determined to be the off state;

[0041] If the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0042] In one embodiment, determining the working state of each switch element in the single H-bridge unit according to the bridge arm current, the first voltage, the second voltage and the target state of the single H-bridge unit of the parallel H-bridge circuit includes:

[0043] If the bridge arm current is not greater than zero, and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the first state, the working state of the switch element located in the upper right bridge arm in the single H-bridge unit is determined to be the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the upper right bridge arm is the off state;

[0044] If the bridge arm current is not greater than zero, and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the second state, it is determined that the working state of the switch element located in the lower left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower left bridge arm is the off state;

[0045] If the bridge arm current is not greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0046] In one embodiment, determining the working state of each switch element in the single H-bridge unit according to the bridge arm current, the first voltage, the second voltage and the target state of the single H-bridge unit of the parallel H-bridge circuit includes:

[0047] If the bridge arm current is not greater than zero, and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the first state, it is determined that the working state of the switch element located in the lower left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower left bridge arm is the off state;

[0048] If the bridge arm current is not greater than zero, and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the second state, the working state of the switch element located in the upper right bridge arm in the single H-bridge unit is determined to be the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the upper right bridge arm is the off state;

[0049] If the bridge arm current is not greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0050] In a second aspect, the present application further provides a current balancing device, which is applied to a parallel H-bridge circuit, wherein the parallel H-bridge circuit includes a plurality of mutually parallel single H-bridge units, each of which includes a plurality of switch elements, and the device includes:

[0051] A first determination module, used to determine the expected state of the parallel H-bridge circuit at the next moment;

[0052] The second determination module is used to determine the target state of each monomer H-bridge unit at the next moment according to the bridge arm current of the parallel H-bridge circuit, the average current of each monomer H-bridge unit at the current moment, and the rated current of the switch element;

[0053] The third determination module is used to control the working state of each switch element in each single H-bridge unit according to the expected state and each target state, so that the difference between the average currents of each single H-bridge unit at the next moment is less than a preset difference.

[0054] In a third aspect, the present application also provides a parallel H-bridge circuit, which includes a plurality of mutually parallel single H-bridge units, each of which includes a plurality of switching elements; the parallel H-bridge circuit applies any of the current balancing methods described above.

[0055] In a fourth aspect, the present application also provides an energy storage system, which includes a control circuit and any of the above-mentioned parallel H-bridge circuits; the control circuit is connected to the parallel H-bridge circuit; and the control circuit applies any of the above-mentioned current balancing methods.

[0056] In a fifth aspect, the present application further provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any of the above methods when executing the computer program.

[0057] In a sixth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of any of the above methods when executed by a processor.

[0058] In a seventh aspect, the present application also provides a computer program product, comprising a computer program, which implements the steps of any of the above methods when executed by a processor.

[0059] The current balancing method, device, parallel H-bridge circuit and energy storage system can determine the expected state of the parallel H-bridge circuit at the next moment, and determine the target state of each monomer H-bridge unit at the next moment according to the bridge arm current of the parallel H-bridge circuit, the average current of each monomer H-bridge unit at the current moment, and the rated current of the switch element. Therefore, when determining the target state of each monomer H-bridge unit at the next moment, the average current of all monomer H-bridge units at the current moment is taken into account. In this way, after controlling the working state of each switch element in each monomer H-bridge unit according to the expected state and each target state, the difference between the average currents of each monomer H-bridge unit at the next moment can be made less than the preset difference, thereby achieving current balancing. In addition, in the above process, there is no need to design corresponding auxiliary capacitors, inductors or conduction time sensors for each monomer switch, thereby reducing hardware costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0061] Figure 1 A schematic diagram of a cascaded H-bridge topology in the related art;

[0062] Figure 2 is a schematic diagram of a monomer H-bridge unit in one embodiment;

[0063] Figure 3 is a schematic diagram of a parallel H-bridge circuit in one embodiment;

[0064] Figure 4 is a schematic diagram of yet another parallel H-bridge circuit in one embodiment;

[0065] Figure 5 is a schematic diagram of yet another parallel H-bridge circuit in one embodiment;

[0066] Figure 6 is a topological schematic diagram of a parallel H-bridge circuit in one embodiment;

[0067] Figure 7 is a schematic diagram of a positive voltage state or a negative voltage state in one embodiment;

[0068] Figure 8 is a schematic diagram of a zero voltage state in one embodiment;

[0069] Fig. 9 is an equivalent current conduction path in one embodiment;

[0070] Fig.10 is a schematic diagram of yet another zero voltage state in an embodiment;

[0071] Fig.11 is yet another equivalent current conduction path in an embodiment;

[0072] Fig.12 is an application environment diagram of a current balancing method in an embodiment;

[0073] Fig.13 is a schematic flow chart of a current balancing method in one embodiment;

[0074] Fig.14 A schematic diagram of a process for determining a target state in one embodiment;

[0075] Fig.15 is a schematic diagram of another process of determining a target state in an embodiment;

[0076] Fig.16 A schematic diagram of a process for determining a target quantity in an embodiment;

[0077] Fig.17 A schematic diagram of a process for determining a working state in an embodiment;

[0078] Fig.18 is a structural block diagram of a current balancing device in one embodiment;

[0079] Fig.19 is a schematic structural diagram of an energy storage system in one embodiment;

[0080] Fig. 20 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0081] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0082] Figure 1 is a schematic diagram of a cascaded H-bridge topology in the related art, Figure 1 A three-phase delta-connected cascaded H-bridge topology is shown in FIG. Figure 1 As shown in FIG. 1 (a), the cascaded H-bridge topology includes an AC power supply 101, a reactor 102, and a series-connected submodule 103. Figure 1 As shown in FIG. (b), the submodule 103 includes an energy storage unit 103a and an integrated switch device 103b. The integrated switch device 103b is composed of three switch elements connected in parallel, and the rated current of the integrated switch device 103b is three times that of a single switch element. In this way, by synthesizing the step-type bridge arm voltage with the voltage of the energy storage unit 103a in multiple submodules 103, a high-voltage AC output with low harmonic distortion (Total Harmonic Distortion, THD) can be obtained at a low switching frequency.

[0083] However, the current flowing through each switch element has an imbalance problem. Based on this, it is necessary to provide a current balancing method applied to a parallel H-bridge circuit. In order to more clearly introduce the current balancing method of the present application, Figure 2~Figure 11 The parallel H-bridge circuit of the present application is introduced.

[0084] Figure 2Schematic diagram of a single H-bridge unit in an embodiment. In an embodiment, a single H-bridge unit 200 is provided. The single H-bridge unit 200 includes a plurality of switch elements 201. The plurality of switch elements 201 constitute an H-bridge.

[0085] The following will take the example of a single H-bridge unit 200 including four switch elements 201, namely, switch element 201a, switch element 201b, switch element 201c and switch element 201d. Figure 2 The switch element 201a, the switch element 201b, the switch element 201c and the switch element 201d are respectively located at the upper left bridge arm, the lower left bridge arm, the upper right bridge arm and the lower right bridge arm of the single H-bridge unit 200.

[0086] Figure 3 FIG. 1 is a schematic diagram of a parallel H-bridge circuit in an embodiment. In an embodiment, a parallel H-bridge circuit 300 is provided. The parallel H-bridge circuit 300 includes a plurality of H-bridge units 200 connected in parallel. Figure 3 For example, the parallel H-bridge circuit 300 includes three H-bridge units 200 connected in parallel.

[0087] Figure 4 FIG. 1 is a schematic diagram of another parallel H-bridge circuit in an embodiment, Figure 4 As shown, the parallel H-bridge circuit 300 includes three H-bridge units 200 connected in parallel, namely, a single H-bridge unit 200a, a single H-bridge unit 200b and a single H-bridge unit 200c.

[0088] Further, in one embodiment, optionally, the left bridge arm of any one of the monomer H-bridge units 200 is connected to the first energy storage unit 401 , and the right bridge arm of any one of the monomer H-bridge units 200 is connected to the second energy storage unit 402 .

[0089] Figure 5 FIG. 1 is a schematic diagram of another parallel H-bridge circuit in one embodiment. In one embodiment, Figure 4 On the basis of, the first energy storage unit 401 is connected to the first terminal unit 501, and the second energy storage unit 402 is connected to the second terminal unit 502. The first terminal unit 501 and the second terminal unit 502 both include a plurality of switch elements 201. The first terminal unit 501 and the second terminal unit 502 are used to connect to an external main circuit.

[0090] The above example uses a parallel H-bridge circuit as an example. Figure 6 FIG. 1 is a topological diagram of a parallel H-bridge circuit in one embodiment. Figure 6 FIG. 2 shows a schematic diagram of a three-phase delta-type energy storage converter when multiple parallel H-bridge circuits 300 are cascaded. Figure 8 As shown, the cascade topology is connected in sequence as follows: terminal unit 1 - energy storage unit 1 - parallel H-bridge circuit 1 - energy storage unit 2 - parallel H-bridge circuit 2 ... energy storage unit m-1 - parallel H-bridge circuit m-1 - energy storage unit m - terminal unit 2. Figure 6 The rest of Figure 1 The principle is the same and will not be repeated here.

[0091] Next, the parallel H-bridge circuit and the status of each monomer H-bridge unit in the parallel H-bridge circuit are introduced. Figure 7 Schematic diagram of a positive voltage state or a negative voltage state in one embodiment. Figure 7 FIG. 5( a ) shows a forward series connection state of the single H-bridge unit 200 . In the forward series connection state, the switch elements 201 a and 201 d of the single H-bridge unit 200 are turned off, and the switch elements 201 c and 201 c are turned on.

