WO2021253155A1 - 一种防输入端错接的保护电路及光伏发电系统 - Google Patents

一种防输入端错接的保护电路及光伏发电系统 Download PDF

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Publication number
WO2021253155A1
WO2021253155A1 PCT/CN2020/096083 CN2020096083W WO2021253155A1 WO 2021253155 A1 WO2021253155 A1 WO 2021253155A1 CN 2020096083 W CN2020096083 W CN 2020096083W WO 2021253155 A1 WO2021253155 A1 WO 2021253155A1
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WIPO (PCT)
Prior art keywords
unit
port
input terminal
terminal
detection unit
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Application number
PCT/CN2020/096083
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English (en)
French (fr)
Inventor
张秀锋
张彦忠
闫广超
张芳坡
田晓康
Original Assignee
华为数字能源技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 华为数字能源技术有限公司 filed Critical 华为数字能源技术有限公司
Priority to CN202080009902.5A priority Critical patent/CN114080741B/zh
Priority to PCT/CN2020/096083 priority patent/WO2021253155A1/zh
Priority to EP20941495.2A priority patent/EP4148931A4/en
Publication of WO2021253155A1 publication Critical patent/WO2021253155A1/zh
Priority to US18/080,112 priority patent/US20230104392A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
    • H02S40/30—Electrical components
    • H02S40/34—Electrical components comprising specially adapted electrical connection means to be structurally associated with the PV module, e.g. junction boxes
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
    • H02H11/002—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of inverted polarity or connection; with switching for obtaining correct connection
    • H02H11/003—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of inverted polarity or connection; with switching for obtaining correct connection using a field effect transistor as protecting element in one of the supply lines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/66—Structural association with built-in electrical component
    • H01R13/665—Structural association with built-in electrical component with built-in electronic circuit
    • H01R13/6683—Structural association with built-in electrical component with built-in electronic circuit with built-in sensor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/66—Structural association with built-in electrical component
    • H01R13/70—Structural association with built-in electrical component with built-in switch
    • H01R13/713—Structural association with built-in electrical component with built-in switch the switch being a safety switch

Definitions

  • This application relates to the field of power electronics technology, and in particular to a protection circuit and a photovoltaic power generation system for preventing misconnection of input terminals.
  • the DC switches of multiple circuits on the DC input side are usually set in the same combiner box.
  • the wiring may cause the positive and negative poles of the DC switch of the same DC to be reversed, or the positive and negative poles of the DC switches corresponding to different DCs are connected incorrectly, which will cause a short circuit after the DC switch is closed.
  • faults such as current back-irrigation may cause local overheating or burnout, and in serious cases, explosions, fires and other safety accidents may occur.
  • the present application provides a protection circuit and a photovoltaic power generation system for preventing the wrong connection of the input terminal, which can prevent the circuit from being harmed by the wrong connection when the positive and negative electrodes of the power supply connected to the input terminal are connected wrongly.
  • an embodiment of the present application provides a protection circuit for preventing the misconnection of an input terminal.
  • the protection circuit includes an input terminal, a misconnection detection unit, a mechanical interlocking unit, and a switch unit.
  • the input terminal is used to connect the output terminal of the DC power supply; the first input terminal of the misconnection detection unit is connected to the first port of the input terminal, the second input terminal of the misconnection detection unit is connected to the second port of the input terminal, and the The output end is coupled to the mechanical interlock unit.
  • the mechanical interlock unit is connected to the switch unit.
  • the first end of the switch unit is used to connect to the input end, and the second end of the switch unit is used to connect to the subsequent circuit.
  • the misconnection detection unit controls the mechanical interlock unit to keep the first end of the switch unit and the second end of the switch unit in a disconnected state when the first port and the second port are connected incorrectly.
  • the protection circuit realizes the detection before the switch unit is closed, that is, the detection is realized before the loop is connected, instead of detecting the wrong connection of the circuit and then opening the loop after the loop is connected, it has higher safety and reliability.
  • the protection circuit includes a mechanical interlocking unit, and when the input terminal is misconnected, the switch unit will be continuously locked to maintain the off state, which further enhances safety.
  • the protection circuit further includes a normally closed switch.
  • the normally closed switch is interlocked with the switch unit. Specifically, when the switch unit is open, the normally closed switch is closed, and when the switch unit is closed, the normally closed switch is open.
  • the normally closed switch includes: a first normally closed contact and a second normally closed contact. The first input terminal of the misconnection detection unit is connected to the first port of the input terminal through a first normally closed contact, and the second input terminal of the misconnection detection unit is connected to the second port of the input terminal through a second normally closed contact.
  • the normally closed switch may further include a contact, which is arranged between the first input terminal of the misconnection detection unit and the first port of the input terminal, or arranged at the second terminal of the misconnection detection unit. Between the input end and the second port of the input end, this application does not specifically limit this.
  • the normally closed switch Since the normally closed switch is interlocked with the switch unit, when it is determined that there is no misconnection in the loop, the normally closed switch can be opened after the switch unit is closed to disconnect the misconnection detection unit and the input terminal to realize the misconnection detection unit and the loop Therefore, it can prevent lightning strikes and surges from destroying the protection circuit, avoiding the additional use of lightning and surge protection devices, and reducing the implementation cost while ensuring safety.
  • the misconnection detection unit includes a detection unit and a control unit.
  • the detection unit is used to detect electrical parameters between the first port and the second port, and the electrical parameters include at least one of the following: voltage, current, and impedance.
  • the control unit is used to compare the electrical parameters with the corresponding preset threshold. When it is determined that the first port and the second port are incorrectly connected according to the comparison result, the mechanical interlock unit is controlled to make the first end of the switch unit and the second end of the switch unit Keep it disconnected.
  • the protection circuit detects the electrical parameters between the first port and the second port before the switch unit is closed to determine whether the wiring of the first port and the second port is wrong, that is, the detection is performed before the loop is turned on, instead of After the circuit is connected, it is detected that the circuit is wrongly connected and then the circuit is disconnected, so it has higher safety and reliability.
  • the misconnection detection unit includes: a detection unit and a control unit.
  • the detection unit is used to divide the voltage between the first port and the second port, and send the divided voltage to the control unit.
  • the control unit is used to disconnect when the divided voltage is less than the preset threshold, so that the mechanical interlock unit loses power, and the switch unit maintains the disconnected state when the mechanical interlock unit loses power.
  • the detection unit of the above protection circuit can prevent the control unit from directly bearing the full voltage of the DC power supply and play a role in protecting the control unit. Similarly, the protection circuit is detected before the switch unit is closed, instead of detecting the wrong connection of the circuit and then opening the loop after the loop is turned on, so it has higher safety and reliability.
  • control end of the control unit is connected to the output end of the detection unit, and the first end of the control unit is connected to the first end of the mechanical interlocking unit.
  • the misconnection detection unit further includes a first clamping diode.
  • the cathode of the first clamping diode is connected to the control terminal of the control unit, and the anode of the first clamping diode is connected to the second terminal of the control unit. Therefore, when the loop is not wrongly connected, the first clamping diode is not turned on, and when a wrong connection occurs in the loop, the first clamping diode is turned on.
  • the control unit is a first switching device.
  • the first switching device is an IGBT device or a MOS device.
  • the detection unit includes a first resistor and a second resistor. The first terminal of the first resistor is connected to the second port of the input terminal, the second terminal of the first resistor is connected to the first port of the input terminal through the second resistor, and the common terminal of the first resistor and the second resistor is connected to the control terminal of the first switching device .
  • the control voltage of the first switching device is the divided voltage of the second resistor.
  • the voltage division value of the second resistor exceeds the operating voltage of the first switching device, and the mechanical interlocking unit releases the control of the switching unit.
  • the first clamping diode is turned on and the second resistor is short-circuited.
  • the voltage division value of the second resistor is less than the operating voltage of the first switching device.
  • the mechanical interlocking unit loses power to control the switching unit Maintain the disconnected state.
  • the misconnection detection unit further includes an overvoltage protection circuit.
  • the overvoltage protection circuit is connected in series between the input terminal and the second terminal of the control unit.
  • the overvoltage protection circuit is used to disconnect the connection between the input terminal and the second terminal of the control unit when the voltage between the first port and the second port of the input terminal is greater than the overvoltage threshold, so as to prevent the loop from being caused by overvoltage. damage. .
  • the overvoltage protection circuit includes a third resistor, a fourth resistor, a sixth resistor, and a second switching device.
  • the first end of the third resistor is connected to the second port of the input end
  • the second end of the third resistor is connected to the control end of the second switching device
  • the second end of the second switching device is connected to the first port of the input end
  • the second switch The first end of the device is connected to the second end of the first switching device
  • the fourth resistor is connected between the control end of the second switching device and the second end of the second switching device
  • the sixth resistor is connected in parallel to the second end of the second switching device. One end and the second end.
  • the misconnection detection unit further includes a current limiting resistor.
  • the first end of the current limiting resistor is connected to the second port of the input end, and the second end of the current limiting resistor is connected to the first end of the first resistor.
  • Current limiting resistors are used to limit current to protect the circuit.
  • the misconnection detection unit further includes: a capacitor and a second clamping diode.
  • the capacitor is connected in parallel at both ends of the first resistor and the second resistor connected in series.
  • the anode of the second clamping diode is connected to the second end of the control unit, and the cathode of the second clamping diode is connected to the first end of the first resistor.
  • Capacitors can be used for energy storage; the second clamp diode is turned on when there is a misconnection in the loop, so that other parts of the misconnection detection unit are short-circuited, and the mechanical interlocking unit is de-energized to control the switching unit to maintain the off state .
  • the mechanical interlocking unit includes an electromagnet, and the switch unit is controlled to maintain an off state when the electromagnet is de-energized.
  • the mechanical interlocking unit loses power.
  • the mechanical interlocking unit has a manual unlocking function, that is, it can be manually unlocked. The way to unlock the switch unit, and then control the switch unit to close.
  • the DC power source is at least one of the following: a photovoltaic unit, a DC converter, and an energy storage unit.
  • the first port of the input terminal is used to connect to the negative output terminal of the DC power supply, and the second port of the input terminal is used to connect the positive output terminal of the DC power supply.
  • each DC power source corresponds to a protection circuit to prevent misconnection of the input terminal.
  • the DC power supply includes at least a first DC power supply and a second DC power supply;
  • the switching unit includes at least a first switching unit and a second switching unit, and the input terminal includes at least The first power input terminal and the second power input terminal;
  • the misconnection detection unit includes: a first detection unit, a second detection unit and a controller.
  • the first power input terminal is used to connect to a first direct current power source, and the second power input terminal is used to connect to a second direct current power source.
