An inverter auxiliary power supply circuit, a power supply method and a power supply system

Abstract

This invention relates to an auxiliary power supply circuit, power supply method, and power supply system for inverters. The power supply system includes at least two inverters, each with its power port connected to a power source and its load port connected to a load. The load ports of each inverter are connected in parallel. The auxiliary power supply for the inverters comes from either the power source or the operating power source of the load. The auxiliary power supply circuit of this application adds a power path from the load side. By introducing the operating power source of the load, auxiliary power can be supplied to the inverter when the inverter's power source is unavailable, ensuring the normal startup and operation of the inverter. This improves the inverter's operational stability and ensures the operational accessibility of the power supply system, including the inverter, under complex operating conditions, thus enhancing the reliability and adaptability of the power supply system.

Description

Technical Field

[0001] This invention relates to the field of inverter control technology, specifically to an inverter auxiliary power supply circuit, power supply method, and power supply system. Background Technology

[0002] In existing power supply systems, such as energy storage systems and photovoltaic energy storage systems, the auxiliary power supply for inverters typically relies on DC power (such as batteries or photovoltaic panels) or AC power. However, when DC power is unavailable (e.g., insufficient battery power, lack of sunlight, etc.) or AC power is unavailable (e.g., AC power failure, off-grid operation, etc.), the inverter may shut down due to the lack of auxiliary power supply, or fail to start normally, thus causing the system to malfunction.

[0003] Therefore, there is an urgent need for an auxiliary power supply circuit that can overcome the shortcomings of traditional auxiliary power supply methods, such as a single power supply path, low system reliability, and the possibility that the inverter may fail to start normally under certain conditions, affecting the system's recovery capability, in order to improve the system's reliability and adaptability. Summary of the Invention

[0004] A primary objective of this invention is to overcome at least one of the aforementioned deficiencies by providing an inverter auxiliary power supply circuit, power supply method, and power supply system. By adding an auxiliary power supply path on the load side, this invention ensures the normal startup and operation of the inverter even when the inverter's power supply is unavailable, such as when DC power and / or AC power is unavailable, thereby improving the system's reliability and adaptability.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides an auxiliary power supply circuit for an inverter, which is applied in a power supply system. The power supply system includes at least two inverters, each inverter's power port is connected to a power source, each inverter's load port is connected to a load, and the load ports of each inverter are connected in parallel. The auxiliary power supply of the inverter comes from the power source or the working power source of the load.

[0006] According to one embodiment of the present invention, the power supply port includes an AC power supply port, the power supply includes an AC power supply, the AC power supply is connected to the AC side of the inverter via the AC power supply port, and the inverter includes a first auxiliary power source, the input side of the first auxiliary power source is connected to both the AC power supply port and the load port, so that the auxiliary power supply of the inverter comes from the AC power supply or the working power supply of the load.

[0007] According to one embodiment of the present invention, the power supply port includes a DC power supply port, the power supply includes a DC power supply, the DC power supply is connected to the DC side of the inverter via the DC power supply port, the inverter includes a second auxiliary power source, the input side of the second auxiliary power source is connected to both the DC bus and the load port, so that the auxiliary power supply of the inverter comes from the DC power supply or the working power supply of the load.

[0008] According to one embodiment of the present invention, the input side of the second auxiliary power source is connected to the load port after passing through a rectifier circuit and a switch, so that the working power supply of the load is converted into DC power by the rectifier circuit to supply power to the second auxiliary power source.

[0009] According to one embodiment of the present invention, the inverter includes a pre-charging circuit and a third auxiliary power source. The input side of the pre-charging circuit is connected to the load port, and the output side of the pre-charging circuit and the input side of the third auxiliary power source are both connected to the DC side of the inverter, so that the working power supply of the load charges the DC bus capacitor on the DC side through the pre-charging circuit, thereby supplying power to the third auxiliary power source.

[0010] According to one embodiment of the present invention, the inverter includes a fourth auxiliary power source and / or a fifth auxiliary power source, and the inverter also includes a sixth auxiliary power source, which is an AC auxiliary power source or a DC auxiliary power source. The input side of the sixth auxiliary power source is connected to the load port so that the auxiliary power supply of the inverter comes from the working power supply of the load.

