CN117706430A - Interface wiring detection method of inverter, power conversion device and energy storage system - Google Patents

Abstract

The application provides an interface wiring detection method of an inverter, a power conversion device and an energy storage system. The output end of the inverter is connected with a grid-connected interface through a grid-connected switch unit, the grid-connected interface is connected with a load interface through a load switch unit, the grid-connected interface is also connected with a load interface through a bypass switch unit, the grid-connected interface is used for being connected with an alternating current power grid, and the load interface is used for being connected with an alternating current load. The method comprises the following steps: when the inverter stops running and the grid-connected switch unit, the load switch unit and the bypass switch unit are disconnected, a first voltage of the grid-connected interface is obtained, and then a wiring detection result of the grid-connected interface and the load interface is confirmed according to the first voltage and a preset grid voltage. The method can detect whether the grid-connected interface and the load interface are reversely connected.

Description

Interface wiring detection method of inverter, power conversion device and energy storage system

Technical Field

The application relates to the technical field of power electronics, in particular to an interface wiring detection method of an inverter, a power conversion device and an energy storage system.

Background

In the photovoltaic energy storage system, an inverter is connected with a power grid through a grid connection interface and is connected with a load through a load interface. Because the grid-connected interface and the load interface are both alternating current interfaces, the shapes of the interfaces are similar, and the specifications of the used wire harnesses are the same or similar, the situation that the grid-connected interface and the load interface are reversely connected can occur during installation, so that the inverter can not supply power to the load, and the inverter can be connected with power grid energy, and the inverter is damaged.

Disclosure of Invention

In view of the above, the present application provides an interface connection detection method, a power conversion device and an energy storage system for an inverter, which can detect whether a grid-connected interface and a load interface are connected reversely.

The first aspect of the application provides an interface wiring detection method of an inverter. The output end of the inverter is connected with a grid-connected interface through a grid-connected switch unit, the grid-connected interface is connected with a load interface through a load switch unit, the grid-connected interface is also connected with the load interface through a bypass switch unit, the grid-connected interface is used for being connected with an alternating current power grid, and the load interface is used for being connected with an alternating current load. The interface wiring detection method comprises the following steps: when the inverter stops running and the grid-connected switch unit, the load switch unit and the bypass switch unit are disconnected, a first voltage of the grid-connected interface is obtained, and then a wiring detection result of the grid-connected interface and the load interface is confirmed according to the first voltage and a preset grid voltage.

It can be understood that under the condition of normal connection of the interfaces, the grid-connected interface is connected with an alternating current power grid, and the load interface is connected with an alternating current load. In the case where the grid-connected interface and the load interface are connected in reverse, the connection relationship between the grid-connected interface and the load interface is actually an ac load, and thus, when the inverter does not output, there is a great difference in the interface voltages of the grid-connected interface between the positive connection and the negative connection. Therefore, in the interface wiring detection method of the inverter, the first voltage of the grid-connected interface can be detected under the condition that the inverter stops running and the grid-connected switch unit, the load switch unit and the bypass switch unit are all disconnected, and at the moment, the first voltage of the grid-connected interface is related to an accessed alternating current power grid or an alternating current load, so that the wiring detection results of the grid-connected interface and the load interface can be confirmed according to the first voltage and the preset power grid voltage. Therefore, according to the method, whether the grid-connected interface and the load interface are reversely connected or not can be detected, so that the situation that the AC load cannot be powered up due to the fact that the interfaces are reversely connected and the inverter is damaged is avoided.

In one embodiment, confirming the connection detection result of the grid-connected interface and the load interface according to the first voltage and the preset grid voltage includes: when the first voltage is consistent with the preset power grid voltage, confirming that the wiring detection result is that the wiring is correct and the alternating current power grid is not powered down; when the first voltage of the grid-connected interface is inconsistent with the preset grid voltage, controlling the bypass switch unit to be conducted; when the bypass switch unit is turned on, obtaining a second voltage of the grid-connected interface; and when the second voltage is consistent with the preset power grid voltage, confirming that the wiring detection result is that the wiring of the grid-connected interface and the load interface is wrong.

In one embodiment, the interface connection detection method further comprises: when the second voltage is inconsistent with the preset power grid voltage, controlling the load switch unit to be conducted, and continuously detecting the third voltage of the grid-connected interface; if the third voltage is detected to be consistent with the preset power grid voltage within the first preset time period, the grid-connected switch unit, the load switch unit and the bypass switch unit are controlled to be disconnected, and the step of acquiring the first voltage of the grid-connected interface is executed in a returning mode.

In one embodiment, the interface connection detection method further comprises: if the third voltage detected in the first preset time period is inconsistent with the preset power grid voltage, the bypass switch unit is controlled to be disconnected, and the inverter is controlled to output the preset voltage; if the output current of the inverter does not trigger the step-by-step current limiting protection or the overcurrent protection, confirming that the wiring detection result is that the wiring is correct and the AC power grid is powered down; and if the output current of the inverter triggers the step-by-step current limiting protection or the overcurrent protection, confirming that the wiring detection result is a wiring error of the grid-connected interface and the load interface.

In one embodiment, the interface connection detection method further comprises: and when the wiring detection result is that the wiring is correct and the alternating current power grid is powered down, controlling the inverter to run off the grid.

In one embodiment, the interface connection detection method further comprises: and when the wiring detection result is that the wiring is correct and the alternating current power grid is not powered down, controlling the inverter to run in a grid-connected mode.

In one embodiment, the grid-tie switch unit comprises two groups of grid-tie switches connected in series, and the load switch unit comprises two groups of load switches connected in series. Furthermore, before controlling the grid-connected operation of the inverter, the interface wiring detection method further comprises the following steps: acquiring an adhesion state of a grid-connected switch unit; when the two groups of grid-connected switches are not adhered, controlling the grid-connected operation of the inverter; acquiring an adhesion state of a load switch unit; when at least one group of grid-connected switches are adhered and both groups of load switches are not adhered, a first prompt message is sent, the first prompt message is used for prompting a user to connect a grid-connected interface to an alternating current load and connect the load interface to an alternating current power grid; and after the grid-connected interface is confirmed to be connected with an alternating current load and the load interface is confirmed to be connected with an alternating current power grid, controlling the inverter to perform grid-connected operation.

In one embodiment, each set of grid-tie switches includes a phase line switch and a neutral line switch. Further, obtaining the adhesion state of the grid-connected switch unit includes: when the neutral line switches in the two groups of grid-connected switches are kept on, controlling the phase line switches in the two groups of grid-connected switches to be alternately conducted, and acquiring the voltage of an alternating current bus; if the voltage of the alternating current bus is consistent with the preset power grid voltage when the phase line switches of the two groups of grid-connected switches are alternately conducted, confirming that at least one group of grid-connected switches are adhered; if the voltage of the alternating current bus is inconsistent with the preset power grid voltage when the phase line switches of the two groups of grid-connected switches are alternately conducted, confirming that the two groups of grid-connected switches are not adhered.

