Power converter and control method thereof, energy storage conversion circuit and energy storage system

Abstract

The invention discloses a power converter and an energy storage system. According to the power converter, a first DC-DC conversion circuit is connected with a first interface circuit and is used for carrying out power conversion on direct current transmitted by the first interface circuit; the DC-AC conversion circuit comprises a DC end and an AC end; wherein a direct current switch is connected between the output end of the first DCDC conversion circuit and the direct current end, and no direct current switch is connected between the input end of the first DCDC conversion circuit and the first interface circuit. According to the mode, the first DCDC conversion circuit and the first interface circuit can be arranged on the same circuit board on the premise of ensuring that the connection state of the optical storage assembly and the power converter can be controlled in time, so that the number of circuit boards in the power converter can be reduced; therefore, the layout complexity of the power converter can be reduced, and the manufacturing and layout cost can be reduced.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and more specifically, to a power converter and its control method, an energy storage conversion circuit and an energy storage system. Background Technology

[0002] Power converters can be used to convert the direct current (DC) generated by photovoltaic energy storage components into alternating current (AC). Most power converters employ a two-stage architecture. Specifically, the two-stage architecture consists of a DC-DC converter and a DC-AC converter.

[0003] DC-DC converter circuits are typically configured to connect to photovoltaic and energy storage components (such as photovoltaic modules or energy storage batteries) via interface circuits to improve the overall performance, reliability, and safety of the power converter. Summary of the Invention

[0004] This application provides a power converter and its control method, an energy storage conversion circuit, and an energy storage system. The various aspects involved in this application's embodiments are described below.

[0005] In a first aspect, a power converter is provided, comprising: a first DC-to-DC converter circuit connected to a first interface circuit, wherein the first DC-to-DC converter circuit is used to convert DC power transmitted through the first interface circuit; and a DC-to-AC converter circuit, comprising a DC terminal and an AC terminal, wherein the DC terminal is connected to the output terminal of the first DC-to-DC converter circuit via a DC bus, and the AC terminal is used to connect to an AC circuit, wherein the DC-to-AC converter circuit is used to convert the DC power output by the first DC-to-DC converter circuit into AC power; wherein a DC switch is connected between the output terminal of the first DC-to-DC converter circuit and the DC terminal, and no DC switch is connected between the input terminal of the first DC-to-DC converter circuit and the first interface circuit.

[0006] In one possible implementation, the DC switch includes: a first DC switch and a second DC switch; the output terminal of the first DC-DC converter circuit includes a positive output terminal and a negative output terminal; the DC bus includes a positive DC bus and a negative DC bus; the DC terminal is connected to the positive output terminal and the negative output terminal through the positive DC bus and the negative DC bus; the first DC switch is connected between the positive output terminal and the DC terminal of the first DC-DC converter circuit; and the second DC switch is connected between the negative output terminal and the DC terminal of the first DC-DC converter circuit.

[0007] In one possible implementation, there are multiple first DC-DC converter circuits, and at least one first DC switch is connected between the positive output terminal of the multiple first DC-DC converter circuits and the DC terminal, and at least one second DC switch is connected between the negative output terminal of the multiple first DC-DC converter circuits and the DC terminal.

[0008] In one possible implementation, the two ends of the at least one first DC switch are respectively connected to the positive output terminal of the plurality of first DC-DC converter circuits and the positive DC bus, and the two ends of the at least one second DC switch are respectively connected to the negative output terminal of the plurality of first DC-DC converter circuits and the negative DC bus.

[0009] As one possible implementation, at least a portion of the positive output terminals of the plurality of first DC-DC converter circuits share a first DC switch.

[0010] As one possible implementation, at least a portion of the first DC-DC converter circuits in the plurality of first DC-DC converter circuits share a second DC switch at their negative output terminals.

[0011] In one possible implementation, the number of the at least one first DC switch is one, the number of the at least one second DC switch is one, a bus capacitor is connected between the positive DC bus and the negative DC bus, the two ends of the first DC switch are respectively connected to one end of the bus capacitor and the DC terminal, and the two ends of the second DC switch are respectively connected to the other end of the bus capacitor and the DC terminal.

[0012] As one possible implementation, at least a portion of the first DC switch and at least a portion of the second DC switch are the same multiplexer.

[0013] As one possible implementation, the power converter also includes a second DC-DC converter circuit, wherein a DC switch is connected between the input terminal of the second DC-DC converter circuit and the second interface circuit, and no DC switch is connected between the output terminal of the second DC-DC converter circuit and the DC terminal.

[0014] As one possible implementation, the power converter further includes a control circuit connected to the DC switch, the control circuit being configured to disconnect the DC switch in response to an abnormal control of the power converter.

[0015] In a second aspect, a power conversion circuit is provided, comprising: a first interface circuit; a first DC-to-DC converter circuit connected to the first interface circuit, wherein the first DC-to-DC converter circuit is used to convert the DC power transmitted through the first interface circuit; and a DC-to-AC converter circuit, comprising a DC terminal and an AC terminal, wherein the DC terminal is connected to the output terminal of the first DC-to-DC converter circuit via a DC bus, and the AC terminal is used to connect to an AC circuit, wherein the DC-to-AC converter circuit is used to convert the DC power output by the first DC-to-DC converter circuit into AC power; wherein a DC switch is connected between the output terminal of the first DC-to-DC converter circuit and the DC terminal, and no DC switch is connected between the input terminal of the first DC-to-DC converter circuit and the first interface circuit.

[0016] Thirdly, a control method for a power converter is provided. The power converter includes a first DC-to-DC converter circuit and a DC-to-AC converter circuit. The first DC-to-DC converter circuit is connected to a first interface circuit for power conversion of DC power transmitted through the first interface circuit. The DC-to-AC converter circuit includes a DC terminal and an AC terminal. The DC terminal is connected to the output terminals of the plurality of first DC-to-DC converter circuits via a DC bus. The AC terminal is used to connect to an AC circuit. The DC-to-AC converter circuit is used to convert the DC power output by the first DC-to-DC converter circuit into AC power. A DC switch is connected between the output terminal of the first DC-to-DC converter circuit and the DC terminal. The method includes: controlling the DC switch to disconnect in response to an abnormality in the power converter.