  • the first terminal of the first switch unit is used to connect to the first power input terminal
  • the first terminal of the second switch unit is used to connect to the second power input terminal
  • the second terminal of the first switch unit and the second terminal of the second switch unit Both ends are used to connect the subsequent circuit.
  • the first detection unit is used to detect the voltages of the first port and the second port of the first power input terminal.
  • the second detection unit is used to detect the voltages of the first port and the second port of the second power input terminal.
  • the controller controls the mechanical interlocking unit to keep the first terminal and the second terminal of the first switch unit disconnected; it is also used to connect the second power supply
  • the mechanical interlocking unit is controlled to keep the first end and the second end of the second switch unit in a disconnected state.
  • the protection circuit is tested to determine whether the wiring of the first port and the second port is wrong before the switch unit is closed, that is, the detection is realized before the loop is connected, rather than the circuit is detected to be wrong after the loop is connected and then disconnected Circuit, so it has higher safety and reliability.
  • the present application also provides another protection circuit for preventing the wrong connection of the input terminal.
  • the protection circuit includes an input terminal, a wrong connection detection unit and an external power supply.
  • the input terminal is used to connect the output terminal of the DC power supply, and the input terminal includes a first port and a second port;
  • the first input terminal of the misconnection detection unit is connected to the first port of the input terminal, and the second input terminal of the misconnection detection unit is connected to the second port of the input terminal.
  • the external power supply and the auxiliary switch are connected in series and then connected in parallel between the first port and the second port, wherein the positive output terminal of the external power supply is connected to the first port.
  • the misconnection detection unit is used to detect the impedance of the first port and the second port, and when the impedance is greater than a preset threshold, it is determined that the first port and the second port are connected incorrectly.
  • the misconnection detection unit of the protection circuit controls the mechanical interlock unit to keep the first end of the switch unit and the second end of the switch unit in an off state when the circuit is misconnected, so as to realize the isolation of the wrong connection circuit before the circuit is connected. And protection to prevent the circuit from being wrongly connected after the switch unit is closed. Since the detection is realized before the switch unit is closed, that is, the detection is realized before the loop is connected, instead of detecting the wrong connection of the circuit and then opening the loop after the loop is connected, it has higher safety and reliability.
  • the protection circuit further includes: a mechanical interlock unit and a switch unit.
  • the misconnection detection unit includes an impedance network unit, an impedance detection unit and a control unit.
  • the first end of the impedance network unit is connected to the first port, and the second end of the impedance network unit is connected to the second port.
  • the output end of the misconnection detection unit is coupled to the mechanical interlock unit, and the mechanical interlock unit is connected to the switch unit.
  • the impedance detection unit is used to obtain the impedance between the first port and the second port.
  • the first end of the switch unit is used to connect to the input end, and the second end of the switch unit is used to connect to the subsequent circuit.
  • the control unit is used to control the mechanical interlocking unit to lose power when the impedance is greater than the preset threshold, and to maintain the switch unit in an off state when the mechanical interlocking unit loses power,
  • the impedance network unit at least includes: a detection resistor and a first diode.
  • the anode of the first diode is connected to the negative output terminal of the DC power supply, and the cathode is connected to the positive output terminal of the DC power supply through a detection resistor.
  • the protection circuit further includes an alarm unit.
  • the wrong connection detection unit is used to send an alarm instruction to the alarm unit when the first port and the second port are connected incorrectly.
  • the alarm unit is used to alarm according to the alarm instruction, and the external power supply is an isolated DC source.
  • the present application also provides a photovoltaic power generation system, including: a DC power supply and the above-mentioned protection circuit for preventing the misconnection of the input end, the DC power supply is at least one of a photovoltaic unit, a DC converter, and an energy storage unit kind.
  • the first port of the input terminal is used to connect to the negative output terminal of the DC power supply, and the second port of the input terminal is used to connect the positive output terminal of the DC power supply.
  • the protection circuit is used to disconnect the DC power supply from the subsequent circuit when the positive output terminal and the negative output terminal of the DC power supply are connected incorrectly.
  • the photovoltaic power generation system includes the protection circuit, and the misconnection detection unit of the protection circuit, when the voltage connected to the first port and the second port is reversed, the mechanical interlock unit is controlled to make the first end of the switch unit and the second end of the switch unit The two ends remain disconnected, which realizes the isolation and protection of the wrong-connected circuit before the circuit is connected, thus improving the safety and reliability of the photovoltaic power generation system.
  • the protection circuit is used to protect the subsequent circuit when the DC power supply connected to the input terminal is misconnected.
  • the protection circuit includes a misconnection detection unit.
  • the misconnection detection unit includes a first input terminal and a second input terminal. The first input end of the connection detection unit is connected to the first port of the input end, the second input end of the misconnection detection unit is connected to the second port of the input end, and the misconnection detection unit can detect whether the DC power supply connected to the input end is misconnected.
  • the output terminal of the misconnection detection unit is connected to the mechanical interlocking unit.
  • the mechanical interlock unit is connected to the switch unit, the first end of the switch unit is connected to the input end, and the second end of the switch unit is connected to the subsequent circuit.
  • the wrong connection detection unit When the wrong connection detection unit detects the wrong connection of the DC power supply connected to the first port and the second port, it controls the mechanical interlock unit to keep the first end of the switch unit and the second end of the switch unit disconnected to avoid the wrong connection of the DC power supply Supply power to the subsequent circuit, so as to realize the isolation and protection of the wrong connection circuit before the power is turned on, so as to avoid the damage of the subsequent circuit from the wrong connection after the switch unit is closed. Since this solution realizes the detection before the switch unit is closed, that is, the detection is realized before the loop is connected, instead of detecting the circuit misconnection after the loop is connected and then disconnecting the loop, it has higher safety and reliability. Moreover, the circuit includes a mechanical interlocking unit, and when the input terminal is misconnected, the switch unit will be continuously locked to maintain the disconnected state, which further enhances safety.
  • Figure 1 is the first schematic diagram when a circuit breaker or fuse is used for circuit protection
  • Figure 2 is the second schematic diagram when a circuit breaker or fuse is used for circuit protection
  • FIG. 3 is a schematic diagram of a protection circuit for preventing misconnection of input terminals according to an embodiment of the application
  • FIG. 4 is a schematic diagram of another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • FIG. 5 is a schematic diagram of yet another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • Fig. 6 is a schematic diagram of a mechanical interlocking unit provided by an embodiment of the application.
  • FIG. 7 is a schematic diagram of yet another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • FIG. 8A is a schematic diagram of another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • FIG. 8B is a schematic diagram of another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • FIG. 8C is a schematic diagram of yet another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • Figure 9A is the first schematic diagram when the loop is misconnected
  • Figure 9B is the second schematic diagram when the loop is misconnected
  • Figure 9C is the third schematic diagram when the loop is misconnected
  • FIG. 10 is a schematic diagram of another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • FIG. 11 is a schematic diagram of yet another protection circuit for preventing misconnection of an input terminal according to an embodiment of the application.
  • FIG. 12 is a schematic diagram of yet another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • FIG. 13 is a schematic diagram of a photovoltaic power generation system provided by an embodiment of the application.
  • the following is an example of a photovoltaic power generation system.
  • the photovoltaic (Photo Voltaic, PV) array converts solar energy into electrical energy for output, and each circuit obtains direct current from the photovoltaic array and performs DC-DC conversion. Then join the DC bus and output the inverter.
  • the part responsible for DC-DC conversion in the split string inverter is located in the MPPT (Maximum Power Point Tracking) combiner box.
  • the DC switches of multiple circuits are usually set in the same MPPT combiner box. Due to the large number of circuits, wiring may cause the positive and negative poles of the same DC switch to be reversed or different DC switches.
  • Figure 1 is the first schematic diagram when a circuit breaker or fuse is used for circuit protection.
  • Figure 1 corresponds to the normal working state.
  • the direction of the current flowing into the positive DC bus is shown by the solid arrow in the figure, and the direction of the current flowing from the negative DC bus is shown by the dotted arrow.
  • the current will not pass through the diode D2.
  • the result of the forward current detection of the diode D2 (that is, the current at the detection points P1 and P2) is zero, and it is determined that there is no connection error at this time, and the circuit breaker K1 will not be controlled to open.
  • the current flowing through the fuse K2 is the current of the single circuit where the fuse K2 is located, so the fuse K2 will not blow.
  • FIG. 2 is the second schematic diagram when a circuit breaker or fuse is used for circuit protection.
  • Figure 2 corresponds to the state when there is a misconnection in a loop.
  • the current of other normal loops will pass through the diode D2 in the loop where the misconnection occurs. Therefore, the result of the forward current detection of the diode D2 (that is, the current at the detection point P1) is The sum of the currents of other parallel circuits, at this time, the circuit breaker K1 in the circuit can be actively opened. For the fuse K2 in the circuit with misconnection, it can also be blown to protect the circuit at this time.
  • this solution can only perform detection after the loop is turned on, that is, after the circuit breaker is closed, and cannot be detected before the loop is turned on, resulting in poor safety and reliability.
  • this application provides a protection circuit and a photovoltaic power generation system to prevent misconnection of the input end.
  • the switch unit in the corresponding circuit can be controlled to remain in the open state to prevent The subsequent circuit is endangered by wrong connection. And because the protection circuit can be detected before the loop is connected, safety and reliability are improved.
  • the embodiment of the application provides a protection circuit for preventing the wrong connection of the input terminal, which can be applied to scenarios such as photovoltaic power generation system or subway power distribution system.
  • the hazards of wrong connection will be described in detail below with reference to the attached drawings.
  • FIG. 3 is a schematic diagram of a protection circuit for preventing misconnection of an input terminal according to an embodiment of the application.
  • the protection circuit includes: a misconnection detection unit 101, a mechanical interlock unit 102 and a switch unit K.
  • the first input terminal of the misconnection detection unit 101 is connected to the first port of the input terminal, which is represented by A in the figure.
  • the second input terminal of the misconnection detection unit 101 is connected to the second port of the input terminal, which is indicated by B in the figure.
  • the output terminal of the misconnection detection unit 101 is connected to the mechanical interlock unit 102.
  • the input terminal is used to connect a DC power source 103, and the DC power source 103 is used to provide DC power.
  • the DC power supply 103 can be a photovoltaic array of the photovoltaic power generation system, and the photovoltaic array converts solar energy into electrical energy for output; when the protection circuit is applied to a subway power distribution system, the DC power supply 103 It can be an external DC power supply.
  • the mechanical interlock unit 102 is connected to the switch unit K.
  • the first end of the switch unit K is connected to the input end, that is, the first end includes two ports, which are respectively connected to the first port A and the second port of the input end B, and the second end of the switch unit K is used to connect the subsequent circuit.