[0092] Figure 7 FIG. 5( b ) shows a negative series connection state of the single H-bridge unit 200 . In the negative series connection state, the switch element 201 b and the switch element 201 c of the single H-bridge unit 200 are turned off, and the switch element 201 a and the switch element 201 d are turned on.

[0093] Figure 7 FIG. 5( c ) shows a blocking state of the single H-bridge unit 200 . In the blocking state, the switch elements 201 a to 201 d , ie, all the switch elements, of the single H-bridge unit 200 are turned off.

[0094] If at least one single H-bridge unit in the parallel H-bridge circuit 300 is in a forward series connection state and the remaining single H-bridge units are in a blocking state, the parallel H-bridge circuit 300 is in a positive voltage state, where the positive voltage state refers to a state where the output voltage of the parallel H-bridge circuit 300 is positive.

[0095] Similarly, if at least one single H-bridge unit in the parallel H-bridge circuit 300 is in a negative series connection state and the remaining single H-bridge units are in a blocking state, the parallel H-bridge circuit 300 is in a negative voltage state. The negative voltage state refers to a state in which the output voltage of the parallel H-bridge circuit 300 is negative.

[0096] Figure 8 is a schematic diagram of a zero voltage state in one embodiment, Figure 8 Figures (a) and (b) in the figure respectively show the soft parallel state of the single H-bridge unit 200. The soft parallel state refers to the state in which the single H-bridge unit 200 is turned on.

[0097] exist Figure 8In the soft parallel state shown in FIG. (a), the positive electrodes of the first energy storage unit 401 and the second energy storage unit 402 are turned on, the switch element 201a of the single H-bridge unit 200 is turned on, and the switch elements 201b, 201c and 201d are all turned off. Figure 8 In the soft parallel state shown in FIG. 7 (b), the negative electrodes of the first energy storage unit 401 and the second energy storage unit 402 are turned on, the switch element 201d of the single H-bridge unit 200 is turned on, and the switch elements 201a, 201b and 201c are all turned off.

[0098] In order to achieve voltage balance by connecting the adjacent first energy storage unit and the second energy storage unit in parallel, if at least one single H-bridge unit in the parallel H-bridge circuit 300 is in Figure 8 In the state shown in Figure (a), at least one monomer H-bridge unit is in Figure 8 In the state shown in FIG. 2 (b), the other single H-bridge units are in a blocking state, and the parallel H-bridge circuit 300 is in a zero voltage state. The zero voltage state refers to a state in which the output voltage of the parallel H-bridge circuit 300 is zero.

[0099] Fig. 9 2 is an equivalent current conduction path in an embodiment, wherein the voltage of the first energy storage unit 401 is denoted as V1, and the voltage of the second energy storage unit 402 is denoted as V2. Fig. 9 Figures (a) and (b) in the figure show the equivalent current conduction path of the parallel H-bridge circuit in the zero voltage state when V1>V2 and the bridge arm current direction is positive. Figure 8 The single H-bridge unit 200 shown in FIG. (a) can conduct current through the anti-parallel diodes of the switch element 201a and the switch element 201c, and is in Figure 8 In the single H-bridge unit 200 shown in FIG. (b), the anti-parallel diode of the switch element 201b is clamped by the reverse voltage and does not conduct current. In this case, Figure 8 Figure (a) shows the active soft parallel state. Figure 8 Figure (b) in the figure is an inactive soft parallel state. The active soft parallel state refers to a state where the single H-bridge unit 200 is turned on and there is a conduction current, and the inactive soft parallel state refers to a state where the single H-bridge unit 200 is turned on but there is no conduction current.

[0100] Similarly, Fig. 9 Figures (c) and (d) in the figure show the equivalent current conduction path of the parallel H-bridge circuit in the zero voltage state when V1 < V2 and the direction of the bridge arm current is positive. In this case, Figure 8 Figure (a) shows the inactive soft parallel state. Figure 8 Figure (b) shows the active soft parallel state.

[0101] Fig.10 is a schematic diagram of yet another zero voltage state in an embodiment, Fig.10 Figures (a) and (b) in FIG. 2 also respectively show the soft parallel state of the single H-bridge unit 200. Fig.10 In the soft parallel state shown in FIG. (a), the positive electrodes of the first energy storage unit 401 and the second energy storage unit 402 are turned on, the switch element 201c of the single H-bridge unit 200 is turned on, and the switch elements 201a, 201b, and 201d are turned off. Fig.10 In the soft parallel state shown in FIG. 7 (b), the negative electrodes of the first energy storage unit 401 and the second energy storage unit 402 are turned on, the switch element 201b of the single H-bridge unit 200 is turned on, and the switch elements 201a, 201c, and 201d are turned off.

[0102] Similar to the principle that the bridge arm current is positive, if at least one single H bridge unit in the parallel H bridge circuit 300 is in Fig.10 In the state shown in Figure (a), at least one monomer H-bridge unit is in Fig.10 If the state is shown in FIG. 2( b ) and the remaining single H-bridge units are in a blocking state, the parallel H-bridge circuit 300 is in a zero voltage state.

[0103] Fig.11 is another equivalent current conduction path in an embodiment, Fig.11 Figures (a) and (b) in the figure show the equivalent current conduction path of the parallel H-bridge circuit in the zero voltage state when V1>V2 and the direction of the bridge arm current is negative. Fig. 9 The principle is similar to Fig.10 In the state of (a) in FIG. 1 , the single H-bridge unit 200 does not conduct current, but is in Fig.10 In the state of (b) in FIG. 1 , the single H-bridge unit 200 conducts current. In this case, Fig.10 Figure (a) shows the inactive soft parallel state. Fig.10 (b) Figure 2 shows the active soft parallel state.

[0104] Similarly, Fig.11 Figures (c) and (d) in the figure show the equivalent current conduction path of the parallel H-bridge circuit in the zero voltage state when V1 < V2 and the direction of the bridge arm current is negative. In this case, Fig.10 Figure (a) shows the active soft parallel state. Fig.10 Figure (b) shows the inactive soft parallel state.

[0105] It can be seen that the zero voltage state of the parallel H-bridge circuit 300 is determined by the direction of the corresponding bridge arm current and the voltage of the two energy storage units connected to the two ends of the parallel H-bridge circuit. At this time, the state of the single H-bridge unit 300 is a soft parallel state or a blocking state. The anti-parallel power diode of the single switch unit 200 plays an important role in conducting current. It should be noted that the above definition defines that the bridge arm current flows from left to right as the positive direction and flows from right to left as the negative direction.

[0106] Table 1 is a state summary table. When the parallel H-bridge circuit 300 is in a positive voltage state, the single H-bridge unit 200 in the parallel H-bridge circuit 300 can be in a forward series state (i.e., state 1) or a blocked state (i.e., state 0). When the parallel H-bridge circuit 300 is in a negative voltage state, the single H-bridge unit 200 in the parallel H-bridge circuit 300 can be in a negative series state (i.e., state 2) or a blocked state (i.e., state 0).

[0107] When the parallel H-bridge circuit 300 is in a zero voltage state, the single H-bridge unit 200 in the parallel H-bridge circuit 300 may be in a soft parallel state or a blocking state (ie, state 0).

[0108] If the bridge arm current of the parallel H-bridge circuit 300 is positive, and the positive electrodes of the adjacent first energy storage unit 401 and the second energy storage unit 402 are turned on, the single H-bridge unit 200 in the parallel H-bridge circuit 300 may be in state 3 in the soft parallel state; if the bridge arm current of the parallel H-bridge circuit 300 is positive, and the negative electrodes of the adjacent first energy storage unit 401 and the second energy storage unit 402 are turned on, the single H-bridge unit 200 in the parallel H-bridge circuit 300 may be in state 4 in the soft parallel state; If the bridge arm current of the parallel H-bridge circuit 300 is negative, and the positive electrodes of the adjacent first energy storage unit 401 and the second energy storage unit 402 are turned on, the single H-bridge unit 200 in the parallel H-bridge circuit 300 can be in state 5 in the soft parallel state; if the bridge arm current of the parallel H-bridge circuit 300 is negative, and the negative electrodes of the adjacent first energy storage unit 401 and the second energy storage unit 402 are turned on, the single H-bridge unit 200 in the parallel H-bridge circuit 300 can be in state 6 in the soft parallel state.

[0109] Among them, state 0 is Figure 7 The state shown in Figure (c) is state 1. Figure 7 The state shown in Figure (a) is state 1. Figure 7 The state shown in Figure (a) is Figure 7 The state shown in Figure (b) is state 3. Figure 8 The state shown in Figure (a) is state 4. Figure 8 The state shown in Figure (b) is state 5. Fig.10The state shown in Figure (a) is state 6. Fig.10 The state of each switch element of the single H-bridge unit 200 in each state is shown in FIG. 1, and will not be described in detail here.

[0110] Table 1 Status summary table

[0111]

[0112] Fig.12 FIG. 1 is an application environment diagram of a current balancing method in an embodiment. The current balancing method provided in the embodiment of the present application can be applied to Fig.12 In the application environment shown, the computer device 1201 can communicate with the parallel H-bridge circuit 300. The computer device 1201 includes but is not limited to a central processing unit (CPU), a digital signal processor (DSP), a field programmable gate array (FPGA) or other programmable logic devices.

[0113] In some application scenarios, the computer device 1201 may also be, but is not limited to, various personal computers, laptops, smart phones or tablet computers. The computer device 1201 may also be an independent physical server, a cloud server, a server cluster or a distributed system consisting of multiple physical servers.