[0017] In one possible implementation, the DC switch includes: a first DC switch and a second DC switch; the output terminal of the first DC-DC converter circuit includes a positive output terminal and a negative output terminal; the DC bus includes a positive DC bus and a negative DC bus; the DC terminal is connected to the positive output terminal and the negative output terminal through the positive DC bus and the negative DC bus; the first DC switch is connected between the positive output terminal and the DC terminal of the first DC-DC converter circuit; and the second DC switch is connected between the negative output terminal and the DC terminal of the first DC-DC converter circuit. The step of controlling the DC switch to open in response to a power converter malfunction includes: controlling the first DC switch and / or the second DC switch to open in response to a power converter malfunction.

[0018] In one possible implementation, there are multiple first DC-DC converter circuits, and at least one first DC switch is connected between the positive output terminal of the multiple first DC-DC converter circuits and the DC terminal, and at least one second DC switch is connected between the negative output terminal of the multiple first DC-DC converter circuits and the DC terminal; in response to an abnormal control of the power converter to disconnect the first DC switch and / or the second DC switch, the method includes: in response to an abnormal control of the power converter to disconnect at least a portion of the first DC switch and / or at least a portion of the second DC switch.

[0019] As one possible implementation, the power converter's anomalies include one or more of the following: DC current anomaly, DC leakage current anomaly, AC current anomaly, AC leakage current anomaly, DC voltage anomaly, temperature anomaly, and operational anomaly.

[0020] Fourthly, an energy storage system is provided, including a power converter as described in the first aspect.

[0021] The power converter provided in this application embodiment places the DC switch between the output terminal of the first DC-DC converter circuit and the DC terminal of the DC-AC converter circuit, and eliminates the DC switch between the input terminal of the first DC-DC converter circuit and the first interface circuit. This approach, while ensuring timely control of the connection status between the optical storage component and the power converter, allows the first DC-DC converter circuit and the first interface circuit to be placed on the same circuit board. This reduces the number of circuit boards in the power converter, thereby reducing the layout complexity and manufacturing and layout costs. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an energy storage system in related technologies.

[0023] Figure 2 This is a schematic diagram of the structure of an energy storage system provided in an embodiment of this application.

[0024] Figure 3 This is a schematic diagram of the structure of an energy storage system provided in an embodiment of this application.

[0025] Figure 4 This is a schematic diagram of the structure of an energy storage system provided in another embodiment of this application.

[0026] Figure 5 This is a schematic diagram of the structure of an energy storage system provided in another embodiment of this application.

[0027] Figure 6 This is a schematic diagram of the structure of an energy storage system provided in another embodiment of this application.

[0028] Figure 7 This is a schematic diagram of the structure of an energy storage system provided in another embodiment of this application.

[0029] Figure 8 This is a schematic diagram of the structure of an energy storage system provided in another embodiment of this application.

[0030] Figure 9 This is a schematic diagram of the structure of an energy storage system provided in another embodiment of this application. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application should fall within the scope of protection of the present application.

[0032] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] To facilitate understanding of this application, firstly, in conjunction with... Figure 1 The existing energy storage system 100 and its power converter 120 are described. For example... Figure 1 As shown, the energy storage system 100 includes a photovoltaic-storage module 110 and a power converter 120.

[0034] The photovoltaic-storage module 110 can also be referred to as a DC power supply. The number of photovoltaic-storage modules 110 can be multiple, and each photovoltaic-storage module (e.g., photovoltaic-storage module 111, 112, or 113) can be one or more photovoltaic modules connected in series or parallel, or each photovoltaic-storage module (e.g., photovoltaic-storage module 111, 112, or 113) can be an energy storage battery. The photovoltaic-storage module 110 is used to generate direct current.

[0035] The power converter 120 includes an interface circuit 121, multiple DC-DC conversion circuits 122, and a DC-AC conversion circuit 123.

[0036] Interface circuit 121 is located between photovoltaic energy storage module 110 and DC-DC converter circuit 122. Interface circuit 121 serves as the interface for power converter 120 to connect to photovoltaic energy storage module 110. It can undertake the task of energy transmission adaptation and ensure the safety and stability of energy storage system through protection mechanisms.

[0037] Each of the multiple DC-DC converter circuits 122 has its input terminal connected to the optical storage component 110 via a corresponding interface circuit to perform power conversion on the DC power generated by the optical storage component 110. For example, the DC-DC converter circuit 122 is connected to the optical storage component 111 via interface circuit 121 to perform power conversion on the DC power generated by the optical storage component 111.

[0038] DC-AC converter circuit 123 is used to convert the direct current output from multiple DC-DC converter circuits 122 into alternating current. DC-AC converter circuit 123 includes a DC terminal and an AC terminal. The DC terminal is connected to the output terminals of the multiple DC-DC converter circuits 122 via a DC bus, and the AC terminal is used to connect to an AC circuit. The AC circuit can be, for example, an AC load, an AC power grid, other power converters, or a generator.

[0039] It should be noted that, Figure 1 The example used here is that each of the three components (optical storage module, interface circuit, and DC-DC converter circuit) is three in number.

[0040] For details, see Figure 1 A DC switch 124 is installed between the input terminal and the interface circuit of each DC-DC converter. The DC switch 124 is used to disconnect the photovoltaic storage component from the power converter when the power converter malfunctions or needs maintenance. However, this arrangement results in a complex layout and high cost.

[0041] The reason for this is that related technologies use DC switches to separate the interface circuit and the DC-DC conversion circuit, requiring the interface circuit and the DC-DC conversion circuit to be integrated on two separate circuit boards. Specifically, as... Figure 1 As shown, when there are multiple interface circuits and DC-DC conversion circuits, a large number of circuit boards are required, and these circuit boards need to be installed in the power converter, which leads to a complex layout and high cost of the power converter.

