Optical storage converter and grid-connected and off-grid switching device, method, system and equipment thereof

Abstract

The invention relates to an optical storage converter and a grid-connected and off-grid switching device, method, system and equipment thereof, the grid-connected and off-grid switching device comprises an electric signal detection unit, a gear switching trigger unit, a grid-connected and off-grid gear switching switch and a control unit, and the control unit outputs a gear switching trigger signal corresponding to an electric signal. And a power-off protection mechanism of the optical storage converter is triggered under a power-off condition, so that the fault problem caused by sudden power-off due to a power grid fault in the prior art is solved; and outputting a control signal corresponding to the gear switching trigger signal through a gear switching trigger unit according to the gear switching trigger signal, so as to perform grid-connected and off-grid state switching on the optical storage converter through a grid-connected and off-grid gear switching switch according to the control signal, thereby realizing automatic switching of the grid-connected and off-grid states. Therefore, the problem caused by the fact that two independent interfaces are adopted to achieve grid-connected and off-grid separated design in the prior art is solved, and the operation stability and safety of the optical storage converter can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic energy storage technology, and in particular to a photovoltaic energy storage converter and an on-grid and off-grid switching device, method, system, and equipment thereof. Background Art

[0002] With the rapid development of photovoltaic energy storage technology, photovoltaic energy storage integrated products are widely used. Taking the micro photovoltaic energy storage system as an example, the micro photovoltaic energy storage system is a mobile energy storage power supply system with the characteristics of flexibility and portability, which makes it applicable to various life scenarios.

[0003] Specifically, the power supply of the photovoltaic energy storage system can meet the power supply needs of most household appliances, and the photovoltaic energy storage system will use solar clean energy as the highest priority criterion, making the most of clean energy, and has good research and promotion and application value. At present, the grid-connected and off-grid AC interface of the photovoltaic energy storage system usually adopts two independent interfaces to achieve the separate grid-connected and off-grid design. However, since the grid-connected and off-grid AC interface of the photovoltaic energy storage system adopts two independent interfaces to achieve the separate grid-connected and off-grid design, in the case of a sudden power outage due to a grid failure, the photovoltaic storage inverter may fail due to the sudden power outage of the entire machine, affecting the safe and stable operation of the photovoltaic energy storage system. Summary of the invention

[0004] The present application provides a photovoltaic energy storage converter and its on-grid and off-grid switching device, method, system, and equipment to solve the problem of poor safe and stable operation performance of photovoltaic energy storage systems caused by power outages due to grid faults in the existing related technologies.

[0005] In a first aspect, an embodiment of the present application provides a grid-connected and off-grid switching device for a photovoltaic storage converter, comprising: an electrical signal detection unit, a switching trigger unit, a grid-connected and off-grid switching switch, and a control unit;

[0006] Wherein, the first detection end of the electrical signal detection unit is electrically connected to the detection end of the grid-connected and off-grid switching switch, the second detection end of the electrical signal detection unit is electrically connected to the AC bus of the photovoltaic storage converter, the third detection end of the electrical signal detection unit is electrically connected to the AC bus of the power grid, the first end of the grid-connected and off-grid switching switch is electrically connected to the AC bus of the photovoltaic storage converter, the second end of the grid-connected and off-grid switching switch is electrically connected to the AC bus of the power grid, the control end of the grid-connected and off-grid switching switch is electrically connected to the output end of the switching trigger unit, the control input end of the switching trigger unit is electrically connected to the switching output end of the control unit, and the detection input end of the control unit is electrically connected to the output end of the electrical signal detection unit;

[0007] The electrical signal detection unit is used to detect electrical signals;

[0008] The control unit is used to output a gear switching trigger signal corresponding to the electrical signal to the gear switching trigger unit according to the electrical signal, and trigger a power-off protection mechanism of the photovoltaic storage converter in the event of a power failure;

[0009] The gear switching trigger unit is used to output a control signal corresponding to the gear switching trigger signal to the on-grid and off-grid switching switch according to the gear switching trigger signal;

[0010] The on-grid and off-grid switching switch is used to switch the on-grid and off-grid states of the photovoltaic storage converter according to the control signal.

[0011] Optionally, the on-grid and off-grid switching switch includes an on-grid and off-grid contactor, a first end of the on-grid and off-grid contactor is electrically connected to the AC busbar of the photovoltaic storage converter, and a second end of the on-grid and off-grid contactor is electrically connected to the AC busbar of the power grid;

[0012] The control signal is divided into a first control signal and a second control signal, the first control signal is used to control the on-grid and off-grid contactor to close, and the second control signal is used to control the on-grid and off-grid contactor to open;

[0013] When the grid-connected and off-grid contactor is closed, the photovoltaic storage converter enters the grid-connected state;

[0014] When the grid-connected and off-grid contactor is disconnected, the photovoltaic storage converter enters an off-grid state.

[0015] Optionally, the electrical signal detection unit includes a current sampling circuit, a first sampling end of the current sampling circuit is electrically connected to the AC bus of the photovoltaic storage converter, a second sampling end of the current sampling circuit is electrically connected to the DC bus of the photovoltaic storage converter, an output end of the current sampling circuit is electrically connected to a detection input end of the control unit, the first sampling end of the current sampling circuit is used to collect the AC bus current signal, the second sampling end of the current sampling circuit is used to collect the DC bus current signal, and the electrical signal includes the DC bus current signal and the AC bus current signal.

[0016] Optionally, the electrical signal detection unit includes a voltage sampling circuit, a first voltage sampling terminal of the voltage sampling circuit is electrically connected to the AC bus of the photovoltaic storage converter, and a second voltage sampling terminal of the voltage sampling circuit is electrically connected to the DC bus of the photovoltaic storage converter. The first voltage sampling terminal of the voltage sampling circuit is used to collect the AC bus voltage signal, and the second voltage sampling terminal of the voltage sampling circuit is used for the DC bus voltage signal. The electrical signal includes the DC bus voltage signal and the AC bus voltage signal.

[0017] In a second aspect, an embodiment of the present application provides a photovoltaic storage converter, comprising a grid-connected and off-grid switching device as described in any one of the first aspects of the present application.

