Off-grid and grid-connected switching control method, power conversion equipment and switch equipment

Abstract

The invention relates to an off-grid and grid-connected switching control method, power conversion equipment and switch equipment, and the control method comprises the steps: in the process of controlling off-grid and grid-connected switching, when the power conversion equipment detects the power failure of commercial power, the power conversion equipment sends a turn-off control signal to the switch equipment to control the switch equipment to disconnect the commercial power from a load; and after a turn-off success signal sent by the switch equipment is received, the off-grid operation mode is switched, so that the problem of load power failure or even damage caused by mode switching of the power conversion equipment when switching of the switch equipment fails is avoided. And the turn-off completion signal and the turn-off control signal for off-grid and grid-connected switching control are level signals with different voltage amplitudes, or the turn-off completion signal and the turn-off control signal are pulse signals and / or edge signals, so that the probability of signal transmission failure can be reduced, accurate off-grid and grid-connected switching is ensured, and the switching speed is increased.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology, and in particular relates to a control method, power conversion device and switching device for grid-connected and off-grid switching. Background Technology

[0002] Residential energy storage systems are rapidly developing. The power conversion system (PCS) of these systems can be connected to the grid via distribution boxes, meter disconnect switches, or manual / main transfer switches, or operate offline when the grid is down, directly driving the load. It is not necessary to have distribution boxes, meter disconnect switches, or manual / main transfer switches all at the same time.

[0003] Traditional on-grid / off-grid switching methods can cause the PCS (Power Control System) to operate in a different mode than it actually is if the switching equipment fails to switch or fails to receive feedback signals. This can lead to power outages or even damage to the PCS. Summary of the Invention

[0004] The purpose of this application is to provide a control method, power conversion device and switching device for off-grid and grid-connected switching, which aims to solve the problem in related technologies that failure of off-grid and grid-connected switching will cause load power loss and even damage to the power conversion device.

[0005] In a first aspect, embodiments of this application provide a control method for off-grid / on-grid switching, applied to power conversion equipment, the control method comprising:

[0006] When a mains power failure is detected, a shutdown control signal is sent to the switching device; the switching device is connected between the mains power and the power conversion device and is used to control the connection between the mains power and the power conversion device; the shutdown control signal is used to control the switching device to disconnect the connection between the mains power and the power conversion device;

[0007] In response to the shutdown success signal sent by the switching device, the power conversion device is controlled to switch to off-grid operation mode; the shutdown completion signal and the shutdown control signal are both level signals with different voltage amplitudes, or the shutdown control signal and the shutdown completion signal are both pulse signals and / or edge signals.

[0008] In one embodiment, the control module for switching the power conversion device to off-grid operation includes: controlling the power conversion device to switch from current source mode to voltage source mode operation.

[0009] In one embodiment, the power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the method further includes: sending the shutdown control signal to the switching device via the first power line, and receiving the shutdown completion signal via the first power line.

[0010] In one embodiment, the power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the power conversion device is also connected to the switching device via a first transmit data line and a first receive data line; the method further includes:

[0011] The shutdown control signal is sent through the first transmit data line, and the shutdown completion signal is received through the first receive data line.

[0012] In one embodiment, the power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the power conversion device is also connected to the switching device via a first transmit / receive data line; the method further includes:

[0013] The shutdown control signal is sent through the first transmit / receive data line, and the shutdown completion signal is received through the first transmit / receive data line.

[0014] In one embodiment, the shutdown control signal is an edge signal; the shutdown completion signal is a pulse signal.

[0015] In one embodiment, the power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the power conversion device is also connected to the switching device via a first transmit / receive data line and a second transmit / receive data line; the method further includes:

[0016] The shutdown control signal is transmitted via the first or the second data line, and the shutdown completion signal is received via the first or the second data line.

[0017] Secondly, embodiments of this application also provide a power conversion device, including a power conversion circuit, a memory, a processor, and a computer program stored in the memory and executable on the processor. The mains side of the power conversion device is connected to the mains power through a switching device. The switching device is used to control the on / off connection between the mains power and the power conversion device. When the processor executes the computer program, it implements the steps of the on / off grid switching control method described above.

[0018] Thirdly, embodiments of this application also provide a control method for off-grid / on-grid switching, applied to switching equipment, the control method comprising:

[0019] The device receives a shutdown control signal sent by the power conversion device; the switching device is connected between the mains power and the power conversion device and is used to control the on / off connection between the mains power and the power conversion device; the device controls the switching device to disconnect the connection between the mains power and the power conversion device according to the shutdown control signal;

[0020] After disconnecting the mains power from the conversion device, a shutdown completion signal is sent to the power conversion device; the shutdown completion signal is used to instruct the power conversion device to switch to off-grid operation mode.