[0042] In view of this, the present application provides a power converter that places a DC switch between the output terminal of the first DC-DC converter circuit and the DC terminal of the DC-AC converter circuit, and eliminates the DC switch between the input terminal of the first DC-DC converter circuit and the first interface circuit. This approach can facilitate the placement of the first DC-DC converter circuit and the first interface circuit on the same circuit board while ensuring timely control of the connection status between the optical storage component and the power converter. This reduces the number of circuit boards in the power converter, thereby reducing the layout complexity of the power converter and reducing manufacturing and layout costs.

[0043] To facilitate understanding of this application, the following is combined with... Figures 2-9 The power converter and energy storage system including the power converter provided in the embodiments of this application will be described in more detail.

[0044] like Figures 2-9 As shown, the energy storage system 200 provided in this embodiment includes a photovoltaic energy storage module 210 and a power converter 220. The photovoltaic energy storage module 210 is the same as the photovoltaic energy storage module 110 described above, and will not be described again here.

[0045] See details Figure 2 The power converter 220 includes a first interface circuit 221, a first DC-DC conversion circuit 222, and a DC-AC conversion circuit 223.

[0046] The first interface circuit 221 is used to connect the DC power generated by the multiple photovoltaic storage components 210 into the power converter 220. The first interface circuit may include one or more of the following circuits and devices: current detection, electromagnetic compatibility (EMC) ring, EMC circuit, bus circuit, or surge protector.

[0047] The input terminal of the first DC-DC converter circuit 222 (hereinafter referred to as the first DC-DC converter 222) is connected to the first interface circuit 221. The first DC-DC converter circuit 222 is used to perform power conversion on the DC power transmitted through the first interface circuit 221. For example, the first DC-DC converter circuit 222 is used to convert the DC power transmitted through the first interface circuit 221 from a first power to a second power.

[0048] This application does not impose specific limitations on the circuit structure of the first DC-DC converter 222. For example, the first DC-DC converter 222 can be a unidirectional or bidirectional power transmission converter such as Boost, Buck, or Buckboost.

[0049] The DC-AC converter circuit 223 (DCAC223 for short) includes a DC terminal and an AC terminal. The DC terminal is connected to the output terminal of the first DC-DC converter circuit 222 via a DC bus, and the AC terminal is used to connect to an AC circuit. The DC-AC converter circuit 223 is used to convert the DC power output from the output terminal of the first DC-DC converter circuit 222 into AC power. For example, the DC-AC converter circuit 223 can be a single-phase inverter, a three-phase inverter, etc.

[0050] Among them, such as Figure 1 As shown, a DC switch 224 is connected between the output terminal of the first DC-DC converter circuit 222 and the DC terminal of the DC-AC converter circuit 223, and no DC switch is connected between the input terminal of the first DC-DC converter circuit 222 and the first interface circuit 221.

[0051] This application does not specifically limit the type of DC switch 224. For example, DC switch 224 can be a mechanical switch with motor control or electromagnetic control, or DC switch 224 can be a power semiconductor switch, or DC switch 224 can be a composite switch formed by series and parallel connection of mechanical switch and power semiconductor switch.

[0052] By placing the DC switch in the power converter between the output terminal of the first DC-DC converter circuit and the DC terminal of the DC-AC converter circuit, and eliminating the DC switch between the input terminal of the first DC-DC converter circuit and the first interface circuit, it is possible to place the first DC-DC converter circuit and the first interface circuit on the same circuit board while ensuring timely control of the connection status between the optical storage component and the power converter. This reduces the number of circuit boards in the power converter, thereby reducing the layout complexity of the power converter and reducing manufacturing and layout costs.

[0053] To improve the safety level of the power converter, in some embodiments, such as Figure 3 As shown, the DC switch 224 includes a first DC switch 224+ and a second DC switch 224-. The first DC switch 224+ is used to control the positive output of the first DC-DC converter circuit 222, and the second DC switch 224- is used to control the negative output of the first DC-DC converter circuit 222.

[0054] Specifically, such as Figure 3As shown, the output terminals of the first DC-DC converter circuit include a positive output terminal (+) and a negative output terminal (-). The DC bus includes a positive DC bus (bus+) and a negative DC bus (bus-). The DC terminal of the DC-AC converter circuit 223 is connected to the positive output terminal (+) and the negative output terminal (-) of the first DC-DC converter circuit 222 via the positive DC bus (bus+) and the negative DC bus (bus-). A first DC switch 224+ is connected between the positive output terminal (+) of the first DC-DC converter circuit 222 and the DC terminal of the DC-AC converter circuit 223. A second DC switch 224- is connected between the negative output terminal (-) of the first DC-DC converter circuit 222 and the DC terminal of the DC-AC converter circuit 223.

[0055] By configuring the DC switch 224 on the output side of the first DC-DC converter circuit 222 to include a first DC switch 224+ for controlling the positive output and a second DC switch 224- for controlling the negative output (i.e., a dual-switch configuration), when it is necessary to disconnect the power converter from the photovoltaic storage component, the positive and negative terminals can be disconnected simultaneously by disconnecting the first DC switch 224+ and the second DC switch 224-, thereby ensuring that the circuit is completely de-energized. At the same time, the dual-switch configuration can also avoid equipment damage caused by misoperation, effectively improving the safety level of the power converter and the system stability.

[0056] The embodiments of this application do not impose a specific limit on the number of the first DC-DC conversion circuits 222.

[0057] For example, such as Figure 2 and Figure 3 As shown, the number of first DC-DC converter circuits 222 can be one.

[0058] For example, such as Figure 4 and Figure 8 As shown, there can be multiple first DC-DC converter circuits 222.

[0059] It should be noted that, Figures 4-8 The example shown below uses three first DC-DC conversion circuits 222. Based on this, the number of first interface circuits 221 and optical storage components 210 are both three. For distinction, as... Figures 4-8 As shown, the three first DC-DC conversion circuits 222 correspond to three optical storage components, namely 211, 212 and 213.

[0060] Of course, this is understandable. Figures 4-8 The number of the first DC-DC converter circuits 222 shown in the examples is merely illustrative. This application does not impose a specific limit on the number of the first DC-DC converter circuits 222, which can be set as needed.