[0018] Optionally, the photovoltaic storage converter further includes a bidirectional inverter module, and the bidirectional inverter module includes: a DC bus capacitor, a first transistor, a second transistor, a third transistor, a fourth transistor, a first inductor, and a second inductor;

[0019] Wherein, the control end of the first transistor, the control end of the second transistor, the control end of the third transistor and the control end of the fourth transistor are electrically connected to the driving control end of the control unit, the first end of the DC bus capacitor, the first end of the first transistor, the first end of the third transistor and the first DC bus of the photovoltaic storage converter are electrically connected, and the second end of the DC bus capacitor, the second end of the second transistor, the second end of the fourth transistor and the second DC bus of the photovoltaic storage converter are electrically connected;

[0020] The second end of the first transistor, the first end of the second transistor and the first end of the first inductor are electrically connected, the second end of the third transistor, the first end of the fourth transistor and the first end of the second inductor are electrically connected, the second end of the first inductor is electrically connected to the grid-connected and off-grid contactor in the grid-connected and off-grid switching device through the first AC bus of the photovoltaic storage converter, and the second end of the second inductor is electrically connected to the grid-connected and off-grid contactor in the grid-connected and off-grid switching device through the second AC bus of the photovoltaic storage converter.

[0021] Optionally, the above-mentioned photovoltaic storage converter further includes: a DC conversion module and a photovoltaic module;

[0022] The input end of the DC conversion module is electrically connected to the output end of the photovoltaic module, the first output end of the DC conversion module is electrically connected to the first end of the DC bus capacitor through the first DC bus electrical connection, and the second output end of the DC conversion module is electrically connected to the second end of the DC bus capacitor through the second DC bus electrical connection.

[0023] Optionally, the above-mentioned photovoltaic storage converter further includes: a power storage module and a display control module, and the DC conversion module includes a first DC conversion module and a second DC conversion module;

[0024] The input end of the first DC conversion module is electrically connected to the output end of the photovoltaic module, the first output end of the first DC conversion module, the first end of the second DC conversion module, the first end of the display control module and the first end of the DC bus capacitor are electrically connected, the second output end of the first DC conversion module, the second end of the second DC conversion module and the second end of the DC bus capacitor are electrically connected, and the third end of the second DC conversion module is connected to the power supply end of the power storage module;

[0025] The second end of the display control module is electrically connected to the AC bus of the photovoltaic storage converter, the first transmission end of the display control unit establishes a communication connection with the communication end of the first DC conversion module via a first communication link, and the second transmission end of the display control unit establishes a communication connection with the communication end of the second DC conversion module via a second communication link.

[0026] In a third aspect, an embodiment of the present application provides a mobile energy storage power supply system, comprising a photovoltaic storage converter as described in any one of the second aspects of the present application.

[0027] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising a photovoltaic storage converter as described in any one of the second aspects of the present application.

[0028] In a fifth aspect, an embodiment of the present application provides a method for switching between a photovoltaic and off-grid storage converter, which is applied to the on-grid and off-grid switching device described in any one of the first aspects of the present application, and the on-grid and off-grid switching method of the photovoltaic and off-grid storage converter includes:

[0029] Detecting the electrical signal by an electrical signal detection unit;

[0030] According to the electrical signal, a control unit outputs a gear-cutting trigger signal corresponding to the electrical signal, and triggers a power-off protection mechanism of the photovoltaic storage converter in the event of a power failure;

[0031] According to the gear switching trigger signal, a control signal corresponding to the gear switching trigger signal is outputted through a gear switching trigger unit;

[0032] According to the control signal, the photovoltaic storage converter is switched to an on-grid or off-grid state through an on-grid or off-grid switching switch.

[0033] In summary, the photovoltaic storage converter and its on-grid and off-grid switching device, method, system, and equipment provided in the embodiments of the present application detect electrical signals through an electrical signal detection unit, and output a gear switching trigger signal corresponding to the electrical signal through a control unit based on the detected electrical signal, and trigger the power-off protection mechanism of the photovoltaic storage converter in the event of a power outage, thereby solving the failure problem caused by sudden power outage due to power grid failure in the existing related technology; and, according to the gear switching trigger signal, a control signal corresponding to the gear switching trigger signal is output through a gear switching trigger unit, so that according to the control signal, the photovoltaic storage converter is switched between on-grid and off-grid states through an on-grid and off-grid switching switch, thereby realizing automatic switching between on-grid and off-grid states, thereby solving the problem caused by the use of two independent interfaces to realize separate on-grid and off-grid designs in the existing related technology, and can effectively improve the stability and safety of the operation of the photovoltaic storage converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0037] Figure 1 A schematic diagram of a grid-connected and off-grid switching device for a photovoltaic storage converter provided in an embodiment of the present application;

[0038] Figure 2 A connection diagram of a grid-connected and off-grid contactor provided as an example of the present application;

[0039] Figure 3 A schematic diagram of current detection and voltage detection by an electrical signal detection unit provided for optional implementation of the present application;

[0040] Figure 4 A schematic diagram of a current sampling circuit connected to a control unit provided in an optional embodiment of the present application;

[0041] Figure 5 A schematic diagram of a voltage sampling circuit connected to a control unit provided in an optional embodiment of the present application;

[0042] Figure 6 A structural block diagram of a photovoltaic storage converter provided in an embodiment of the present application;

[0043] Figure 7 A schematic diagram of the structure of a photovoltaic storage converter provided as an example of the present application;

[0044] Figure 8 A schematic diagram of the overall operation of a photovoltaic storage converter and the self-protection process of fault detection provided in an example of the present application;

[0045] Fig. 9 A structural block diagram of a mobile energy storage power supply system provided in an embodiment of the present application;

[0046] Fig.10 A schematic diagram of the structure of an electrical device provided in an embodiment of the present application;

[0047] Fig.11 A flowchart of the steps of a method for switching a photovoltaic storage converter between on-grid and off-grid provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0049] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0050] In the existing related technologies, the design of photovoltaic storage converters requires small size, high efficiency, low standby power consumption, safety and reliability, and the functions of bidirectional power supply and on-grid and off-grid operation. That is, the photovoltaic storage converter can be reliably started and operated in any off-grid or on-grid mode. This requires that the photovoltaic storage converter can operate normally off-grid after the power grid is cut off, and ensure that the photovoltaic storage converter can operate normally on-grid after the power grid is restored.

[0051] Based on the above, the embodiments of the present application provide a photovoltaic storage converter and its on-grid and off-grid switching device, method, system, and equipment. By adding an on-grid and off-grid switching device in the photovoltaic storage converter, automatic on-grid and off-grid switching is achieved, so that the photovoltaic storage converter can trigger its own protection mechanism in time when the power is cut off due to a grid fault or the power is turned on without warning, thereby preventing itself from failing.