[0021] Fourthly, embodiments of this application also provide a switching device, including a disconnecting device, a memory, a processor, and a computer program stored in the memory and executable on the processor. The disconnecting device is used to control the connection and disconnection between the mains power and the power conversion device. When the processor executes the computer program, it implements the steps of the on / off grid switching control method as described in the third aspect.

[0022] The beneficial effects of this application embodiment compared to related technologies are as follows: During the control of grid-connected / off-grid switching, when the power conversion device detects a mains power failure, it sends a shutdown control signal to the switching equipment to control the switching equipment to disconnect the connection between the mains power and the load. Only after receiving a shutdown success signal from the switching equipment will it switch to off-grid operation mode. This avoids the problem of the power conversion device switching modes and causing load power failure or even damage when the switching equipment fails to switch. Furthermore, the shutdown completion signal and shutdown control signal used for grid-connected / off-grid switching control are level signals with different voltage amplitudes, or both are pulse signals and / or edge signals, which can reduce the probability of signal transmission failure, ensure accurate grid-connected / off-grid switching, and improve switching speed. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an energy storage system provided in an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the structure of an energy storage system provided in an embodiment of this application;

[0025] Figure 3 A flowchart illustrating a control method for grid-connected / off-grid switching according to an embodiment of this application;

[0026] Figure 4 This is a control circuit diagram for off-grid / parallel switching provided in an embodiment of this application;

[0027] Figure 5 This is a control circuit diagram for off-grid / parallel switching provided in an embodiment of this application;

[0028] Figure 6 This is a control circuit diagram for off-grid / parallel switching provided in an embodiment of this application;

[0029] Figure 7 This is a control circuit diagram for off-grid / parallel switching provided in an embodiment of this application;

[0030] Figure 8 This is a control circuit diagram for off-grid / parallel switching provided in an embodiment of this application;

[0031] Figure 9 This is a control circuit diagram for off-grid / parallel switching provided in an embodiment of this application;

[0032] Figure 10 This is a control circuit diagram for off-grid / parallel switching provided in an embodiment of this application;

[0033] Figure 11 A schematic diagram of a control device for off-grid / on-grid switching provided in an embodiment of this application;

[0034] Figure 12 This is a schematic diagram of the structure of a power conversion device provided in an embodiment of this application;

[0035] Figure 13 A flowchart illustrating a control method for grid-connected / off-grid switching according to an embodiment of this application;

[0036] Figure 14 This is a schematic diagram of the structure of a switching device provided in an embodiment of this application. Detailed Implementation

[0037] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0038] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0039] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0041] Residential energy storage systems are rapidly developing. The power conversion equipment in these systems can be connected to the grid via distribution boxes, meter disconnect switches, or manual / automatic transfer switches, or operate offline when the grid is down, directly driving the load. Distribution boxes typically contain a main relay that controls the connection and disconnection of mains power and the load. The distribution box includes an incoming mains line and multiple load branches, distributing mains power to the loads on different branches. Meter disconnect switches are usually designed to adapt to the meter socket and the meter, connecting them; they can also be called meter adapters. Meter disconnect switches contain relays to control the connection and disconnection between mains power and the load. Automatic / manual transfer switches function similarly to distribution boxes, being simplified versions, and also contain transfer switches to control the connection and disconnection between mains power and the load. Therefore, the control of switching equipment discussed later mainly refers to controlling the relays and other disconnecting devices within the switching equipment used to control the connection and disconnection between mains power and the load.

[0042] See Figure 1 and Figure 2 Distribution boxes, meter disconnect switches, or manual / automatic transfer switches are not required to be present simultaneously. When the energy storage system switches from grid-connected to off-grid operation, the power conversion equipment needs to send control signals to the switching equipment. Upon receiving the signal, the switching equipment immediately disconnects the corresponding internal relays to break the connection between the mains power and the load. The power conversion equipment can directly supply power to the load through the switching equipment, or directly supply power to the load or distribution equipment connected to it.

[0043] In traditional on-grid / off-grid switching methods, the on-grid / off-grid switching control signal and the feedback signal of the main relay switching completion are transmitted through the communication module. If the main relay switching fails or the feedback signal reception fails, the power converter's operating mode will not match the actual operation, which may cause power outages or even damage to the PCS.