[0061] Given that there are multiple first DC-DC conversion circuits 222, in order to freely control the connection status of these multiple first DC-DC conversion circuits 222 with the corresponding multiple optical storage components, such as Figures 4-8 As shown, at least one first DC switch 224+ is connected between the positive output terminal of the plurality of first DC-DC converter circuits 222 and the DC terminal of DC-AC converter circuit 223, and at least one second DC switch 224- is connected between the negative output terminal of the plurality of first DC-DC converter circuits 222 and the DC terminal of DC-AC converter circuit 223.

[0062] This application does not specifically limit the number of at least one first DC switch or at least one second DC switch. The number of at least one first DC switch 224+ or at least one second DC switch 224- can be the same as or different from the number of first DC-DC converter circuits 222. Specifically, the number of at least one first DC switch 224+ or at least one second DC switch 224- should be less than or equal to the number of first DC-DC converter circuits. Furthermore, the number of at least one first DC switch 224+ and at least one second DC switch 224- can also be the same as or different. This can be related to the placement and / or arrangement of the first DC switches 224+ and second DC switches 224- as described below.

[0063] At least one first DC switch 224+ and / or at least one second DC switch 224- mentioned in the embodiments of this application may have an automatic disconnection function. For example, in the event of a special circumstance, one or more corresponding first DC switches 224+ and / or one or more second DC switches 224- may be automatically disconnected to isolate the DC and AC terminals of the power converter. Special circumstances include, for example, the detection of an abnormality in the photoelectric storage component 210 or the first interface circuit 221 corresponding to the input terminal of one or more first DC-DC converter circuits 222; an abnormality in the load or power grid at the AC terminal of the DC-AC converter circuit 223; or a short circuit or other abnormality in the first DC-DC converter circuit or the DC-AC converter circuit 223.

[0064] At least one first DC switch 224+ and / or at least one second DC switch 224- mentioned in the embodiments of this application may have an automatic closing function. For example, in some situations, one or more corresponding first DC switches 224+ and / or one or more second DC switches 224- may automatically close to restore normal operation of the power converter. Some situations include: detecting and eliminating an abnormality in the photoelectric storage component or the first interface circuit at the input of the first DC-DC converter circuit; detecting and eliminating an abnormality in the load or AC power grid at the AC end of the DC-AC converter circuit 223; and eliminating an abnormality in the first DC-DC converter circuit or the DC-AC converter circuit 223.

[0065] In this embodiment of the application, the placement of at least one first DC switch 224+ and at least one second DC switch 224- is not specifically limited. As long as at least one first DC switch 224+ is connected between the positive output terminal of the plurality of first DC-DC converter circuits and the DC terminal of the DC-AC converter circuit 223, and at least one second DC switch 224- is connected between the negative output terminal of the plurality of first DC-DC converter circuits and the DC terminal of the DC-AC converter circuit 223, it is acceptable.

[0066] In one implementation, at least one first DC switch 224+ is directly connected to the positive output terminal of the plurality of first DC-DC converter circuits 221, and at least one second DC switch 224- is directly connected to the negative output terminal of the plurality of first DC-DC converter circuits 221. Specifically, as shown... Figures 4-7 As shown, at least one first DC switch 224+ is connected to the positive output terminal and the positive DC bus bus+ of a plurality of first DC-DC converter circuits 221, respectively; at least one second DC switch 224- is connected to the negative output terminal and the negative DC bus bus- of a plurality of first DC-DC converter circuits 221, respectively. A bus capacitor C is connected between the positive DC bus bus+ and the negative DC bus bus-.

[0067] By directly setting at least one first DC switch 224+ at the positive output terminal of multiple first DC-DC converter circuits 221 and directly setting at least one second DC switch 224- at the negative output terminal of multiple first DC-DC converter circuits 221, the outputs of multiple first DC-DC converter circuits 221 can be controlled separately. This allows for targeted power-off control or output restoration control when an abnormality occurs or maintenance is required, improving the control flexibility of the power converter.

[0068] This application does not specify the number of at least one first DC switch 224+ directly connected between the positive output terminal and the positive DC bus bus+ of the plurality of first DC-DC converter circuits 221 and / or the number of at least one second DC switch 224+ connected between the negative output terminal and the negative DC bus bus- of the plurality of first DC-DC converter circuits 221.

[0069] In some embodiments, the number of at least one first DC switch 224+ or the number of at least one second DC switch 224- is the same as the number of multiple first DC-DC converter circuits, for example, as shown below. Figure 4 As shown.

[0070] In other embodiments, the number of at least one first DC switch 224+ or at least one second DC switch 224- is less than the number of a plurality of first DC-DC converter circuits, wherein the number of at least one first DC switch 224+ and the number of at least one second DC switch 224- may be the same or different.

[0071] For example, Figure 5 The number of first DC switches 224+ is 2, the number of first DC-DC converter circuits 222 is 3, and the number of second DC switches 224- is 3.

[0072] For example, Figure 6 The number of second DC switches 224- is 2, the number of first DC-DC converter circuits 222 is 3, and the number of first DC switches 224+ is 3.

[0073] For example, Figure 7 The number of first DC switches 224+ is 1, the number of second DC switches 224+ is 1, and the number of first DC-DC converter circuits 222 is 3.

[0074] To reduce the number of first DC switches 224+, thus reducing costs. As an example, such as... Figure 5 and Figure 7 As shown, at least a portion of the first DC-DC converter circuits 222 share a first DC switch 224+ at their positive output terminals. That is, at least a portion of the positive input terminals of the first DC-DC converter circuits 222 are connected together to the same first DC switch 224+.

[0075] For example, such as Figure 5 As shown, the positive input terminals of the first two DC-DC converter circuits 222 in the first DC-DC converter circuit 222 are connected together to the same first DC switch 224+. Figure 7As shown, the positive input terminals of the first DC-DC converter circuit 222 are all connected together to the same first DC switch 224+.

[0076] By sharing a first DC switch 224+ with the positive output terminals of at least a portion of the multiple first DC-DC converter circuits 222, the number of at least one first DC switch 224+ can be reduced so that the number of at least one first DC switch 224+ is less than the number of at least one first DC-DC converter circuit, thereby reducing the switching cost.