[0114] Fig.13 FIG. 1 is a flow chart of a current balancing method in an embodiment. In an exemplary embodiment, as shown in FIG. Fig.13 As shown, a current balancing method is provided, which is applied to Fig.12 The computer device in is used as an example to illustrate, including the following S1301 to S1303.

[0115] S1301, determining the expected state of the parallel H-bridge circuit at the next moment.

[0116] In this embodiment, the desired state S refers to the state that the parallel H-bridge circuit 300 is expected to reach. Optionally, the desired state can be any one of a positive voltage state, a negative voltage state, or a zero voltage state. For example, S=1 indicates that the desired state is a positive voltage state, S=0 indicates that the desired state is a zero voltage state, and S=-1 indicates that the desired state is a negative voltage state.

[0117] Optionally, the computer device may plan and store the expected state of the parallel H-bridge circuit 300 in each time period in advance, and determine the expected state S of the parallel H-bridge circuit 300 at the next moment from the storage at the current moment. The computer device may also determine the expected state S at the next moment based on the current state of the parallel H-bridge circuit 300. This embodiment is not limited to this.

[0118] S1302, determining the target state of each single H-bridge unit at the next moment according to the bridge arm current of the parallel H-bridge circuit, the average current of each single H-bridge unit at the current moment, and the rated current of the switch element.

[0119] In this embodiment, the bridge arm current Is of the parallel H-bridge circuit 300 refers to the current flowing through the entire bridge arm of the parallel H-bridge circuit 300. Figure 5 , the bridge arm current Is may be a current passing through the first terminal unit 501 or the second terminal unit 502 .

[0120] The average current of the single H-bridge unit 200 at the current moment refers to the average value of the current flowing through each switch element 201 in the single H-bridge unit 200 at the current moment. It can be understood that each single H-bridge unit 200 corresponds to an average current. Figure 4 For example, the single H-bridge unit 200a corresponds to an average current a, the single H-bridge unit 200b corresponds to an average current b, the single H-bridge unit 200c corresponds to an average current c, and so on.

[0121] The computer device may obtain the bridge arm current Is and each average current through a sensor, and the sensor includes but is not limited to a current sensor.

[0122] Then, the computer device may obtain the rated current Irated of the switch element from the storage. Optionally, the rated current Irated of each switch element may be the same.

[0123] Afterwards, the computer device can determine the target state of each single H-bridge unit 200 at the next moment according to the bridge arm current Is, the rated current Irated and the average currents.

[0124] The next moment is the next moment of the current moment. The target state S refers to the state that the monomer H-bridge unit 200 is expected to reach under the expected state S of the parallel H-bridge circuit 300. The target state can be any one of the forward series state, the blocking state or the soft parallel state. The soft parallel state can include an active soft parallel state or an inactive soft parallel state.

[0125] For example, assuming that the parallel H-bridge circuit includes n single H-bridge units, the target state of the j-th single H-bridge unit at the next moment is recorded as Sh[j]. Wherein, j is 1 to n, and n is an integer greater than or equal to 1. Figure 4 For example, Sh[1] is the target state of the single H-bridge unit 200a, Sh[2] is the target state of the single H-bridge unit 200b, and Sh[3] is the target state of the single H-bridge unit 200c.

[0126] Among them, Sh[j] takes the value of 1, 0 or -1. When the state of the parallel H-bridge circuit is a positive voltage state or a negative voltage state, 1 indicates that the single H-bridge unit is in a positive series state or a negative series state, and 0 and -1 both indicate that the single H-bridge unit is in a blocking state.

[0127] When the state of the parallel H-bridge circuit is a zero voltage state, 1 indicates that the single H-bridge unit is in an active soft parallel state, 0 indicates that the single H-bridge unit is in an inactive soft parallel state, and -1 indicates that the single H-bridge unit is in a blocking state.

[0128] Optionally, the computer device may input the bridge arm current Is, the rated current Irated and each average current into a state determination model, and the state determination model outputs the target state Sh[j] of each single H-bridge unit at the next moment.

[0129] The state determination model can be trained based on the bridge arm current samples, rated current samples, average current samples and the corresponding target state labels of each single H-bridge unit during current balancing. Current balancing can be that the difference between the average currents of each single H-bridge unit in the parallel H-bridge circuit is less than a preset difference.

[0130] The state determination model may include, but is not limited to, a Convolutional Neural Network (CNN) model, a Recurrent Neural Network (RNN), a Fully Convolutional Neural Network (FCN) model, a Generative Adversarial Network (GAN) model, a Back-propagation (BP) machine learning model, a Radial Basis Function (RBF) model, a Deep Belief Networks (DBN) model, an Elman model, or at least one of a combination thereof.

[0131] S1303, according to the expected state and each target state, controlling the working state of each switch element in each single H-bridge unit so that the difference between the average currents of each single H-bridge unit at the next moment is less than a preset difference.

[0132] In this embodiment, after the target state Sh[j] of each single H-bridge unit is determined, the working state of each switch element in each single H-bridge unit can be determined according to the expected state S and each target state Sh[j].

[0133] Optionally, the computer device stores different first correspondences between the desired state S, the target state Sh[j], and the working state of each switch element in the monomer H-bridge unit. For example, the computer device may store the first correspondence shown in Table 1. Furthermore, for each monomer H-bridge unit, after determining the desired state S of the parallel H-bridge circuit and the target state of the monomer H-bridge unit, the working state of each switch element in the monomer H-bridge unit may be determined according to the first correspondence.

[0134] Furthermore, the computer device can control the working state of each switch element in each monomer H-bridge unit so that the difference between the average currents of each monomer H-bridge unit at the next moment is less than the preset difference. The preset difference can be set according to demand, for example, it can be a number close to 0. It can be understood that the smaller the absolute value of the preset difference, the better the current balancing effect.

[0135] Optionally, the computer device can control the working state of each switch element in each monomer H-bridge unit according to the driving signal, for example, when the driving signal is at a high level, the working state of the switch element is controlled to be an on state, and when the driving signal is at a low level, the working state of the switch element is controlled to be an off state.

[0136] For example, please refer to Figure 4 Taking the monomer H-bridge unit 200a as an example, if the working state of each switch element in the monomer H-bridge unit 200a is determined to be the state shown in state 5 in Table 1 according to the expected state S and the target state Sh1 of the monomer H-bridge unit 200a, the computer device will control the working state of the switch element 201c in the monomer H-bridge unit 200a to be the on state, and control the working states of the switch elements 201a, 201b and 201d in the monomer H-bridge unit 200a to be the off state.

[0137] It should be noted that the computer device can determine the working state of all the switching elements of each monomer H-bridge unit in the same parallel H-bridge circuit, and then uniformly control the working state of each switching element in each monomer H-bridge unit. The computer device can also control the working state of the switching element of a monomer H-bridge unit after determining the working state of the switching element in the monomer H-bridge unit. This embodiment is not limited to this.

[0138] In the above current balancing method, since the expected state of the parallel H-bridge circuit at the next moment can be determined, and the target state of each monomer H-bridge unit at the next moment is determined according to the bridge arm current of the parallel H-bridge circuit, the average current of each monomer H-bridge unit at the current moment, and the rated current of the switch element, the average current of all monomer H-bridge units at the current moment is considered when determining the target state of each monomer H-bridge unit at the next moment. In this way, after controlling the working state of each switch element in each monomer H-bridge unit according to the expected state and each target state, the difference between the average currents of each monomer H-bridge unit at the next moment can be made less than the preset difference, thereby achieving current balancing. In addition, in the above process, there is no need to design corresponding auxiliary capacitors, inductors or conduction time sensors and other additional hardware for each monomer switch, thereby reducing hardware costs.

[0139] Fig.14 FIG. 1 is a flow chart of determining a target state in an embodiment. In an exemplary embodiment, as shown in FIG. Fig.14 As shown, S1302 includes S1401 to S1402.

[0140] S1401, determining a target number of single H-bridge units in a first state in a parallel H-bridge circuit according to the bridge arm current and the rated current; the first state indicates that the single H-bridge unit is turned on and current exists.

[0141] In this embodiment, the first state indicates that the single H-bridge unit is turned on and current exists. Combined with Table 1, the first state is the state where Sh[j]>0. The target number Na is the number of single H-bridge units with Sh[j]>0 in the parallel H-bridge circuit.

[0142] Optionally, the computer device may determine the target quantity according to the quotient between the bridge arm current Is and the rated current Irated. For example, the computer device may use the quotient between the bridge arm current Is and the rated current Irated as the target quantity.

[0143] S1402, determining each target state according to the target quantity and the average current of each single H-bridge unit at the current moment.

[0144] In this embodiment, optionally, the computer device may determine each target state Sh[j] according to the target number Na and the average current of each monomer H-bridge unit at the current moment. For example, the computer device may determine the target state Sh[j] of Na monomer H-bridge units whose average current at the current moment is less than a preset threshold as 1, and determine the target state Sh[j] of the monomer H-bridge unit with the smallest average current among the remaining monomer H-bridge units as 0, and then determine the target state Sh[j] of the remaining monomer H-bridge units as -1. The preset threshold can be set as required.

[0145] In the above embodiment, since the target number of monomer H-bridge units in the first state in the parallel H-bridge circuit can be determined based on the bridge arm current and the rated current, and the first state indicates that the monomer H-bridge unit is turned on and current exists, the target number of monomer H-bridge units that are turned on and current exists when the current flowing through the switch element does not exceed the rated current can be determined. Afterwards, each target state can be determined more accurately based on the target number and the average current of each monomer H-bridge unit at the current moment.