The second aspect of the application provides a power conversion device, which comprises an inverter, a grid-connected switch unit, a load switch unit, a bypass switch unit, a grid-connected interface, a load interface and a controller; the output end of the inverter is connected with a grid-connected interface through a grid-connected switch unit, the grid-connected interface is connected with a load interface through a load switch unit, the grid-connected interface is connected with an alternating current power grid through a bypass switch unit, and the load interface is connected with an alternating current load; the controller is configured to perform the method for detecting an interface connection of an inverter according to the first aspect or any one of the embodiments of the first aspect.

A third aspect of the present application provides an energy storage system, the energy storage system comprising a battery pack, a photovoltaic module, and the power conversion device according to the second aspect, the power conversion device further comprising a photovoltaic interface for connecting to the photovoltaic module, and a battery interface for connecting to the battery pack.

A fourth aspect of the present application provides an electronic device, including a processor and a memory, where the memory is configured to store a program, an instruction, or a code, and the processor is configured to execute the program, the instruction, or the code in the memory, so as to complete the method for detecting an interface connection of an inverter according to the first aspect or any embodiment of the first aspect.

The fifth aspect of the present application provides an interface connection detection device of an inverter, including an acquisition module and a confirmation module, where the acquisition module is configured to acquire a first voltage of a grid-connected interface when the inverter stops running and all of a grid-connected switch unit, a load switch unit and a bypass switch unit are disconnected; the confirming module is used for confirming the wiring detection results of the grid-connected interface and the load interface according to the first voltage and the preset grid voltage.

A sixth aspect of the present application provides a computer readable storage medium storing a computer program loaded by a processor to perform the method for detecting an interface connection of an inverter according to the first aspect or any embodiment of the first aspect.

In addition, the technical effects caused by any possible implementation manners of the second aspect to the sixth aspect may refer to the technical effects caused by different implementation manners of the first aspect, which are not described herein.

Drawings

Fig. 1 is a schematic diagram of a power conversion device according to an embodiment of the present application.

Fig. 2 is a schematic diagram of an energy storage system according to an embodiment of the present application.

Fig. 3 is a flowchart of an interface connection detection method of an inverter according to an embodiment of the present application.

Fig. 4 is a detailed flow chart of an interface connection detection method of the inverter shown in fig. 3.

Fig. 5 is another flowchart of an interface connection detection method of an inverter according to an embodiment of the present application.

Fig. 6 is a detailed flowchart of step S301 in fig. 5.

Fig. 7 is a schematic diagram of an electronic device according to an embodiment of the present application.

Fig. 8 is a schematic diagram of an interface connection detection device of an inverter according to an embodiment of the present application.

Detailed Description

It should be noted that the terms "first" and "second" in the specification, claims and drawings of this application are used for distinguishing between similar objects and not for describing a particular sequential or chronological order.

It should be further noted that the method disclosed in the embodiments of the present application or the method shown in the flowchart, including one or more steps for implementing the method, may be performed in an order that the steps may be interchanged with one another, and some steps may be deleted without departing from the scope of the claims.

Some embodiments will be described below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.

Fig. 1 is a schematic diagram of a power conversion device according to an embodiment of the present application.

As shown in fig. 1, the power conversion apparatus 100 includes an inverter 10, a grid-connected switching unit 20, a grid-connected interface 30, a bypass switching unit 40, a load interface 50, a load switching unit 60, and a controller 70.

The output terminal (r, s, t, n) of the inverter 10 is connected to the grid-connected interface 30 via the grid-connected switching unit 20, and to the load interface 50 via the load switching unit 60. Grid-tie interface 30 is also connected to load interface 50 through bypass switch element 40. The grid-tie interface 30 is used to connect the ac power grid 200 via an ac bus that includes at least one of the three-phase lines R, S, T, and in some cases may also include a neutral line N. The load interface 50 is used to connect terminals (a, b, c, n) of the ac load 300, wherein terminal n of the ac load 300 is also connected to a protected ground (protecting earthing, PE). The grid-connected switching unit 20, the load switching unit 60, the bypass switching unit 40, and the inverter 10 are also connected to the controller 70.

Based on such a design, when the output power of the inverter 10 is stable and sufficient, the load switching unit 60 may be in a conductive state, and the inverter 10 at this time may be electrically connected to the load interface 50 through the load switching unit 60, and thus output power to the ac load 300 through the load interface 50.

In addition, in the case where the ac power grid 200 is operating normally, the grid-connected switching unit 20 may be in a conductive state, and the inverter 10 at this time may be electrically connected to the ac power grid 200 through the grid-connected switching unit 20 and the grid-connected interface 30, so as to be in a grid-connected operating state. Further, in case that the output power of the inverter 10 is insufficient to meet the requirement of the ac load 300, but the ac power grid 200 is normally operated, the bypass switching unit 40 may be in a conductive state, and the ac power grid 200 at this time may be electrically connected to the ac load 300 through the grid-connected interface 30, the bypass switching unit 40 and the load interface 50, thereby transmitting power to the ac load 300, thereby enabling the ac load 300 to be supplied with power by the ac power grid 200 together with the inverter 10.

Before or during the initial start-up of the inverter 10, since the inverter 10 has not yet output, in order to avoid the risk of overstressing the inverter 10 due to an excessive pressure difference between the output end of the inverter 10 and the ac power grid 200, the grid-connected switching unit 20 may be switched to the off state first, so that the inverter 10 is disconnected from the ac power grid 200. Ac load 300 may be powered by ac grid 200 at this time. After the output of the inverter 10 is stable, the grid-connected switching unit 20 may be switched to a conductive state again to electrically connect the inverter 10 with the ac power grid 200. The ac load 300 may be supplied by the inverter 10 at this time, or the ac load 300 may be supplied by the inverter 10 together with the ac grid 200.

During the power supply, if the output power of the inverter 10 is unstable, the load switching unit 60 may be switched to an off state such that the inverter 10 is disconnected from the ac load 300, and the inverter 10 stops supplying power to the ac load 300 to protect the ac load 300. In addition, if the ac power grid 200 is powered down or unstable, the grid-connected switching unit 20 may be switched to an off state, such that the inverter 10 is disconnected from the ac power grid 200 and is in an off-grid operation state, and the ac power grid 200 stops supplying power to the ac load 300 to protect the ac load 300.

In the embodiments of the present application, the power conversion device 100 may be applied to an energy storage system.

Referring to fig. 2, an energy storage system 1000 may include a power conversion device 100 and a battery pack 400. Correspondingly, the power conversion device 100 further comprises a battery interface 80. Therefore, the input terminals (in+, in-) of the inverter 10 may be electrically connected to the positive and negative poles (+, -) of the motor pack through the battery interface 80, so that the battery pack 400 may transmit the direct current to the inverter 10 through the battery interface 80, and the inverter 10 further converts the direct current into the alternating current and outputs the alternating current.

In some embodiments, the energy storage system 1000 may also include a photovoltaic assembly 500. Correspondingly, the power conversion device 100 further comprises a photovoltaic interface 90. Thus, the input of the inverter 10 can be electrically connected to the output (dc+, DC-) of the photovoltaic module 500 via the photovoltaic interface 90, so that the photovoltaic module 500 can also transmit direct current to the inverter 10 via the photovoltaic interface 90. The energy storage system 1000 may also be referred to as a photovoltaic energy storage system (may be referred to as a photovoltaic energy storage system).