[0052] Figure 1 This is a structural block diagram of a grid-connected and off-grid switching device of a photovoltaic storage converter provided in an embodiment of the present application. In a specific implementation, the grid-connected and off-grid switching device provided in an embodiment of the present application can be arranged between the photovoltaic storage inverter and the power grid, so that the photovoltaic storage inverter can be connected to the AC power grid through the grid-connected and off-grid switching device, such as Figure 1 As shown, the grid-connected and off-grid switching device of the photovoltaic storage converter can specifically include: an electric signal detection unit 110, a switching trigger unit 120, a grid-connected and off-grid switching switch 130 and a control unit 140; wherein the first detection end of the electric signal detection unit 110 is electrically connected to the detection end of the grid-connected and off-grid switching switch 130, so that the electric signal detection unit 110 can detect the grid-connected and off-grid switching switch 130 through the first detection end of the electric signal detection unit 110, and the second detection end of the electric signal detection unit 110 is electrically connected to the AC bus 150 of the photovoltaic storage converter. The electrical signal detection unit 110 is connected so that it can detect the AC bus 150 of the photovoltaic storage converter through the second detection end of the electrical signal detection unit 110, and the third detection end of the electrical signal detection unit 110 is electrically connected to the AC bus 160 of the power grid, so that the electrical signal detection unit 110 can detect the AC bus 160 of the power grid through the third detection end of the electrical signal detection unit 110, and then the switching of the on-grid and off-grid switching device can be realized based on the electrical signal detected by the electrical signal detection unit 110, thereby realizing the on-grid and off-grid state switching of the photovoltaic storage converter.

[0053] Specifically, the electrical signal detection unit 110 in the embodiment of the present application is used to detect electrical signals, and the detection input end of the control unit 140 is electrically connected to the output end of the electrical signal detection unit 110, so that the control unit 140 can obtain the electrical signal detected by the electrical signal detection unit 110, and the control input end of the gear switching trigger unit 120 is electrically connected to the switching output end of the control unit 140, so that the control unit 140 can output a gear switching trigger signal corresponding to the electrical signal to the gear switching trigger unit 120 based on the electrical signal detected by the electrical signal detection unit 110, and trigger the power-off protection mechanism of the photovoltaic storage converter in the event of a power outage, thereby effectively avoiding faults caused by sudden power outages in the power grid, that is, solving the fault problem caused by sudden power outages due to power grid faults in the existing related technologies.

[0054] It can be seen that the control unit 140 in the embodiment of the present application is used to output a gear switching trigger signal corresponding to the electrical signal to the gear switching trigger unit 120 based on the electrical signal, and trigger the power-off protection mechanism of the photovoltaic storage converter in the event of a power outage, thereby solving the fault problem caused by sudden power outage due to power grid fault in the existing related technology.

[0055] In addition, the grid-connected and off-grid switching device in the embodiment of the present application can realize grid-connected and off-grid switching through the grid-connected and off-grid switching switch 130. Specifically, when the first end of the grid-connected and off-grid switching switch 130 is electrically connected to the AC bus 150 of the photovoltaic storage converter, and the second end of the grid-connected and off-grid switching switch 130 is electrically connected to the AC bus 160 of the power grid, if the first end of the grid-connected and off-grid switching switch 130 and the second end of the grid-connected and off-grid switching switch 130 are in a closed and on state, the AC bus 150 of the photovoltaic storage converter and the AC bus 160 of the power grid are electrically connected. Line 160 is in a connected and conducting state, so that the photovoltaic storage converter enters a grid-connected state, and then can operate based on the working mode of the grid-connected state; if the first end of the grid-connected and off-grid switching switch 130 and the second end of the grid-connected and off-grid switching switch 130 are in a disconnected state, the photovoltaic storage converter AC bus 150 is disconnected from the grid AC bus 160, that is, the photovoltaic storage converter AC bus 150 and the grid AC bus 160 enter a disconnected state, so that the photovoltaic storage converter enters an off-grid state, and then the photovoltaic storage converter enters an off-grid working mode.

[0056] In a specific implementation, the control end of the on-grid and off-grid switching switch 130 is electrically connected to the output end of the switching trigger unit 120, so that the on-grid and off-grid switching switch 130 can switch the photovoltaic storage converter between on-grid and off-grid states according to the control signal output by the switching trigger unit 120. The switching trigger unit 120 is used to output a control signal corresponding to the switching trigger signal to the on-grid and off-grid switching switch 130 according to the switching trigger signal; the on-grid and off-grid switching switch 130 is used to switch the photovoltaic storage converter between on-grid and off-grid states according to the control signal.

[0057] For example, in the case where the control signal output by the switching trigger unit 120 is divided into a first control signal and a second control signal, the first control signal can be used to trigger the first end of the on-grid switching switch 130 and the second end of the on-grid switching switch 130 to close, so that the first end of the on-grid switching switch 130 and the second end of the on-grid switching switch 130 enter a closed conduction state, thereby making the photovoltaic storage converter AC bus 150 and the grid AC bus 160 enter a connected conduction state, controlling the photovoltaic storage converter to enter a grid-connected state, that is, the on-grid switching switch 130 The photovoltaic storage converter is controlled to switch to the grid-connected state according to the first control signal; similarly, the first end of the grid-connected and off-grid switching switch 130 can be triggered to disconnect from the second end of the grid-connected and off-grid switching switch 130 by the second control signal, so that the first end of the grid-connected and off-grid switching switch 130 and the second end of the grid-connected and off-grid switching switch 130 enter the disconnected state, thereby disconnecting the photovoltaic storage converter AC bus 150 from the grid AC bus 160, and controlling the photovoltaic storage converter to enter the off-grid state, that is, the grid-connected and off-grid switching switch 130 controls the photovoltaic storage converter to switch to the off-grid state according to the second control signal.

[0058] Of course, the embodiment of the present application may also use the first control signal to control the photovoltaic storage converter to enter the grid-connected state, and use the second control signal to control the photovoltaic storage converter to enter the off-grid state, that is, the first control signal controls the triggering of the first end of the on-grid and off-grid switching switch 130 to be disconnected from the second end of the on-grid and off-grid switching switch 130, and the second control signal controls the triggering of the first end of the on-grid and off-grid switching switch 130 to be closed from the second end of the on-grid and off-grid switching switch 130, and the embodiment of the present application does not limit this.