[0146] In an exemplary embodiment, optionally, the above S1403 may be implemented in the following manner:

[0147] Each target state is determined according to the target quantity and the priority order of each monomer H-bridge unit; each priority order is related to the average current of each monomer H-bridge unit at the current moment.

[0148] In this embodiment, each priority order is related to the average current of each monomer H-bridge unit at the current moment. Optionally, each priority order is negatively correlated with the magnitude of the average current of each monomer H-bridge unit at the current moment. For example, the smaller the average current of the monomer H-bridge unit at the current moment, the higher the priority order of the monomer H-bridge unit.

[0149] Furthermore, the computer device determines the target state Sh[j] according to the target number Na and the above-mentioned priority order. For example, the computer device may determine the target state Sh[j] of the first Na monomer H-bridge units with the largest priority order to be 1, and determine the target state Sh[j] of the monomer H-bridge unit with the largest priority order among the remaining monomer H-bridge units to be 0, and then determine the target state Sh[j] of the remaining monomer H-bridge units to be -1.

[0150] In the above embodiment, since each priority order is related to the average current of each monomer H-bridge unit at the current moment, the average current at the current moment can be considered according to the target number and the priority order of each monomer H-bridge unit. For example, the monomer H-bridge unit with a smaller average current at the current moment can have a higher priority to be turned on at the next moment, thereby accurately determining each target state to achieve the purpose of current balancing.

[0151] Fig.15 FIG. 1 is a flowchart of another method for determining a target state in an embodiment. In an exemplary embodiment, as shown in FIG. Fig.15 As shown, the above-mentioned "determining each target state according to the target quantity and the priority order of each monomer H-bridge unit; each priority order is related to the average current of each monomer H-bridge unit at the current moment" includes S1501 to S1503.

[0152] S1501, determining the priority order according to the average current of each single H-bridge unit at the current moment.

[0153] In this embodiment, optionally, the computer device may sort the average currents of the individual H-bridge units at the current moment in order from small to large, and use the sorting results as the priority orders.

[0154] Further optionally, each priority order can be represented by a sorting array Isorted. The sorting array Isorted includes Isorted[1], Isorted[2]...Isorted[n], with a total of n elements, Isorted[1] represents the priority order of the first monomer H bridge unit, Isorted[2] represents the priority order of the second monomer H bridge unit, and so on, Isorted[n] represents the priority order of the nth monomer H bridge unit. Among them, the element value is a natural number from 0 to n-1, and the priority order decreases in sequence, that is, 0 represents the corresponding monomer H bridge unit has the highest priority order, and n-1 represents the corresponding monomer H bridge unit has the highest priority order.

[0155] Furthermore, the computer device can determine the sorting array Isorted according to the average current of each monomer H-bridge unit at the current moment, that is, determine the priority order. For example, the larger the element of the sorting array Isorted, the smaller the average current of the corresponding monomer H-bridge unit.

[0156] In one embodiment, the computer device can determine the average current of each monomer H-bridge unit at the current moment through an n-dimensional average current array Iaver. The average current array Iaver includes Iaver[1], Iaver[2], ... Iaver[n], Iaver[1] represents the average current of the first monomer H-bridge unit, Iaver[2] represents the average current of the second monomer H-bridge unit, and so on, Iaver[n] represents the average current of the nth monomer H-bridge unit.

[0157] Afterwards, the computer device sorts the elements of the array Isorted from small to large according to the element values ​​of the array Iaver to determine the sorted array Isorted. Figure 4 For example, assuming that Iaver={1.5, 3.3, 2.1}, that is, Iaver[1]=1.5, Iaver[2]=3.3, Iaver[3]=2.1, then the computer device sorting array Isorted={0, 2, 1}, that is, Isorted[1]=0, Isorted[2]=2, Isorted[3]=1. In other words, the average current of the single H-bridge unit 200a is the smallest, and its corresponding priority order is the largest, and the average current of the single H-bridge unit 200b is the largest, and its corresponding priority order is the smallest.

[0158] S1502 : For each monomer H-bridge unit, determine the difference between the target number and the priority order of the monomer H-bridge unit.

[0159] In this embodiment, continuing the example of S1502, the computer device can respectively determine the difference Na-Isorted[j] between the target number Na and each element in the sorted array Isorted, that is, determine the difference between the target number Na and the priority order of the monomer H-bridge unit.

[0160] S1503, determining the target state of the monomer H-bridge unit according to the difference and the sign function.

[0161] Furthermore, the computer device may process the difference obtained in S1502 according to the matching function to obtain the target state Sh[j] of the monomer H-bridge unit.

[0162] Exemplarily, the computer device determines the target state Sh[j] according to the following equation (1).

[0163] Sh[j] = sgn(Na - Isorted[j]) (1)

[0164] Wherein, sgn represents the sign function, when (Na - Isorted[j]) < 0, Sh[j] = -1, when (Na - Isorted[j]) > 0, Sh[j] = 1, when (Na - Isorted[j]) = 0, Sh[j] = 0. Thus, the target state of the monomer H-bridge unit with the first Na positions sorted from small to large in average current is Sh[j] = 1, the target state of the monomer H-bridge unit with the Nath position sorted from small to large in average current is Sh[j] = 0, and the target state of the remaining monomer H-bridge units is Sh[j] = -1.

[0165] In the above embodiment, since each priority order can be determined according to the size of the average current of each monomer H-bridge unit at the current moment, and for each monomer H-bridge unit, the difference between the target number and the priority order of the monomer H-bridge unit is determined, and then the target state of the monomer H-bridge unit is determined according to the difference and the sign function, in this way, the monomer H-bridge unit with a smaller average current at the current moment will be preferentially turned on, so that the average current of the turned-on monomer H-bridge unit increases, and the average current of the monomer H-bridge unit that is not turned on decreases, so that current balancing can be achieved in the dynamic adjustment process.

[0166] Fig.16 FIG. 1 is a flow chart of determining a target quantity in an embodiment. In an exemplary embodiment, as shown in FIG. Fig.16 As shown, S1402 includes S1601 to S1602.

[0167] S1601, determine the quotient between the bridge arm current and the rated current.

[0168] S1602, rounding up the quotient to obtain the target quantity.

[0169] In this embodiment, the computer device may determine the target number Na according to the following formula (2).

[0170] Na=∏(|Is| / Irated) (2)

[0171] Among them, ∏ means rounding up.

[0172] In the above embodiment, since the quotient between the bridge arm current and the rated current can be determined and the quotient is rounded up to obtain the target number, the minimum target number of single H-bridge units that are turned on and have current when the current flowing through the switching element does not exceed the rated current can be determined, which is conducive to efficiently achieving current balancing.

[0173] In an exemplary embodiment, optionally, the above S1302 may be implemented in the following manner:

[0174] When the stop condition is not met, the working state of each switching element in the monomer H-bridge unit is determined according to the expected state and the target state of the monomer H-bridge unit, and when the stop condition is met, each switching element is controlled according to the working state of each switching element in each monomer H-bridge unit; the stop condition is used to determine whether all the monomer H-bridge units in the parallel H-bridge circuit have been traversed.

[0175] In this embodiment, taking the parallel H-bridge circuit including n monomer H-bridge units as an example, after the computer device determines the working state of each switch element in the monomer H-bridge unit according to the expected state S and the target state Sh[j] of the monomer H-bridge unit each time, it can judge whether all the monomer H-bridge units in the parallel H-bridge circuit have been traversed according to whether j is less than n. If j is less than n, it means that all the monomer H-bridge units in the parallel H-bridge circuit have not been traversed. The computer device can update the value of j according to j=j+1 and continue to determine the working state of each switch element in the next monomer H-bridge unit. If j is not less than n, it means that all the monomer H-bridge units in the parallel H-bridge circuit have been traversed. The computer device can control each switch element according to the working state of each switch element in the monomer H-bridge unit. It should be noted that the initial value of j can be 1.

[0176] For example, assuming n=3, please refer to Figure 4 , the initial value of j is 1. The computer device first determines the working state of each switch element in the monomer H-bridge unit 200a according to the expected state S and the target state Sh[1] of the monomer H-bridge unit 200a. Since j<n, the computer device updates j=2, and determines the working state of each switch element in the monomer H-bridge unit 200b according to the expected state S and the target state Sh[2] of the monomer H-bridge unit 200b. Since j is still less than n, the computer device continues to update j=3, and determines the working state of each switch element in the monomer H-bridge unit 200c according to the expected state S and the target state Sh[3] of the monomer H-bridge unit 200b. At this time, j=n, and the computer device controls the working state of each switch element in the monomer H-bridge unit 200a, the working state of each switch element in the monomer H-bridge unit 200b, and the working state of each switch element in the monomer H-bridge unit 200c according to the above-determined working state.

[0177] In the above embodiment, since the stop condition is used to determine whether all the single H-bridge units in the parallel H-bridge circuit have been traversed, when the stop condition is not met, the working state of each switching element in the single H-bridge unit is determined according to the expected state and the target state of the single H-bridge unit, and when the stop condition is met, each switching element is controlled according to the working state of each switching element in each single H-bridge unit, so that the entire parallel H-bridge circuit can be efficiently controlled to achieve current balancing.

[0178] In an exemplary embodiment, optionally, the above-mentioned “determining the working state of each switch element in the single-cell H-bridge unit according to the expected state and the target state of the single-cell H-bridge unit” can be implemented as follows:

[0179] (1) If the desired state is a positive voltage state, and the target state of the single H-bridge unit is a first state, it is determined that the working state of the switch elements located at the upper left bridge arm and the lower right bridge arm in the single H-bridge unit is an off state, and the working state of the switch elements located at the lower left bridge arm and the upper right bridge arm in the single H-bridge unit is an on state.