In one embodiment, the inverter 10 may also be a bi-directional inverter (also referred to as bi-directional converter, power Conversion System, PCS), and the inverter 10 may have not only an inverting (i.e., converting direct current to alternating current, direct Current to Alternating Current, DC-AC) function, but also a rectifying (i.e., converting alternating current to direct current, alternating Current to Direct Current, AC-DC) function.

Therefore, in the case where the photovoltaic interface 90 is connected to the photovoltaic module 500 and the battery interface 80 is connected to the battery pack 400, when the output power of the photovoltaic module 500 is greater than the power required by the ac load 300, a part of the output power of the photovoltaic module 500 is used to power the ac load 300 via the power conversion device 100, and another part is used to charge the battery pack 400. When the output power of the photovoltaic module 500 is smaller than the power required by the ac load 300, the battery pack 400 discharges, and both the power output by the battery pack 400 and the output power of the photovoltaic module 500 are input to the power conversion device 100, and the power conversion device 100 supplies power to the ac load 300. In this manner, during peak ac grid 200 power usage, ac load 300 may not need to draw power from ac grid 200, and energy storage system 1000 may thereby achieve spontaneous use. Also, in case the ac power grid 200 allows feeding, the surplus power output by the power conversion device 100 may also be fed into the ac power grid 200. When the ac power grid 200 is at low power consumption, the ac load 300 can draw power from the ac power grid 200, and the power conversion device 100 in the energy storage system 1000 can convert the ac power of the ac power grid 200 into dc power and output the dc power to the battery pack 400, so that the battery pack 400 can be charged.

Based on the design, the power consumption of the power grid and the power consumption peak of the staggered alternating current power grid 200 can be effectively reduced, so that the power cost can be reduced, and the power supply load of the alternating current power grid 200 and a transformer connected with the alternating current power grid 200 in a peak period can be reduced, so that the power consumption in each period can be more uniform, and the running efficiency of the alternating current power grid 200 can be improved.

In some embodiments, the power conversion device 100 may further include a direct current conversion (Direct Current to Direct Current, DC-DC) circuit (not shown). Then the DC-DC circuit is provided between the photovoltaic interface 90 and the inverter 10 for maximum power tracking. At this time, the battery interface 80 may be connected to the output side (i.e., direct current bus) of the DC-DC circuit. In some scenarios, after the photovoltaic module 500 performs maximum power tracking through the DC-DC circuit, its output power is transmitted to the DC bus, and is used as the input power of the inverter 10 together with the output power of the battery pack 400.

In the embodiment of the present application, the circuit configuration of the inverter 10 is not limited, and for example, the inverter 10 may be a full bridge inverter or a half bridge inverter or the like. The inverter 10 may control the power conversion process and the operating state by the controller 70. The controller 70 may employ a micro control unit (Microcontroller Unit, MCU) or other control circuitry.

The grid-connected switch unit 20 may include at least two groups of grid-connected switches connected in series to prevent the whole grid-connected switch unit 20 from being unable to open because one group of grid-connected switches is stuck. Moreover, each group of grid-connected switches can be correspondingly arranged according to the wiring requirements of the grid-connected interfaces 30.

For example, as shown in fig. 1 and 2, the grid-connected switch unit 20 is provided with two groups of grid-connected switches, respectively: K1-K4, K1 '-K4'. When the grid-connected interface 30 needs to be connected to the three-phase line and the neutral line (i.e. three-phase four-wire grid-connected), each group of grid-connected switches may include a phase line switch corresponding to the three-phase line R, S, T (see K1-K3 or K1' to K3' in fig. 1 and 2) and a neutral line switch corresponding to the neutral line N (see K4 or K4' in fig. 1 and 2), so that the output end r, s, t, N of the inverter 10 may be connected to the phase line R, S, T and the neutral line N one by one through the corresponding grid-connected switches. For another example, when the grid-connected interface 30 needs to be connected to a three-phase line (i.e., three-phase three-line grid-connected), each group of grid-connected switches may include a phase line switch corresponding to the three-phase line, and the neutral line switch is omitted. Correspondingly, the output ends r, s and t of the inverter 10 can be connected with the phase lines R, S, T one by one through corresponding grid-connected switches.

Similarly, the bypass switch unit 40 may also include at least two groups of bypass switches connected in series, the load switch unit 60 may also include at least two groups of load switches connected in series, and each group of bypass switches and each group of load switches may be configured accordingly according to the wiring requirements of the load interface 50.

For example, as shown in fig. 1 and 2, the load interface 50 is connected to the terminal a, b, c, n of the ac load 300, and correspondingly, each set of load switches may also include switching elements K5-K8 or K5 '-K8' corresponding to the terminal a, b, c, n, so that the output r, s, t, n of the inverter 10 may be connected to the terminal a, b, c, n one by one through a corresponding bypass switch. Each set of load switches may include switching elements K9-K12 or K9 '-K12' corresponding to terminals a, b, c, n such that output r, s, t, n of inverter 10 may be connected one-to-one with terminals a, b, c, n through the corresponding load switch.

It is understood that the grid-connected switch may employ a corresponding type of switching element according to practical situations, for example, at least one of a mechanical switch including but not limited to a relay, a contactor, etc., and a semiconductor switch including but not limited to a triode, a MOSFET, an IGBT, etc. may be employed. The grid-tie switch may be controlled in on-off state by the controller 70. The phase line switch and the neutral line switch in the same group of grid-connected switches can be controlled independently. The grid-connected switches of different groups can be controlled independently. The structure and control manner of the load switch and the bypass switch are the same as or similar to those of the grid-connected switch, so that reference is made to the related description of the grid-connected switch, and the description is not repeated here.

The ac power grid 200 may be, for example, a utility grid, other local power grid, or a micro-grid. Ac load 300 may be, for example, various types of ac loads in a home.

The battery pack 400 may include a battery cell (not shown) and a battery management system (Battery Management System, BMS, not shown), where the battery cell may be one battery cell, or may be a plurality of battery cells connected in series, parallel, or series-parallel, and the positive and negative poles of the battery cell constitute the positive and negative poles of the battery pack 400. The BMS is connected to the battery cell unit and the controller 70. Accordingly, the controller 70 may manage the charge and discharge states of the battery cells through the BMS. In some embodiments, the energy storage system 1000 of fig. 2 may further include a dc converter (not shown). One end of the dc converter is electrically connected to the positive and negative electrodes of the battery pack 400, and the other end of the dc converter is electrically connected to the battery interface 80. The dc converter may also be connected to the controller 70 or the BMS so that the dc power may be converted under the control of the controller 70 or the BMS to adjust the charge power or the discharge power of the battery pack 400. It will be appreciated that the circuit structure of the dc converter is not limited, and the dc converter may include any of a Boost (Boost) circuit, a Buck (Buck) circuit, and/or a Buck-Boost (Buck-Boost) circuit. Further examples, the dc converter may employ a dual active full bridge (Dual Active Bridge, DAB) converter. It is understood that the dc converter may be integrated into the battery pack 400 or may be provided separately, which is not limited herein.