[0044] In this regard, this application provides a reliable control method for off-grid / parallel switching. Please refer to the embodiments. Figure 3 , combined Figure 1 and Figure 2 The control method for switching between grid connection and off-grid can be applied to power conversion equipment. The control method includes:

[0045] Step S110: When a mains power failure is detected, a shutdown control signal is sent to the switching device. The switching device is connected between the mains power and the load and is used to control the connection between the mains power and the load; the shutdown control signal is used to control the switching device to disconnect the mains power from the load.

[0046] For example, switching equipment is such as a distribution box (see...) Figure 1 ) and meter disconnect switch (see Figure 2 The switching equipment includes a disconnecting device connected to the mains power and the load, such as a relay or a disconnecting switch. The power conversion equipment is, for example, an electrical device including a power conversion circuit. The power conversion equipment detects the mains power status through a detection circuit, and when a mains power failure is detected, sends a shutdown control signal to the switching equipment, causing the switching equipment to control the disconnecting device to disconnect the mains power and the load.

[0047] In step S120, in response to the shutdown success signal sent by the switching equipment, the power conversion equipment is controlled to switch to off-grid operation mode; the shutdown completion signal and the shutdown control signal are level signals with different voltage amplitudes, or the shutdown control signal and the shutdown completion signal are both pulse signals and / or edge signals.

[0048] In this embodiment, after receiving the shutdown control signal and successfully disconnecting the mains power from the load, the switching device returns a shutdown completion signal. The power conversion device only switches to off-grid operation mode after receiving the shutdown success signal from the switching device, ensuring that the operating mode of the power conversion device matches the actual situation and avoiding power outages or even damage to the power conversion device.

[0049] Specifically, the shutdown completion signal and the shutdown control signal are level signals with different voltage amplitudes, or both the shutdown control signal and the shutdown completion signal are pulse signals and / or edge signals. This allows the system to identify the difference between the shutdown completion signal and the shutdown control signal, improving the reliability of grid-connected / off-grid switching control. Furthermore, transmitting the shutdown completion signal and shutdown control signal through level signals and / or edge signals offers higher signal transmission reliability compared to signal transmission via a communication module. This avoids signal transmission failures that could lead to grid-connected / off-grid switching failures, resulting in load power loss or even damage to the power conversion equipment.

[0050] In some embodiments, controlling the power conversion device to switch to off-grid operation mode in step S120 includes: controlling the power conversion device to switch from current source mode to voltage source mode operation.

[0051] When connected to the grid, the power grid typically provides a stable voltage, and the power conversion equipment needs to match this voltage for safe grid connection. The power conversion equipment adjusts its current to adapt to voltage fluctuations in the grid, ensuring a smooth power input or output; in this case, it needs to operate in current source mode. In off-grid mode, the power conversion equipment provides a stable voltage to the load (such as household appliances or independent loads) to ensure the normal operation of the power supply. Therefore, the output voltage of the power conversion equipment needs to remain stable, while the current is adjusted according to load demand; in this case, it needs to operate in voltage source mode.

[0052] Please see Figure 4 and Figure 5 In some embodiments, the power conversion device and the switching device are connected via a first power line to provide a first operating voltage to the switching device. This first operating voltage serves as the operating voltage of the switching device to ensure its normal operation. For example, the power conversion device is wired to the second interface J2 of the switching device via a first interface J1. Both interfaces J1 and J2 are provided with terminals for a 12V power supply line, a ground line GND, a first communication line GANH, and a second communication line GANL. The first power line is a 12V power supply line.

[0053] The control method for off-grid / parallel switching also includes: sending a shutdown control signal to the switching equipment via a first power line, and receiving a shutdown completion signal via the first power line. That is, in this embodiment, the control signal used for off-grid / parallel switching is multiplexed and transmitted via a power line, which has the advantages of simple implementation and low cost. Furthermore, communication for off-grid / parallel switching is performed via hard wiring such as power lines, resulting in faster communication speed and effectively improving the switching speed. Moreover, the power conversion equipment only performs the final off-grid / parallel switching after receiving a shutdown success signal from the switching equipment, thereby ensuring accurate switching between the two grids.

[0054] Please see Figure 4 , Figure 4 The circuit diagram illustrates one of the above solutions. The voltage output circuit 110 of the power conversion device includes two anti-reverse diodes D1 and D2, a BOOST circuit 120, a MOSFET Q1, and an amplifier U1 for voltage detection. The voltage input circuit 210 of the switching device includes an input protection diode D3, an anti-reverse diode D4, a MOSFET Q2, and an amplifier U2 for voltage detection.