[0180] Taking j=1, that is, the single H-bridge unit 200a as an example, if S=1 and Sh[1]=1, it can be determined that the single H-bridge unit 200a is in state 1 in Table 1. In this case, the computer device determines that the working state of the switch element 201a and the switch element 201d in the single H-bridge unit 200a is the cut-off state (that is, the off state in Table 1), and the working state of the switch element 201b and the switch element 201c is the on state (that is, the on state in Table 1). The same is true for other single H-bridge units. In this way, when the working state of the switch elements of all single H-bridge units in the same parallel H-bridge circuit is determined, the target state of the parallel H-bridge circuit is also determined. The following examples are all taken as j=1, and will not be repeated here.

[0181] (2) If the desired state is a positive voltage state, and the target state of the single-cell H-bridge unit is the second state or the third state, it is determined that the working state of each switch element in the single-cell H-bridge unit is the cut-off state; the second state indicates that the single-cell H-bridge unit is not turned on or is turned on but there is no current; the third state indicates that the single-cell H-bridge unit is not turned on.

[0182] In this embodiment, the second state indicates that the single H-bridge unit is not conducting or is conducting but there is no current, that is, Sh[j]=0; the third state indicates that the single H-bridge unit is not conducting, that is, Sh[j]=-1.

[0183] Exemplarily, if S=1, and Sh[1]=0 or -1, it can be determined that the monomer H-bridge unit 200a is in state 0 in Table 1. In this case, the computer device determines that the working states of the switch elements 201a, 201b, 201c and 201d in the monomer H-bridge unit 200a are all cut-off states.

[0184] In the above embodiment, when the expected state is a positive voltage state, the working state of each switch element in the single H-bridge unit can be determined efficiently and accurately according to the expected state and the target state of the single H-bridge unit.

[0185] In an exemplary embodiment, optionally, the above-mentioned “determining the working state of each switch element in the single-cell H-bridge unit according to the expected state and the target state of the single-cell H-bridge unit” can be implemented as follows:

[0186] (1) If the desired state is a negative voltage state, and the target state of the single H-bridge unit is the first state, it is determined that the working state of the switch element located at the lower left bridge arm and the upper right bridge arm in the single H-bridge unit is the cut-off state, and the working state of the switch element located at the upper left bridge arm and the lower right bridge arm in the single H-bridge unit is the on state.

[0187] Exemplarily, if S=-1, and Sh[1]=1, it can be determined that the monomer H-bridge unit 200a is in state 2 in Table 1. In this case, the computer device determines that the working state of the switch element 201b and the switch element 201c in the monomer H-bridge unit 200a is the cut-off state, and the working state of the switch element 201a and the switch element 201d is the on state.

[0188] (2) If the desired state is a negative voltage state, and the target state of the single H-bridge unit is the second state or the third state, then it is determined that the working state of each switch element in the single H-bridge unit is the off state.

[0189] Exemplarily, if S=-1, and Sh[1]=0 or -1, it can be determined that the monomer H-bridge unit 200a is in state 0 in Table 1. In this case, the computer device determines that the working states of the switch elements 201a, 201b, 201c and 201d in the monomer H-bridge unit 200a are all cut-off states.

[0190] In the above embodiment, when the expected state is a negative voltage state, the working state of each switch element in the single H-bridge unit can be determined efficiently and accurately according to the expected state and the target state of the single H-bridge unit.

[0191] Fig.17 FIG. 1 is a flow chart of determining a working state in an embodiment. In an exemplary embodiment, as shown in FIG. Fig.17 As shown, the above-mentioned “determining the working state of each switch element in the monomer H-bridge unit according to the expected state and the target state of the monomer H-bridge unit” may include the following steps:

[0192] S1701: If the expected state is a zero voltage state, obtain a first voltage of the first energy storage unit and a second voltage of the second energy storage unit.

[0193] In this embodiment, please refer to Figure 4, the left bridge arm of any one of the monomer H-bridge units is connected to the first energy storage unit 401, and the right bridge arm of any one of the monomer H-bridge units is connected to the second energy storage unit 402. If S=0, that is, when the expected state S of the parallel H-bridge circuit is a zero voltage state, the computer device will obtain the first voltage V1 of the first energy storage unit 401 and the second voltage V2 of the second energy storage unit 402.

[0194] S1702, determining the working state of each switch element in the single H-bridge unit according to the bridge arm current, the first voltage, the second voltage and the target state of the single H-bridge unit of the parallel H-bridge circuit.

[0195] Optionally, the computer device can determine the working state of each switch element in the single-body H-bridge unit according to the direction of the bridge arm current Is, the magnitude relationship between the first voltage V1 and the second voltage V2, and the target state Sh[j]. For example, the computer device stores the second corresponding relationship between the direction of the bridge arm current Is, the magnitude relationship between the first voltage V1 and the second voltage V2, the target state Sh[j], and the working state of each switch element in the single-body H-bridge unit. In this way, the computer device can determine the working state of each switch element in the single-body H-bridge unit according to the bridge arm current of the parallel H-bridge circuit, the first voltage, the second voltage, the target state of the single-body H-bridge unit, and the second corresponding relationship.

[0196] Continuing with the above example of j=1, if S=0, the computer device can determine the working state of each switch element in the single H-bridge unit 200a according to the bridge arm current Is, the first voltage V1, the second voltage V2 and the target state Sh[1].

[0197] In the above embodiment, since the first voltage of the first energy storage unit and the second voltage of the second energy storage unit are also obtained when the expected state is a zero voltage state, and the working state of each switching element in the single H-bridge unit is determined according to the bridge arm current, the first voltage, the second voltage and the target state of the single H-bridge unit of the parallel H-bridge circuit, the working state of each switching element in the single H-bridge unit can be accurately and efficiently determined.

[0198] In an exemplary embodiment, optionally, the above S1702 may be implemented in the following manner:

[0199] (1) If the bridge arm current is greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the first state, it is determined that the working state of the switch element located in the upper left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit other than the upper left bridge arm is the off state.

[0200] In this embodiment, if Is>0, and V1>V2, it means that the bridge arm current of the parallel H circuit is positive, and the positive electrodes of the adjacent first energy storage unit and the second energy storage unit are turned on. In this case, if Sh[1]=1, it can be determined that the single H bridge unit 200a is in state 3 in Table 1, and then the computer device determines that the working state of the switch element 201a in the single H bridge unit 200a is the on state, and the working states of the switch elements 201b, 201c and 201d in the single H bridge unit 200a are all in the off state.

[0201] (2) If the bridge arm current is greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the second state, the working state of the switch element located in the lower right bridge arm in the single H-bridge unit is determined to be the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower right bridge arm is the off state.

[0202] Exemplarily, if Is>0, V1>V2 and Sh[1]=0, it can be determined that the monomer H-bridge unit 200a is in state 4 in Table 1. In this case, the computer device determines that the working state of the switch element 201d in the monomer H-bridge unit 200a is the on state, and the working states of the switch element 201a, the switch element 201b and the switch element 201c in the monomer H-bridge unit 200a are all the off state.

[0203] (3) If the bridge arm current is greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0204] Exemplarily, if Is>0, V1>V2 and Sh[1]=-1, it can be determined that the monomer H-bridge unit 200a is in state 0 in Table 1. In this case, the computer device determines that the working states of the switch elements 201a, 201b, 201c and 201d in the monomer H-bridge unit 200a are all cut-off states.

[0205] The above embodiment efficiently determines the working state of each switch element in the single H-bridge unit when the bridge arm current is positive and the positive electrode of the adjacent energy storage unit is turned on, when the expected state is a zero voltage state.

[0206] In an exemplary embodiment, optionally, the above S1702 may be implemented in the following manner:

[0207] (1) If the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the first state, the working state of the switch element located in the lower right bridge arm of the single H-bridge unit is determined to be the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower right bridge arm is the off state.

[0208] In this embodiment, if Is>0, and V1≤V2, it means that the bridge arm current of the parallel H circuit is positive, and the negative electrodes of the adjacent first energy storage unit and the second energy storage unit are turned on. In this case, if Sh[1]=1, it can be determined that the single H bridge unit 200a is in state 4 in Table 1, and then the computer device determines that the working state of the switch element 201d in the single H bridge unit 200a is the on state, and the working states of the switch elements 201a, 201b and 201c in the single H bridge unit 200a are all in the off state.

[0209] (2) If the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the second state, it is determined that the working state of the switch element located in the upper left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit other than the switch element located in the upper left bridge arm is the off state.

[0210] Exemplarily, if Is>0, V1≤V2 and Sh[1]=0, it can be determined that the monomer H-bridge unit 200a is in state 3 in Table 1. In this case, the computer device determines that the working state of the switch element 201a in the monomer H-bridge unit 200a is the on state, and the working states of the switch element 201b, the switch element 201c and the switch element 201d in the monomer H-bridge unit 200a are all the off state.

[0211] (3) If the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0212] Exemplarily, if Is>0, V1≤V2 and Sh[1]=-1, it can be determined that the monomer H-bridge unit 200a is in state 0 in Table 1. In this case, the computer device determines that the working states of the switch elements 201a, 201b, 201c and 201d in the monomer H-bridge unit 200a are all cut-off states.

[0213] The above embodiment efficiently determines the working state of each switch element in the single H-bridge unit when the bridge arm current is positive and the negative electrode of the adjacent energy storage unit is turned on, when the expected state is a zero voltage state.