[0011] According to one embodiment of the present invention, when a DC auxiliary power source is selected as the sixth auxiliary power source, the input side of the sixth auxiliary power source is connected to the load port after passing through a rectifier circuit and a switch, so that the working power supply of the load is converted into DC power by the rectifier circuit to supply power to the sixth auxiliary power source.

[0012] Specifically, this invention provides an inverter auxiliary power supply method applied in a power supply system, which employs the inverter auxiliary power supply circuit described above. When power is available, the inverter’s auxiliary power supply comes from the power supply or the load’s operating power supply. When the power supply is unavailable, the inverter's auxiliary power supply comes from the load's operating power supply.

[0013] According to one embodiment of the present invention, if the auxiliary power supply of the inverter comes from the working power supply of the load, after the inverter is running normally, the power supply is switched to the auxiliary power supply of the inverter.

[0014] In particular, the present invention also provides a power supply system comprising at least two inverters, wherein the at least two inverters employ an inverter auxiliary power supply circuit as described above, and / or wherein the at least two inverters perform an inverter auxiliary power supply method as described above, such that the auxiliary power supply of each inverter comes from the power source or the operating power source of the load.

[0015] According to one embodiment of the present invention, the power supply system includes, but is not limited to, an energy storage system and a photovoltaic energy storage system.

[0016] Compared with the prior art, the advantages and beneficial effects of the inverter auxiliary power supply circuit, power supply method and power supply system of this invention patent application are as follows: In this application, a power supply path for the load side is added to the auxiliary power supply circuit of the inverter. After the working power of the load is introduced, the auxiliary power supply of the inverter can be supplied when the power supply of the inverter is unavailable, so as to ensure the normal start-up and normal operation of the inverter, thereby improving the working stability of the inverter. In addition, it also ensures the operational accessibility of the power supply system including the inverter under complex working conditions, and improves the working reliability and adaptability of the power supply system. Attached Figure Description

[0017] The following sections will describe some specific embodiments of the invention in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic diagram of the circuit structure of a traditional power supply system; Figure 2 This is a schematic diagram of the circuit structure of a traditional inverter auxiliary power supply circuit; Figure 3 This is a schematic diagram of the circuit structure of the inverter auxiliary power supply circuit according to Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the circuit structure of the inverter auxiliary power supply circuit according to Embodiment 2 of the present invention; Figure 5 This is another circuit structure diagram of the inverter auxiliary power supply circuit according to Embodiment 2 of the present invention; Figure 6 This is another circuit structure diagram of the inverter auxiliary power supply circuit according to Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the circuit structure of the inverter auxiliary power supply circuit according to Embodiment 3 of the present invention; Figure 8 This is a schematic diagram of the circuit structure of the inverter auxiliary power supply circuit according to Embodiment 4 of the present invention; Figure 9 This is a schematic diagram of the circuit connection between the output sides of the first auxiliary source and the third auxiliary source in Embodiment 4 of the present invention; Figure 10 This is a schematic diagram of the circuit structure of the inverter auxiliary power supply circuit according to Embodiment 5 of the present invention; Figure 11This is another circuit structure diagram of the inverter auxiliary power supply circuit according to Embodiment 5 of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] like Figure 1 As shown, a power supply system generally includes a DC power source, an inverter, an AC power source, and a load. The DC side of the inverter is connected to the DC power source, which includes, but is not limited to, photovoltaic panels and / or energy storage batteries. The AC side of the inverter is connected to the AC power source and the load. The AC power source can be the power grid or a device that can output AC power, such as a generator. In this embodiment, the power grid is used as an example.

[0021] For large-capacity power supply systems with multiple inverters connected in parallel, the system includes at least two inverters. For each inverter, the DC power supply components connected to it, such as photovoltaic panels, energy storage batteries, and loads, can be selectively installed. Therefore, the overall structure of the power supply system is complex and diverse, leading to higher design requirements for the inverters, such as auxiliary power supply. Auxiliary power supply provides a stable, isolated, low-voltage operating power supply to the control circuit, drive circuit, sampling circuit, protection circuit, relays, and communication modules before the DC power output is established, before voltage fluctuations occur, or before the main power circuit operates. This ensures the inverter can start up, operate, and be protected normally, providing a stable operating voltage for the inverter's startup and normal operation.