[0077] To reduce the number of second DC switches 224-, thus reducing costs. As another example, such as... Figure 6 and Figure 7 At least a portion of the first DC-DC converter circuits 222 share a second DC switch 224- at their negative output terminals. That is, at least a portion of the negative input terminals of the first DC-DC converter circuits 222 are connected together to the same second DC switch 224-.

[0078] For example, such as Figure 6 As shown, the negative input terminals of the first two DC-DC converter circuits 222 in the first DC-DC converter circuit 222 are connected together to the same second DC switch 224-. For example, as... Figure 7 As shown, the negative input terminals of the first DC-DC converter circuit are all connected together to the same second DC switch 224-.

[0079] By sharing a second DC switch 224- with the negative output terminals of at least a portion of the multiple first DC-DC converter circuits 222, the number of at least one second DC switch 224- can be reduced so that the number of at least one second DC switch 224- is less than the number of multiple first DC-DC converter circuits, thereby reducing the switching cost.

[0080] As another example, at least some of the first DC-DC converter circuits 222 share a first DC switch 224+ for their positive outputs and a second DC switch 224- for their negative outputs. That is, the positive inputs of at least some of the first DC-DC converter circuits 222 are connected together to the same first DC switch 224+, and the negative inputs of at least some of the first DC-DC converter circuits 222 are connected together to the same second DC switch 224-.

[0081] For example, such as Figure 7As shown, the positive input terminals of the three first DC-DC converter circuits 222 are all connected together to the same first DC switch 224+, and the negative input terminals of the three first DC-DC converter circuits 222 are all connected together to the same second DC switch 224-.

[0082] This setting allows for a further reduction in the number of switches, thereby reducing switch costs.

[0083] Wherein, at least a portion of the first DC-DC conversion circuit is part or all of the plurality of first DC-DC conversion circuits 222. For example, as Figure 5 and Figure 6 As shown, at least a portion of the first DC-DC converter circuit is a part of a plurality of first DC-DC converter circuits. Furthermore, at least a portion of the first DC-DC converter circuit sharing the first DC switch 224+ and at least a portion of the first DC-DC converter circuit sharing the second DC switch 224- can be different or the same. For example, as... Figure 7 As shown, at least a portion of the first DC-DC converter circuits are all of the multiple first DC-DC converter circuits.

[0084] As another implementation method, such as Figure 8 As shown, a bus capacitor C is connected between the positive DC bus bus+ and the negative DC bus bus-. There is at least one first DC switch 224+ and at least one second DC switch 224-. The two ends of the first DC switch 224+ are respectively connected to one end of the bus capacitor C and the DC terminal of the DC-AC conversion circuit 223. The two ends of the second DC switch 224- are respectively connected to the other end of the bus capacitor C and the DC terminal of the DC-AC conversion circuit 223.

[0085] By setting a first DC switch 224+ and a second DC switch 224- at the two ends of the bus capacitor C respectively, the on / off control of multiple first DC-DC converter circuits 222 can be achieved with only 2 switches, greatly reducing the cost of switches.

[0086] To further reduce the control cost of the switch, in some embodiments, such as Figures 4-8 As shown, at least a portion of the first DC switch 224+ and at least a portion of the second DC switch 224- are the same pole disconnect switch (i.e., Figures 4-8The first DC switch 224+ and the second DC switch 224- connected by dashed lines belong to the same pole isolation switch. At least a portion of the first DC switch 224+ can be part or all of at least one first DC switch 224+. At least a portion of the second DC switch 224- can be part or all of at least one first DC switch 224+. At least a portion of the first DC switch 224+ and at least a portion of the second DC switch 224- should correspond to the same first DC-DC converter circuit 222.

[0087] By multiplexing multiple different DC switches into the same multiplexer, the control efficiency of the DC switch 224 in the power converter can be improved and the control cost of the switch can be reduced.

[0088] In some embodiments, the power converter may include a second DC-DC converter 225 (hereinafter referred to as the second DC-DC converter 225) in addition to one or more first DC-DC converter circuits 222. Specifically, a DC switch 224 is connected between the input terminal of the second DC-DC converter 225 and the second interface circuit 226, and no DC switch is connected between the output terminal of the second DC-DC converter 225 and the DC terminal of the DC-AC converter 223. It should be noted that the second DC-DC converter 225 has the same or similar function and structure as the first DC-DC converter 222, only the way the DC switch is connected is different. The second interface circuit 226 has the same or similar function and structure as the first interface circuit 221, only the way the DC switch is connected is different.

[0089] For example, such as Figure 9 As shown, the power converter 220 includes two first DC-DC converter circuits 222 and one second DC-DC converter circuit 225. The output terminals of the two first DC-DC converter circuits 222 are connected to the DC terminal of the DC-DC converter circuit 223 via a first DC switch 224+ and a second DC switch 224-, respectively. No DC switch is connected between the input terminals of the two first DC-DC converter circuits 222 and the corresponding two first interface circuits 221. The input terminal of the one second DC-DC converter circuit 225 is connected to the corresponding second interface circuit 226 via a first DC switch 224+ and a second DC switch 224-. No DC switch is connected between the output terminal of the one second DC-DC converter circuit 225 and the DC terminal of the DC-DC converter circuit 223.

[0090] In some embodiments, such as Figure 9 As shown, at least some of the DC switches 224 connected to the output terminals of the multiple first DC-DC converter circuits 222 and / or connected to the input terminals of the second DC-DC converter circuit 225 can share a single multiplexer switch.

[0091] By connecting a DC switch 224 to the output of the first DC-DC converter 222 inside the power converter and a DC switch 224 to the input of the second DC-DC converter 225, the internal space of the power converter can be fully utilized for flexible layout, further improving the internal space utilization of the power converter and reducing costs.

[0092] As mentioned above, some or all of the DC switches described earlier may have automatic disconnection or automatic closing functions. In view of this, in some embodiments, the power converter further includes a control circuit. The control circuit is connected to the DC switch and is used to disconnect the DC switch in response to an abnormal control of the power converter. The control circuit may be, for example, a controller containing software programs or an analog circuit including logic decision circuitry.