[0214] In an exemplary embodiment, optionally, the above S1702 may be implemented in the following manner:

[0215] (1) If the bridge arm current is not greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the first state, the working state of the switch element located in the upper right bridge arm of the single H-bridge unit is determined to be the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the upper right bridge arm is determined to be the off state.

[0216] In this embodiment, if Is≤0, and V1>V2, it means that the bridge arm current of the parallel H circuit is negative, and the positive electrodes of the adjacent first energy storage unit and the second energy storage unit are turned on. In this case, if Sh[1]=1, it can be determined that the single H bridge unit 200a is in state 5 in Table 1, and then the computer device determines that the working state of the switch element 201c in the single H bridge unit 200a is the on state, and the working states of the switch element 201a, the switch element 201b and the switch element 201d in the single H bridge unit 200a are all in the off state.

[0217] (2) If the bridge arm current is not greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the second state, it is determined that the working state of the switch element located in the lower left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower left bridge arm is the off state.

[0218] Exemplarily, if Is≤0, V1>V2 and Sh[1]=0, it can be determined that the monomer H-bridge unit 200a is in state 6 in Table 1. In this case, the computer device determines that the working state of the switch element 201b in the monomer H-bridge unit 200a is the on state, and the working states of the switch element 201a, the switch element 201c and the switch element 201d in the monomer H-bridge unit 200a are all the off state.

[0219] (3) If the bridge arm current is not greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0220] Exemplarily, if Is≤0, V1>V2 and Sh[1]= -1, it can be determined that the monomer H-bridge unit 200a is in state 0 in Table 1. In this case, the computer device determines that the working states of the switch element 201a, the switch element 201b, the switch element 201c and the switch element 201d in the monomer H-bridge unit 200a are all in the cut-off state.

[0221] The above embodiment efficiently determines the working state of each switch element in the single H-bridge unit when the bridge arm current is negative and the positive electrode of the adjacent energy storage unit is turned on, when the expected state is a zero voltage state.

[0222] In an exemplary embodiment, optionally, the above S1702 may be implemented in the following manner:

[0223] (1) If the bridge arm current is not greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the first state, it is determined that the working state of the switch element located in the lower left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit other than the lower left bridge arm is the off state.

[0224] In this embodiment, if Is≤0, and V1≤V2, it means that the bridge arm current of the parallel H circuit is negative, and the negative electrodes of the adjacent first energy storage unit and the second energy storage unit are turned on. In this case, if Sh[1]=1, it can be determined that the single H bridge unit 200a is in state 6 in Table 1, and then the computer device determines that the working state of the switch element 201b in the single H bridge unit 200a is the on state, and the working states of the switch elements 201a, 201c and 201d in the single H bridge unit 200a are all in the off state.

[0225] (2) If the bridge arm current is not greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the second state, the working state of the switch element located in the upper right bridge arm of the single H-bridge unit is determined to be the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the upper right bridge arm is determined to be the off state.

[0226] Exemplarily, if Is≤0, V1≤V2 and Sh[1]=0, it can be determined that the monomer H-bridge unit 200a is in state 5 in Table 1. In this case, the computer device determines that the working state of the switch element 201c in the monomer H-bridge unit 200a is the on state, and the working states of the switch element 201a, the switch element 201b and the switch element 201d in the monomer H-bridge unit 200a are all the off state.

[0227] (3) If the bridge arm current is not greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0228] Exemplarily, if Is≤0, V1≤V2, and Sh[1]= -1, it can be determined that the monomer H-bridge unit 200a is in state 0 in Table 1. In this case, the computer device determines that the operating states of the switching elements 201a, 201b, 201c, and 201d in the monomer H-bridge unit 200a are all in the off state.

[0229] In the above embodiment, when the desired state is the zero-voltage state, the operating state of each switching element in the monomer H-bridge unit can be efficiently determined when the arm current is negative and the negative electrodes of adjacent energy storage units are conducting.

[0230] To more clearly introduce the current balancing method of the present application, the current balancing process in a parallel H-bridge circuit is described below in conjunction with the following process. In one embodiment, the computer device can execute the current balancing method according to the following process.

[0231] S1. Obtain the desired state S, and determine the target quantity Na according to Equation (2), and then proceed to S2.

[0232] S2. Sort the elements of the array Isorted from smallest to largest according to the element values in the array Iaver to determine the sorted array Isorted, and then proceed to S3.

[0233] S3. Determine the target state Sh[j] according to Equation (1), assign an initial value of 1 to j, and then proceed to S4.

[0234] S4. Judge the value of S. If S = 1, proceed to S5; if S = 0, proceed to S9; if S = -1, proceed to S32.

[0235] S5. Judge the value of Sh[j]. If Sh[j]>0, proceed to S6; if Sh[j]≤0, proceed to S7.

[0236] S6. The state of the j-th monomer H-bridge unit should be state 1 in Table 1. Determine that the switching elements 201a and 201d in the j-th monomer H-bridge unit are turned off, and the switching elements 201b and 201c are turned on, and then proceed to S8.

[0237] S7. The state of the j-th monomer H-bridge unit should be state 0 in Table 1. Determine that all the switching elements in the j-th monomer H-bridge unit are turned off, and then proceed to S8.

[0238] S8. Judge the value of j. If j < n, let j = j + 1 to update the value of j, and return to S5. If j ≥ n, the process can be ended.

[0239] S9. Judge the value of Is. If Is>0, proceed to S10; if Is>0, proceed to S21.

[0240] S10, Determine the relative magnitudes of V1 and V2. If V1 > V2, proceed to S11; if V1 ≤ V2, proceed to S16.

[0241] S11, Determine the value of Sh[j]. If Sh[j] > 0, proceed to S12; if Sh[j] = 0, proceed to S13; if Sh[j] = -1, proceed to S14.

[0242] S12, The state of the j-th single-cell H-bridge unit should be state 3 in Table 1. Determine that switch element 201a in the j-th single-cell H-bridge unit is turned on, and switch elements 201b, 201c, and 201d are turned off, then proceed to S15.

[0243] S13, The state of the j-th single-cell H-bridge unit should be state 4 in Table 1. Determine that switch element 201d in the j-th single-cell H-bridge unit is turned on, and switch elements 201a, 201b, and 201c are turned off, then proceed to S15.

[0244] S14, The state of the j-th single-cell H-bridge unit should be state 0 in Table 1. Determine that all switch elements in the j-th single-cell H-bridge unit are turned off, then proceed to S15.

[0245] S15, Determine the value of j. If j < n, let j = j + 1 to update the value of j and return to S11; if j ≥ n, the process can end.

[0246] S16, Determine the value of Sh[j]. If Sh[j] > 0, proceed to S17; if Sh[j] = 0, proceed to S18; if Sh[j] = -1, proceed to S19.

[0247] S17, The state of the j-th single-cell H-bridge unit should be state 4 in Table 1. Determine that switch element 201d in the j-th single-cell H-bridge unit is turned on, and switch elements 201a, 201b, and 201c are turned off, then proceed to S20.

[0248] S18, The state of the j-th single-cell H-bridge unit should be state 3 in Table 1. Determine that switch element 201a in the j-th single-cell H-bridge unit is turned on, and switch elements 201b, 201c, and 201d are turned off, then proceed to S20.

[0249] S19, The state of the j-th single-cell H-bridge unit should be state 0 in Table 1. Determine that all switch elements in the j-th single-cell H-bridge unit are turned off, then proceed to S20.

[0250] S20. Determine the value of j. If j < n, let j = j + 1 to update the value of j, and return to S16. If j ≥ n, the process can end.

[0251] S21. Determine the relative magnitudes of V1 and V2. If V1 > V2, proceed to S22. If V1 ≤ V2, proceed to S27.

[0252] S22. Determine the value of Sh[j]. If Sh[j] > 0, proceed to S23. If Sh[j] = 0, proceed to S24. If Sh[j] = -1, proceed to S25.

[0253] S23. The state of the j-th single H-bridge unit should be state 5 in Table 1. Determine that the switching element 201c in the j-th single H-bridge unit is turned on, and the switching elements 201a, 201b, and 201d are turned off. Then proceed to S26.

[0254] S24. The state of the j-th single H-bridge unit should be state 6 in Table 1. Determine that the switching element 201b in the j-th single H-bridge unit is turned on, and the switching elements 201a, 201c, and 201d are turned off. Then proceed to S26.

[0255] S25. The state of the j-th single H-bridge unit should be state 0 in Table 1. Determine that all the switching elements in the j-th single H-bridge unit are turned off. Then proceed to S26.

[0256] S26. Determine the value of j. If j < n, let j = j + 1 to update the value of j, and return to S22. If j ≥ n, the process can end.

[0257] S27. Determine the value of Sh[j]. If Sh[j] > 0, proceed to S28. If Sh[j] = 0, proceed to S29. If Sh[j] = -1, proceed to S30.

[0258] S28. The state of the j-th single H-bridge unit should be state 6 in Table 1. Determine that the switching element 201b in the j-th single H-bridge unit is turned on, and the switching elements 201a, 201c, and 201d are turned off. Then proceed to S31.

[0259] S29. The state of the j-th single H-bridge unit should be state 5 in Table 1. Determine that the switching element 201c in the j-th single H-bridge unit is turned on, and the switching elements 201a, 201b, and 201d are turned off. Then proceed to S31.

[0260] S30. The state of the j-th single H-bridge unit should be state 0 in Table 1. Determine that all the switching elements in the j-th single H-bridge unit are turned off. Then proceed to S31.