The photovoltaic module 500 may include one photovoltaic panel or include a plurality of photovoltaic panels connected in series, parallel, or series-parallel, without limitation. In some embodiments, when the power conversion device 100 further includes a DC-DC circuit for maximum power tracking, the DC-DC circuit may also be disposed in the photovoltaic panel, and of course, may be disposed independently, which is not limited herein.

It should be understood that the number of the photovoltaic modules 500 and the battery packs 400 may be not limited, and may be specifically selected according to the actual situation, which is within the scope of protection of the present application. The number of battery interfaces 80 in the power conversion device 100 corresponds to the number of battery packs 400, and the number of photovoltaic interfaces 90 corresponds to the number of photovoltaic modules 500.

In the power conversion device 100, the battery interface 80 and the photovoltaic interface 90 are both dc interfaces, and the battery interface 80 and the photovoltaic interface 90 are different in the specifications of the insertion hole and the wire harness used, and are easy to distinguish, so that reverse connection is not easy.

The grid-connected interface 30 and the load interface 50 are both ac interfaces, but the jacks of the grid-connected interface 30 and the load interface 50 are similar in appearance, and the specifications of the used wire harnesses are the same or similar, so that when the grid-connected interface 30 needs to be connected to the ac power grid 200 and the load interface 50 needs to be connected to the ac load 300, the situation that the grid-connected interface 30 and the load interface 50 are reversely connected may occur. In this case, the ac load 300 is actually connected to the grid-connected interface 30, and the ac power grid 200 is actually connected to the load interface 50, so that the inverter 10 cannot supply power to the ac load 300 through the load interface 50, and damage to the inverter 10 may be caused by accessing power grid energy through the load interface 50.

Therefore, the embodiment of the application provides an inverter interface wiring detection method, which can detect whether the grid-connected interface 30 and the load interface 50 are reversely connected, so that the safe operation of the inverter 10 and the normal power supply of the ac load 300 are facilitated.

The following describes an interface connection detection method of an inverter provided in an embodiment of the present application.

Fig. 3 is a flowchart of an interface connection detection method of an inverter according to an embodiment of the present application. In the embodiment of the present application, the interface wiring detection method of the inverter may be performed by the controller 70 in the power conversion apparatus 100 described above. Of course, in other embodiments, the method may also be implemented by a device/electronic device/processor or the like dedicated to detecting the interface wiring condition of the inverter 10 described above.

Specifically, as shown in fig. 3, the method for detecting the interface connection of the inverter includes:

step S101: and when the inverter stops running and the grid-connected switch unit, the load switch unit and the bypass switch unit are all disconnected, acquiring a first voltage of the grid-connected interface.

In step S101, the first voltage refers to an interface voltage of the grid-connected interface 30 in a case where the inverter 10 stops operating and the grid-connected switching unit 20, the load switching unit 60, and the bypass switching unit 40 are all turned off. The controller 70 may detect the first voltage of the grid-tie interface 30 through a voltage detection circuit. The voltage detection circuit may be provided independently, or may be integrated into the controller 70, which is not limited herein.

Step S102: and confirming the wiring detection results of the grid-connected interface and the load interface according to the first voltage and the preset grid voltage.

In step S102, the preset grid voltage refers to the grid voltage in the case where the ac grid 200 is operating normally. The method for obtaining the preset power grid voltage is not limited, for example, the preset power grid voltage may be stored in the controller 70 in advance, or may be obtained by the controller 70 communicating with the APP end or the device end (for example, a mobile phone, a tablet, a computer, an upper computer, or other electronic terminals).

It will be appreciated that when the inverter 10 is not operating and the grid-connected switching unit 20, the load switching unit 60 and the bypass switching unit 40 are all off, since the inverter 10 is not output, in the case where the grid-connected interface 30 and the load interface 50 are properly wired (hereinafter referred to as positive connection), it will be that the grid-connected interface 30 is connected to the ac power grid 200 and disconnected from the inverter 10, and the load interface 50 is connected to the ac load 300 and disconnected from both the inverter 10 and the ac power grid 200. If the grid-connected interface 30 and the load interface 50 are connected in error (hereinafter referred to as reverse connection), the grid-connected interface 30 is connected to the ac load 300, and the ac power grid 200 is connected to the load interface 50. Since the interface connection relationship between the forward and reverse connection changes, there is a great difference in the interface voltage of the grid-connected interface 30 between the forward and reverse connection when the inverter 10 does not output.

Therefore, in the method for detecting the connection of the interface of the inverter according to the embodiment of the present application, when the inverter 10 stops operating and the grid-connected switch unit 20, the load switch unit 60 and the bypass switch unit 40 are all turned off, the first voltage of the grid-connected interface 30 may be detected, and the first voltage may be related to the ac power grid 200 (corresponding to the positive connection condition) or related to the ac load 300 (corresponding to the negative connection condition), and further, the connection detection result of the grid-connected interface 30 and the load interface 50 may be confirmed according to the first voltage and the preset power grid voltage. Therefore, by the method of the embodiment of the application, whether the grid-connected interface 30 and the load interface 50 are reversely connected can be detected, so that the situation that the alternating current load 300 cannot be powered up due to the fact that the grid-connected interface 30 and the load interface 50 are reversely connected is prevented, and the inverter 10 is damaged is avoided.

It is further understood that if the inverter 10 is not operating and the grid-connected switching unit 20, the load switching unit 60 and the bypass switching unit 40 are all off, the grid-connected interface 30 is connected to the ac power grid 200 when the grid-connected interface 30 and the load interface 50 are being connected, and thus, at this time, the ac power grid 200 provides ac power to cause the grid-connected interface 30 to generate a first voltage that is consistent with the grid voltage of the ac power grid 200.

When the grid-connected interface 30 and the load interface 50 are connected reversely, the grid-connected interface 30 is connected with the ac load 300, and the ac load 300 is in the power-off state because the bypass switch unit 40, the load switch unit 60 and the grid-connected switch unit 20 are all disconnected at this time, so that the first voltage of the grid-connected interface 30 is 0, that is, the first voltage may not be consistent with the grid voltage of the ac grid 200.

In addition, when the inverter 10 stops running and the grid-connected switch unit 20, the load switch unit 60 and the bypass switch unit 40 are all turned off, if the ac power grid 200 is powered down at this time, the first voltage of the grid-connected interface 30 is 0 no matter whether the grid-connected interface 30 and the load interface 50 are connected in forward or reverse, and the first voltage of the grid-connected interface 30 is inconsistent with the grid voltage of the ac power grid 200.

Therefore, in the case that the first voltage is inconsistent with the grid voltage, the connection detection result may be a misconnection, or the ac grid 200 may not be powered down. Therefore, it is further required to identify that the first voltage is inconsistent with the grid voltage due to the reverse connection of the interface, so as to avoid erroneous judgment.

Therefore, in the embodiment of the present application, referring to fig. 4, in step S102, confirming the connection detection result of the grid-connected interface 30 and the load interface 50 according to the first voltage and the preset grid voltage may include:

Step S202: and confirming whether the first voltage is consistent with the preset power grid voltage.