[0022] The auxiliary power supply for the inverter can come from the DC bus on the DC side of the inverter or the AC power supply on the AC side. Under normal circumstances, it is one of the following two: 1) AC power supply on the AC side: The auxiliary power supply is supplied by AC power. After AC-DC conversion, it provides the inverter with low voltage such as DC12V or DC24V. 2) DC bus power supply on the DC side: The auxiliary power supply is supplied from the DC bus. After DC-DC conversion, it provides the low voltage such as DC12V or DC24V required by the inverter.

[0023] However, in some cases, when DC power is unavailable (e.g., insufficient battery power, lack of sunlight, etc.) or AC power is unavailable (e.g., AC power failure, off-grid operation, etc.), the inverter may shut down or fail to start normally due to a lack of auxiliary power supply. This can cause some inverters to disconnect from the power supply system due to auxiliary power issues, resulting in the power supply system malfunctioning. For example, Figure 1 When the power supply system shown is in off-grid operation mode, since the auxiliary power supply of the inverter has no AC power source, if the photovoltaic panels or energy storage batteries of one or more inverters have problems—such as at night, on cloudy days, or insufficient energy storage of the energy storage batteries, which may cause the DC voltage of the inverter to also be lost, the corresponding inverter will shut down or fail to start normally because the auxiliary power source cannot work properly, thus causing the power supply branch to be disconnected from the power supply system.

[0024] To address the above issues, the inverter auxiliary power supply circuit, power supply method, and power supply system of this application, by adding a power supply path to the load side in the inverter auxiliary power supply circuit and introducing the load's working power supply, can supply power to the inverter auxiliary power source when the inverter's power supply is unavailable, such as when DC power and / or AC power is unavailable, thereby ensuring the normal startup and operation of the inverter, thus improving the inverter's operational stability. Furthermore, it also ensures the operational accessibility of the power supply system including the inverter under complex operating conditions, improving the operational reliability and adaptability of the power supply system.

[0025] There are various implementation methods for the specific inverter auxiliary power supply circuit and power supply method. For example, the auxiliary power supply (DC auxiliary power supply or AC auxiliary power supply) built into the inverter itself can be used to introduce the working power supply of the load for power supply, or an additional auxiliary power supply (DC auxiliary power supply or AC auxiliary power supply) can be used to introduce the working power supply of the load for power supply.

[0026] by Figure 2 Taking a conventional inverter auxiliary power supply circuit as an example, in traditional technology, the inverter's power port is connected to the power source, and each inverter's load port is connected to the load. The load ports of each inverter are connected in parallel (not shown in the figure). The inverter's auxiliary power supply comes from the power source. The power port includes an AC power port and a DC power port. The power source can include, for example, an AC power source, a photovoltaic panel, and an energy storage battery. The AC power port is located on the AC side of the inverter, and the DC power port is located on the DC side of the inverter. The AC power source is connected to the AC side of the inverter via the AC power port, and the DC power source (photovoltaic panel and energy storage battery) is connected to the DC side of the inverter via the DC power port, such as by connecting to the DC bus.

[0027] like Figure 2As shown, the inverter is configured with a first auxiliary power source and a second auxiliary power source. The first auxiliary power source is an AC auxiliary power source, and its input side is connected to the AC power supply port, meaning the first auxiliary power source is connected to the AC power supply so that the inverter's auxiliary power supply comes from the AC power source. The second auxiliary power source is a DC auxiliary power source, and its input side is connected to the DC bus (not shown in the figure). The DC power supply (photovoltaic panels and energy storage batteries) connected to the DC side of the inverter can also be connected to the second auxiliary power source, so that the inverter's auxiliary power supply comes from the DC power supply. The auxiliary power source configuration in the inverter can be configured with only the first auxiliary power source, only the second auxiliary power source, or both, allowing for adaptive adjustments according to requirements.

[0028] In addition, the inverter is equipped with a first pre-charge circuit. The input side of the first pre-charge circuit is connected to the AC power port, and the output side of the first pre-charge circuit is connected to the DC side of the inverter. The input side of the second auxiliary power source is also connected to the DC bus of the DC side of the inverter. The existence of the first pre-charge circuit can charge the DC bus capacitor of the DC side through the first pre-charge circuit, thereby supplying power to the second auxiliary power source.

[0029] In addition, an AC relay can be configured on the AC side of the inverter to control the connection between the inverter and the load port and the AC power port.