  • the misconnection detection unit 101 is used to control the mechanical interlock unit 102 to keep the first end of the switch unit K and the second end of the switch unit K in an open state when the voltages connected to the first port A and the second port B are reversed. That is, at this time, the mechanical interlock unit 102 can lock the switch unit K to avoid safety failures such as a short circuit or current backflow caused by the closing of the switch unit K. When there is no wiring error, the mechanical interlock unit 102 releases the control of the switch unit K, and the switch unit K can be closed or opened under normal control.
  • the mechanical interlocking unit 102 may be an electromagnetic device, such as an electromagnet, or a controllable mechanical device.
  • an electromagnetic device such as an electromagnet
  • the mechanical interlocking unit 102 is connected in a wrong connection.
  • the switch unit K is automatically locked under the control of the detection unit 101, for example, the handle of the switch unit K is automatically locked by the triggering action of an electromagnetic device, so that the handle is kept in an open state and cannot be closed.
  • the protection circuit is used to protect the subsequent circuit when the DC power supply connected to the input terminal is misconnected.
  • the protection circuit includes a misconnection detection unit, and the misconnection detection unit includes a first input terminal and a second input terminal.
  • the first input terminal of the misconnection detection unit is connected to the first port of the input terminal, and the second input terminal of the misconnection detection unit is connected to the second port of the input terminal.
  • the misconnection detection unit can detect whether the DC power supply connected to the input terminal is misconnected .
  • the output terminal of the misconnection detection unit is connected to the mechanical interlocking unit.
  • the mechanical interlock unit is connected to the switch unit, the first end of the switch unit is connected to the input end, and the second end of the switch unit is connected to the subsequent circuit.
  • the wrong connection detection unit When the wrong connection detection unit detects the wrong connection of the DC power supply connected to the first port and the second port, it controls the mechanical interlock unit to keep the first end of the switch unit and the second end of the switch unit disconnected to avoid the wrong connection of the DC power supply Supply power to the subsequent circuit, so as to realize the isolation and protection of the wrong connection circuit before the power is turned on, so as to avoid the damage of the subsequent circuit from the wrong connection after the switch unit is closed. Since this solution realizes the detection before the switch unit is closed, that is, the detection is realized before the loop is connected, instead of detecting the circuit misconnection after the loop is connected and then disconnecting the loop, it has higher safety and reliability. Moreover, the circuit includes a mechanical interlocking unit, and when the input terminal is misconnected, the switch unit will be continuously locked to maintain the disconnected state, which further enhances safety.
  • FIG. 4 is a schematic diagram of another protection circuit for preventing misconnection of input terminals according to an embodiment of the present application.
  • the protection circuit includes: a misconnection detection unit 101, a mechanical interlock unit 102, a normally closed switch 104, and a switch unit K.
  • the misconnection detection unit 101 includes a detection unit 101a and a control unit 101b.
  • the detection unit 101a is used to divide the voltage between the first port A and the second port B, and send the divided voltage to the control unit 101b.
  • the detection unit 101a can prevent the control unit 101b from directly bearing the full voltage of the DC power supply 103, and plays a role of protecting the control unit 101b.
  • control end of the control unit 101b is connected to the output end of the detection unit 101a, the first end of the control unit 101b is connected to the first end of the mechanical interlocking unit, and the second end of the control unit 101b is connected to the first port A of the input end. , The second end of the mechanical interlock unit 102 is connected to the second port B of the input end.
  • the control unit 101b is used for disconnecting when the divided voltage is less than the preset threshold, so that the mechanical interlocking unit 102 loses power, and when the mechanical interlocking unit 102 loses power, the switch unit K is kept in the disconnected state.
  • the control unit 101b is also used to close when the divided voltage is greater than or equal to the preset threshold, so that the mechanical interlock unit 102 is energized. When the mechanical interlock unit 102 is energized, the control of the switch unit K is released, so that the switch unit K can Close or open under normal control.
  • the normally closed switch 104 is interlocked with the switch unit K, that is, the normally closed switch 104 is closed when the switch unit K is opened, and the normally closed switch 104 is opened when the switch unit K is closed.
  • the normally closed switch 104 may be a micro switch S, which specifically includes: a first normally closed contact and a second normally closed contact.
  • the first input terminal of the misconnection detection unit 101 is connected to the first port A of the input terminal through a first normally closed contact, and the second input terminal of the misconnection detection unit 101 is connected to the second port of the input terminal through a second normally closed contact.
  • the second end of the control unit 101b is connected to the first port A of the input end through the first normally closed contact, and the second end of the mechanical interlock unit 102 is connected to the second port B of the input end through the second normally closed contact.
  • the normally closed switch of the protection circuit provided by the embodiment of the application is interlocked with the switch unit.
  • the normally closed switch opens, that is, when it is determined that there is no wrong connection in the loop, the normally closed switch unit is closed.
  • the switch can be disconnected to disconnect the wrong connection detection unit and the input terminal, and realize the isolation between the wrong connection detection unit and the loop, so it can prevent lightning strikes and surges from destroying the protection circuit, avoiding additional use of lightning and surge protection
  • the device reduces the implementation cost while ensuring safety.
  • only the normally closed switch 104 includes two switch bodies, which are respectively arranged at points A and B and the two input ends of the detection unit 101a.
  • the normally closed switch 104 can also include only one switch body, that is, it is only set between point A or point B and the input terminal of the detection unit 101a. This solution can be applied to all the above and below implementations. For example, I won’t repeat them here.
  • FIG. 5 is a schematic diagram of another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • the control unit is specifically the first switching device.
  • the detection unit of the protection circuit includes a first resistor R1 and a second resistor R2, wherein the first end of the first resistor R1 is connected to the second port B of the input terminal, and the second end of the first resistor R2 is connected to the input terminal through the second resistor R1.
  • the common terminal of the first port A, the first resistor R1 and the second resistor R2 is connected to the control terminal of the first switching device.
  • the type of the first switching device can be any of the following: Insulated Gate Bipolar Transistor (IGBT) or Metal Oxide Semiconductor Filed Effect Transistor, MOSFET, hereinafter referred to as MOS tube ), SiC MOSFET (Silicon Carbide Metal Oxide Semiconductor Filed Effect Transistor, silicon carbide field effect transistor), etc.
  • IGBT Insulated Gate Bipolar Transistor
  • MOSFET Metal Oxide Semiconductor Filed Effect Transistor
  • MOS tube Metal Oxide Semiconductor Filed Effect Transistor
  • SiC MOSFET Silicon Carbide Metal Oxide Semiconductor Filed Effect Transistor, silicon carbide field effect transistor
  • the first switching device is specifically be a PMOS transistor or an NMOS transistor, which is not specifically limited in the embodiment of the present application.
  • the first switching device is specifically an NMOS transistor as an example for description, which is represented by Q1 in the figure.
  • the misconnection detection unit 101 also includes a first clamping diode D1 and a capacitor C.
  • the cathode of the first clamping diode D1 is connected to the control terminal of the control unit, that is, to the gate of Q1
  • the anode of the first clamping diode D1 is connected to the second terminal of the control unit, and the first terminal of the control unit is the drain of Q1 ,
  • the second end of the control unit is the source of Q1.
  • the first end of the capacitor C is connected to the first end of the first resistor R1, and the second end of the capacitor C is connected to the second end of the control unit.
  • the misconnection detection unit 101 further includes a current-limiting resistor R5, a first end of the current-limiting resistor R5 is connected to the second port B of the input end, and a second end of the current-limiting resistor R5 is connected to the first port of the first resistor R1. end.
  • the current-limiting resistor R5 is used to limit the current in the misconnection detection unit 101 to protect the circuit, and at the same time play a role of lightning protection and surge protection.
  • the second port of the input terminal is connected to the positive output terminal of the DC power supply 103, and the first port of the input terminal is connected to the negative output terminal of the DC power supply 103.
  • the first clamp diode D1 is not turned on.
  • the input voltage of the gate of Q1 is the divided voltage of the second resistor R2.
  • the drain and source of Q1 On, the first end of the mechanical interlocking unit is connected to the drain of Q1, and the second end of the mechanical interlocking unit is connected to the first end of the first resistor R1.
  • the capacitor C supplies power to the mechanical interlock unit 102 so that the mechanical interlock unit 102 releases the control of the switch unit K. It can be understood that when the capacitor C does not exist, the mechanical interlock unit 102 is connected in parallel at both ends of the detection unit, and it can also be powered by the DC power supply 103.
  • the first port of the input terminal is connected to the positive output terminal of the DC power supply 103, and the second port of the input terminal is connected to the DC The negative output terminal of the power supply 103.
  • the first clamping diode D1 is turned on, the voltage input to the gate of Q1 is zero, and the drain and source of Q1 are disconnected.
  • the mechanical interlocking unit 102 loses power to control the switch unit K to maintain the disconnected state.
  • the misconnection detection unit 101 further includes a second clamping diode D2.
  • the anode of the second clamping diode D2 is connected to the second end of the control unit, that is, to the source of Q1, and the cathode of the second clamping diode D2 is connected to the first end of the first resistor R1.
  • the second clamp diode D2 is in a non-conducting state when the loop is not connected reversely, and is turned on when a misconnection occurs in the loop, so that other parts of the misconnection detection unit 101 are short-circuited, and the mechanical interlock unit 102 is de-energized.
  • the switch unit K is controlled to maintain the off state.
  • the mechanical interlock unit 102 is a controllable mechanical or electromagnetic device, such as an electromagnet, which will be described in detail below with reference to the accompanying drawings.
  • the mechanical interlocking unit may include an electromagnet and a pin, or it may include an electromagnet and a connecting rod structure.
  • FIG. 6 is a schematic diagram of a mechanical interlocking unit provided by an application embodiment.
  • the illustrated mechanical interlock unit 101 includes a normally open electromagnet 101a and a pin 101b.
  • the normally open electromagnet 101a is used to control the expansion and contraction state of the pin 101a.
  • the pin 101a is attracted to unlock the switch unit K.
  • the normally open relay 101a loses power, the pin 101a is released so that the pin 101a locks the switch unit K and maintains the switch unit K in an off state.
  • the mechanical interlock unit 101 also has a manual unlocking function. That is, when the mechanical interlocking unit 101 loses power, the locking of the mechanical interlocking unit 101 on the switch unit K can be unlocked manually. At this time, when the circuit is not misconnected and the DC power supply 103 does not provide an output voltage, the mechanical interlock unit 101 can unlock the switch unit K by manually unlocking, and then control the switch unit K to close.
  • the DC power supply 103 when applied to a photovoltaic power generation system, is a PV array, the first port A of the input end is used for the negative output end of the PV array, and the second port B of the input end is used for connecting the positive output of the PV array end.