[0055] When the power conversion device and the switching device are communicating normally, MOSFET Q1 is in the off state. The 12V power supply is output to the switching device through the anti-reverse diode D1. The 12V power supply is detected by amplifier U2 in the voltage detection circuit within the switching device. When the switching device detects the 12V signal, it will not perform grid disconnection / off operation. At this time, MOSFET Q2 is in the off state. When the power conversion device needs to disconnect from the grid, the first controller of the power conversion device controls the switching frequency of MOSFET Q1, thereby using the BOOST circuit 120 to generate an 18V pulse signal (i.e., a turn-off control signal) on the first power line, which is then superimposed on the 12V power supply and output to the switching device. After the amplifier U2 of the switching device detects the 18V pulse signal, the second controller of the switching device controls the disconnection device 211 to disconnect, and after the disconnection is completed, controls the on / off state of MOSFET Q2, thereby generating a 24V-30V pulse signal (i.e., a turn-off completion signal) on the first power line where MOSFET Q2 is located, which is superimposed on the 12V signal voltage and transmitted to the power conversion device. The first controller of the power conversion device can also detect voltage through amplifier U1. After detecting a 24V-30V pulse signal, it confirms and completes the off-grid conversion, and then switches from current source mode to voltage source mode, that is, enters off-grid operation mode.

[0056] Please see Figure 5 , Figure 5 Another circuit diagram to implement the above scheme is shown below. The voltage output circuit 110 of the power conversion device includes a reverse protection diode D5, a MOSFET Q3, and an amplifier U3 for voltage detection. The voltage input circuit 210 of the switching device includes an input protection diode D6, a switching MOSFET Q4, and an amplifier U4 for voltage detection.

[0057] When the power conversion device and the switching device are communicating normally, MOSFET Q3 is in the off state. The 12V power supply is output to the switching device through the anti-reverse diode D5. The 12V power supply is detected by amplifier U4 in the switching device. When the switching device detects the 12V signal, it will not perform grid disconnection / off-grid operation. At this time, MOSFET Q4 is in the off state. When the power conversion device needs to disconnect from the grid, the first controller of the power conversion device controls MOSFET Q3 to turn on, thereby briefly pulling the 12V power supply output to 0V, generating a 0V pulse signal (including a falling edge signal), which is the shutdown control signal. After the amplifier U4 of the switching device detects the 0V pulse signal, the second controller of the switching device controls the disconnection device 211 to disconnect, and after the disconnection is completed, controls MOSFET Q4 to turn on briefly, thereby briefly dropping the 12V voltage to 0V, generating a 0V pulse signal (including a falling edge signal), which is the shutdown success signal, and is transmitted to the power conversion device. The first controller of the power conversion device can also detect voltage through amplifier U3. After detecting a 0V pulse signal or falling edge signal, it confirms and completes the off-grid conversion, and then switches from current source mode to voltage source mode, that is, enters off-grid operation mode.

[0058] Please see Figure 6 and Figure 7 The power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device. The power conversion device is also connected to the switching device via a first transmit data line and a first receive data line. For example, the power conversion device is wired to the second interface J2 of the switching device via a first interface J1. The first interface J1 and the second interface J2 are provided with terminals for a 12V power supply line, a ground line GND, a first communication line GANH, a second communication line GANL, a first transmit data line PIN1, and a first receive data line PIN2. The first power line is a 12V power supply line, and the first transmit data line PIN1 and the first receive data line PIN2 are independently configured lines.

[0059] The control methods for switching between grid connection and off-grid also include:

[0060] A shutdown control signal is sent via the first transmit data line PIN1, and a shutdown completion signal is received via the first receive data line PIN2.

[0061] Please see Figure 6 , Figure 6 The diagram shows one possible circuit for implementing the above scheme. When there is no trigger signal (i.e., no shutdown control signal or shutdown completion signal), the first transmit data line PIN1 and the first receive data line PIN2 are at 0V potential.

[0062] Specifically, the voltage output circuit 110 on the power conversion device side includes two reverse protection diodes D7 and D8, a PMOS transistor Q5, and an amplifier U5 used for voltage detection. The voltage input circuit 210 on the switching device side includes an input protection diode D9, a reverse protection diode D10, a PMOS transistor Q6, and an amplifier U6 used for voltage detection.