[0059] In summary, the off-grid switching device provided in the embodiment of the present application includes an electrical signal detection unit 110, a gear switching trigger unit 120, a grid-connected and off-grid switching switch 130 and a control unit 140. The electrical signal is detected by the electrical signal detection unit 110, and the electrical signal is fed back to the control unit 140, so that the control unit 140 can output a gear switching trigger signal corresponding to the electrical signal to the gear switching trigger unit 120 based on the electrical signal, and trigger the power-off protection mechanism of the photovoltaic storage converter in the event of a power outage, thereby solving the fault problem caused by sudden power outage of the power grid in the existing related technology; and the grid-connected and off-grid switching The control end of the gear switch 130 is electrically connected to the output end of the gear switching trigger unit 120, so that the gear switching trigger unit 120 can output a control signal corresponding to the gear switching trigger signal to the on-grid and off-grid gear switching switch 130 according to the gear switching trigger signal output by the control unit 140, so as to switch the on-grid and off-grid states of the photovoltaic storage converter according to the control signal through the on-grid and off-grid gear switching switch 130, thereby realizing automatic switching of the on-grid and off-grid states, solving the problems caused by the use of two independent interfaces to realize the separate design of on-grid and off-grid in the existing related technology, and can effectively improve the stability and safety of the operation of the photovoltaic storage converter.

[0060] Optionally, the grid-connected and off-grid switching switch 130 in the embodiment of the present application may include a grid-connected and off-grid contactor, such as Figure 2 As shown, the first end of the on-grid and off-grid contactor is electrically connected to the AC bus 150 of the photovoltaic storage converter, and the second end of the on-grid and off-grid contactor is electrically connected to the AC bus 160 of the power grid, so that the on-grid and off-grid contactor can be used as a single AC on-grid and off-grid interface of the photovoltaic storage converter to achieve automatic on-grid and off-grid switching. Among them, the DC conversion module can be used to achieve the maximum power output control of photovoltaic power generation, that is, to achieve maximum power point tracking (MPPT) control; the DC / AC module can be used as a bidirectional inverter module in the photovoltaic storage converter, specifically, it can be a DC to AC bidirectional module to support on-grid and off-grid switching functions.

[0061] Optionally, the control signal output by the gear shift trigger unit 120 can be divided into a first control signal and a second control signal, wherein the first control signal is used to control the closing of the grid-connected and off-grid contactor, and the second control signal is used to control the disconnection of the grid-connected and off-grid contactor; when the grid-connected and off-grid contactor is closed, the photovoltaic storage converter can be connected to the grid interface through the closed grid-connected and off-grid contactor, that is, the photovoltaic storage converter enters the grid-connected state; when the grid-connected and off-grid contactor is disconnected, the connection between the photovoltaic storage converter and the grid interface can be disconnected, that is, the photovoltaic storage converter enters the off-grid state.

[0062] Optionally, the electrical signal detection unit 110 in the embodiment of the present application may include a current sampling circuit 111, so as to detect the current signal through the current sampling circuit 111 to realize current signal detection, and the detected current signal may be transmitted to the control unit 140 as the electrical signal detected by the electrical signal detection unit 110, so that the control unit 140 can obtain the current signal detected by the current sampling circuit 111, and process it based on the current signal to make a judgment according to the signal processing result, such as generating a gear switching trigger signal according to the detected electrical signal, and sending the gear switching trigger signal to the gear switching trigger unit 120, so as to trigger the gear switching trigger unit 120 to control the on-grid and off-grid gear switching switch 130 through the gear switching trigger signal to realize the on-grid and off-grid state switching.

[0063] In some optional embodiments of the present application, the first sampling end of the current sampling circuit 111 is electrically connected to the AC bus 150 of the photovoltaic storage converter, so that the electrical signal detection unit 110 can collect current from the AC bus 150 of the photovoltaic storage converter through the first sampling end of the current sampling circuit 111, such as Figure 3As shown, AC bus current sampling is realized, and the collected AC bus current signal can be transmitted to the control unit 140 as a detected electrical signal; the second sampling end of the current sampling circuit 111 is electrically connected to the DC bus of the photovoltaic storage converter, so that the electrical signal detection unit 110 can collect current from the DC bus of the photovoltaic storage converter through the second sampling end of the current sampling circuit 111, thereby realizing DC bus current sampling, and the collected DC bus current signal can be transmitted to the control unit 140 as a detected electrical signal; and the output end of the current sampling circuit 111 is electrically connected to the detection input end of the control unit 140, so that the control unit 140 can obtain various current signals collected by the current sampling circuit 111 as detected electrical signals, and then the control unit 140 can process based on the current signal, generate a gear switching trigger signal corresponding to the electrical signal, and trigger the power-off protection mechanism of the photovoltaic storage converter in the case of power failure to prevent itself from malfunctioning. The first sampling terminal of the current sampling circuit 111 is used to collect the AC bus current signal, and the second sampling terminal of the current sampling circuit 111 is used to collect the DC bus current signal. The electrical signal includes the DC bus current signal and the AC bus current signal.

[0064] For example, when the photovoltaic storage converter self-protection mechanism is set as the photovoltaic storage converter power-off protection mechanism, when the power is turned on without warning after a power grid failure or a power grid power failure, the control unit 140 can process the electrical signal detected by the electrical signal detection unit 110, such as the DC bus current signal and the AC bus current signal collected by the current sampling circuit 111, and trigger the photovoltaic storage converter self-protection mechanism according to the processing result to prevent itself from being affected by the power grid failure and malfunctioning, thereby effectively ensuring the normal operation of the photovoltaic storage converter and improving the operational stability and safety of the photovoltaic storage converter. Among them, the DC bus current signal refers to the current signal of the DC bus, and the AC bus current signal refers to the current signal of the AC bus.

[0065] In some optional embodiments of the present application, the electrical signal detection unit 110 may be implemented using a detection circuit such as an electrical signal detection amplifier circuit or an integrated electrical signal detection circuit, and the embodiments of the present application do not impose any specific restrictions on this.

[0066] As an example of the present application, the current sampling circuit 111 included in the electrical signal detection unit 110 as a current signal detection circuit can be composed of a resistor, a capacitor and an amplifier. In a specific implementation, the electrical signal detection unit 110 can include one or more current sampling circuits 111, each of which can include a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first capacitor C1, a second capacitor C2, a third capacitor C3 and a first amplifier OP1, such as Figure 4 As shown, the first end of the first resistor R1 is used to connect the first connection point of the current detection point, the second end of the first resistor R1, the in-phase input end of the first amplifier OP1, the second end of the third resistor R3 and the second end of the first capacitor C1 are electrically connected, and the first end of the third resistor R3 and the first end of the first capacitor C1 are electrically connected to the power supply end of the current sampling circuit 111; the power supply end can be used to provide a voltage of 1.5V to power the first amplifier OP1; the first end of the second resistor R2 is used to connect the second connection point of the current detection point, the second end of the second resistor R2, the inverting input end of the first amplifier OP1, the first end of the fourth resistor R4 and the first end of the second capacitor C2 are electrically connected, and the second end of the fourth resistor R4 is electrically connected to the second end of the second capacitor C2; the output end of the first amplifier OP1 is electrically connected to the first end of the third capacitor C3 and the current detection output end Iout of the current sampling circuit 111 through the fifth resistor R5, so as to transmit the detected current signal to the control unit 140 through the current detection output end Iout, so that the control unit 140 can obtain the current signal detected by the current sampling circuit 111 to achieve current detection. Among them, the second end of the third capacitor C3 can be electrically connected to the reference ground of the current sampling circuit 111, so that the current sampling circuit 111 can be filtered through the third capacitor C3 to ensure the stability of the output current signal; the current detection point refers to the current detection point, and the current detection point can be any connection point on the AC bus 150 of the photovoltaic storage converter, or any connection point on the DC bus of the photovoltaic storage converter. This application example does not limit this.