Step S203A: and when the first voltage is consistent with the preset power grid voltage, confirming that the wiring detection result is that the wiring is correct and the alternating current power grid is not powered down.

Step S203B: and when the first voltage of the grid-connected interface is inconsistent with the preset grid voltage, controlling the bypass switch unit to be conducted.

Step S204: and when the bypass switch unit is conducted, acquiring a second voltage of the grid-connected interface.

In step S204, the second voltage is the interface voltage of the grid-connected interface 30 when the inverter 10 stops running and the grid-connected switch unit 20 and the load switch unit 60 are both turned off and the bypass switch unit 40 is turned on. The controller 70 may detect the second voltage of the grid-connected interface 30 through a voltage detection circuit, which is the same as or similar to the first voltage.

Step S205: and confirming whether the second voltage is consistent with the preset power grid voltage.

Step S206A: and when the second voltage is consistent with the preset power grid voltage, confirming that the wiring detection result is that the wiring of the grid-connected interface and the load interface is wrong.

Conversely, when the second voltage is inconsistent with the preset grid voltage, it indicates that the two voltages are inconsistent due to the power failure of the ac grid 200.

In general, in the case of a grid connection interface 30 that is connected in reverse to the load interface 50, the load interface 50 is connected to the ac power grid 200. If the ac power grid 200 is operating normally at this time, the bypass switch unit 40 is turned on, and the grid connection interface 30 and the load interface 50 are connected. Further, the ac power grid 200 connected to the load interface 50 is also connected to the grid-connected interface 30, so that the grid-connected interface 30 can generate a second voltage consistent with the preset grid voltage. If the ac power grid 200 is powered down at this time, even if the bypass switch unit 40 is turned on, so that the grid-connected interface 30 is connected to the ac power grid 200, the second voltage of the grid-connected interface 30 is also 0, that is, the second voltage may not be consistent with the grid voltage. Therefore, in the above steps, it can be further confirmed that the grid connection interface 30 and the load interface 50 are reversely connected or the ac power grid 200 is powered down according to the second voltage and the preset grid voltage.

It will be appreciated that the power grid may quickly resume power after a momentary power loss, or may not resume power until after a power loss. Thus, in order to timely continue to execute the detection logic after the ac power grid 200 is powered back, please continue to refer to fig. 4, the interface connection detection method may further include:

Step S206B: and when the second voltage is inconsistent with the preset power grid voltage, controlling the load switch unit to be conducted, and continuously detecting the third voltage of the grid-connected interface.

It will be appreciated that the purpose of controlling the conduction of the load switching unit 60 here is to provide for off-grid operation of the inverter 10 so that in the event of a prolonged power outage of the ac grid 200 the inverter 10 may be subsequently quickly started to continue executing the detection logic.

In step S206B, the third voltage is the interface voltage of the grid-connected interface 30 when the inverter 10 is stopped and the grid-connected switching unit 20 is turned off and the bypass switching unit 40 and the load switching unit 60 are both turned on. The third voltage may be obtained in the same or similar manner as the first voltage and the second voltage, and reference is specifically made to the foregoing description, and the description thereof will not be repeated here.

Step S207: and confirming whether the third voltage detected in the first preset time period is consistent with the preset grid voltage.

The first preset duration may be set correspondingly according to actual situations, for example, may be 30s (seconds). The controller 70 may detect the third voltage of the grid-tie interface 30 multiple times within the first preset time period.

Step S208A: if the third voltage is detected to be consistent with the preset power grid voltage within the first preset time period, the grid-connected switch unit, the load switch unit and the bypass switch unit are controlled to be disconnected, and the step of acquiring the first voltage of the grid-connected interface is executed in a returning mode (namely, step S201/step S101).

In the above process, by continuously detecting the third voltage and detecting that the third voltage is consistent with the preset power grid voltage within the first preset time period, the ac power grid 200 can be directly confirmed to restore power supply, and then the detection logic of steps S101 to S102 can be continuously executed. If the third voltages detected in the first preset time period are inconsistent with the preset grid voltage, it is indicated that the ac grid 200 is still in the power-down state.

In order to continue to execute the detection logic even in the event of a long-term power loss of the ac power grid 200, please refer to fig. 4 again, the interface connection detection method may further include:

step S208B: and if the third voltage detected in the first preset time period is inconsistent with the preset power grid voltage, controlling the bypass switch unit to be disconnected and controlling the inverter to output the preset voltage.

As can be appreciated, in step S208B, the controller 70 controls the inverter 10 to operate off-grid briefly to output a preset voltage. The preset voltage and the operation time period may be set according to actual situations, for example, the preset voltage may be determined according to the required voltage of the ac load 300 and the output capability of the inverter 10. Alternatively, the preset voltage may be user-defined, and may be set to 50V, for example. The 50V can avoid the safety risk caused by the too high voltage and also avoid the overcurrent stress risk caused by the too high output current of the inverter 10 caused by the too low voltage. The off-grid operation time period may be set to, for example, 1 to 2 seconds or more.

Step S209A: and if the output current of the inverter does not trigger the step-by-step current limiting protection or the overcurrent protection, confirming that the wiring detection result is that the wiring is correct and the AC power grid is powered down.

In step S209A, the controller 70 may detect an output current at the output terminal of the inverter 10 through an internal or external current detection circuit.

Understandably, both the step-by-step current limiting protection and the overcurrent protection are used to control the inverter 10 to stop operating when the output current of the inverter 10 exceeds a preset current threshold, so as to prevent the inverter 10 from being damaged due to excessive output current. The preset current threshold corresponds to a short-circuit current of the inverter 10 or approximates to the short-circuit current of the inverter 10, and the magnitude thereof may be determined according to practical situations, which is not limited herein.

In some embodiments, the preset current threshold that triggers the wave-by-wave current limiting protection and that triggers the over-current protection may be different. The step-by-step current limiting protection point is a first preset current threshold, and the overcurrent protection point is a second preset current threshold. The step-by-step current limiting protection is usually triggered by hardware, when the output current reaches a first preset current protection threshold value, the step-by-step current limiting is triggered, and then the output of the inverter triggers the wave blocking in the current output period and continues to be output in the next period. The over-current protection is typically triggered by software, such as a program in the controller, and the inverter stops outputting when the output current continues to reach a second preset current threshold.

It will be appreciated that in the above steps, both the grid-tie switch unit 20 and the bypass switch unit 40 are turned off and the load switch unit 60 is turned on. If the connection between the load interface 50 and the grid-connected interface 30 is correct, the inverter 10 is connected to the load interface 50, and the grid-connected interface 30 is connected to the ac power grid 200, and at this time, the preset voltage output by the inverter 10 is transmitted to the load interface 50, so that the inverter 10 can generate a corresponding output current. The output current depends on the preset voltage and the equivalent impedance of the connected ac load 300. In some embodiments, the preset voltage may be a value less than the nominal voltage of the inverter when operating normally off-grid, to avoid triggering the step-by-step current limiting and the over-current protection when the load interface 50 is properly wired to the grid-tie interface 30. In this way, when the load interface 50 and the grid-connected interface 30 are connected correctly, and the load interface 50 is connected to a conventional load and the preset voltage meets the requirement, the output current of the inverter will not trigger the step-by-step current limiting protection or the overcurrent protection.