  • the locking of the switch unit K by the mechanical interlock unit 101 can be manually unlocked, so that the switch unit K can be closed.
  • the misconnection detection unit of the protection circuit can control the mechanical interlock unit to keep the first end of the switch unit and the second end of the switch unit disconnected when the voltages connected to the first port and the second port are reversed.
  • Status realizes the isolation and protection of the wrong connection circuit before the circuit is connected, so as to avoid the circuit being damaged by the wrong connection after the switch unit is closed. Since the detection is realized before the switch unit is closed, that is, the detection is realized before the loop is connected, instead of detecting the wrong connection of the circuit and then opening the loop after the loop is connected, it has higher safety and reliability.
  • the normally closed switch can be opened to disconnect the misconnection detection unit and the input terminal, reduce power loss, and realize the isolation between the misconnection detection unit and the loop. Therefore, the protection circuit can be prevented from being damaged by lightning strikes and surges, and the additional use of anti-lightning and surge devices is avoided, and the implementation cost is reduced while ensuring safety.
  • FIG. 7 is a schematic diagram of still another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • the control unit is specifically the first switching device, and the first switching device is an NMOS transistor as an example, denoted by Q1.
  • the detection unit of the protection circuit 101 includes a first resistor R1 and a second resistor R2, wherein the first end of the first resistor R1 is connected to the second port B of the input end through the current limiting resistor R5, and the second end of the first resistor R2 passes through the Two resistors R1 are connected to the second end of Q1, that is, the source of Q1.
  • the common terminal of the first resistor R1 and the second resistor R2 is connected to the control terminal of the first switching device Q1, that is, the gate of Q1.
  • the misconnection detection unit 101 also includes a first clamping diode D1 and a capacitor C.
  • the cathode of the first clamping diode D1 is connected to the control terminal of the control unit, and the anode of the first clamping diode D1 is connected to the second terminal of the control unit.
  • the first end of the capacitor C is connected to the first end of the first resistor R1, and the second end of the capacitor C is connected to the second end of the control unit.
  • the anode of the second clamping diode D2 is connected to the second end of the control unit, and the cathode of the second clamping diode D2 is connected to the first end of the first resistor R1.
  • the second clamp diode D2 is in a non-conducting state when the loop is not connected reversely, and is turned on when a misconnection occurs in the loop, so that other parts of the misconnection detection unit 101 are short-circuited, and the mechanical interlock unit 102 is de-energized.
  • the switch unit K is controlled to maintain the off state.
  • the difference between the embodiment of this application and the fourth embodiment is that it also includes an overvoltage protection circuit.
  • the overvoltage protection circuit is connected in series between the input terminal and the second terminal of the control unit Q1.
  • the overvoltage protection circuit is used to disconnect the connection between the input terminal and the second terminal of the control unit when the voltage between the first port and the second port of the input terminal is greater than the overvoltage threshold, so that the mechanical interlock unit 102 controls the switch The unit maintains the disconnected state, thereby avoiding damage to the circuit due to overvoltage.
  • the overvoltage protection circuit shown in the figure specifically includes a third resistor R3, a fourth resistor R4, and a second switching device Q2.
  • the second switching device Q2 is a PMOS transistor as an example. Then, the control terminal of Q2 is the gate, the first terminal is the drain, and the second terminal is the source.
  • the first terminal of the third resistor R3 is connected to the second port B of the input terminal
  • the second terminal of the third resistor R3 is connected to the control terminal of the second switching device Q2
  • the second terminal of the second switching device Q2 is connected to the first port A of the input terminal.
  • the first terminal of the second switching device Q2 is connected to the second terminal of the first switching device Q1
  • the fourth resistor R4 is connected between the control terminal of the second switching device Q2 and the second terminal of the second switching device Q2.
  • the input voltage of the control terminal of the second switching device Q2 is the divided voltage of the fourth resistor R4, and the corresponding overvoltage voltage value of the loop can be preset.
  • the voltage is greater than the overvoltage voltage value, it is considered that if the switching unit K is closed at this time, the loop There will be overvoltage in the system, which may damage the circuit.
  • the divided voltage of the fourth resistor R4 is less than the operating voltage of the second switching device Q2, In order to keep the drain and source of the second switching device Q2 closed; and when the input voltage of the misconnection detection unit 101 is greater than the overvoltage voltage value, the divided voltage of the fourth resistor R4 is greater than or equal to that of the second switching device Q2.
  • the operating voltage is used to disconnect the drain and source of the second switching device Q2.
  • a sixth resistor R6 is also connected between the drain and the source of the second switching device Q2.
  • the sixth resistor R6 is used to limit current to protect the circuit and make the first port A of the input terminal and the first switching device when Q2 is off.
  • a loop is formed between the second ends of Q1.
  • the second port B of the input terminal is connected to the positive output terminal of the DC power supply 103, and the first port A of the input terminal is connected to the negative output terminal of the DC power supply 103.
  • the divided voltage of the fourth resistor R4 is less than the operating voltage of the second switching device Q2, and the drain and source of the second switching device Q2 remain closed.
  • the sixth resistor R6 is short-circuited. At this time, the first clamp diode D1 is not turned on, and the input voltage of the gate of Q1 is the divided voltage of the first resistor R2.
  • the drain and source of Q1 are turned on At this time, the first end of the mechanical interlocking unit is connected to the drain of Q1, and the second end of the mechanical interlocking unit is connected to the first end of the first resistor R1.
  • the capacitor C supplies power to the mechanical interlock unit 102 so that the mechanical interlock unit 102 releases the control of the switch unit K. It can be understood that when the capacitor C does not exist, the mechanical interlock unit 102 is connected in parallel at both ends of the detection unit, and it can also be powered by the DC power supply 103.
  • the divided voltage of the fourth resistor R4 is greater than or equal to the operating voltage of the second switching device Q2, and the drain and source of the second switching device Q2 are disconnected, At this time, the sixth resistor R6 is connected to the circuit, and the sixth resistor R6 can limit current to protect the circuit.
  • the resistance value of the sixth resistor R6 can be set to be larger.
  • the voltage of the control terminal of Q1 is less than the operating voltage of Q1, and the mechanical interlock unit is controlled to make the switch unit the second One end and the second end of the switch unit remain disconnected.
  • the first port of the input terminal is connected to the positive output terminal of the DC power supply 103, and the second port of the input terminal is connected to the DC The negative output terminal of the power supply 103.
  • the body diode of the second switching device Q2 is turned on, so that the first clamping diode D1 is turned on, the voltage input to the gate of Q1 is zero, and the drain and source of Q1 are disconnected.
  • the mechanical interlock unit 102 Power is lost to control the switch unit K to maintain the off state.
  • the misconnection detection unit of the protection circuit can control the mechanical interlock unit to keep the first end of the switch unit and the second end of the switch unit disconnected when the voltages connected to the first port and the second port are reversed.
  • Status realizes the isolation and protection of the wrong connection circuit before the circuit is connected, so as to avoid the circuit being damaged by the wrong connection after the switch unit is closed. Since the detection is realized before the switch unit is closed, that is, the detection is realized before the loop is connected, instead of detecting the wrong connection of the circuit and then opening the loop after the loop is connected, it has higher safety and reliability.
  • the normally closed switch can be opened to disconnect the misconnection detection unit and the input terminal, reduce power loss, and realize the isolation between the misconnection detection unit and the loop. Therefore, the protection circuit can be prevented from being damaged by lightning strikes and surges, and the additional use of anti-lightning and surge devices is avoided, and the implementation cost is reduced while ensuring safety.
  • the misconnection detection unit also includes an overvoltage protection circuit, which can control the mechanical interlocking unit to lose power during overvoltage to keep the second end of the switch unit in an open state, so as to prevent the overvoltage from damaging the circuit after the switch unit is closed.
  • the impedance between the first port and the second port is detected to determine whether there is a wiring error in the connection between the first port and the second port.
  • FIG. 8A is a schematic diagram of another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • the protection circuit for preventing the misconnection of the input terminal includes: an input terminal, a misconnection detection unit 101 and an external power supply 106.
  • the input terminal is used to connect the output terminal of the DC power supply 103, and the input terminal includes a first port and a second port, which are represented by letters A and B in the figure, respectively.
  • the first input terminal of the misconnection detection unit 101 is connected to the first port A of the input terminal, and the second input terminal of the misconnection detection unit 101 is connected to the second port B of the input terminal.
  • the external power supply 105 and the auxiliary switch J1 are connected in series and then connected in parallel between the first port A and the second port B. Wherein, the positive output terminal of the external power supply 105 is connected to the first port A.
  • the misconnection detection unit 105 is used to detect the impedance of the first port A and the second port B, and when the impedance is greater than a preset threshold, it is determined that the first port A and the second port B are incorrectly wired, thereby realizing the wrong connection before the loop is connected. Isolation and protection of the circuit to prevent the circuit from being harmed by wrong connection after the switch unit is closed. Since the detection is realized before the switch unit is closed, that is, the detection is realized before the loop is connected, instead of detecting the wrong connection of the circuit and then opening the loop after the loop is connected, it has higher safety and reliability.
  • the following takes the external power supply 105 as a direct current source as an example for introduction, which may be an isolated direct current source.
  • FIG. 8B is a schematic diagram of yet another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • the protection circuit corresponding to FIG. 8B further includes a mechanical interlock unit 102 and a switch unit K.
  • the misconnection detection unit includes: an impedance network unit 106, an impedance detection unit 101c, and a control unit 101b.
  • the first end of the impedance network unit 106 is connected to the first port A, and the second end is connected to the second port B.
  • the output terminal of the misconnection detection unit is coupled to the mechanical interlock unit 102, and the mechanical interlock unit 102 is connected to the switch unit K.
  • the impedance detection unit 101c is used to obtain the impedance between the first port A and the second port B.
  • the first end of the switch unit K is used to connect the input end, that is, the first port A and the second port B are connected, and the second end of the switch unit K is connected to the subsequent circuit.
  • the embodiment of the present application does not specifically limit the implementation of the subsequent circuit .
  • the control unit 101b is used to control the mechanical interlock unit 102 to lose power when the impedance between the first port A and the second port B is greater than a preset threshold, and to maintain the switch unit in an off state when the mechanical interlock unit 102 loses power.
  • impedance network unit 106 Further, the specific implementation of the impedance network unit 106 will be described in detail below.
  • FIG. 8C is a schematic diagram of yet another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • the impedance network unit includes: a first diode D3 and a detection resistor R0.
  • the direct current source 105 and the auxiliary switch J1 are connected in series and then connected in parallel between the first port A and the second port B of the input end, wherein the positive output end of the direct current source 105 is connected to the first port A of the input end, and the negative output end is connected to the output End of the second port B.