[0063] When the power conversion device and the switching device are communicating normally, PMOS transistor Q5 is in the off state. When the switching device detects a 0V signal, it will not perform grid disconnection / off operation. At this time, PMOS transistor Q6 is in the off state. When the power conversion device needs to disconnect from the grid, the first controller of the power conversion device controls the short-term opening of PMOS transistor Q5, thereby generating a 12V pulse signal or rising edge signal (i.e., a turn-off control signal) on the first transmit data line PIN1 and outputting it to the switching device. After the second controller of the switching device detects the 12V pulse signal or rising edge signal through amplifier U6, it disconnects the disconnection device 211, and after the disconnection is completed, it controls the on / off state of PMOS transistor Q6, thereby generating a 12V pulse signal or rising edge signal (i.e., a turn-off success signal) on the first receive data line PIN2 where PMOS transistor Q6 is located and transmitting it to the power conversion device. The first controller of the power conversion device can also perform voltage detection through amplifier U5, and after detecting the 12V pulse signal or rising edge signal, it confirms and completes the grid disconnection conversion, and then switches from current source mode to voltage source mode, that is, enters the grid disconnection operation mode.

[0064] Please see Figure 7 , Figure 7 One circuit diagram is shown to implement the above scheme. When there is no trigger signal (i.e., no shutdown control signal and shutdown completion signal), the first transmit data line PIN1 and the first receive data line PIN2 are at a potential of 12V.

[0065] Specifically, the voltage output circuit 110 on the power conversion device side includes a reverse protection diode D11, a current-limiting resistor R4, an NMOS transistor Q7, and an amplifier U7 used for voltage detection. The voltage input circuit 210 on the switching device side includes an input protection diode D12, a current-limiting resistor R5, an NMOS transistor Q8, and an amplifier U8 used for voltage detection.

[0066] When the power conversion device and the switching device are communicating normally, NMOS transistor Q7 is in the off state. When the switching device detects a 12V power supply signal, it will not perform grid disconnection / off-grid operation. At this time, NMOS transistor Q8 is in the off state. When the power conversion device needs to disconnect from the grid, the first controller of the power conversion device controls the short-term opening of NMOS transistor Q7, thereby generating a 0V pulse signal or falling edge signal (i.e., a turn-off control signal) on the first transmit data line PIN1 and outputting it to the switching device. After the second controller of the switching device detects the 0V pulse signal or falling edge signal through amplifier U8, it disconnects the disconnection device 211 and controls the on / off state of NMOS transistor Q8 after the disconnection is completed, thereby generating a 0V pulse signal or falling edge signal (i.e., a turn-off success signal) on the first receive data line PIN2 where NMOS transistor Q8 is located and transmitting it to the power conversion device. The first controller of the power conversion device can also perform voltage detection through amplifier U7, and after detecting the 0V pulse signal or falling edge signal, it confirms and completes the grid disconnection conversion, and then switches from current source mode to voltage source mode, that is, enters the grid disconnection operation mode.

[0067] Please see Figure 8 and Figure 9 The power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device. The power conversion device is also connected to the switching device via a first transmit / receive data line. For example, the power conversion device is wired to the second interface J2 of the switching device via a first interface J1. The first interface J1 and the second interface J2 are equipped with terminals for a 12V power supply line, a ground line GND, a first communication line GANH, a second communication line GANL, and a first transmit / receive data line PIN11. The first power line is a 12V power supply line, and the first transmit / receive data line PIN11 is an independently configured line.

[0068] The control methods for switching between grid connection and off-grid also include:

[0069] A shutdown control signal is sent through the first transmit / receive data line PIN11, and a shutdown completion signal is received through the first transmit / receive data line PIN11.

[0070] Please see Figure 8 , Figure 8 The diagram shows one possible circuit for implementing the above scheme. When there is no trigger signal (i.e., no shutdown control signal or shutdown completion signal), the first transmit / receive data line PIN11 is at a potential of 0V.

[0071] Specifically, the voltage output circuit 110 on the power conversion device side includes two reverse protection diodes D13 and D24, a PMOS transistor Q9, and an amplifier U9 used for voltage detection. The voltage input circuit 210 on the switching device side includes an input protection diode D14, a reverse protection diode D15, a PMOS transistor Q10, and an amplifier U10 used for voltage detection.

[0072] When the power conversion device and the switching device are communicating normally, PMOS transistor Q9 is in the off state. When the switching device detects a 0V signal, it will not perform grid disconnection / off operation. At this time, PMOS transistor Q10 is in the off state. When the power conversion device needs to disconnect from the grid, the first controller of the power conversion device controls the short-term opening of PMOS transistor Q9, thereby generating a 12V pulse signal (including the rising edge signal) on the first transmit / receive data line PIN11, which is the shutdown control signal, and outputs it to the switching device. After the second controller of the switching device detects the 12V pulse signal or the rising edge signal through amplifier U10, it disconnects the disconnection device 211, and after the disconnection is completed, it controls the on / off state of PMOS transistor Q10, thereby generating a 12V pulse signal (including the rising edge signal) on the first transmit / receive data line PIN11 where PMOS transistor Q10 is located, which is the shutdown success signal, and transmits it to the power conversion device. The first controller of the power conversion device can also detect voltage through amplifier U9. After detecting a 12V pulse signal or rising edge signal, it confirms and completes the off-grid conversion, and then switches from current source mode to voltage source mode, that is, enters off-grid operation mode.