Step S209B: and if the output current of the inverter triggers the step-by-step current limiting protection or the overcurrent protection, confirming that the wiring detection result is a wiring error of the grid-connected interface and the load interface.

It can be understood that if the load interface 50 and the grid-connected interface 30 are connected incorrectly, which means that the inverter 10 is connected to the grid-connected interface 30, and the load interface 50 is connected to the ac power grid 200, the preset voltage output by the inverter 10 will be transmitted to the grid-connected interface 30 at this time, so that the inverter 10 can generate a corresponding output current. The output current depends on the preset voltage and the equivalent impedance of the connected ac grid 200. Since the power failure of the ac power grid 200 corresponds to a short circuit between the phase line and the neutral line of the ac power grid 200, the equivalent impedance of the power grid is greatly reduced, for example, may approach 0. Therefore, the output current of the inverter 10 will be equal to or close to the short-circuit current at this time. Therefore, in this case, the step-by-step current limiting protection function or the overcurrent protection function of the inverter 10 will be triggered.

Therefore, according to whether the output current of the inverter 10 triggers the step-by-step current limiting protection or the overcurrent protection, the connection condition of the grid-connected interface 30 and the load interface 50 can be confirmed.

In a comprehensive view, the interface wiring detection method of the embodiment of the present application can detect the wiring conditions of the grid-connected interface 30 and the load interface 50, and can avoid erroneous judgment caused by the power failure of the ac power grid 200, whether the ac power grid 200 is in normal operation (i.e., not powered down), or in the case of recovering from normal operation after the power failure of the ac power grid 200, or in the case of long-term power failure of the ac power grid 200. Therefore, the interface wiring detection method is higher in detection accuracy and more reliable in detection result. In this way, the situation that the power conversion device 100 cannot supply power to the ac load 300 and even is damaged due to the wrong connection of the interface can be effectively prevented, so that the use safety and the use experience of the power conversion device 100 can be effectively improved.

For example, after step S203A, the interface connection detection method may further include:

and when the wiring detection result is that the wiring is correct and the alternating current power grid is not powered down, controlling the inverter to run in a grid-connected mode.

As another example, after step S206A, the interface connection detection method may further include:

and when the wiring detection result is that the wiring is correct and the alternating current power grid is not powered down, controlling the inverter to run in a grid-connected mode.

It will be appreciated that by controlling the inverter 10 to be in a proper operating state accordingly based on the wiring detection result, normal operation of the inverter 10 can be ensured, thereby avoiding affecting the service life of the inverter 10 and the power supply of the ac load 300.

In this embodiment of the present application, considering that the grid-connected switching unit 20 may have a switching element stuck and cannot be disconnected, so that the inverter 10 cannot be smoothly switched to the grid-connected operation state, referring to fig. 5, before controlling the grid-connected operation of the inverter 10, the interface connection detection method may further include:

step S301: and obtaining the adhesion state of the grid-connected switch unit.

In step S301, the controller 70 may detect an electrical signal associated with the grid-connected switching unit 20 through an internal or external detection circuit, so that the stuck state of the grid-connected switching unit 20 may be confirmed according to the electrical signal.

The electrical signal associated with the grid-connected switching unit 20 may be, for example, a voltage signal of an ac bus to which the grid-connected switching unit 20 is connected, or may be a voltage signal or a current signal of the grid-connected interface 30 and the load interface 50, and the like, and is not particularly limited herein, as long as it is used to confirm the adhesion state of the grid-connected switching unit 20.

In the embodiment of the present application, as shown in fig. 1 and 2, the grid-connected switch unit 20 may include two groups of grid-connected switches connected in series, and thus, the adhesion state of the grid-connected switch unit 20 may include the adhesion state of the two groups of grid-connected switches.

Step S302: and when the two groups of grid-connected switches are not adhered, controlling the grid-connected operation of the inverter.

In this embodiment, when it is determined that the two groups of grid-connected switch units 20 are not adhered, the controller 70 may control both the grid-connected switch units 20 and the load switch units 60 to be turned off, and the bypass switch unit 40 to be turned on, so that the ac power grid 200 may supply power to the ac load 300. At the same time, the controller 70 may control the inverter 10 to start. After the inverter 10 stably outputs, the controller 70 controls the grid-connected switch unit 20 to be turned on, and the bypass switch unit 40 and the load switch unit 60 are turned off, so that the inverter 10 can be in a grid-connected operation state, and meanwhile continuous and stable power supply to the ac load 300 is ensured.

Step S303: and acquiring the adhesion state of the load switch unit.

Understandably, step S303 may be performed in the case that at least one group of grid-connected switches is stuck.

In step S303, the manner of obtaining the blocking state of the load switch unit 60 is the same as or similar to the manner of obtaining the blocking state of the grid-connected switch unit 20, and the description in step S301 is specifically referred to, so that the description is not repeated here.

In the embodiment of the present application, as shown in fig. 1 and 2, the load switch unit 60 may include two sets of load switches connected in series, and thus, the stuck state of the load switch unit 60 may include the stuck state of the two sets of load switches.

Step S304: when at least one group of grid-connected switches are adhered and both groups of load switches are not adhered, a first prompt message is sent, the first prompt message is used for prompting a user to connect a grid-connected interface to an alternating current load and connect the load interface to an alternating current power grid.

Step S305: and after the grid-connected interface is confirmed to be connected with an alternating current load and the load interface is confirmed to be connected with an alternating current power grid, controlling the inverter to perform grid-connected operation.

It will be appreciated that the grid-tie switch unit 20 requires two sets of normally functioning grid-tie switches to be put into service according to the corresponding industry standard requirements. Therefore, in the case that both groups of grid-connected switches are not adhered, the grid-connected switch unit 20 can be controlled to be turned on, so that the inverter 10 can be operated in a grid-connected mode.

When at least one group of grid-connected switches in the grid-connected switch unit 20 are adhered, the grid-connected switch unit 20 cannot meet the requirements of industry standards, and therefore cannot be put into use. Therefore, in the case that neither of the two groups of load switches in the load switch unit 60 is adhered, the grid-connected interface 30 may be connected to the ac load 300, and the load interface 50 may be connected to the ac power grid 200. In this way, the load switch unit 60 can serve as the grid-connected switch unit 20, and can be used to connect or disconnect the ac power grid 200 connected to the load interface 50 from the inverter 10. The grid-connected switch unit 20 can serve as a load switch unit 60, and can be used for connecting or disconnecting the ac load 300 connected to the grid-connected interface 30 with the inverter 10. Thus, the load interface 50 and the grid-connected interface 30 are exchanged, and the load switch unit 60 and the grid-connected switch unit 20 are exchanged.

After replacement, the load switch unit 60 serving as the grid-connected switch unit 20 has two groups of switches with normal functions, and thus can meet the requirements of industry standards, and can be put into use.