  • the auxiliary switch J1 can be a relay.
  • the anode of the first diode D3 is connected to the negative output terminal of the DC power supply 103, and the cathode is connected to the positive output terminal of the DC power supply 103 through the detection resistor R0.
  • the impedance detection unit 101c is used to obtain the impedance between the first port A and the second port B of the input terminal.
  • the control unit 101b is configured to control the mechanical interlock unit 102 to lose power when the impedance is greater than a preset threshold.
  • the first diode D3 When the wires in the loop are connected correctly, after the DC source 105 is connected to the circuit, the first diode D3 is turned on, and the impedance between the first port A and the second port B is the impedance of the detection resistor R0 and the first diode
  • the sum of the on-resistance of D3 can be set to a preset threshold slightly greater than the sum of the above impedances. At this time, the impedance between the first port and the second port of the input terminal detected by the detection unit is less than the preset threshold, and the mechanical interlocking unit 102 is energized to release the control of the switch unit K, and the switch unit K can be closed normally.
  • Figure 9A is the first schematic diagram when the circuit is misconnected.
  • Figure 9A shows a schematic diagram of a single circuit when there is a misconnection inside.
  • the control unit 101b is When the impedance is greater than a preset threshold, the mechanical interlock unit 102 is controlled to lose power, and when the mechanical interlock unit 102 loses power, the switch unit K is maintained in an off state.
  • FIG. 9B is the second schematic diagram when the loop is misconnected
  • FIG. 9C is the third schematic diagram when the loop is misconnected.
  • the loop between the first port A and the second port B of the input terminal except for the detection resistor R0 And the first diode D3 will also include a switch unit.
  • the loop sequentially includes: a first port A, a first diode D3, a detection resistor R0, a switch unit K2, The first diode and the detection resistor, and the second port B in the loop where the DC power supply 2 is located.
  • the control unit 101b controls the mechanical interlocking unit to lose power.
  • the switch unit is maintained in an off state.
  • the loop when the DC source 105 is connected to the loop, the loop includes in turn: the first port A, the first diode and the detection resistor in the loop where the DC power supply 2 is located, and the switch unit K2 , The first diode D3, the detection resistor R0, and the second port B.
  • the control unit 101b controls the mechanical interlocking unit to lose power, and the mechanical interlocking unit loses power.
  • the switch unit is maintained in an off state.
  • the auxiliary switch can be controlled to be turned off to isolate the DC source 105 from the loop.
  • the misconnection detection unit of the protection circuit controls the mechanical interlock unit to keep the first end of the switch unit and the second end of the switch unit in an off state when the circuit is misconnected, realizing the connection before the loop is connected. Isolation and protection of the wrong connection circuit to avoid the damage of the circuit after the switch unit is closed. Since the detection is realized before the switch unit is closed, that is, the detection is realized before the loop is connected, instead of detecting the wrong connection of the circuit and then opening the loop after the loop is connected, it has higher safety and reliability.
  • the protection circuit further includes an alarm unit.
  • the wrong connection detection unit 101 is also used to send an alarm instruction to the alarm unit when the first port A and the second port B are connected incorrectly, so that the alarm unit makes an alarm according to the alarm instruction.
  • the protection circuit may also include a normally closed switch, that is, the normally closed switch 104 in the above embodiment.
  • the normally closed switch is interlocked with the switch unit K. When the switch unit K is disconnected, the normally closed switch When closed, when the switch unit is closed, the normally closed switch opens.
  • the protection circuit When the protection circuit includes a normally closed switch, it can also realize the isolation between the wrong connection detection unit and the DC circuit, so it can prevent lightning and surge from destroying the protection circuit, avoiding the additional use of lightning and surge protection devices, and ensuring safety While reducing the cost of implementation.
  • the above embodiment takes one circuit as an example for description. In actual application scenarios, the number of DC circuits may also be multiple. The following describes the implementation and working principle of the protection circuit when at least two DC circuits are included.
  • FIG. 10 is a schematic diagram of another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • each loop includes a DC power supply and an independent protection circuit to prevent misconnection of the input terminals.
  • the protection circuit included in each loop includes a misconnection detection unit 101, a mechanical interlock unit 102, and a switch unit K.
  • the wrong connection detection unit 101 can adopt the implementation manner in any of the above protection circuit embodiments, and the details are not described in the embodiment of the present application.
  • FIG. 11 is a schematic diagram of another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • multiple DC circuits share a misconnection detection unit 101, and the misconnection detection unit 101 simultaneously detects whether the voltages connected to the first port and the second port of the multiple circuits are connected reversely, And at the same time control the mechanical interlock unit 102 of multiple circuits.
  • the misconnection detection unit 101 controls the mechanical interlock unit 102 of the circuit where the voltages connected to the first port and the second port are reversed to keep the switch unit K of the circuit in an off state.
  • the wrong connection detection unit 101 can adopt the method described in the sixth embodiment of the protection circuit.
  • the following takes two DC loops as an example and detailed description in conjunction with the accompanying drawings. When the number of DC loops is greater than two, the principle is similar.
  • FIG. 12 is a schematic diagram of yet another protection circuit for preventing misconnection of input terminals according to an embodiment of the application.
  • the DC power supply includes at least a first DC power supply 103a and a second DC power supply 103b.
  • the switch unit includes at least: a first switch unit K1 and a second switch unit K2, and the input terminal includes at least a first power input terminal and a second power input terminal (not shown in the figure).
  • the misconnection detection unit 101 includes: a first detection unit 101c1, a second detection unit 101c2, and a controller 101d.
  • the first power input terminal is used to connect to the first direct current power source 103a
  • the second power input terminal is used to connect to the second direct current power source 101c2.
  • the first terminal of the first switch unit K1 is used to connect to the first power input terminal
  • the first terminal of the second switch unit K2 is used to connect to the second power input terminal
  • the second end of K2 is used to connect the subsequent circuit.
  • the first detection unit 101c1 is used to detect the voltages of the first port and the second port of the first power input terminal.
  • the second detection unit 101c2 is used to detect the voltages of the first port and the second port of the second power input terminal.
  • the controller 101d is used to control the mechanical interlocking unit (ie, the first mechanical interlocking unit 102a in the figure) to make the first terminal and the second terminal of the first switch unit when the first port and the second port of the first power input terminal are connected Terminal remains disconnected; it is also used to control the mechanical interlocking unit (ie, the second mechanical interlocking unit 102b in the figure) to make the second The first end and the second end of the two switch units are kept in an open state.
  • the mechanical interlocking unit ie, the first mechanical interlocking unit 102a in the figure
  • the controller 101d may be an application-specific integrated circuit (ASIC), a programmable logic device (Programmable Logic Device, PLD), a digital signal processor (Digital Signal Processor, DSP), or a combination thereof .
  • ASIC application-specific integrated circuit
  • PLD programmable logic device
  • DSP Digital Signal Processor
  • the above-mentioned PLD can be a Complex Programmable Logic Device (CPLD), Field-Programmable Gate Array (FPGA), Generic Array Logic (GAL) or any combination thereof.
  • CPLD Complex Programmable Logic Device
  • FPGA Field-Programmable Gate Array
  • GAL Generic Array Logic
  • a set of wrong connection detection unit can be used to control multiple mechanical interlocking units, which can save cost and reduce the volume of the protection circuit for preventing the wrong connection of the input terminal.
  • the photovoltaic power generation system includes at least two DC circuits: the first circuit and the second circuit as an example.
  • the DC power supply can be a photovoltaic unit, a DC converter or an energy storage unit, and the switch
  • the unit includes at least: a first switch unit and a second switch unit, and the input terminal includes at least a first power input terminal and a second power input terminal.
  • the following takes the DC power supply as the PV array as an example, including the first PV array and the second PV array.
  • the first PV array, the first switch unit and the first power input terminal are located in the first loop, and the second PV array, the second switch unit and the second power input terminal are located in the second loop.
  • the first power input terminal is used to connect to the first PV array, and the second power input terminal is used to connect to the second PV array;
  • the first terminal of the first switch unit is used to connect to the first power input terminal
  • the first terminal of the second switch unit is used to connect to the second power input terminal
  • the second terminal of the first switch unit and the second terminal of the second switch unit Both ends are used to connect the subsequent circuit.
  • the first detection unit 101c1 is used to detect the voltages of the first port and the second port of the first power input terminal.
  • the second detection unit 101c2 is used to detect the voltages of the first port and the second port of the second power input terminal.
  • the controller 101d is used to control the mechanical interlock unit of the first loop to keep the first terminal and the second terminal of the first switch unit disconnected when the voltage of the connection between the first port and the second port of the first power input terminal is reversed Status; It is also used to control the mechanical interlock unit of the second loop to keep the first terminal and the second terminal of the second switch unit disconnected when the voltage of the connection between the first port and the second port of the second power input terminal is reversed state.
  • the wrong connection detection unit can be separately arranged in the switch unit, or can be installed in the DC combiner box of the photovoltaic power generation system.
  • the embodiment of this application does not specifically limit this.
  • the wrong connection detection unit is installed in the DC combiner box, the wrong connection detection unit is installed in the DC combiner box.
  • the function of the controller connected to the detection unit can be realized by the controller of the DC combiner box, that is, the controller of the wrong connection detection unit can be integrated with the controller of the DC combiner box, and the controller of the wrong connection detection unit can also be set separately.
  • the embodiments are not specifically limited.
  • an embodiment of the present application also provides a photovoltaic power generation system using the protection circuit, which will be described in detail below with reference to the accompanying drawings.
  • FIG. 13 is a schematic diagram of a photovoltaic power generation system provided by an embodiment of the application.
  • the DC power supply is a PV array as an example for introduction.
  • the DC power supply may be other DC power supply devices, such as a DC converter or an energy storage unit.
  • the photovoltaic system includes a PV array 203 and a protection circuit to prevent misconnection of the input terminals.
  • the PV array 203 is used to convert solar energy into electrical energy for output, that is, it acts as a DC power source.
  • the protection circuit for preventing the misconnection of the input terminal includes a misconnection detection unit 101 and a mechanical interlock unit 102.
  • a misconnection detection unit 101 the protection circuit for preventing the wrong connection of the input terminal.
  • the protection circuit for preventing the wrong connection of the input terminal can be installed in the combiner box of the photovoltaic power generation system to facilitate management and maintenance.
  • the photovoltaic power generation system provided by the embodiments of the present application includes a protection circuit to prevent misconnection of the input end.
  • the misconnection detection unit of the protection circuit controls the mechanical
  • the interlocking unit keeps the first end of the switch unit and the second end of the switch unit in an open state, and realizes the isolation and protection of the wrong connection circuit before the circuit is connected, so as to avoid the circuit being damaged by the wrong connection after the switch unit is closed. Since the detection is realized before the switch unit is closed, that is, the detection is realized before the loop is connected, instead of detecting the wrong connection of the circuit after the loop is connected and then opening the loop, the safety and reliability of the photovoltaic power generation system are improved.