[0030] Example 1: The inverter auxiliary power supply circuit in this embodiment is... Figure 2 Based on the traditional inverter auxiliary power supply circuit shown, a connection to the load port is added to the input side of the first auxiliary power source, that is, the working power supply of the load is added to the power supply source of the first auxiliary power source.

[0031] Specifically, such as Figure 3 As shown, the input side of the first auxiliary power source is connected to both the AC power supply port and the load port, so that the auxiliary power supply of the inverter comes from the AC power supply or the operating power supply of the load. In this embodiment, the AC power supply port is the grid port, and the AC power supply is the power grid.

[0032] In this embodiment, the connection between the input side of the first auxiliary power source and the load port is a three-phase power supply, that is, the three-phase wires of the input side of the first auxiliary power source and the load port are all connected. Alternatively, a single-phase power supply or a two-phase power supply can also be used, as long as the working power of the load can be successfully obtained from the load port, which will not be elaborated here.

[0033] Example 2: The inverter auxiliary power supply circuit in this embodiment is... Figure 2 Based on the traditional inverter auxiliary power supply circuit shown, a connection to the load port is added to the input side of the second auxiliary power source, that is, the working power supply of the load is added to the power supply source of the second auxiliary power source.

[0034] Specifically, such as Figure 4 As shown, the input side of the second auxiliary power source is connected to both the DC bus and the load port, so that the auxiliary power supply of the inverter comes from the DC power supply or the operating power supply of the load. For safety reasons, a unidirectional device, such as a diode, is installed on the connection line between the input side of the second auxiliary power source and the DC bus.

[0035] Since the second auxiliary power source is a DC auxiliary power source, a rectifier circuit can be configured inside it to convert the load operating power obtained from the load port from AC to DC, thereby meeting the power supply requirements of the second auxiliary power source. Alternatively, the rectifier circuit can be placed outside the second auxiliary power source, so that the load operating power is converted to DC before supplying power to the second auxiliary power source.

[0036] like Figure 5 As shown, a rectifier circuit is provided between the input side of the second auxiliary power source and the load port. The input side of the second auxiliary power source is connected to the load port after passing through the rectifier circuit and a switch (e.g., a normally closed relay), so that the load's operating power supply is converted to DC by the rectifier circuit to power the second auxiliary power source. For safety reasons, not only is a unidirectional conductive device provided on the connection line between the input side of the second auxiliary power source and the DC bus (not shown in the figure), but a unidirectional conductive device (e.g., a diode) is also provided on the connection line between the rectifier circuit and the input side of the second auxiliary power source.

[0037] Additionally, the switch on the line connecting the input side of the second auxiliary power source to the load port can also be located on the DC side of the rectifier circuit. That is, as shown... Figure 6 As shown, the switch is connected in series on the DC transmission line between the rectifier circuit and the input side of the second auxiliary power source.

[0038] The connection between the input side of the second auxiliary source and the load port shown in this embodiment can be as follows: Figure 4 The two-phase power supply shown can also be adopted as follows: Figure 5 , Figure 6 The three-phase power supply shown can also be replaced by a single-phase power supply, provided that the working power of the load can be successfully obtained from the load port. This will not be elaborated further here.

[0039] Example 3: The inverter auxiliary power supply circuit in this embodiment is... Figure 2 Based on the traditional inverter auxiliary power supply circuit shown, a second pre-charging circuit has been added.

[0040] The inverter includes a second pre-charge circuit and a third auxiliary power source. In this embodiment, the third auxiliary power source is the inverter's original DC auxiliary power source (the second auxiliary power source), such as... Figure 7As shown, the input side of the second pre-charge circuit is connected to the load port via a switch, and the output side of the pre-charge circuit and the input side of the second auxiliary power source are both connected to the DC side of the inverter, so that the working power supply of the load charges the DC bus capacitor on the DC side through the pre-charge circuit, thereby supplying power to the second auxiliary power source.

[0041] Example 4: The inverter auxiliary power supply circuit in this embodiment is... Figure 2 Based on the traditional inverter auxiliary power supply circuit shown, a sixth auxiliary power source (AC auxiliary power source) has been added.

[0042] The inverter includes a fourth auxiliary power source and a fifth auxiliary power source. In this embodiment, the fourth auxiliary power source is the inverter's original AC auxiliary power source (first auxiliary power source), and the fifth auxiliary power source is the inverter's original DC auxiliary power source (second auxiliary power source), as detailed below. Figure 8 As shown, the sixth auxiliary power source in this embodiment is an AC auxiliary power source. The input side of the sixth auxiliary power source is connected to the load port so that the auxiliary power supply of the inverter comes from the working power supply of the load.