[0073] Please see Figure 9 , Figure 9 The diagram shows one possible circuit for implementing the above scheme. When there is no trigger signal (i.e., no shutdown control signal or shutdown completion signal), the first transmit / receive data line PIN11 is at a potential of 12V.

[0074] Specifically, the voltage output circuit 110 on the power conversion device side includes a reverse protection diode D16, a current-limiting resistor R6, an NMOS transistor Q11, and an amplifier U11 used for voltage detection. The voltage input circuit 210 on the switching device side includes an input protection diode D17, a current-limiting resistor R7, an NMOS transistor Q12, and an amplifier U12 used for voltage detection.

[0075] When the power conversion device and the switching device are communicating normally, NMOS transistor Q11 is in the off state. When the switching device detects a 12V signal, it will not perform grid disconnection / off operation. At this time, NMOS transistor Q12 is in the off state. When the power conversion device needs to disconnect from the grid, the first controller of the power conversion device controls the short-term opening of NMOS transistor Q11, thereby generating a 0V pulse signal (including a falling edge signal) on the first transmit / receive data line PIN11, which is the shutdown control signal, and outputs it to the switching device. After the second controller of the switching device detects the 0V pulse signal through amplifier U12, it disconnects the disconnection device 211, and after the disconnection is completed, it controls the on / off state of NMOS transistor Q12, thereby generating a 0V pulse signal (including a falling edge signal) on the first transmit / receive data line PIN11 where NMOS transistor Q12 is located, which is the shutdown success signal, and transmits it to the power conversion device. The first controller of the power conversion device can also perform voltage detection through amplifier U11. After detecting a 0V pulse signal or falling edge signal, it confirms and completes the off-grid conversion, and then switches from current source mode to voltage source mode, that is, enters off-grid operation mode.

[0076] Please see Figure 10 The power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device. The power conversion device is also connected to the switching device via a first transmit / receive data line and a second transmit / receive data line. For example, the power conversion device is wired to the second interface J2 of the switching device via a first interface J1. The first interface J1 and the second interface J2 are provided with terminals for a 12V power supply line, a ground line GND, a first transmit / receive data line PIN11, and a second transmit / receive data line PIN12. The first power line is a 12V power supply line, and the first transmit / receive data line PIN11 and the second transmit / receive data line PIN12 are independently configured lines.

[0077] The control methods for switching between grid connection and off-grid also include:

[0078] A shutdown control signal is sent via the first transmit / receive data line PIN11 or the second transmit / receive data line PIN12, and a shutdown completion signal is received via the first transmit / receive data line PIN11 or the second transmit / receive data line PIN12.

[0079] Figure 10 This diagram shows one circuit scheme for implementing the above solution, with the following operating logic: Figure 8 and Figure 9 The plan is the same, only Figure 10 The proposed solution is compared to Figure 8 or Figure 9 The proposed solution includes an extra circuit, and the circuit logic is similar, so I won't go into detail here. This is understandable. Figure 10In the dual-line scheme shown, the two lines can be used alternately, or one line can be used first and then switched to the other after a failure.

[0080] Please see Figure 11 This application embodiment also provides a control device for off-grid / parallel switching, the control device comprising:

[0081] The transceiver module 1101 is used to send a shutdown control signal to a switching device when a mains power failure is detected; the switching device is connected between the mains power and the load and is used to control the connection between the mains power and the load; the shutdown control signal is used to control the switching device to disconnect the connection between the mains power and the load.

[0082] Control module 1102 is used to control the power conversion device to switch to off-grid operation mode in response to the shutdown success signal sent by the switching device; the shutdown completion signal and the shutdown control signal are level signals with different voltage amplitudes, or the shutdown control signal and the shutdown completion signal are both pulse signals and / or edge signals.

[0083] In some embodiments, the control module 1102 is specifically used to control the power conversion device to switch from current source mode to voltage source mode.

[0084] In some embodiments, the power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line;

[0085] The transceiver module 1101 is specifically used to send the shutdown control signal to the switching device through the first power line, and to receive the shutdown completion signal through the first power line.