  • the protection circuit can also have the normally closed switch described in the above embodiment.
  • the normally closed switch can be opened to disconnect the misconnection detection unit from the input.
  • the connection of the terminal reduces the power loss of the photovoltaic power generation system, and realizes the isolation of the wrong connection detection unit and the circuit, so it can prevent lightning and surge from destroying the protection circuit, avoiding the additional use of lightning and surge protection devices, and ensuring safety While reducing the cost of photovoltaic power generation system.
  • the mechanical interlocking unit has a manual unlocking function when the power is off. Therefore, when the circuit line is connected correctly and the PV array is not performing DC output, the mechanical interlocking unit is unlocked on the switch unit by manual unlocking, so that The switch unit can be closed normally.
  • At least one (item) refers to one or more, and “multiple” refers to two or more.
  • “And/or” is used to describe the association relationship of associated objects, indicating that there can be three types of relationships. For example, “A and/or B” can mean: only A, only B, and both A and B. , Where A and B can be singular or plural. The character “/” generally indicates that the associated objects before and after are in an “or” relationship. "The following at least one item (a)” or similar expressions refers to any combination of these items, including any combination of a single item (a) or a plurality of items (a).
  • At least one (a) of a, b or c can mean: a, b, c, "a and b", “a and c", “b and c", or "a and b and c" ", where a, b, and c can be single or multiple.

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  • Protection Of Static Devices (AREA)
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Abstract

一种防输入端错接的保护电路及光伏发电系统，其中，该保护电路包括：输入端、错接检测单元(101)、机械连锁单元(102)和开关单元(K)。输入端用于连接直流电源(103)的输出端；错接检测单元(101)的第一输入端连接输入端的第一端口(A)，错接检测单元(101)的第二输入端连接输入端的第二端口(B)；错接检测单元(101)的输出端耦合于机械连锁单元(102)；机械连锁单元(102)连接开关单元(K)；开关单元(K)的第一端用于连接输入端，开关单元(K)的第二端用于连接后级电路；错接检测单元(101)用于当第一端口(A)和第二端口(B)接线错误时，控制机械连锁单元(102)使开关单元(K)的第一端和开关单元(K)的第二端保持断开状态。利用该保护电路能够在输入端连接的电源正负极错接时，防止电路受到错接的危害。

Description

一种防输入端错接的保护电路及光伏发电系统 技术领域
本申请涉及电力电子技术领域，尤其涉及一种防输入端错接的保护电路及光伏发电系统。
背景技术
在直流发电或配电的系统中，例如光伏发电系统或地铁配电系统，广泛存在将多个回路的直流电汇入到汇流母排中的场景。
为了方便安装和后期维护，通常会将直流输入侧的多个回路的直流开关设置于同一个汇流箱中。但是由于回路较多，接线时可能会导致同一路直流电的直流开关的正、负极接反，或者不同路直流电对应的直流开关之间的正负极错接，这样将导致直流开关闭合后出现短路或电流反灌等故障，造成局部过热或者烧毁，严重时会引起爆炸、火灾等安全事故。
发明内容
本申请提供了一种防输入端错接的保护电路及光伏发电系统，能够在输入端连接的电源正负极错接时，防止电路受到错接的危害。
第一方面，本申请实施例提供了一种防输入端错接的保护电路，该保护电路包括：输入端、错接检测单元、机械连锁单元和开关单元。输入端用于连接直流电源的输出端；错接检测单元的第一输入端连接所述输入端的第一端口，错接检测单元的第二输入端连接输入端的第二端口，错接检测单元的输出端耦合于所述机械连锁单元。机械连锁单元连接开关单元。开关单元的第一端用于连接输入端，开关单元的第二端用于连接后级电路。错接检测单元当第一端口和第二端口接线错误时，控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态。
该保护电路是在开关单元闭合前实现检测，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。而且该保护电路包括机械连锁单元，在输入端错接时，将持续抱死开关单元以维持断开状态，进一步增强了安全性。
结合第一方面，在第一种可能的实现方式中，该保护电路还包括常闭开关。常闭开关与开关单元互锁。具体而言，即开关单元断开时，常闭开关闭合，开关单元闭合时，常闭开关断开。在一些实施例中，常闭开关包括：第一常闭触点和第二常闭触点。错接检测单元的第一输入端通过第一常闭触点连接输入端的第一端口，错接检测单元的第二输入端通过第二常闭触点连接输入端的第二端口。在另一些实施例中，常闭开关还可以包括一个触点，该触点设置在错接检测单元的第一输入端和输入端的第一端口之间，或者设置在错接检测单元的第二输入端和输入端的第二端口之间，本申请对此不作具体限定。
由于常闭开关与开关单元连锁，当确定回路中无错接情况时，开关单元闭合后，常闭开关可以断开，以断开错接检测单元与输入端的连接，实现错接检测单元和回路的隔离，因此可防止雷击、浪涌破坏保护电路，避免了额外增加使用防雷击和浪涌的器件，在保证安全性的同时降低了实现成本。
结合第一方面，在第二种可能的实现方式中，错接检测单元包括检测单元和控制单元。 其中，检测单元用于检测第一端口和第二端口之间的电气参量，电气参量包括以下至少一种：电压、电流和阻抗。控制单元用于将电气参量与对应的预设阈值进行比较，根据比较结果确定第一端口和第二端口的接线错误时，控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态。
该保护电路是在开关单元闭合前通过检测第一端口和第二端口之间的电气参量以确定第一端口和第二端口的接线是否发生错误，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。
结合第一方面，在第三种可能的实现方式中，错接检测单元包括：检测单元和控制单元。检测单元用于将第一端口和所述第二端口之间的电压进行分压，将分压后的电压发送给控制单元。控制单元用于在分压后的电压小于预设阈值时断开，以使机械连锁单元失电，机械连锁单元失电时使开关单元维持断开状态。
以上保护电路的检测单元能够避免控制单元直接承受直流电源的全部电压，起到保护控制单元的作用。同样，该保护电路是在开关单元闭合前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。
结合第一方面，在第四种可能的实现方式中，控制单元的控制端连接检测单元的输出端，控制单元的第一端连接机械连锁单元的第一端。
结合第一方面，在第五种可能的实现方式中，错接检测单元还包括第一箝位二极管。第一箝位二极管的阴极连接控制单元的控制端，第一箝位二极管的阳极连接控制单元的第二端。因此，当回路未错接时，第一钳位二极管未导通，当回路中出现错接时，第一钳位二极管导通。
结合第一方面，在第六种可能的实现方式中，控制单元为第一开关器件。第一开关器件为IGBT器件或MOS器件。检测单元包括第一电阻和第二电阻。第一电阻的第一端连接输入端的第二端口，第一电阻的第二端通过第二电阻连接输入端的第一端口，第一电阻和第二电阻的公共端连接第一开关器件的控制端。
此时，第一开关器件的控制电压为第二电阻的分压。当回路未出现错接时，该第二电阻的分压值超过第一开关器件的动作电压，机械连锁单元解除对开关单元的控制。当回路中出现错接时，第一钳位二极管导通，第二电阻被短路，该第二电阻的分压值小于第一开关器件的动作电压，此时机械连锁单元失电以控制开关单元维持断开状态。
结合第一方面，在第七种可能的实现方式中，错接检测单元还包括过压保护电路。过压保护电路串联于输入端和控制单元的第二端之间。过压保护电路用于在输入端的第一端口和第二端口之间的电压大于过压阈值时，断开输入端与控制单元的第二端之间的连接，进而能够避免回路因为过压而损坏。。
结合第一方面，在第八种可能的实现方式中，过压保护电路包括第三电阻、第四电阻、第六电阻和第二开关器件。其中，第三电阻的第一端连接输入端的第二端口，第三电阻的第二端连接第二开关器件的控制端；第二开关器件的第二端连接输入端的第一端口，第二开关器件的第一端连接第一开关器件的第二端；第四电阻连接在第二开关器件的控制端和第二开关器件的第二端之间；第六电阻并联在第二开关器件的第一端和第二端。
结合第一方面，在第九种可能的实现方式中，错接检测单元还包括限流电阻。限流电阻的第一端连接输入端的第二端口，限流电阻的第二端连接第一电阻的第一端。限流电阻用于限流以保护电路。
结合第一方面，在第十种可能的实现方式中，错接检测单元还包括：电容和第二箝位二极管。电容并联在串联的第一电阻和第二电阻的两端。第二箝位二极管的阳极连接控制单元的第二端，第二箝位二极管的阴极连接第一电阻的第一端。