Grid-tie switch unit 20, acting as load switch unit 60, may have one set of switches that are functioning properly, another set of switches that are stuck, or both sets of switches may be stuck. The inverter 10 is to supply power to the ac load 300 for a long period of time due to the self-service strategy of the energy storage system 1000, so the load switch unit 60 is to maintain the on state. Therefore, in the grid-connected switch unit 20 serving as the load switch unit 60, whether one group of switches are adhered or both groups of switches are adhered, the load switch unit 60 can be in a conductive state, so that the load switch unit 60 can still realize the function of communicating the ac load 300 with the inverter 10.

Therefore, through the above-described switching self-checking process, it can be ensured that the switching unit connected to the grid-connected interface 30 is controllable, thereby ensuring that the off-grid operation state of the inverter 10 can be switched normally and smoothly. At the same time, the ac load 300 may still be powered normally.

Further, as shown in fig. 1 and 2, each set of grid-connected switches in the embodiments of the present application may include a phase line switch and a neutral line switch, so that in step S301, the adhesion state of the two sets of grid-connected switches may be confirmed according to the electrical signals associated with the phase line switch and the neutral line switch.

Specifically, referring to fig. 6, the process of obtaining the adhesion state of the grid-connected switch unit may include:

step S401: when the neutral line switches in the two groups of grid-connected switches are kept on, the phase line switches in the two groups of grid-connected switches are controlled to be alternately turned on, and the voltage of the alternating current bus is obtained.

That is, during the first period, the controller 70 controls the neutral switches K4 and K4' of the two sets of grid-connected switches to be on, controls the phase line switches K1 to K3 of one set of grid-connected switches to be on, and controls the phase line switches K1' to K3' of the other set of grid-connected switches to be off. In a second period after the first period, the controller 70 controls the neutral line switches K4 and K4' of the two groups of grid-connected switches to be kept on, and controls the phase line switches K1 to K3 of one group of grid-connected switches to be turned off and the phase line switches K1' to K3' of the other group of grid-connected switches to be turned on.

As can be appreciated, the ac bus includes a phase line (R/S/T as shown in fig. 1 and 2) and a neutral line (N as shown in fig. 1 and 2), and thus, during the first period and the second period, the controller 70 can detect a phase voltage between the phase line and the neutral line (the neutral line may serve as a voltage reference point), that is, a voltage of the ac bus, through the voltage detection circuit.

Step S402: and confirming whether the voltage of the alternating current bus is consistent with the preset power grid voltage or not when the phase line switches of the two groups of grid-connected switches are alternately conducted.

Step S403A: and if the voltage of the alternating current bus is consistent with the preset power grid voltage when the phase line switches of the two groups of grid-connected switches are alternately conducted, confirming that at least one group of grid-connected switches are adhered.

Step S403B: if the voltage of the alternating current bus is inconsistent with the preset power grid voltage when the phase line switches of the two groups of grid-connected switches are alternately conducted, confirming that the two groups of grid-connected switches are not adhered.

Understandably, when the neutral line switch of the two groups of grid-connected switches is kept on and the phase line switch of one group of grid-connected switches is stuck, the phase line switch is in an on state because the phase line switch cannot be normally turned off. Therefore, the phase lines corresponding to the ac power grid 200 and the phase line switch, the inverter 10, and the neutral line may be connected in a loop, so that the voltage between the phase line and the neutral line may be consistent with the grid voltage of the ac power grid 200.

When the neutral line switches of the two groups of grid-connected switches are kept on and the phase line switch of one group of grid-connected switches is not adhered, the phase line switch can be normally turned off, so that the phase line, the inverter 10 and the neutral line corresponding to the alternating current power grid 200 and the phase line switch cannot be connected into a loop, and the voltage between the phase line and the neutral line is basically equal to 0, that is, the voltage between the phase line and the neutral line is inconsistent with the preset power grid voltage.

Therefore, in the process, whether the two groups of grid-connected switches are adhered or not can be confirmed according to the voltage of the alternating current bus and the preset power grid voltage.

Of course, in some embodiments, each set of grid-tie switches may also include phase line switches, excluding neutral line switches. In this case, the process of acquiring the stuck state of the grid-connected switching unit 20 may omit the neutral line switch. For example, the phase line switches in the two groups of grid-connected switches can be directly controlled to be alternately conducted, and the voltage between the phase line and a voltage reference point (such as ground) is obtained, wherein the voltage is the voltage of an alternating current bus. And further, the adhesion condition of the two groups of grid-connected switches can be confirmed according to the voltage of the alternating current bus and the preset power grid voltage.

In addition, the interface wiring detection method of the embodiment of the application can further comprise the following steps:

when the connection detection result is that the connection of the grid-connected interface and the load interface is wrong (i.e. after step S206A or step S209B or after step S209B), outputting second prompting information, wherein the second prompting information is used for prompting that the connection of the grid-connected interface and the load interface is wrong.

It will be appreciated that in some embodiments, the power conversion apparatus 100 or other devices in the energy storage system 1000 may be provided with a display screen, and the controller 70 may output the second prompt information to the display screen to visually display the second prompt information. In other embodiments, the controller 70 may also output the second prompting message to the device side or the APP side through wireless communication. In this way, the user or related personnel can conveniently know that the current grid-connected interface 30 and the load interface 50 are reversely connected, and corresponding maintenance measures need to be taken.

It should be noted that, for simplicity of description, the foregoing method embodiments are all described as a series of acts, but it should be understood by those skilled in the art that the present application is not limited by the order of acts described, as some steps may be performed in other orders or concurrently in accordance with the present application.

Referring to fig. 7, a schematic diagram of an electronic device provided in an embodiment of the present application is shown.

As shown in fig. 7, the electronic device 600 may include a processor 601 and a memory 602.

The processor 601 may be a central processing unit (central processing unit, CPU), but may also be other general purpose processors, digital signal processors (digital signal processor, DSP), application specific integrated circuits (application specific integrated circuit, ASIC), field programmable gate arrays (field programmable gate array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or any conventional processor or the like.

The Memory 602 may be, but is not limited to, a read-Only Memory (ROM) or other type of static storage device that can store static information and instructions, a random access Memory (random access Memory, RAM) or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-Only Memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), a compact disc read-Only Memory (Compact Disc Read-Only Memory) or other optical disk storage, a compact disc storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory 602 may be stand alone and may be coupled to the processor 601 via a bus. The memory 602 may also be integral with the processor 601.

The memory 602 is used for storing a program, instructions or codes for executing the above method for detecting the interface wiring of the inverter. The processor 601 is configured to execute programs, instructions or codes stored in the memory 602 to complete some or all of the steps of the interface wiring detection method of the inverter in the embodiments shown in fig. 3 to 6.

Referring to fig. 8, a schematic diagram of an interface connection detection device of an inverter according to an embodiment of the present application is shown. The inverter interface wiring detection device 700 can be used to implement the inverter interface wiring detection method described above.

As shown in fig. 8, the interface wiring detection device 700 of the inverter includes an acquisition module 701 and a confirmation module 702 connected.