[0086] In some embodiments, the power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the power conversion device is also connected to the switching device via a first transmit data line and a first receive data line.

[0087] The transceiver module 1101 is specifically used to send the shutdown control signal through the first transmit data line and receive the shutdown completion signal through the first receive data line.

[0088] In some embodiments, the power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the power conversion device is also connected to the switching device via a first transmit / receive data line.

[0089] The transceiver module 1101 is specifically used to send the shutdown control signal through the first transceiver data line and to receive the shutdown completion signal through the first transceiver data line.

[0090] In some embodiments, the shutdown control signal is an edge signal; the shutdown completion signal is a pulse signal.

[0091] In some embodiments, the power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the power conversion device is also connected to the switching device via a first transmit / receive data line and a second transmit / receive data line, respectively.

[0092] The transceiver module 1101 is specifically used to send the shutdown control signal through the first transceiver data line or the second transceiver data line, and to receive the shutdown completion signal through the first transceiver data line or the second transceiver data line.

[0093] For details on the specific implementation method and related beneficial effects of the control device for switching between on-grid and off-grid operation, please refer to the description of the specific embodiments of the control method described above, which will not be repeated here.

[0094] Please see Figure 12 This application also provides a power conversion device 100, including a power conversion circuit 111, a memory 112, a processor 113, and a computer program 114 stored in the memory 112 and executable on the processor 113. The mains power side of the power conversion device 100 is connected to the mains power through a switching device 200. The switching device 200 is used to control the connection and disconnection between the mains power and the power conversion device 100. When the processor 113 executes the computer program 114, it implements the steps of the on / off grid switching control method as described in any of the above embodiments.

[0095] Please see Figure 12 and Figure 13 This application embodiment also provides a control method for off-grid / parallel switching, which is applied to a switchgear 200. The control method includes:

[0096] Step S210: Receive the shutdown control signal sent by the power conversion device.

[0097] The switching device 200 is connected between the mains power and the power conversion device 100 and is used to control the on / off of the mains power and the power conversion device 100; according to the off control signal, the switching device 200 is controlled to disconnect the connection between the mains power and the power conversion device 100.

[0098] Step S220: After disconnecting the mains power from the conversion device, a shutdown completion signal is sent to the power conversion device.

[0099] The shutdown completion signal is used to indicate that the power conversion device 100 switches to off-grid operation mode. The shutdown completion signal and the shutdown control signal have different voltage amplitudes, or the shutdown control signal and the shutdown completion signal are pulse signals and / or edge signals.

[0100] It is understood that the control method for off-grid switching applied to the switching device 200 in this embodiment can be adapted to the control method for off-grid switching applied to the power conversion device 100 in any of the previous embodiments.

[0101] In this embodiment, the control method for switching between grid connection and off-grid connection applied to the switchgear 200 sends a switching success signal to the power conversion device 100 after confirming that the switching between grid connection and off-grid connection has been successfully implemented. This ensures that the working mode of the power conversion device 100 matches the actual operation, thus avoiding power outages or even damage to the power conversion device.

[0102] Please see Figure 14 This application embodiment also provides a switching device 200, including a disconnection device 211, a memory 212, a processor 213, and a computer program 214 stored in the memory 212 and executable on the processor 213. The disconnection device 211 is used to control the connection and disconnection between the mains power and the power conversion device 100. When the processor 213 executes the computer program 214, it implements the steps of the control method for switching between grid connection and off-grid connection applied to the switching device 200.

[0103] This application also provides a power system including the power conversion device 100 and / or the switching device 200 described above.

[0104] It is understood that the power conversion device 100 described above can be a single power device, a battery pack with battery modules, or an energy storage device comprising multiple battery packs with battery modules.

[0105] Those skilled in the art will understand that Figure 12 This is merely an example of the power conversion device 100 and does not constitute a limitation on the power conversion device 100. It may include more or fewer components than shown, or combine certain components, or different components, such as input / output devices, network access devices, etc.

[0106] Additionally, processors 113 / 213 can be a Central Processing Unit (CPU), or other general-purpose controllers, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose controller can be a microcontroller or any conventional controller.

[0107] In some embodiments, memory 112 / 212 may be an internal storage unit of power conversion device 100 or switching device 200, such as a hard disk or memory of power conversion device 100 or switching device 200. In other embodiments, memory 112 / 212 may also be an external storage device of power conversion device 100 or switching device 200, such as a pluggable hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on power conversion device 100 or switching device 200. Furthermore, memory 112 / 212 may include both internal storage units of power conversion device 100 or switching device 200 and external storage devices. Memory 112 / 212 is used to store operating system, application programs, boot loader, data, and other programs. Memory 112 / 212 can also be used to temporarily store data that has been output or will be output.