[0261] S31. Determine the value of j. If j < n, let j = j + 1 to update the value of j and return to S27; if j ≥ n, the process can end.

[0262] S32. Determine the value of Sh[j]. If Sh[j] > 0, enter S33; if Sh[j] ≤ 0, enter S34.

[0263] S33. The state of the j-th single H-bridge unit should be state 2 in Table 1. Determine that the switching element 201a and the switching element 201d in the j-th single H-bridge unit are turned on, and the switching element 201b and the switching element 201c are turned off, and then enter S35.

[0264] S34. The state of the j-th single H-bridge unit should be state 0 in Table 1. Determine that all the switching elements in the j-th single H-bridge unit are turned off, and then enter S8.

[0265] S35. Determine the value of j. If j < n, let j = j + 1 to update the value of j and return to S5; if j ≥ n, the process can end.

[0266] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same moment, but can be executed at different moments. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0267] Based on the same inventive concept, the embodiments of the present application also provide a current balancing device for implementing the current balancing method involved above. The implementation solution provided by this device to solve the problem is similar to the implementation solution described in the above method. Therefore, the specific limitations in one or more embodiments of the current balancing device provided below can refer to the limitations on the current balancing method in the above text, and will not be repeated here.

[0268] Fig.18 For the structural block diagram of the current balancing device in an embodiment, in an exemplary embodiment, as Fig.18As shown, a current balancing device 1800 is provided, which is applied to any of the above-mentioned parallel H-bridge circuits 300, wherein the parallel H-bridge circuit 300 includes a plurality of mutually parallel single H-bridge units 200, wherein the single H-bridge unit 200 includes a plurality of switch elements 201, and the current balancing device 1800 includes: a first determination module 1801, a second determination module 1802 and a third determination module 1803, wherein:

[0269] The first determining module 1801 is used to determine the expected state of the parallel H-bridge circuit at the next moment.

[0270] The second determination module 1802 is used to determine the target state of each single H-bridge unit at the next moment according to the bridge arm current of the parallel H-bridge circuit, the average current of each single H-bridge unit at the current moment, and the rated current of the switch element.

[0271] The third determination module 1803 is used to control the working state of each switch element in each single H-bridge unit according to the expected state and each target state, so that the difference between the average currents of each single H-bridge unit at the next moment is less than a preset difference.

[0272] In the above current balancing device, since the expected state of the parallel H-bridge circuit at the next moment can be determined, and the target state of each monomer H-bridge unit at the next moment is determined according to the bridge arm current of the parallel H-bridge circuit, the average current of each monomer H-bridge unit at the current moment, and the rated current of the switch element, the average current of all monomer H-bridge units at the current moment is considered when determining the target state of each monomer H-bridge unit at the next moment. In this way, after controlling the working state of each switch element in each monomer H-bridge unit according to the expected state and each target state, the difference between the average currents of each monomer H-bridge unit at the next moment can be made less than the preset difference, thereby achieving current balancing. In addition, in the above process, there is no need to design corresponding auxiliary capacitors, inductors or conduction time sensors and other additional hardware for each monomer switch, thereby reducing hardware costs.

[0273] Optionally, the second determining module 1802 includes:

[0274] The first determining unit is used to determine the target number of single H-bridge units in the parallel H-bridge circuit in the first state according to the bridge arm current and the rated current; the first state indicates that the single H-bridge unit is turned on and there is current.

[0275] The second determination unit is used to determine each target state according to the target quantity and the average current of each single H-bridge unit at the current moment.

[0276] Optionally, the second determination unit is further used to determine each target state according to the target quantity and the priority order of each monomer H-bridge unit; each priority order is related to the average current of each monomer H-bridge unit at the current moment.

[0277] Optionally, the second determining unit includes:

[0278] The first determination subunit is used to determine the priority order according to the average current of each single H-bridge unit at the current moment.

[0279] The second determining subunit is used to determine, for each monomer H-bridge unit, a difference between the target quantity and the priority order of the monomer H-bridge unit.

[0280] The third determination subunit is used to determine the target state of the monomer H-bridge unit according to the difference and the sign function.

[0281] Optionally, the first determination unit is used to determine a quotient between the bridge arm current and the rated current; and round up the quotient to obtain a target quantity.

[0282] Optionally, the third determination module 1803 is used to determine the working state of each switching element in the monomer H-bridge unit according to the expected state and the target state of the monomer H-bridge unit when the stop condition is not met, and control each switching element according to the working state of each switching element in each monomer H-bridge unit when the stop condition is met; the stop condition is used to determine whether all the monomer H-bridge units in the parallel H-bridge circuit have been traversed.

[0283] Optionally, the third determination module 1803 is used to determine that the working state of the switch elements located at the upper left bridge arm and the lower right bridge arm in the monomer H-bridge unit is the cut-off state, and the working state of the switch elements located at the lower left bridge arm and the upper right bridge arm in the monomer H-bridge unit is the on state if the expected state is a positive voltage state and the target state of the monomer H-bridge unit is the first state; if the expected state is a positive voltage state and the target state of the monomer H-bridge unit is the second state or the third state, determine that the working state of each switch element in the monomer H-bridge unit is the cut-off state; the second state indicates that the monomer H-bridge unit is not turned on or is turned on but there is no current; the third state indicates that the monomer H-bridge unit is not turned on.

[0284] Optionally, the third determination module 1803 is used to determine that the working state of the switch elements located at the lower left bridge arm and the upper right bridge arm in the monomer H-bridge unit is the cut-off state, and the working state of the switch elements located at the upper left bridge arm and the lower right bridge arm in the monomer H-bridge unit is the on state if the expected state is the negative voltage state and the target state of the monomer H-bridge unit is the first state;

[0285] If the desired state is a negative voltage state, and the target state of the single H-bridge unit is the second state or the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

[0286] Optionally, the left bridge arm of any one of the monomer H-bridge units is connected to the first energy storage unit, and the right bridge arm of any one of the monomer H-bridge units is connected to the second energy storage unit; the third determination module 1803 is used to obtain the first voltage of the first energy storage unit and the second voltage of the second energy storage unit if the expected state is a zero voltage state; determine the working state of each switching element in the monomer H-bridge unit according to the bridge arm current, the first voltage, the second voltage of the parallel H-bridge circuit and the target state of the monomer H-bridge unit.

[0287] Optionally, the third determination module 1803 is used to determine that if the bridge arm current is greater than zero and the first voltage is greater than the second voltage, then when the target state of the monomer H-bridge unit is the first state, the working state of the switch element located in the upper left bridge arm in the monomer H-bridge unit is the on state, and the working state of the switch element in the monomer H-bridge unit except the upper left bridge arm is the off state; if the bridge arm current is greater than zero and the first voltage is greater than the second voltage, then when the target state of the monomer H-bridge unit is the second state, the working state of the switch element located in the lower right bridge arm in the monomer H-bridge unit is the on state, and the working state of the switch element in the monomer H-bridge unit except the lower right bridge arm is the off state; if the bridge arm current is greater than zero and the first voltage is greater than the second voltage, then when the target state of the monomer H-bridge unit is the third state, it is determined that the working state of each switch element in the monomer H-bridge unit is the off state.

[0288] Optionally, the third determination module 1803 is used to determine that if the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the monomer H-bridge unit is the first state, the working state of the switch element located in the lower right bridge arm in the monomer H-bridge unit is the on state, and the working state of the switch element in the monomer H-bridge unit except the lower right bridge arm is the off state; if the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the monomer H-bridge unit is the second state, the working state of the switch element located in the upper left bridge arm in the monomer H-bridge unit is the on state, and the working state of the switch element in the monomer H-bridge unit except the upper left bridge arm is the off state; if the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the monomer H-bridge unit is the third state, it is determined that the working state of each switch element in the monomer H-bridge unit is the off state.

[0289] Optionally, the third determination module 1803 is used to determine that the working state of the switch element located in the upper right bridge arm of the monomer H-bridge unit is the on state, and the working state of the switch element in the monomer H-bridge unit except the upper right bridge arm is the off state if the bridge arm current is not greater than zero and the first voltage is greater than the second voltage, then when the target state of the monomer H-bridge unit is the first state; if the bridge arm current is not greater than zero and the first voltage is greater than the second voltage, then when the target state of the monomer H-bridge unit is the second state, determine that the working state of the switch element located in the lower left bridge arm of the monomer H-bridge unit is the on state, and the working state of the switch element in the monomer H-bridge unit except the lower left bridge arm is the off state; if the bridge arm current is not greater than zero and the first voltage is greater than the second voltage, then when the target state of the monomer H-bridge unit is the third state, determine that the working state of each switch element in the monomer H-bridge unit is the off state.

[0290] Optionally, the third determination module 1803 is used to determine that if the bridge arm current is not greater than zero and the first voltage is not greater than the second voltage, then when the target state of the monomer H-bridge unit is the first state, the working state of the switch element located in the lower left bridge arm in the monomer H-bridge unit is the on state, and the working state of the switch element in the monomer H-bridge unit except the lower left bridge arm is the off state; if the bridge arm current is not greater than zero and the first voltage is not greater than the second voltage, then when the target state of the monomer H-bridge unit is the second state, the working state of the switch element located in the upper right bridge arm in the monomer H-bridge unit is the on state, and the working state of the switch element in the monomer H-bridge unit except the upper right bridge arm is the off state; if the bridge arm current is not greater than zero and the first voltage is not greater than the second voltage, then when the target state of the monomer H-bridge unit is the third state, it is determined that the working state of each switch element in the monomer H-bridge unit is the off state.