[0067] Of course, in addition to detecting the current signal as the detected electrical signal through the current sampling circuit 111, the electrical signal detection unit 110 in the embodiment of the present application can also detect the voltage signal through the voltage sampling circuit 112, and can transmit the detected voltage signal as the detected electrical signal to the control unit 140, and the embodiment of the present application does not limit this.

[0068] Optionally, the electrical signal detection unit 110 in the embodiment of the present application includes a voltage sampling circuit 112, which detects a voltage signal through the voltage sampling circuit 112 to realize voltage signal detection, and the detected voltage signal can be transmitted to the control unit 140 as the electrical signal detected by the electrical signal detection unit 110, so that the control unit 140 can obtain the voltage signal detected by the voltage sampling circuit 112, and process it based on the voltage signal to make a judgment according to the signal processing result, such as generating a gear switching trigger signal according to the detected electrical signal, and sending the gear switching trigger signal to the gear switching trigger unit 120, so as to trigger the gear switching trigger unit 120 to control the on-grid and off-grid gear switching switch 130 through the gear switching trigger signal to realize on-grid and off-grid state switching.

[0069] In some optional embodiments of the present application, the first voltage sampling terminal of the voltage sampling circuit 112 is electrically connected to the AC bus 150 of the photovoltaic storage converter, so that the electrical signal detection unit 110 can collect the voltage of the AC bus 150 of the photovoltaic storage converter through the first voltage sampling terminal of the voltage sampling circuit 112, and can transmit the collected AC bus voltage signal as the detected electrical signal to the control unit 140; the second voltage sampling terminal of the voltage sampling circuit 112 is electrically connected to the DC bus of the photovoltaic storage converter, so that the electrical signal detection unit 110 can collect the voltage of the DC bus of the photovoltaic storage converter through the second voltage sampling terminal of the voltage sampling circuit 112, and can transmit the collected DC bus voltage signal as the detected electrical signal to the control unit 140. Among them, the first voltage sampling end of the voltage sampling circuit 112 is used to collect the AC bus voltage signal, and the second voltage sampling end of the voltage sampling circuit 112 is used for the DC bus voltage signal. The electrical signal includes the DC bus voltage signal and the AC bus voltage signal. The DC bus voltage signal refers to the voltage signal of the DC bus, and the AC bus voltage signal refers to the voltage signal of the AC bus.

[0070] Optionally, the electrical signal detection unit 110 in the embodiment of the present application may include one or more voltage sampling circuits 112 to detect DC bus voltage signals and AC bus voltage signals through the voltage sampling circuits 112. The embodiment of the present application does not impose any specific limitation on the number of voltage sampling circuits 112.

[0071] For example, the electrical signal detection unit 110 may include two voltage sampling circuits 112; wherein, the voltage sampling end of one voltage sampling circuit 112 serves as a first voltage sampling end, is electrically connected to the AC bus 150 of the photovoltaic storage converter, and is used to collect the voltage of the AC bus 150 of the photovoltaic storage converter, and output the AC bus voltage signal to the control unit 140; the voltage sampling end of the other voltage sampling circuit 112 serves as a second voltage sampling end, is electrically connected to the DC bus of the photovoltaic storage converter, and is used to collect the voltage of the DC bus of the photovoltaic storage converter, and output the DC bus voltage signal to the control unit 140.

[0072] In a specific implementation, the voltage sampling circuit 112 may be implemented by using resistors, capacitors, and amplifiers. The embodiment of the present application does not specifically limit the specific structure of the voltage sampling circuit 112. For example, each voltage sampling circuit 112 may include a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fourth capacitor C4, a fifth capacitor C5, and a second amplifier OP2. Figure 5 As shown, the in-phase input terminal of the second amplifier OP2 is electrically connected to the first end Vin(+) of the voltage detection point through the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9 connected in series in sequence, the inverting input terminal of the second amplifier OP2 is electrically connected to the second end Vin(-) of the voltage detection point through the tenth resistor R10, the eleventh resistor R11 and the twelfth resistor R12 connected in series in sequence, and the in-phase input terminal of the second amplifier OP2, the second end of the thirteenth resistor R13 and the second end of the fourth capacitor C4 are electrically connected, and the first end of the thirteenth resistor R13 and the first end of the fourth capacitor C4 are electrically connected to the power supply of the voltage sampling circuit 112. The power supply end is electrically connected; the power supply end can be used to provide a voltage of 1.5V to power the second amplifier OP2; the inverting input end of the second amplifier OP2, the first end of the fourteenth resistor R14 and the first end of the fifth capacitor C5 are electrically connected, and the second end of the fourteenth resistor R14 is electrically connected to the second end of the second capacitor; the output end of the second amplifier OP2 is electrically connected to the voltage detection output end Vout of the voltage sampling circuit 112, so as to transmit the detected voltage signal to the control unit 140 through the voltage detection output end Vout, so that the control unit 140 can obtain the voltage signal detected by the voltage sampling circuit 112 to realize voltage detection. Among them, the voltage detection point refers to the voltage detection point, and the voltage detection point can be any voltage detection point on the AC bus 150 of the photovoltaic storage converter, or any voltage detection point on the DC bus of the photovoltaic storage converter, and this application example does not limit this.

[0073] In a specific implementation, the on-grid and off-grid switching device provided in the embodiment of the present application can be integrated in the photovoltaic storage converter, so that the photovoltaic storage converter can realize automatic switching between the on-grid and off-grid states through the on-grid and off-grid switching device, thereby solving the problems caused by the use of two independent interfaces to realize separate on-grid and off-grid designs in the existing related technologies, and automatically triggering its own protection mechanism in the event of a power outage in the grid to terminate the working operation, so that the photovoltaic storage converter can resume normal operation through manual reset by the user after the power grid is restored, thereby effectively improving the stability and safety of the operation of the photovoltaic storage converter.