[0093] In view of this, embodiments of this application also provide a control method for a power converter, which is used to control the power converter described above. In some embodiments, the power converter includes a first DC-to-DC converter circuit and a DC-to-AC converter circuit. The first DC-to-DC converter circuit is connected to a first interface circuit for power conversion of DC power transmitted through the first interface circuit. The DC-to-AC converter circuit includes a DC terminal and an AC terminal. The DC terminal is connected to the output terminals of multiple first DC-to-DC converter circuits via a DC bus, and the AC terminal is used to connect to an AC circuit. The DC-to-AC converter circuit is used to convert the DC power output by the first DC-to-DC converter circuit into AC power. A DC switch is connected between the output terminal and the DC terminal of the first DC-to-DC converter circuit. That is, the structure of the power converter 220 is as follows: Figure 2 As shown, in view of this, the control method of the power converter includes: controlling the DC switch to disconnect in response to a power converter malfunction.

[0094] In some embodiments, the DC switch includes: a first DC switch and a second DC switch; the output terminal of the first DC-DC converter circuit includes a positive output terminal and a negative output terminal; the DC bus includes a positive DC bus and a negative DC bus; the DC terminal is connected to the positive output terminal and the negative output terminal through the positive DC bus and the negative DC bus; the first DC switch is connected between the positive output terminal and the DC terminal of the first DC-DC converter circuit; and the second DC switch is connected between the negative output terminal and the DC terminal of the first DC-DC converter circuit. That is, the structure of the power converter is as follows: Figure 3 As shown, in view of this, the DC switch disconnection in response to a power converter malfunction includes: disconnecting the first DC switch and / or the second DC switch in response to a power converter malfunction.

[0095] In some embodiments, there are multiple first DC-DC converter circuits, and at least one first DC switch is connected between the positive output terminal and the DC terminal of each of the multiple first DC-DC converter circuits, and at least one second DC switch is connected between the negative output terminal and the DC terminal of each of the multiple first DC-DC converter circuits; that is, the structure of the power converter is as follows: Figures 4-9 As shown, in view of this, the response to a power converter malfunction controls the first DC switch and / or the second DC switch to disconnect, including: responding to a power converter malfunction controls at least a portion of the first DC switch and / or at least a portion of the second DC switch to disconnect.

[0096] This application does not specifically limit the power converter malfunction.

[0097] Power converter malfunctions include one or more of the following: DC current malfunction, DC leakage current malfunction, AC current malfunction, AC leakage current malfunction, DC voltage malfunction, temperature malfunction, and operational malfunction.

[0098] As an example, a power converter malfunction is characterized by an abnormal DC current or DC leakage current. Therefore, a current detection circuit can also be incorporated into the power converter. For instance, a current detection circuit may be installed between the input of at least one DC-DC converter circuit and the photovoltaic storage component, between the output of the DC-DC converter circuit and the connected DC switch, between the output of the DC-DC converter circuit and the DC-AC converter circuit, or internally within the DC-DC converter circuit. The current detection circuit may include a DC current detection circuit and / or a DC leakage current detection circuit, etc.

[0099] The control circuit can be connected to the current detection circuit to read the detection value. If the control circuit detects an abnormal current, it will automatically disconnect the DC switch. Abnormal currents include: forward overcurrent, reverse current, current oscillation, DC leakage current exceeding the standard, and excessive current differences between different circuits.

[0100] Automatic disconnection of DC switches includes: controlling at least one DC switch through which abnormal current flows to disconnect, controlling other switches linked to that switch to disconnect together, or controlling all switches to disconnect together. By automatically disconnecting DC switches, abnormal current can be eliminated, allowing the remaining circuitry of the power converter to operate normally or to shut down completely, thus ensuring system safety. Specifically, when DC leakage current exceeds the limit, the DC-DC input circuit with low DC insulation resistance is preferentially disconnected to reduce leakage current.

[0101] As another example, power converter malfunctions manifest as abnormal AC current or AC leakage current. Therefore, current detection circuits can also be incorporated into the power converter. For instance, a current detection circuit can be installed inside the DC-AC conversion circuit or between the AC terminal of the DC-AC conversion circuit and the AC circuit. The current detection circuit includes AC detection circuits and / or leakage current detection circuits, etc.

[0102] The control circuit can be connected to the current detection circuit to read the current detection value. If the control circuit detects an abnormal current, it will automatically disconnect the DC switch. Abnormal currents include: AC overcurrent, oscillation, excessive harmonics, and excessive leakage current.

[0103] The automatic disconnection operation of the DC switches includes: controlling at least one DC switch through which the abnormal current flows to disconnect to eliminate the current abnormality, or controlling other switches linked to that switch to disconnect together to reduce the current, or controlling all switches to disconnect together to reduce the current, thereby allowing the remaining circuits of the power converter that are not disconnected to operate normally (e.g., the remaining circuits can generate, charge, or generate reactive power normally), or completely shutting down, ensuring system safety. Specifically, when the leakage current exceeds the limit, the DC-DC input circuit with low DC insulation resistance is disconnected first to reduce the leakage current.

[0104] As another example, a power converter malfunction is a DC voltage malfunction. Therefore, a voltage sampling circuit can also be incorporated into the power converter. For example, a voltage sampling circuit can be installed at the input terminal of at least one DC-DC converter circuit, the output terminal of at least one DC-DC converter circuit, the DC bus, the DC terminal of a DC-AC converter circuit, or the AC terminal of a DC-AC converter circuit.

[0105] The control circuit can be connected to the voltage sampling circuit to read the detected values. If the control circuit detects an abnormal voltage, it will automatically disconnect the DC switch. Abnormal voltage conditions include: undervoltage, overvoltage, reverse voltage, sudden voltage changes, voltage oscillation, high voltage harmonics, and excessive voltage differences between different circuits.

[0106] The automatic disconnection operation of the DC switch includes: controlling at least one DC switch to disconnect due to abnormal voltage, or controlling other switches linked to the abnormal voltage switch to disconnect together, or controlling all switches to disconnect together, thereby eliminating the abnormal voltage, maintaining the normal operation of the remaining circuits of the power converter that are not disconnected, or completely shutting down the system, thus ensuring system safety.