[0043] The output of the sixth auxiliary source can be connected in parallel with the output of the first auxiliary source, such as... Figure 9 As shown, this forms a low-voltage DC output for the inverter, and unidirectional conducting devices, such as diodes, are connected in series on the output sides of the first auxiliary source and the sixth auxiliary source to ensure safe operation.

[0044] In this embodiment, the connection between the input side of the sixth auxiliary power source and the load port is a three-phase power supply, that is, the three-phase wires of the input side of the sixth auxiliary power source and the load port are all connected. Alternatively, a single-phase power supply or a two-phase power supply can also be used, as long as the working power of the load can be successfully obtained from the load port, which will not be elaborated here.

[0045] Example 5: The inverter auxiliary power supply circuit in this embodiment is... Figure 2 Based on the traditional inverter auxiliary power supply circuit shown, a sixth auxiliary source (DC auxiliary source) has been added.

[0046] The inverter includes a fourth auxiliary power source and a fifth auxiliary power source. In this embodiment, the fourth auxiliary power source is the inverter's original AC auxiliary power source (first auxiliary power source), and the fifth auxiliary power source is the inverter's original DC auxiliary power source (second auxiliary power source), as detailed below. Figure 10 As shown, the sixth auxiliary power source is a DC auxiliary power source. The input side of the sixth auxiliary power source is connected to the DC bus (not shown in the figure) and the load port, so that the auxiliary power supply of the inverter comes from the DC power supply or the working power supply of the load.

[0047] Since the sixth auxiliary power source is a DC auxiliary power source, a rectifier circuit can be configured inside the sixth auxiliary power source to convert the load operating power obtained from the load port from AC to DC, thereby meeting the power supply requirements of the sixth auxiliary power source.

[0048] It is also possible to Figure 10 As shown, the rectifier circuit is placed outside the sixth auxiliary power source, thereby converting the load's operating power supply into DC power before supplying power to the sixth auxiliary power source. The input side of the sixth auxiliary power source is connected to the load port after passing through the rectifier circuit and a switch (e.g., a normally closed relay), so that the load's operating power supply is converted into DC power by the rectifier circuit to supply power to the sixth auxiliary power source. For safety reasons, a unidirectional conducting device (e.g., a diode) can be installed on the connection line between the input side of the sixth auxiliary power source and the DC bus, and a unidirectional conducting device (e.g., a diode) can also be installed on the connection line between the rectifier circuit and the input side of the sixth auxiliary power source.

[0049] Alternatively, the aforementioned switch can also be located on the DC side of the rectifier circuit, that is, connected in series on the DC transmission line between the rectifier circuit and the input side of the sixth auxiliary source. Any method that enables connection between the sixth auxiliary source and the load port should be protected under this application.

[0050] In this embodiment of the inverter auxiliary power supply circuit, after the addition of a sixth auxiliary power source, the input side of the sixth auxiliary power source is only connected to the load port, specifically as follows: Figure 11 As shown, this allows the inverter's auxiliary power supply to come from the load's operating power supply.

[0051] In this embodiment, the connection between the input side of the sixth auxiliary power source and the load port is a three-phase power supply, that is, the three-phase wires of the input side of the sixth auxiliary power source are connected to the load port. Alternatively, a single-phase power supply or a two-phase power supply can also be used, as long as the working power of the load can be successfully obtained from the load port, which will not be elaborated here.

[0052] Example 6: This embodiment describes an inverter auxiliary power supply method applied to a power supply system, which adopts the inverter auxiliary power supply circuit as described in any one of Embodiments 1 to 5. When power is available, the inverter’s auxiliary power supply comes from the power supply or the load’s operating power supply. When the power supply is unavailable, the inverter's auxiliary power supply comes from the load's operating power supply.

[0053] If the auxiliary power supply of the inverter comes from the working power supply of the load, after the inverter is running normally, the auxiliary power supply of the inverter is switched to the power supply to ensure the stable operation of the system.