电容可以用于储能；第二箝位二极管在回路中出现错接时导通，以使错接检测单元中的其它部分被短路，进而使机械连锁单元失电以控制开关单元维持断开状态。
结合第一方面，在第十一种可能的实现方式中，机械连锁单元包括电磁铁，电磁铁失电时控制开关单元维持断开状态。
结合第一方面，在第十二种可能的实现方式中，当第一端口和第二端口接线错误时，机械连锁单元失电，机械连锁单元失电时具有手动解锁功能，即可以通过手动解锁的方式解除对开关单元的锁定，进而控制开关单元闭合。
结合第一方面，在第十三种可能的实现方式中，直流电源为以下至少一种：光伏单元、直流变换器和储能单元。输入端的第一端口用于连接直流电源的负输出端，输入端的第二端口用于连接直流电源的正输出端。
结合第一方面，在第十四种可能的实现方式中，直流电源为至少两个，每个直流电源对应一个防输入端错接的保护电路。
结合第一方面，在第十五种可能的实现方式中，直流电源至少包括第一直流电源和第二直流电源；开关单元至少包括：第一开关单元和第二开关单元，输入端至少包括第一电源输入端和第二电源输入端；错接检测单元包括：第一检测单元、第二检测单元和控制器。第一电源输入端用于连接第一直流电源，第二电源输入端用于连接第二直流电源。第一开关单元的第一端用于连接第一电源输入端，第二开关单元的第一端用于连接第二电源输入端；第一开关单元的第二端和第二开关单元的第二端均用于连接后级电路。第一检测单元用于检测第一电源输入端的第一端口和第二端口的电压。第二检测单元用于检测第二电源输入端的第一端口和第二端口的电压。控制器在第一电源输入端的第一端口和第二端口错接时，控制机械连锁单元使所述第一开关单元的第一端和第二端保持断开状态；还用于在第二电源输入端的第一端口和第二端口错接时，控制机械连锁单元使第二开关单元的第一端和第二端保持断开状态。
该保护电路是在开关单元闭合前通过检测以确定第一端口和第二端口的接线是否发生错误，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。
第二方面，本申请还提供了另一种防输入端错接的保护电路，该保护电路包括：输入端、错接检测单元和外接电源。输入端用于连接直流电源的输出端，输入端包括第一端口和第二端口；。错接检测单元的第一输入端连接输入端的第一端口，错接检测单元的第二输入端连接输入端的第二端口。外接电源与辅助开关先串联然后并联在第一端口和第二端口之间，其中，外接电源的正输出端连接所述第一端口。错接检测单元用于检测第一端口和 第二端口的阻抗，当阻抗大于预设阈值时确定第一端口和第二端口接线错误。
该保护电路的错接检测单元当回路出现错接时，控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态，实现了回路接通前对错接回路的隔离与保护，以避免开关单元闭合后电路受到错接的危害。由于是在开关单元闭合前实现检测，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。
结合第二方面，在第一种可能的实现方式中，该保护电路还包括：机械连锁单元和开关单元。错接检测单元包括：阻抗网络单元、阻抗检测单元和控制单元。阻抗网络单元的第一端连接所述第一端口，阻抗网络单元的第二端连接所述第二端口。错接检测单元的输出端耦合于机械连锁单元，机械连锁单元连接开关单元。阻抗检测单元用于获取第一端口和第二端口之间的阻抗。开关单元的第一端用于连接输入端，开关单元的第二端用于连接后级电路。控制单元用于在阻抗大于预设阈值时控制机械连锁单元失电，机械连锁单元失电时使所述开关单元维持断开状态，
结合第二方面，在第二种可能的实现方式中，阻抗网络单元至少包括：检测电阻和第一二极管。第一二极管的阳极连接直流电源的负输出端，阴极通过检测电阻连接直流电源的正输出端。
结合第三方面，在第二种可能的实现方式中，该保护电路还包括告警单元。错接检测单元用于在第一端口和第二端口接线错误时向告警单元发送告警指令。告警单元用于根据告警指令进行告警，外接电源为隔离型直流源。
第三方面，本申请还提供了一种光伏发电系统，包括：直流电源和以上所述的防输入端错接的保护电路，直流电源为光伏单元、直流变换器和储能单元中的至少一种。输入端的第一端口用于连接直流电源的负输出端，输入端的第二端口用于连接直流电源的正输出端。保护电路用于在直流电源的正输出端和负输出端错接时，断开直流电源与后级电路的连接。
由于光伏发电系统包括了该保护电路，而该保护电路的错接检测单元当第一端口和第二端口连接的电压接反时，控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态，实现了回路接通前对错接回路的隔离与保护，因此提升了光伏发电系统的安全性和可靠性。
从以上技术方案可以看出，本申请实施例提供的技术方案至少具有以下优点：
该保护电路用于在输入端连接的直流电源错接的情况下，对后续电路进行保护，该保护电路包括错接检测单元，错接检测单元包括第一输入端和第二输入端，其中错接检测单元第一输入端连接输入端的第一端口，错接检测单元的第二输入端连接输入端的第二端口，错接检测单元能够检测输入端连接的直流电源是否错接。错接检测单元的输出端连接机械连锁单元。机械连锁单元连接开关单元，开关单元的第一端连接输入端，开关单元的第二端连接后级电路。错接检测单元当检测第一端口和第二端口连接的直流电源错接时，控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态，避免错接的直流电源给后级电路供电，从而实现电源接通前对错接回路的隔离与保护，以避免开关单元闭合 后后级电路受到错接的危害。由于本方案是在开关单元闭合前实现检测，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。而且该电路包括机械连锁单元，在输入端错接时，将持续抱死开关单元以维持断开状态，进一步增强了安全性。
附图说明
图1为采用断路器或熔丝进行电路保护时的示意图一；
图2为采用断路器或熔丝进行电路保护时的示意图二；
图3为本申请实施例提供的一种防输入端错接的保护电路的示意图；
图4为本申请实施例提供的另一种防输入端错接的保护电路的示意图；
图5为本申请实施例提供的又一种防输入端错接的保护电路的示意图；
图6为本申请实施例提供的一种机械连锁单元的示意图；
图7为本申请实施例提供的再一种防输入端错接的保护电路的示意图；
图8A为本申请实施例提供的另一种防输入端错接的保护电路的示意图；
图8B为本申请实施例提供的又一种防输入端错接的保护电路的示意图；
图8C为本申请实施例提供的再一种防输入端错接的保护电路的示意图；
图9A为回路发生错接时的示意图一；
图9B为回路发生错接时的示意图二；
图9C为回路发生错接时的示意图三；
图10为本申请实施例提供的另一种防输入端错接的保护电路的示意图；
图11为本申请实施例提供的又一种防输入端错接的保护电路的示意图；
图12为本申请实施例提供的再一种防输入端错接的保护电路的示意图；
图13为本申请实施例提供的一种光伏发电系统的示意图。
具体实施方式
为了使本领域技术人员更好地理解本申请实施例提供的技术方案，下面首先说明本申请提供的技术方案的应用场景。
下面以光伏发电系统为例进行说明。
对于光伏发电系统，当光伏发电系统采用分体式组串逆变器时，光伏(Photo Voltaic，PV)阵列将太阳能转换为电能进行输出，每路回路从光伏阵列获取直流电后进行DC-DC变换，然后汇入直流母线并输逆变器。其中分体式组串逆变器中负责进行DC-DC变换的部分位于MPPT(Maximum Power Point Tracking，最大功率点跟踪)汇流箱内。为了方便安装和后期维护，通常会将多个回路的直流开关设置于同一个MPPT汇流箱中，由于回路较多，接线时可能会导致同一台直流开关的正、负极接反或者不同直流开关之间的正负极接反，导致直流开关合闸之后出现短路或者电流反灌等安全故障。目前采用在每路回路上串联断路器或者保险丝的方案进行保护，下面结合附图进行说明。
参见图1，该图为采用断路器或熔丝进行电路保护时的示意图一。
图1对应正常工作时的状态，流入正直流母线的电流的方向如图中的实线箭头所示，从负直流母线流出的电流的方向如虚线箭头所示，此时电流不会经过二极管D2，二极管 D2的正向电流检测(即检测点P1、P2的电流)结果为零，判定此时无连接错误，不会控制断路器K1断开。对于回路中的保险丝K2，流经保险丝K2的电流为保险丝K2所在单路回路的电流，因此保险丝K2不会熔断。
参见图2，该图为采用断路器或熔丝进行电路保护时的示意图二。
图2对应一路回路中出现错接情况时的状态，其它正常回路的电流都会通过出现错接情况的回路中的二极管D2，因此二极管D2的正向电流检测(即检测点P1的电流)结果为其它并联的回路的电流之和，此时可以通过主动断开回路中的断路器K1。对于出现错接情况的回路中的保险丝K2，此时也能够熔断以保护电路。
但是以上方案当并联的回路数量较多时，由于发生错接后流经二极管D2的电流很大，造成实际应用中二极管的选型和热设计困难。此外，该方案只能在回路导通之后，即断路器闭合后才能进行检测，而不能在回路导通前进行检测，导致安全性和可靠性差。
为了解决以上技术问题，本申请提供了一种防输入端错接的保护电路及光伏发电系统，能够在输入端连接的直流电源错接时，控制相应回路中的开关单元保持断开状态，防止后级电路受到错接的危害。并且由于保护电路能够在回路接通之前进行检测，进而提升了安全性和可靠性。
保护电路实施例一：
本申请实施例提供了一种防输入端错接的保护电路，可以应用于光伏发电系统或地铁配电系统等场景中，用于在输入端连接的电源正负极接反时，防止电路受到错接的危害，下面结合附图具体说明。
参见图3，该图为本申请实施例提供的一种防输入端错接的保护电路的示意图。
该保护电路包括：错接检测单元101、机械连锁单元102和开关单元K。
其中，错接检测单元101的第一输入端连接输入端的第一端口，图中以A表示。错接检测单元101的第二输入端连接输入端的第二端口，图中以B表示。错接检测单元101的输出端连接机械连锁单元102。
输入端用于连接直流电源103，直流电源103用于提供直流电。例如，当该保护电路应用于光伏发电系统时，直流电源103可以为光伏发电系统的光伏阵列，光伏阵列将太阳能转换为电能进行输出；当该保护电路应用于地铁配电系统时，直流电源103可以为外接的直流电源。
机械连锁单元102连接开关单元K。
开关单元K的第一端连接输入端，即第一端包括两个端口，分别于输入端的第一端口A和第二端口连接B，开关单元K的第二端用于连接后级电路。
错接检测单元101用于当第一端口A和第二端口B连接的电压接反时，控制机械连锁单元102使开关单元K的第一端和开关单元K的第二端保持断开状态。即此时机械连锁单元102能够锁死开关单元K，避免开关单元K闭合导致出现短路或者电流反灌等安全故障。而当无接线错误时，机械连锁单元102解除对开关单元K的控制，开关单元K可以正常受控进行闭合或断开。
在一些实施例中，机械连锁单元102可以为电磁装置，例如电磁铁，或可控的机械装 置，当第一端口A和第二端口B连接的电压接反时，机械连锁单元102在错接检测单元101的控制下自动锁死开关单元K，例如电磁装置触发动作自动锁死开关单元K的手柄，使手柄保持在断开状态无法闭合。