The obtaining module 701 is configured to obtain a first voltage of the grid-connected interface when the inverter stops running and the grid-connected switch unit, the load switch unit and the bypass switch unit are all turned off.

The confirmation module 702 is configured to confirm a connection detection result of the grid-connected interface and the load interface according to the first voltage and a preset grid voltage.

It will be appreciated that the division of the modules in the above-described inverter interface connection detection device 700 is for illustration only, and in other embodiments, the inverter interface connection detection device 700 may be divided into different modules as needed to perform all or part of the functions of the above-described inverter interface connection detection device 700.

The specific implementation of each module in the embodiments of the present application may also correspond to the corresponding description of the embodiments of the method for detecting the interface connection of the inverter shown in fig. 3 to 6, so that the detailed description thereof will not be repeated here.

The functional modules in the embodiments of the present application may be all integrated into one processing module/unit, or each module may be separately used as one module, or two or more modules may be integrated into one module; the integrated modules may be implemented in hardware or in hardware plus software functional modules.

The integrated modules described above may also be stored in a computer readable storage medium if implemented as software functional modules and sold or used as a stand-alone product. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially or partly contributing to the prior art, and the computer software product may be stored in a storage medium, and include several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a removable storage device, ROM, RAM, magnetic or optical disk, or other medium capable of storing program code.

The embodiments of the present application also provide a computer readable storage medium for storing a computer program or code, which when loaded and executed by a processor, implements the steps in the embodiments of the method for detecting an interface connection of an inverter described above, for example, fig. 3 to 6. Computer-readable storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data. Embodiments of the computer readable storage medium may refer to the description of the memory 602 in fig. 7, which is not repeated here.

Finally, it should be noted that the above embodiments are merely for illustrating the technical solution of the present application and not for limiting, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present application may be modified or substituted without departing from the spirit and scope of the technical solution of the present application.

Claims (10)

1. The interface wiring detection method of the inverter is characterized in that an output end of the inverter is connected with a grid-connected interface through a grid-connected switch unit and a load interface through a load switch unit, the grid-connected interface is also connected with the load interface through a bypass switch unit, the grid-connected interface is used for being connected with an alternating current power grid, and the load interface is used for being connected with an alternating current load; the interface wiring detection method comprises the following steps:

When the inverter stops running and the grid-connected switch unit, the load switch unit and the bypass switch unit are all disconnected, acquiring a first voltage of the grid-connected interface;

and confirming the wiring detection results of the grid-connected interface and the load interface according to the first voltage and the preset grid voltage.

2. The method for detecting the connection of the interface according to claim 1, wherein the step of confirming the connection detection results of the grid-connected interface and the load interface according to the first voltage and a preset grid voltage comprises the steps of:

when the first voltage is consistent with the preset power grid voltage, confirming that the wiring detection result is that the wiring is correct and the alternating current power grid is not powered down;

when the first voltage of the grid-connected interface is inconsistent with the preset grid voltage, controlling the bypass switch unit to be conducted;

when the bypass switch unit is conducted, obtaining a second voltage of the grid-connected interface;

and when the second voltage is consistent with the preset power grid voltage, confirming that the wiring detection result is that the wiring of the grid-connected interface and the load interface is wrong.

3. The interface wiring detection method as in claim 2, wherein said interface wiring detection method further comprises:

When the second voltage is inconsistent with the preset power grid voltage, controlling the load switch unit to be conducted, and continuously detecting a third voltage of the grid-connected interface;

if the third voltage is detected to be consistent with the preset power grid voltage within the first preset time period, the grid-connected switch unit, the load switch unit and the bypass switch unit are controlled to be disconnected, and the step of acquiring the first voltage of the grid-connected interface is executed in a returning mode.

4. The interface wiring detection method as in claim 3, wherein said interface wiring detection method further comprises:

if the third voltage detected in the first preset time period is inconsistent with the preset power grid voltage, the bypass switch unit is controlled to be disconnected, and the inverter is controlled to output preset voltage;

if the output current of the inverter does not trigger the step-by-step current limiting protection or the overcurrent protection, confirming that the wiring detection result is correct in wiring and the AC power grid is powered down;

and if the output current of the inverter triggers the step-by-step current limiting protection or the overcurrent protection, confirming that the wiring detection result is the wiring error of the grid-connected interface and the load interface.

5. The interface wiring detection method as in claim 4, wherein the interface wiring detection method further comprises:

and when the wiring detection result is that the wiring is correct and the alternating current power grid is powered down, controlling the inverter to run off the grid.

6. The interface wiring detection method according to any one of claims 1 to 4, wherein the interface wiring detection method further comprises:

and when the wiring detection result is that the wiring is correct and the alternating current power grid is not powered down, controlling the inverter to run in a grid-connected mode.

7. The interface wiring detection method according to claim 6, wherein the grid-connected switch unit includes two groups of grid-connected switches connected in series, and the load switch unit includes two groups of load switches connected in series;

before controlling the grid-connected operation of the inverter, the interface wiring detection method further comprises the following steps:

acquiring an adhesion state of the grid-connected switch unit;

when two groups of grid-connected switches are not adhered, controlling the inverter to perform grid-connected operation;

acquiring an adhesion state of the load switch unit;

when at least one group of grid-connected switches are adhered and both groups of load switches are not adhered, a first prompt message is sent, wherein the first prompt message is used for prompting a user to connect the grid-connected interface to the alternating current load and connect the load interface to the alternating current power grid;

And after the grid-connected interface is confirmed to be connected with the alternating current load and the load interface is confirmed to be connected with the alternating current power grid, controlling the inverter to perform grid-connected operation.

8. The method for detecting interface connection according to claim 7, wherein each group of grid-connected switches includes a phase line switch and a neutral line switch, and the obtaining the adhesion state of the grid-connected switch unit includes:

when the neutral line switches in the two groups of grid-connected switches are kept on, controlling the phase line switches in the two groups of grid-connected switches to be alternately conducted, and acquiring the voltage of an alternating current bus;

if the voltage of the alternating current bus is consistent with the preset power grid voltage when the phase line switches of the two groups of grid-connected switches are alternately conducted, confirming that at least one group of grid-connected switches are adhered;

and if the voltage of the alternating current bus is inconsistent with the preset power grid voltage when the phase line switches of the two groups of grid-connected switches are alternately conducted, confirming that the two groups of grid-connected switches are not adhered.

9. The power conversion device is characterized by comprising an inverter, a grid-connected switch unit, a load switch unit, a bypass switch unit, a grid-connected interface, a load interface and a controller; the output end of the inverter is connected with the grid-connected interface through the grid-connected switch unit, and is connected with the load interface through the load switch unit, the grid-connected interface is also connected with the load interface through the bypass switch unit, the grid-connected interface is used for being connected with an alternating current power grid, and the load interface is used for being connected with an alternating current load; the controller is configured to execute the interface wiring detection method of the inverter according to any one of claims 1 to 8.

10. An energy storage system comprising a battery pack, a photovoltaic module, and the power conversion apparatus of claim 9, the power conversion apparatus further comprising a photovoltaic interface for connection to the photovoltaic module, and a battery interface for connection to the battery pack.