[0291] Each module in the above current balancing device can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0292] In one embodiment, please refer to Figure 2~Figure 3 , a parallel H-bridge circuit 300 is provided, the parallel H-bridge circuit 300 includes a plurality of mutually parallel single H-bridge units 200, each of which includes a plurality of switch elements 201. The parallel H-bridge circuit applies any of the above current balancing methods.

[0293] In one embodiment, an energy storage system is also provided. Fig.19 FIG. 1 is a schematic diagram of the structure of an energy storage system in an embodiment. Fig.19 As shown, the energy storage system 1900 includes a control circuit 1901 and any of the above-mentioned parallel H-bridge circuits 300. The control circuit is connected to the parallel H-bridge circuit; and the control circuit applies any of the above-mentioned current balancing methods.

[0294] Fig. 20 FIG. 1 is an internal structure diagram of a computer device in an embodiment. In an exemplary embodiment, a computer device is provided. The computer device may be a server. The internal structure diagram thereof may be as shown in FIG. Fig. 20 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store relevant data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a current balancing method is implemented.

[0295] Those skilled in the art will understand that Fig. 20 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0296] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0297] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0298] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0299] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present 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. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0300] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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.

[0301] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A current balancing method, characterized in that: Applied to a parallel H-bridge circuit, the parallel H-bridge circuit includes a plurality of mutually parallel single H-bridge units, the single H-bridge units include a plurality of switch elements, the method includes: Determining the expected state of the parallel H-bridge circuit at the next moment; Determine the target state of each of the single H-bridge units at the next moment according to the bridge arm current of the parallel H-bridge circuit, the average current of each of the single H-bridge units at the current moment, and the rated current of the switch element; According to the desired state and each of the target states, controlling the working state of each switch element in each of the single H-bridge units so that the difference between the average currents of each of the single H-bridge units at the next moment is less than a preset difference; Determining the target state of each of the single H-bridge units at the next moment according to the bridge arm current of the parallel H-bridge circuit, the average current of each of the single H-bridge units at the current moment, and the rated current of the switch element includes: Determining a target number of single H-bridge units in a first state in the parallel H-bridge circuit according to the bridge arm current and the rated current; the first state indicates that the single H-bridge unit is turned on and current exists; The target states are determined according to the target quantity and the priority order of each of the monomer H-bridge units; and each of the priority orders is related to the average current of each of the monomer H-bridge units at the current moment.

2. The method according to claim 1, characterized in that Determining each of the target states according to the target quantity and the priority order of each of the monomer H-bridge units includes: Determining the priority order according to the average current of each of the monomer H-bridge units at the current moment; For each of the monomer H-bridge units, determining a difference between the target number and a priority order of the monomer H-bridge unit; Based on the difference and the sign function, a target state of the monomeric H-bridge unit is determined.

3. The method according to claim 1, characterized in that The step of determining a target number of single H-bridge units in the first state in the parallel H-bridge circuit according to the bridge arm current and the rated current includes: Determining a quotient between the bridge arm current and the rated current; The target quantity is obtained by rounding up the quotient.

4. The method according to any one of claims 1 to 3, characterized in that: The controlling the working state of each switch element in each of the monomer H-bridge units according to the expected state and each of the target states includes: In the case where the stop condition is not met, determining the working state of each switch element in the monomer H-bridge unit according to the desired state and the target state of the monomer H-bridge unit; the stop condition is used to determine whether all the monomer H-bridge units in the parallel H-bridge circuit have been traversed; When the stop condition is met, each of the switch elements is controlled according to the working state of each switch element in each of the single H-bridge units.

5. The method according to claim 4, characterized in that The step of determining the working state of each switch element in the monomer H-bridge unit according to the expected state and the target state of the monomer H-bridge unit includes: If the desired state is a positive voltage state, and the target state of the single H-bridge unit is a first state, determining that the working state of the switch elements located at the upper left bridge arm and the lower right bridge arm in the single H-bridge unit is an off state, and the working state of the switch elements located at the lower left bridge arm and the upper right bridge arm in the single H-bridge unit is an on state; If the desired state is the positive voltage state, and the target state of the monomer H-bridge unit is the second state or the third state, it is determined that the working state of each switch element in the monomer H-bridge unit is the cut-off state; the second state indicates that the monomer H-bridge unit is not turned on or is turned on but there is no current; the third state indicates that the monomer H-bridge unit is not turned on.

6. The method according to claim 4, characterized in that The step of determining the working state of each switch element in the monomer H-bridge unit according to the expected state and the target state of the monomer H-bridge unit includes: If the desired state is a negative voltage state, and the target state of the single H-bridge unit is a first state, determining that the working state of the switch elements located at the lower left bridge arm and the upper right bridge arm in the single H-bridge unit is an off state, and the working state of the switch elements located at the upper left bridge arm and the lower right bridge arm in the single H-bridge unit is an on state; If the desired state is the negative voltage state, and the target state of the single H-bridge unit is the second state or the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

7. The method according to claim 4, characterized in that The left bridge arm of any one of the monomer H-bridge units is connected to the first energy storage unit, and the right bridge arm of any one of the monomer H-bridge units is connected to the second energy storage unit; the working state of each switch element in the monomer H-bridge unit is determined according to the desired state and the target state of the monomer H-bridge unit, including: If the desired state is a zero voltage state, obtaining a first voltage of the first energy storage unit and a second voltage of the second energy storage unit; The working state of each switch element in the single H-bridge unit is determined according to the bridge arm current of the parallel H-bridge circuit, the first voltage, the second voltage and the target state of the single H-bridge unit.

8. The method according to claim 7, characterized in that The determining the working state of each switch element in the single H-bridge unit according to the bridge arm current of the parallel H-bridge circuit, the first voltage, the second voltage and the target state of the single H-bridge unit includes: If the bridge arm current is greater than zero, and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the first state, it is determined that the working state of the switch element located in the upper left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit other than the switch element located in the upper left bridge arm is the off state; If the bridge arm current is greater than zero, and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the second state, it is determined that the working state of the switch element located in the lower right bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower right bridge arm is the off state; If the bridge arm current is greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

9. The method according to claim 7, characterized in that: The determining the working state of each switch element in the single H-bridge unit according to the bridge arm current of the parallel H-bridge circuit, the first voltage, the second voltage and the target state of the single H-bridge unit includes: If the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the first state, it is determined that the working state of the switch element located in the lower right bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower right bridge arm is the off state; If the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the second state, it is determined that the working state of the switch element located in the upper left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit other than the switch element located in the upper left bridge arm is the off state; If the bridge arm current is greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

10. The method according to claim 7, characterized in that The determining the working state of each switch element in the single H-bridge unit according to the bridge arm current of the parallel H-bridge circuit, the first voltage, the second voltage and the target state of the single H-bridge unit includes: If the bridge arm current is not greater than zero, and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the first state, it is determined that the working state of the switch element located in the upper right bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the upper right bridge arm is the off state; If the bridge arm current is not greater than zero, and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the second state, it is determined that the working state of the switch element located in the lower left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the lower left bridge arm is the off state; If the bridge arm current is not greater than zero and the first voltage is greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

11. The method according to claim 7, characterized in that The determining the working state of each switch element in the single H-bridge unit according to the bridge arm current of the parallel H-bridge circuit, the first voltage, the second voltage and the target state of the single H-bridge unit includes: If the bridge arm current is not greater than zero, and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the first state, it is determined that the working state of the switch element located in the lower left bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit other than the lower left bridge arm is the off state; If the bridge arm current is not greater than zero, and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the second state, it is determined that the working state of the switch element located in the upper right bridge arm of the single H-bridge unit is the on state, and the working state of the switch element in the single H-bridge unit except the switch element located in the upper right bridge arm is the off state; If the bridge arm current is not greater than zero and the first voltage is not greater than the second voltage, then when the target state of the single H-bridge unit is the third state, it is determined that the working state of each switch element in the single H-bridge unit is the cut-off state.

12. A current balancing device, characterized in that: Applied to a parallel H-bridge circuit, the parallel H-bridge circuit includes a plurality of mutually parallel single H-bridge units, the single H-bridge units include a plurality of switch elements, and the device includes: A first determination module, used to determine the expected state of the parallel H-bridge circuit at the next moment; A second determination module is used to determine the target state of each of the monomer H-bridge units at the next moment according to the bridge arm current of the parallel H-bridge circuit, the average current of each of the monomer H-bridge units at the current moment, and the rated current of the switch element; A third determination module, configured to control the working state of each switch element in each of the monomer H-bridge units according to the expected state and each of the target states, so that the difference between the average currents of each of the monomer H-bridge units at the next moment is less than a preset difference; The second determining module comprises: A first determining unit, configured to determine a target number of single H-bridge units in a first state in the parallel H-bridge circuit according to the bridge arm current and the rated current; the first state indicates that the single H-bridge unit is turned on and current exists; The second determining unit is used to determine each of the target states according to the target quantity and the priority order of each of the monomer H-bridge units; each of the priority orders is related to the average current of each of the monomer H-bridge units at a current moment.

13. A parallel H-bridge circuit, characterized in that: The parallel H-bridge circuit includes a plurality of mutually parallel single H-bridge units, each of which includes a plurality of switch elements; the parallel H-bridge circuit applies the current balancing method as described in any one of claims 1 to 11.

14. An energy storage system, characterized in that: The energy storage system comprises a control circuit and a parallel H-bridge circuit as claimed in claim 13; the control circuit is connected to the parallel H-bridge circuit; The control circuit applies the current balancing method according to any one of claims 1 to 11.

15. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 11 are implemented.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 11 are implemented.

17. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 11 are implemented.

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