[0054] Example 7: This embodiment describes a power supply system, which is an energy storage system, including at least two inverters, wherein the at least two inverters employ an inverter auxiliary power supply circuit as described in any one of Embodiments 1 to 5, and / or wherein the at least two inverters execute an inverter auxiliary power supply method as described in Embodiment 6, so that the auxiliary power supply of each inverter comes from the power source or the operating power source of the load.

[0055] Example 8: This embodiment describes a power supply system, which is a photovoltaic energy storage system, including at least two inverters. The at least two inverters employ an inverter auxiliary power supply circuit as described in any one of Embodiments 1 to 5, and / or the at least two inverters execute an inverter auxiliary power supply method as described in Embodiment 6, so that the auxiliary power supply of each inverter comes from the power supply or the operating power supply of the load.

[0056] It should be noted that the power supply system mentioned above is not limited to energy storage system or photovoltaic-storage system, but can also be a photovoltaic system or other AC / DC hybrid power supply system.

[0057] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An inverter auxiliary power supply circuit, applied in a power supply system, characterized in that, The power supply system includes at least two inverters. The power ports of each inverter are connected to the power source, and the load ports of each inverter are connected to the load. The load ports of each inverter are connected in parallel. The auxiliary power supply of the inverters comes from the power source or the working power source of the load.

2. The inverter auxiliary power supply circuit according to claim 1, characterized in that, The power port includes an AC power port, the power source includes an AC power source, the AC power source is connected to the AC side of the inverter via the AC power port, and the inverter includes a first auxiliary power source, the input side of the first auxiliary power source is connected to both the AC power port and the load port, so that the auxiliary power supply of the inverter comes from the AC power source or the working power supply of the load.

3. The inverter auxiliary power supply circuit according to claim 1, characterized in that, The power port includes a DC power port, the power source includes a DC power source, the DC power source is connected to the DC side of the inverter via the DC power port, the inverter includes a second auxiliary power source, the input side of the second auxiliary power source is connected to the DC bus and the load port, so that the auxiliary power supply of the inverter comes from the DC power source or the working power supply of the load.

4. The inverter auxiliary power supply circuit according to claim 3, characterized in that, The input side of the second auxiliary power source is connected to the load port after passing through a rectifier circuit and a switch, so that the working power supply of the load is converted into DC power by the rectifier circuit to power the second auxiliary power source.

5. The inverter auxiliary power supply circuit according to claim 1, characterized in that, The inverter includes a pre-charging circuit and a third auxiliary power source. The input side of the pre-charging circuit is connected to the load port, and the output side of the pre-charging circuit and the input side of the third auxiliary power source are both connected to the DC side of the inverter, so that the working power supply of the load charges the DC bus capacitor on the DC side through the pre-charging circuit, thereby supplying power to the third auxiliary power source.

6. The inverter auxiliary power supply circuit according to claim 1, characterized in that, The inverter includes a fourth auxiliary power source and / or a fifth auxiliary power source, and the inverter also includes a sixth auxiliary power source, which is an AC auxiliary power source or a DC auxiliary power source. The input side of the sixth auxiliary power source is connected to the load port so that the auxiliary power supply of the inverter comes from the working power supply of the load.

7. The inverter auxiliary power supply circuit according to claim 6, characterized in that, When the sixth auxiliary power source is a DC auxiliary power source, the input side of the sixth auxiliary power source is connected to the load port after passing through a rectifier circuit and a switch, so that the working power supply of the load is converted into DC power by the rectifier circuit to supply power to the sixth auxiliary power source.

8. A method for supplying auxiliary power to an inverter, applied in a power supply system, characterized in that, The inverter auxiliary power supply circuit as described in any one of claims 1 to 7 is adopted. When power is available, the inverter’s auxiliary power supply comes from the power supply or the operating power supply of the load. When the power supply is unavailable, the inverter's auxiliary power supply comes from the operating power supply of the load.

9. The inverter auxiliary power supply method according to claim 8, characterized in that, If the auxiliary power supply of the inverter comes from the working power supply of the load, the auxiliary power supply of the inverter will be switched to the working power supply of the load after the inverter is running normally.

10. A power supply system, characterized in that, It includes at least two inverters, wherein at least two inverters employ an inverter auxiliary power supply circuit as described in any one of claims 1 to 7, and / or wherein at least two inverters perform an inverter auxiliary power supply method as described in claim 8 or 9, such that the auxiliary power supply of each inverter comes from the power source or the operating power source of the load.

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