[0074] like Figure 6 As shown, the embodiment of the present application provides a photovoltaic storage converter 600, which includes an on-grid and off-grid switching device 610. The on-grid and off-grid switching device 610 can be the on-grid and off-grid switching device described in any of the above embodiments of the present application, so that the photovoltaic storage converter 600 can detect the electrical signal through the electrical signal detection unit 110, and output the gear switching trigger signal corresponding to the electrical signal to the gear switching trigger unit 120 through the control unit 140 based on the electrical signal, and trigger the power-off protection mechanism of the photovoltaic storage converter itself in the case of power failure, thereby solving the problem of power failure. The invention can solve the fault problem caused by sudden power failure of the power grid in the existing related technology; and, according to the gear switching trigger signal, the gear switching trigger unit 120 outputs a control signal corresponding to the gear switching trigger signal to the grid-connected and off-grid switching switch 130, so as to switch the grid-connected and off-grid states of the photovoltaic storage converter through the grid-connected and off-grid switching switch 130 according to the control signal, thereby realizing automatic switching of the grid-connected and off-grid states, solving the problem caused by the use of two independent interfaces to realize the separate design of grid-connected and off-grid in the existing related technology, and can effectively improve the stability and safety of the operation of the photovoltaic storage converter.

[0075] In a specific implementation, the photovoltaic storage converter provided in the embodiment of the present application may include not only a grid-connected and off-grid switching device, but also other circuit modules, such as a bidirectional inverter module, a DC conversion module, a photovoltaic module, etc. The embodiment of the present application does not impose specific restrictions on this.

[0076] Optionally, based on the above embodiment, the photovoltaic energy storage converter provided in the embodiment of the present application further includes a bidirectional inverter module, the bidirectional inverter module includes: a DC bus capacitor, a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a first inductor L1 and a second inductor L2; Figure 2 or Figure 3As shown, the control end of the first transistor Q1, the control end of the second transistor Q2, the control end of the third transistor Q3 and the control end of the fourth transistor Q4 are electrically connected to the driving control end of the control unit 140, the first end of the DC bus capacitor, the first end of the first transistor Q1, the first end of the third transistor Q3 and the first DC bus of the photovoltaic storage converter are electrically connected, the second end of the DC bus capacitor, the second end of the second transistor Q2, the second end of the fourth transistor Q4 and the second DC bus of the photovoltaic storage converter are electrically connected; the second end of the first transistor Q1, the first end of the second transistor Q2 and the first end of the first inductor L1 are electrically connected, the second end of the third transistor Q3, the first end of the fourth transistor Q4 and the first end of the second inductor L2 are electrically connected, the second end of the first inductor L1 is electrically connected to the grid-connected and off-grid contactor in the grid-connected and off-grid switching device through the first AC bus of the photovoltaic storage converter, and the second end of the second inductor L2 is electrically connected to the grid-connected and off-grid contactor in the grid-connected and off-grid switching device through the second AC bus of the photovoltaic storage converter. Among them, the first transistor Q1, the second transistor Q2, the third transistor Q3 and the fourth transistor Q4 are used as switch tubes in the bidirectional inverter module, so that the control unit 140 can adjust the duty cycle by controlling the switch tubes, thereby adjusting the output voltage to achieve output voltage regulation. The DC bus capacitor refers to the capacitor on the DC bus. For example, when the DC bus is divided into a first DC bus and a second DC bus, if one end of a capacitor is connected to the first DC bus and the other end of the capacitor is connected to the second DC bus, the capacitor can be determined as the DC bus capacitor.

[0077] Optionally, the photovoltaic storage converter in the embodiment of the present application also includes: a DC conversion module and a photovoltaic module; the input end of the DC conversion module is electrically connected to the output end of the photovoltaic module, the first output end of the DC conversion module is electrically connected to the first end of the DC bus capacitor through the first DC bus electrical connection, and the second output end of the DC conversion module is electrically connected to the second end of the DC bus capacitor through the second DC bus electrical connection.

[0078] Optionally, the photovoltaic storage converter also includes: a power storage module and a display control module, the DC conversion module includes a first DC conversion module and a second DC conversion module; the input end of the first DC conversion module is electrically connected to the output end of the photovoltaic module, the first output end of the first DC conversion module, the first end of the second DC conversion module, the first end of the display control module and the first end of the DC bus capacitor are electrically connected, the second output end of the first DC conversion module, the second end of the second DC conversion module and the second end of the DC bus capacitor are electrically connected, and the third end of the second DC conversion module is electrically connected to the power supply end of the power storage module; the second end of the display control module is electrically connected to the AC bus of the photovoltaic storage converter, the first transmission end of the display control unit establishes a communication connection with the communication end of the first DC conversion module through a first communication link, and the second transmission end of the display control unit establishes a communication connection with the communication end of the second DC conversion module through a second communication link. Wherein, the power storage module can be used as a storage battery BMS module of the photovoltaic storage converter to realize bidirectional charging and discharging of the storage battery.

[0079] As an example of the present application, the AC / DC power supply device of the photovoltaic storage converter can be composed of a photovoltaic module, a first DC conversion module, a second DC conversion module, an auxiliary power supply circuit, a DC bus, a bidirectional inverter module, an AC power grid, an AC / DC auxiliary power supply module and a storage battery BMS module; wherein the photovoltaic module can be used as a photovoltaic MPPT module in the photovoltaic storage converter, and specifically can provide photovoltaic power generation access to the first DC conversion module in the photovoltaic storage converter, such as Figure 7 As shown; the first DC conversion module is used as a DC / DC module in the photovoltaic storage converter to realize the maximum power output control of photovoltaic power generation, that is, to realize MPPT control; the bidirectional inverter module is used as a DC / AC module in the photovoltaic storage converter to realize the DC-to-AC bidirectional module and support the on-grid and off-grid switching function; in order to expand the capacity in parallel and increase the machine power, the second DC conversion module is used as a reserved photovoltaic DCDC module in the photovoltaic storage converter; the display control module is an external module for manually issuing instructions, and the display control module can establish a communication connection with the first DC conversion module, the second DC conversion module and the bidirectional inverter module through the 485 communication bus to form a 485 communication loop to realize communication control; the energy storage battery BMS module is used as a bidirectional charging and discharging module of the energy storage battery of the photovoltaic converter to realize bidirectional charging and discharging of the energy storage battery; the AC / DC auxiliary power supply module supports simultaneous access to the AC and DC buses, and can convert high-voltage isolation into low-voltage DC to power the system control circuits, chips, etc., thereby meeting the power supply requirements of the system control circuits and chips.