[0107] As another example, a power converter malfunction is a temperature anomaly. Therefore, at least one temperature detection circuit is installed inside or on the casing of the power converter to detect the internal and external ambient temperature and / or the temperature of critical components.

[0108] The control circuit can be connected to the temperature detection circuit to read the temperature readings. If the control circuit detects an abnormal temperature, it will automatically disconnect the DC switch. Abnormal temperatures include: excessively low temperature, excessively high temperature, and excessively rapid temperature changes.

[0109] The automatic disconnection of DC switches includes: controlling at least one DC switch associated with a temperature anomaly to disconnect, controlling other switches linked to that switch to disconnect together, or controlling all switches to disconnect together, thereby eliminating the voltage anomaly, maintaining the normal operation of the remaining circuits of the power converter, or completely shutting down the system, ensuring system safety. Switches associated with temperature anomalies include those where the ambient temperature detected by the temperature detection circuit is close to the switch, critical components detected by the temperature detection circuit are close to or connected to the switch, and circuits detected by the temperature detection circuit can be disconnected by the switch. Critical components include: power semiconductors, heat sinks, reactors, capacitors, power resistors, relays, connection terminals, copper strips, and structural housings.

[0110] As yet another example, a power converter malfunction refers to an operational anomaly in the power converter. Therefore, the control circuitry can be the controller within the power converter.

[0111] The controller can identify the operating status of the power converter. When it detects an abnormality in the power converter's operation, it automatically disconnects the DC switch. Abnormalities include: voltage abnormality, current abnormality, temperature abnormality, power abnormality, external device abnormality, and receiving remote control commands. External device abnormalities include: photovoltaic DC-to-ground insulation abnormality, photovoltaic module abnormality, DC arcing, battery abnormality, module-level power electronics (MLPE) device abnormality, power grid abnormality, and load abnormality.

[0112] The automatic disconnection operation of the DC switch includes: disconnecting the DC switch corresponding to the abnormal external device so that the rest of the power converter can operate normally, or controlling other switches linked to the abnormal switch to disconnect together, or controlling all switches to disconnect together to ensure system safety.

[0113] In addition, such as Figures 2-9As shown, this application embodiment also provides a power conversion circuit 230. This power conversion circuit 230 is a circuit structure within the power converter 220. For example, the power conversion circuit 230 is the structure of the power converter 220 described above, excluding the control circuit. That is, the structure of the power conversion circuit 230 is as follows.

[0114] The power conversion circuit 230 includes: a first interface circuit; a first DC-to-DC converter circuit connected to the first interface circuit, the first DC-to-DC converter circuit being used to convert the DC power transmitted through the first interface circuit; and a DC-to-AC converter circuit, including a DC terminal and an AC terminal, the DC terminal being connected to the output terminal of the first DC-to-DC converter circuit via a DC bus, the AC terminal being used to connect to an AC circuit, the DC-to-AC converter circuit being used to convert the DC power output by the first DC-to-DC converter circuit into AC power; wherein, a DC switch is connected between the output terminal and the DC terminal of the first DC-to-DC converter circuit, and no DC switch is connected between the input terminal of the first DC-to-DC converter circuit and the first interface circuit.

[0115] Optionally, the DC switch includes: a first DC switch and a second DC switch; the output terminal of the first DC-DC converter circuit includes a positive output terminal and a negative output terminal; the DC bus includes a positive DC bus and a negative DC bus; the DC terminal is connected to the positive output terminal and the negative output terminal through the positive DC bus and the negative DC bus; the first DC switch is connected between the positive output terminal and the DC terminal of the first DC-DC converter circuit; and the second DC switch is connected between the negative output terminal and the DC terminal of the first DC-DC converter circuit.

[0116] Optionally, there are multiple first DC-DC converter circuits, and at least one first DC switch is connected between the positive output terminal and the DC terminal of the multiple first DC-DC converter circuits, and at least one second DC switch is connected between the negative output terminal and the DC terminal of the multiple first DC-DC converter circuits.

[0117] Optionally, at least one first DC switch is connected at both ends to the positive output terminal and positive DC bus of a plurality of first DC-DC converter circuits, respectively, and at least one second DC switch is connected at both ends to the negative output terminal and negative DC bus of a plurality of first DC-DC converter circuits, respectively.

[0118] Optionally, at least some of the first DC-DC converter circuits in a plurality of first DC-DC converter circuits share a first DC switch at their positive output terminals.

[0119] Optionally, at least a portion of the first DC-DC converter circuits may share a second DC switch at their negative output terminals.

[0120] Optionally, at least one first DC switch and at least one second DC switch are provided. A bus capacitor is connected between the positive DC bus and the negative DC bus. The two ends of the first DC switch are connected to one end of the bus capacitor and the DC end, respectively. The two ends of the second DC switch are connected to the other end of the bus capacitor and the DC end, respectively.

[0121] Optionally, at least a portion of the first DC switch and at least a portion of the second DC switch are the same multiplexer.

[0122] Optionally, the power conversion circuit 230 further includes a second DC-DC conversion circuit, wherein a DC switch is connected between the input terminal of the second DC-DC conversion circuit and the second interface circuit, and no DC switch is connected between the output terminal of the second DC-DC conversion circuit and the DC terminal.

[0123] This application embodiment also provides an energy storage system 200, which includes a power converter 220 as described in any of the preceding descriptions.

[0124] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any other combination. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this disclosure are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a machine-readable storage medium or transmitted from one machine-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The machine-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs (DVDs)), or semiconductor media (e.g., solid-state drives (SSDs)).

[0125] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments of this disclosure can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0126] In the several embodiments provided in this disclosure, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0127] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0128] In addition, the functional units in the various embodiments of this disclosure can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0129] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A power converter, characterized by, Comprise: A first direct current-direct current (DC-DC) conversion circuit connected with the first interface circuit, the first DC-DC conversion circuit being configured to perform power conversion on direct current transmitted through the first interface circuit; A direct current-alternating current (DC-AC) conversion circuit comprising a direct current end and an alternating current end, the direct current end being connected with an output end of the first DC-DC conversion circuit through a direct current bus, and the alternating current end being configured to be connected with an alternating current circuit, the DC-AC conversion circuit being configured to convert direct current output by the first DC-DC conversion circuit into alternating current; Wherein, a direct current switch is connected between the output end of the first DC-DC conversion circuit and the direct current end, and no direct current switch is connected between the input end of the first DC-DC conversion circuit and the first interface circuit.