[0108] This application also provides a computer program product, including computer program 114 / 214, which, when run, causes the above-mentioned on-grid switching control method to be executed.

[0109] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above method embodiments of this application can be implemented by a computer program 114 / 214 instructing related hardware. This computer program 114 / 214 can be stored in a computer-readable storage medium. When executed by the processor 113 / 213, the computer program 114 / 214 can implement the steps of the various method embodiments described above. The computer program 114 / 214 includes computer program 114 / 214 code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium may include at least: any entity or device capable of carrying computer program 114 / 214 code to a photographing device / terminal device, recording media, computer memory 112 / 212, ROM (Read-Only Memory), RAM (Random Access Memory), CD-ROM (Compact Disc Read-Only Memory), magnetic tape, floppy disk, and optical data storage devices, etc. The computer-readable storage medium mentioned in this application may be a non-volatile storage medium; in other words, it may be a non-transient storage medium.

[0110] It should be understood that all or part of the steps of the above embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented in whole or in part as a computer program 114 / 214 product. The computer program 114 / 214 product includes one or more computer instructions. The computer instructions can be stored in the above-described computer-readable storage medium.

[0111] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0112] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0113] In the embodiments provided in this application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0114] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0115] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A control method for switching between grid-connected and off-grid environments, characterized in that, The control method, applied to power conversion equipment, includes: When a mains power failure is detected, a shutdown control signal is sent to the switching device; the switching device is connected between the mains power and the load and is used to control the connection between the mains power and the load; the shutdown control signal is used to control the switching device to disconnect the connection between the mains power and the load; In response to the shutdown success signal sent by the switching device, the power conversion device is controlled to switch to off-grid operation mode; the shutdown completion signal and the shutdown control signal are level signals with different voltage amplitudes, or the shutdown control signal and the shutdown completion signal are both pulse signals and / or edge signals.

2. The control method as described in claim 1, characterized in that, The module for controlling the power conversion device to switch to off-grid operation includes: Control the power conversion device to switch from current source mode to voltage source mode.

3. The control method as described in claim 1, characterized in that, The power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; The method further includes: The shutdown control signal is sent to the switching device via the first power line, and the shutdown completion signal is received via the first power line.

4. The control method as described in claim 1, characterized in that, The power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the power conversion device is also connected to the switching device via a first transmit data line and a first receive data line. The method further includes: The shutdown control signal is sent through the first transmit data line, and the shutdown completion signal is received through the first receive data line.

5. The control method as described in claim 1, characterized in that, The power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the power conversion device is also connected to the switching device via a first transmit / receive data line. The method further includes: The shutdown control signal is transmitted through the first transmit / receive data line, and the shutdown completion signal is received through the first transmit / receive data line.

6. The control method as described in claim 5, characterized in that, The shutdown control signal is an edge signal; the shutdown completion signal is a pulse signal.

7. The control method as described in claim 1, characterized in that, The power conversion device is connected to the switching device via a first power line to provide a first operating voltage to the switching device via the first power line; the power conversion device is also connected to the switching device via a first transmit / receive data line and a second transmit / receive data line, respectively. The method further includes: The shutdown control signal is transmitted via the first or the second data line, and the shutdown completion signal is received via the first or the second data line.

8. A power conversion device, characterized in that, The device includes a power conversion circuit, a memory, a processor, and a computer program stored in the memory and executable on the processor. The mains side of the power conversion device is connected to the mains power via a switching device. The switching device is used to control the connection and disconnection between the mains power and the power conversion device. When the processor executes the computer program, it implements the steps of the on / off grid switching control method as described in any one of claims 1 to 7.

9. A control method for switching between grid-connected and off-grid environments, characterized in that, The control method, applied to switching equipment, includes: The device receives a shutdown control signal sent by the power conversion device; the switching device is connected between the mains power and the power conversion device and is used to control the on / off connection between the mains power and the power conversion device; the device controls the switching device to disconnect the connection between the mains power and the power conversion device according to the shutdown control signal; After disconnecting the mains power from the conversion device, a shutdown completion signal is sent to the power conversion device; the shutdown completion signal is used to instruct the power conversion device to switch to off-grid operation mode.

10. A switching device, characterized in that, The device includes a disconnection device, a memory, a processor, and a computer program stored in the memory and executable on the processor. The disconnection device is used to control the switching between the mains power and the power conversion device. When the processor executes the computer program, it implements the steps of the on / off grid switching control method as described in claim 9.

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