[0080] In the specific implementation, the photovoltaic storage converter whole machine operation and fault detection self-protection process are as follows: Figure 8As shown, the photovoltaic storage converter can detect whether it is connected to the grid through a program, that is, determine whether the grid has electricity, so as to use the electricity stored in the battery when it is not connected to the grid or the grid has no electricity, and when the grid has electricity, it is input through the bidirectional inverter module so that the auxiliary power module obtains electric energy. Specifically, when the photovoltaic storage converter is not connected to the grid or the grid has no electricity, the electric signal detected by the electric signal detection unit can be used to determine whether the energy storage battery has electricity; if the energy storage battery has electricity, it can be input through the storage module, that is, the energy storage battery BMS module as the storage module outputs electric energy, so that the auxiliary power module obtains electric energy; when the energy storage battery has no electricity, the electricity converted by the photovoltaic panel can be used to supply power to the auxiliary power supply, that is, determine whether the photovoltaic module is working, and when the photovoltaic module is working, it is input through the photovoltaic module so that the auxiliary power module obtains electric energy, so that the control unit, the electric signal detection unit and the gear switching trigger unit of the off-grid switching device can be triggered based on the electric energy obtained by the auxiliary power module, that is, the electric signal detection unit, the control unit work and the gear switching trigger unit start, so that the whole machine works normally. For example, when the control unit includes an MCU-controlled driver chip, the auxiliary power supply module can be used to convert the voltage of the electric energy into a voltage to supply power to the MCU-controlled driver chip, so that the MCU-controlled driver chip can control the switch tube to adjust the duty cycle, adjust the output voltage, and output it to the BMS module or the bidirectional inverter module, thereby enabling the photovoltaic storage converter to operate normally.

[0081] Among them, the MCU control driver chip can be integrated in the control unit 140 of the on-grid and off-grid switching device, so that the control unit 140 can detect in real time whether the power grid is off. When the power grid is not detected, the photovoltaic storage converter operates normally; when the power grid is not detected, the photovoltaic storage converter can be triggered to trigger its own protection mechanism according to the detected power grid outage and end its operation; after the power grid is restored, it can be determined whether there is a user manually closing the switch, so that the user can restart by manually closing the switch, so that the photovoltaic storage converter can resume normal operation.

[0082] In one embodiment of the present application, the photovoltaic storage converter provided in the embodiment of the present application can be applied to a mobile energy storage power supply system, so that the mobile energy storage power supply system can be powered by the photovoltaic storage converter.

[0083] like Fig. 9 As shown, an embodiment of the present application provides a mobile energy storage power supply system 900, which includes a photovoltaic storage converter 910. The photovoltaic storage converter 910 can be the photovoltaic storage converter described in any of the above embodiments of the present application.

[0084] like Fig.10As shown, an embodiment of the present application provides an electrical device 100, which includes a photovoltaic storage converter 910. The photovoltaic storage converter 910 can include the on-grid and off-grid switching device described in any of the above embodiments of the present application, so that the electrical device 100 can detect the electrical signal through the electrical signal detection unit 110, and feed the electrical signal back to the control unit 140, so that the control unit 140 outputs a gear switching trigger signal corresponding to the electrical signal to the gear switching trigger unit 120 based on the electrical signal, and triggers the power-off protection mechanism of the photovoltaic storage converter in the case of power failure, thereby solving the problem of the existing related technology caused by sudden power failure of the power grid. and the control end of the on-grid and off-grid switching switch 130 is electrically connected to the output end of the switching trigger unit 120, so that the switching trigger unit 120 outputs a control signal corresponding to the switching trigger signal to the on-grid and off-grid switching switch 130 according to the switching trigger signal output by the control unit 140, so that the on-grid and off-grid switching switch 130 switches the photovoltaic storage converter to the on-grid and off-grid state according to the control signal, thereby realizing automatic switching of the on-grid and off-grid state, solving the problem caused by the use of two independent interfaces to realize the separate design of on-grid and off-grid in the existing related technology, and can effectively improve the stability and safety of the operation of the photovoltaic storage converter. Among them, the electrical equipment 100 can include but is not limited to electrical equipment such as air conditioners and refrigerators, and the embodiments of the present application are not limited to this.

[0085] like Fig.11 As shown, an embodiment of the present application provides a schematic flow chart of the steps of a method for switching a photovoltaic storage converter on and off the grid. The method for switching a photovoltaic storage converter on and off the grid provided in the embodiment of the present application can be applied to any of the on-grid and off-grid switching devices in the above embodiments of the present application, and can specifically include the following steps:

[0086] Step 1110, detecting an electrical signal by an electrical signal detection unit;

[0087] Step 1120, according to the electrical signal, outputting a gear-cutting trigger signal corresponding to the electrical signal through a control unit, and triggering a power-off protection mechanism of the photovoltaic energy storage converter in the event of a power failure;

[0088] Step 1130, according to the gear switching trigger signal, outputting a control signal corresponding to the gear switching trigger signal through a gear switching trigger unit;

[0089] Step 1140: Switch the photovoltaic energy storage converter to an on-grid or off-grid state through an on-grid or off-grid switching switch according to the control signal.

[0090] Specifically, the grid-connected and off-grid switching method of the photovoltaic storage converter provided in the embodiment of the present application can be applied to the grid-connected and off-grid switching device described in any one of the above embodiments of the present application, and the electrical signal is detected by the electrical signal detection unit in the grid-connected and off-grid switching device, and the electrical signal is processed by the control unit based on the detected electrical signal, and a gear switching trigger signal corresponding to the electrical signal is output, and the power-off protection mechanism of the photovoltaic storage converter is triggered in the case of power failure, thereby effectively avoiding faults caused by sudden power failures of the power grid, and solving the fault problem caused by sudden power failures due to power grid faults in the existing related technologies. According to the gear switching trigger signal, and, the control signal corresponding to the gear switching trigger signal is output by the gear switching trigger unit, so that according to the control signal, the photovoltaic storage converter is switched between the grid-connected and off-grid states through the grid-connected and off-grid switching switch, thereby realizing automatic switching of the grid-connected and off-grid states, solving the problem caused by the use of two independent interfaces to realize the separate design of grid-connected and off-grid in the existing related technologies, and can effectively improve the stability and safety of the operation of the photovoltaic storage converter.

[0091] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, i.e., they may be located in one place or distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0092] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the relevant technology can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiment.