2. The power converter of claim 1, wherein, The direct current switch comprises: A first direct current switch and a second direct current switch, the output end of the first DC-DC conversion circuit comprising a positive output end and a negative output end, the direct current bus comprising a positive direct current bus and a negative direct current bus, the direct current end being connected with the positive output end and the negative output end through the positive direct current bus and the negative direct current bus, the first direct current switch being connected between the positive output end of the first DC-DC conversion circuit and the direct current end, and the second direct current switch being connected between the negative output end of the first DC-DC conversion circuit and the direct current end.

3. The power converter of claim 2, wherein, The number of the first DC-DC conversion circuits is multiple, at least one first direct current switch being connected between the positive output ends of the multiple first DC-DC conversion circuits and the direct current end, and at least one second direct current switch being connected between the negative output ends of the multiple first DC-DC conversion circuits and the direct current end.

4. The power converter of claim 3, wherein, Two ends of the at least one first direct current switch are respectively connected with the positive output ends of the multiple first DC-DC conversion circuits and the positive direct current bus, and two ends of the at least one second direct current switch are respectively connected with the negative output ends of the multiple first DC-DC conversion circuits and the negative direct current bus.

5. The power converter of claim 4, wherein, The positive output ends of at least part of the multiple first DC-DC conversion circuits share one first direct current switch.

6. A power converter as claimed in claim 4 or 5, characterised in that, The negative output ends of at least part of the multiple first DC-DC conversion circuits share one second direct current switch.

7. The power converter of claim 3, wherein, The number of the at least one first direct current switch is one, the number of the at least one second direct current switch is one, a bus capacitor is connected between the positive direct current bus and the negative direct current bus, two ends of the first direct current switch are respectively connected with one end of the bus capacitor and the direct current end, and two ends of the second direct current switch are respectively connected with the other end of the bus capacitor and the direct current end.

8. The power converter of claim 3, wherein, At least part of the at least one first direct current switch and at least part of the at least one second direct current switch are the same multi-way isolation switch.

9. The power converter of claim 1, wherein, Further comprise: A second DCDC conversion circuit, a direct current switch is connected between an input terminal of the second DCDC conversion circuit and the second interface circuit, and no direct current switch is connected between an output terminal of the second DCDC conversion circuit and the direct current terminal.

10. The power converter of any of claims 1-3 or 9, wherein, Further comprising: A control circuit connected with the direct current switch, the control circuit being configured to control the corresponding direct current switch to be turned off in response to the power converter being abnormal.

11. A power conversion circuit, characterized by, Comprise: A first interface circuit; A first direct current-direct current (DCDC) conversion circuit connected with the first interface circuit, the first DCDC conversion circuit being configured to perform power conversion on direct current transmitted through the first interface circuit; A direct current-alternating current (DCAC) conversion circuit comprising a direct current terminal and an alternating current terminal, the direct current terminal being connected with an output terminal of the first DCDC conversion circuit through a direct current bus, and the alternating current terminal being configured to be connected with an alternating current circuit, the DCAC conversion circuit being configured to convert direct current output by the first DCDC conversion circuit into alternating current; Wherein, a direct current switch is connected between an output terminal of the first DCDC conversion circuit and the direct current terminal, and no direct current switch is connected between an input terminal of the first DCDC conversion circuit and the first interface circuit.

12. A control method of a power converter, characterized by, The power converter comprises a first direct current-direct current (DCDC) conversion circuit and a direct current-alternating current (DCAC) conversion circuit, the first DCDC conversion circuit being connected with a first interface circuit to perform power conversion on direct current transmitted through the first interface circuit; the direct current-alternating current (DCAC) conversion circuit comprises a direct current terminal and an alternating current terminal, the direct current terminal being connected with output terminals of the plurality of first DCDC conversion circuits through a direct current bus, and the alternating current terminal being configured to be connected with an alternating current circuit, the DCAC conversion circuit being configured to convert direct current output by the first DCDC conversion circuit into alternating current; wherein, a direct current switch is connected between an output terminal of the first DCDC conversion circuit and the direct current terminal; The method comprises: Controlling the direct current switch to be turned off in response to the power converter being abnormal.

13. The method of claim 12, wherein, The direct current switch comprises: a first direct current switch and a second direct current switch, an output terminal of the first DCDC conversion circuit comprises a positive output terminal and a negative output terminal, the direct current bus comprises a positive direct current bus and a negative direct current bus, the direct current terminal is connected with the positive output terminal and the negative output terminal through the positive direct current bus and the negative direct current bus, the first DCDC conversion circuit is connected with the direct current terminal through the first direct current switch, and the second DCDC conversion circuit is connected with the direct current terminal through the second direct current switch; The controlling the direct current switch to be turned off in response to the power converter being abnormal comprises: Controlling the first direct current switch and / or the second direct current switch to be turned off in response to the power converter being abnormal.

14. The method of claim 13, wherein, The number of the first DCDC conversion circuits is a plurality, at least one first direct current switch is connected between positive output terminals of the plurality of first DCDC conversion circuits and the direct current terminal, and at least one second direct current switch is connected between negative output terminals of the plurality of first DCDC conversion circuits and the direct current terminal. controlling at least some of the first DC switches and / or at least some of the second DC switches to open in response to the power converter anomaly. controlling at least some of the first DC switches and / or at least some of the second DC switches to open in response to the power converter anomaly.

15. The method according to any of claims 12-14, characterized by, the power converter anomaly comprises one or more of: a DC current anomaly, a DC leakage current anomaly, an AC current anomaly, an AC leakage current anomaly, a DC voltage anomaly, a temperature anomaly, an operational anomaly.

16. An energy storage system characterized by, a power converter as claimed in any one of claims 1 to 10.

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