[0093] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0094] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A grid-connected and off-grid switching device for a photovoltaic storage converter, characterized in that: include: Electric signal detection unit, gear switching trigger unit, on-grid and off-grid gear switching switch and control unit; Wherein, the first detection end of the electrical signal detection unit is electrically connected to the detection end of the grid-connected and off-grid switching switch, the second detection end of the electrical signal detection unit is electrically connected to the AC bus of the photovoltaic storage converter, the third detection end of the electrical signal detection unit is electrically connected to the AC bus of the power grid, the first end of the grid-connected and off-grid switching switch is electrically connected to the AC bus of the photovoltaic storage converter, the second end of the grid-connected and off-grid switching switch is electrically connected to the AC bus of the power grid, the control end of the grid-connected and off-grid switching switch is electrically connected to the output end of the switching trigger unit, the control input end of the switching trigger unit is electrically connected to the switching output end of the control unit, and the detection input end of the control unit is electrically connected to the output end of the electrical signal detection unit; The electrical signal detection unit is used to detect electrical signals; The control unit is used to output a gear switching trigger signal corresponding to the electrical signal to the gear switching trigger unit according to the electrical signal, and trigger a power-off protection mechanism of the photovoltaic storage converter in the event of a power failure; The gear switching trigger unit is used to output a control signal corresponding to the gear switching trigger signal to the on-grid and off-grid switching switch according to the gear switching trigger signal; The on-grid and off-grid switching switch is used to switch the on-grid and off-grid states of the photovoltaic storage converter according to the control signal.

2. The on-grid and off-grid switching device according to claim 1, characterized in that: The on-grid and off-grid switching switch comprises an on-grid and off-grid contactor, a first end of the on-grid and off-grid contactor is electrically connected to the AC busbar of the photovoltaic storage converter, and a second end of the on-grid and off-grid contactor is electrically connected to the AC busbar of the power grid; The control signal is divided into a first control signal and a second control signal, the first control signal is used to control the on-grid and off-grid contactor to close, and the second control signal is used to control the on-grid and off-grid contactor to open; When the grid-connected and off-grid contactor is closed, the photovoltaic storage converter enters the grid-connected state; When the grid-connected and off-grid contactor is disconnected, the photovoltaic storage converter enters an off-grid state.

3. The on-grid and off-grid switching device according to claim 1, characterized in that: The electrical signal detection unit includes a current sampling circuit, a first sampling end of the current sampling circuit is electrically connected to the AC bus of the photovoltaic storage converter, a second sampling end of the current sampling circuit is electrically connected to the DC bus of the photovoltaic storage converter, an output end of the current sampling circuit is electrically connected to a detection input end of the control unit, the first sampling end of the current sampling circuit is used to collect an AC bus current signal, the second sampling end of the current sampling circuit is used to collect a DC bus current signal, and the electrical signal includes the DC bus current signal and the AC bus current signal.

4. The on-grid and off-grid switching device according to claim 1, characterized in that: The electrical signal detection unit includes a voltage sampling circuit, a first voltage sampling end of the voltage sampling circuit is electrically connected to the AC bus of the photovoltaic storage converter, and a second voltage sampling end of the voltage sampling circuit is electrically connected to the DC bus of the photovoltaic storage converter. The first voltage sampling end of the voltage sampling circuit is used to collect the AC bus voltage signal, and the second voltage sampling end of the voltage sampling circuit is used for the DC bus voltage signal. The electrical signal includes the DC bus voltage signal and the AC bus voltage signal.

5. A photovoltaic storage converter, characterized in that: The photovoltaic storage converter comprises the on-grid and off-grid switching device as described in any one of claims 1 to 4.

6. The photovoltaic storage converter according to claim 5, characterized in that: The photovoltaic storage converter further includes a bidirectional inverter module, which includes: a DC bus capacitor, a first transistor, a second transistor, a third transistor, a fourth transistor, a first inductor and a second inductor; Wherein, the control end of the first transistor, the control end of the second transistor, the control end of the third transistor and the control end of the fourth transistor are electrically connected to the driving control end of the control unit, the first end of the DC bus capacitor, the first end of the first transistor, the first end of the third transistor and the first DC bus of the photovoltaic storage converter are electrically connected, and the second end of the DC bus capacitor, the second end of the second transistor, the second end of the fourth transistor and the second DC bus of the photovoltaic storage converter are electrically connected; The second end of the first transistor, the first end of the second transistor and the first end of the first inductor are electrically connected, the second end of the third transistor, the first end of the fourth transistor and the first end of the second inductor are electrically connected, the second end of the first inductor is electrically connected to the grid-connected and off-grid contactor in the grid-connected and off-grid switching device through the first AC bus of the photovoltaic storage converter, and the second end of the second inductor is electrically connected to the grid-connected and off-grid contactor in the grid-connected and off-grid switching device through the second AC bus of the photovoltaic storage converter.

7. The photovoltaic storage converter according to claim 6, characterized in that: Also includes: DC conversion modules and photovoltaic modules; The input end of the DC conversion module is electrically connected to the output end of the photovoltaic module, the first output end of the DC conversion module is electrically connected to the first end of the DC bus capacitor through the first DC bus electrical connection, and the second output end of the DC conversion module is electrically connected to the second end of the DC bus capacitor through the second DC bus electrical connection.

8. The photovoltaic converter according to claim 7, characterized in that: Also includes: A power storage module and a display control module, wherein the DC conversion module includes a first DC conversion module and a second DC conversion module; The input end of the first DC conversion module is electrically connected to the output end of the photovoltaic module, the first output end of the first DC conversion module, the first end of the second DC conversion module, the first end of the display control module and the first end of the DC bus capacitor are electrically connected, the second output end of the first DC conversion module, the second end of the second DC conversion module and the second end of the DC bus capacitor are electrically connected, and the third end of the second DC conversion module is connected to the power supply end of the power storage module; The second end of the display control module is electrically connected to the AC bus of the photovoltaic storage converter, the first transmission end of the display control unit establishes a communication connection with the communication end of the first DC conversion module via a first communication link, and the second transmission end of the display control unit establishes a communication connection with the communication end of the second DC conversion module via a second communication link.

9. A mobile energy storage power supply system, characterized in that: include: A photovoltaic storage converter as claimed in any one of claims 5 to 8.

10. An electrical device, characterized in that: It comprises the photovoltaic storage converter as described in any one of claims 5 to 8.

11. A method for switching a photovoltaic storage converter between a grid and an off-grid, characterized in that: Applied to the on-grid and off-grid switching device according to any one of claims 1 to 4, the on-grid and off-grid switching method comprises: Detecting the electrical signal by an electrical signal detection unit; According to the electrical signal, a control unit outputs a gear-cutting trigger signal corresponding to the electrical signal, and triggers a power-off protection mechanism of the photovoltaic storage converter in the event of a power failure; According to the gear switching trigger signal, a control signal corresponding to the gear switching trigger signal is outputted through a gear switching trigger unit; According to the control signal, the photovoltaic storage converter is switched to an on-grid or off-grid state through an on-grid or off-grid switching switch.

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