综上所述，该保护电路用于在输入端连接的直流电源错接的情况下，对后续电路进行保护，该保护电路包括错接检测单元，错接检测单元包括第一输入端和第二输入端，其中错接检测单元第一输入端连接输入端的第一端口，错接检测单元的第二输入端连接输入端的第二端口，错接检测单元能够检测输入端连接的直流电源是否错接。错接检测单元的输出端连接机械连锁单元。机械连锁单元连接开关单元，开关单元的第一端连接输入端，开关单元的第二端连接后级电路。错接检测单元当检测第一端口和第二端口连接的直流电源错接时，控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态，避免错接的直流电源给后级电路供电，从而实现电源接通前对错接回路的隔离与保护，以避免开关单元闭合后后级电路受到错接的危害。由于本方案是在开关单元闭合前实现检测，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。而且该电路包括机械连锁单元，在输入端错接时，将持续抱死开关单元以维持断开状态，进一步增强了安全性。
下面结合具体的实现方式说明本申请提供的保护电路的工作原理。
保护电路实施例二：
参见图4，该图为本申请实施例提供的另一种防输入端错接的保护电路的示意图。
该保护电路包括：错接检测单元101、机械连锁单元102、常闭开关104和开关单元K。
其中，错接检测单元101包括检测单元101a和控制单元101b。
其中，检测单元101a用于将第一端口A和第二端口B之间的电压进行分压，将分压后的电压发送给控制单元101b。检测单元101a能够避免控制单元101b直接承受直流电源103的全部电压，起到保护控制单元101b的作用。
在一些实施例中，控制单元101b的控制端连接检测单元101a的输出端，控制单元101b的第一端连接机械连锁单元的第一端，控制单元101b的第二端连接输入端的第一端口A，机械连锁单元102的第二端连接输入端的第二端口B。
控制单元101b用于当分压后的电压小于预设阈值时断开，以使机械连锁单元102失电，机械连锁单元102失电时使开关单元K保持断开状态。控制单元101b还用于当分压后的电压大于或等于预设阈值时闭合，以使机械连锁单元102得电，机械连锁单元102得电时解除对开关单元K的控制，以使开关单元K可以正常受控进行闭合或断开。
常闭开关104与开关单元K连锁，即开关单元K断开时常闭开关104闭合，开关单元K闭合时常闭开关104断开。
在一些实施例中，常闭开关104可以为微动开关S，具体包括：第一常闭触点和第二常闭触点。其中，错接检测单元101的第一输入端通过第一常闭触点连接输入端的第一端口A，错接检测单元101的第二输入端通过第二常闭触点连接输入端的第二端口B。
此时，控制单元101b的第二端通过第一常闭触点连接输入端的第一端口A，机械连锁单元102的第二端通过第二常闭触点连接输入端的第二端口B。
综上所述，本申请实施例提供的保护电路的常闭开关与开关单元连锁，当开关单元闭合时常闭开关断开，即当确定回路中无错接情况时，开关单元闭合后，常闭开关可以断开，以断开错接检测单元与输入端的连接，实现错接检测单元和回路的隔离，因此可防止雷击、浪涌破坏保护电路，避免了额外增加使用防雷击和浪涌的器件，在保证安全性的同时降低了实现成本。
下面结合检测单元和控制单元的具体实现方式说明该保护电路的工作原理。
图4中仅是以常闭开关104包括两个开关本体，分别设置在点A、B和检测单元101a的两个输入端。在另一种实现方式中，常闭开关104也可以仅包括一个开关本体，即仅设置在点A或点B与检测单元101a的输入端之间，该方案可以适用于以上和以下所有的实施例，在此不再赘述。
保护电路实施例三：
参见图5，该图为本申请实施例提供的又一种防输入端错接的保护电路的示意图。
控制单元具体为第一开关器件。
该保护电路的检测单元包括第一电阻R1和第二电阻R2，其中，第一电阻R1第一端连接输入端的第二端口B，第一电阻R2的第二端通过第二电阻R1连接输入端的第一端口A，第一电阻R1和第二电阻R2的公共端连接第一开关器件的控制端。
该第一开关器件的类型可以为以下任意一种：绝缘栅双极型晶体管(Insulated Gate Bipolar Transistor，IGBT)或金属氧化物半导体场效应晶体管(Metal Oxide Semiconductor Filed Effect Transistor，MOSFET，以下简称MOS管)、SiC MOSFET(Silicon Carbide Metal Oxide Semiconductor Filed Effect Transistor，碳化硅场效应管)等。当第一开关器件为MOS管时，具体可以为PMOS管或NMOS管，本申请实施例对此不作具体限定。下面以第一开关器件具体为NMOS管为例进行说明，图中以Q1表示。
错接检测单元101还包括第一箝位二极管D1和电容C。
该第一箝位二极管D1的阴极连接控制单元的控制端，即连接Q1的栅极，第一箝位二极管D1的阳极连接控制单元的第二端，控制单元的第一端为Q1的漏极，控制单元的第二端为Q1的源极。
电容C的第一端连接第一电阻R1的第一端，电容C的第二端连接控制单元的第二端。
在一些实施例中，错接检测单元101还包括限流电阻R5，限流电阻R5的第一端连接输入端的第二端口B，限流电阻R5的第二端连接第一电阻R1的第一端。限流电阻R5用于限制错接检测单元101中的电流以保护电路，同时起到防雷、防浪涌的作用。
下面具体说明该保护电路的工作原理。
当回路未出现错接时，输入端的第二端口连接直流电源103的正输出端，输入端的第一端口连接直流电源103的负输出端。第一钳位二极管D1未导通，此时Q1的栅极的输入电压为第二电阻R2的分压，该第二电阻的分压值超过Q1的动作电压时，Q1的漏极和源极导通，此时机械连锁单元的第一端与Q1的漏极连接，机械连锁单元的第二端与第一电阻R1的第一端连接。此时电容C为机械连锁单元102供电以使机械连锁单元102解除对 开关单元K的控制。可以理解的是，当不存在电容C时，机械连锁单元102并联在检测单元的两端，也可以由直流电源103进行供电。
当回路中出现错接时，具体为端口A、B与直流电源103之间的部分电路出现导线错接时，输入端的第一端口连接直流电源103的正输出端，输入端的第二端口连接直流电源103的负输出端。此时第一钳位二极管D1导通，Q1栅极输入的电压为零，Q1的漏极和源极之间断开，此时机械连锁单元102失电以控制开关单元K维持断开状态。
在一些实施例中，错接检测单元101还包括第二箝位二极管D2。
该第二箝位二极管D2的阳极连接控制单元的第二端，即连接Q1的源极，第二箝位二极管D2的阴极连接第一电阻R1的第一端。第二箝位二极管D2在回路未接反时处于未导通状态，在回路中出现错接时导通，以使错接检测单元101中的其它部分被短路，进而使机械连锁单元102失电以控制开关单元K维持断开状态。
在一些实施例中，机械连锁单元102为可控的机械或电磁装置，例如可以为电磁铁，下面结合附图具体说明。
机械连锁单元可以包括电磁铁和销钉，也可以包括电磁铁和连杆结构，下面以机械连锁单元包括电磁铁和销钉为例进行介绍。
参见图6，该图为申请实施例提供的一种机械连锁单元的示意图。
图示的机械连锁单元101包括常开式电磁铁101a和销钉101b。
常开式电磁铁101a用于控制销钉101a的伸缩状态，当常开式电磁铁101a通电时，吸合销钉101a以解除对开关单元K的锁定。当常开式继电器101a失电时，释放销钉101a，以使销钉101a锁定开关单元K，使开关单元K维持断开状态。
此外，该机械连锁单元101还具有手动解锁功能。即当机械连锁单元101失电时，可以通过手动解锁的方式解除机械连锁单元101对开关单元K的锁定。此时，在回路未出现错接且直流电源103未提供输出电压时，机械连锁单元101，可以通过手动解锁的方式解除对开关单元K的锁定，进而控制开关单元K闭合。
在一些实施例中，当应用于光伏发电系统时，直流电源103为PV阵列，输入端的第一端口A用于PV阵列的负输出端，输入端的第二端口B用于连接PV阵列的正输出端。当回路中未出现错接且PV阵列无直流输出时，例如当夜间或无阳光时，可以手动解锁机械连锁单元101对开关单元K的锁定，以使开关单元K能够闭合。
综上所述，该保护电路的错接检测单元当第一端口和第二端口连接的电压接反时，能够控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态，实现了回路接通前对错接回路的隔离与保护，以避免开关单元闭合后电路受到错接的危害。由于是在开关单元闭合前实现检测，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。并且当确定回路中无错接情况时，开关单元闭合后，常闭开关可以断开，以断开错接检测单元与输入端的连接，降低了功率损耗，实现错接检测单元和回路的隔离，因此可防止雷击、浪涌破坏保护电路，避免了额外增加使用防雷击和浪涌的器件，在保证安全性的同时降低了实现成本。
下面结合检测单元和控制单元的另一种实现方式说明该保护电路的工作原理。
保护电路实施例四：
参见图7，该图为本申请实施例提供的再一种防输入端错接的保护电路的示意图。
控制单元具体为第一开关器件，继续以第一开关器件为NMOS管为例，以Q1表示。
该保护电路101的检测单元包括第一电阻R1和第二电阻R2，其中，第一电阻R1第一端通过限流电阻R5连接输入端的第二端口B，第一电阻R2的第二端通过第二电阻R1连接Q1的第二端，即Q1的源极。第一电阻R1和第二电阻R2的公共端连接第一开关器件Q1的控制端，即Q1的栅极。
错接检测单元101还包括第一箝位二极管D1和电容C。
该第一箝位二极管D1的阴极连接控制单元的控制端，第一箝位二极管D1的阳极连接控制单元的第二端。
电容C的第一端连接第一电阻R1的第一端，电容C的第二端连接控制单元的第二端。
第二箝位二极管D2的阳极连接控制单元的第二端，第二箝位二极管D2的阴极连接第一电阻R1的第一端。第二箝位二极管D2在回路未接反时处于未导通状态，在回路中出现错接时导通，以使错接检测单元101中的其它部分被短路，进而使机械连锁单元102失电以控制开关单元K维持断开状态。
本申请实施例与实施例四的区别在于，还包括过压保护电路。过压保护电路串联于输入端和控制单元Q1的第二端之间。
过压保护电路用于在输入端的第一端口和第二端口之间的电压大于过压阈值时，断开输入端与控制单元的第二端之间的连接，以使机械连锁单元102控制开关单元维持断开状态，进而能够避免回路因为过压而损坏。
图中所示的过压保护电路具体包括了第三电阻R3、第四电阻R4和第二开关器件Q2。
下面以第二开关器件Q2为PMOS管为例进行说明，则Q2的控制端为栅极，第一端为漏极，第二端为源极。
第三电阻R3的第一端连接输入端的第二端口B，第三电阻R3的第二端连接第二开关器件Q2的控制端，第二开关器件Q2的第二端连接输入端的第一端口A，第二开关器件Q2的第一端连接第一开关器件Q1的第二端，第四电阻R4连接在第二开关器件Q2的控制端和第二开关器件Q2的第二端之间。
第二开关器件Q2的控制端的输入电压为第四电阻R4的分压，可以预设回路对应的过压电压值，当电压大于该过压电压值时则认为此时如果闭合开关单元K，回路中将出现过压，可能会损坏回路。通过设置第三电阻R3和第四电阻R4的电阻值，使得在错接检测单元101的输入电压小于该过压电压值时，第四电阻R4的分压小于第二开关器件Q2的动作电压，以使第二开关器件Q2的漏极和源极维持闭合；而当错接检测单元101的输入电压大于该过压电压值时，第四电阻R4的分压大于或等于第二开关器件Q2的动作电压，以使第二开关器件Q2的漏极和源极断开。
第二开关器件Q2的漏极和源极之间还连接有第六电阻R6，第六电阻R6用于限流以保护电路，并使Q2断开时输入端的第一端口A和第一开关器件Q1的第二端之间形成回路。
下面具体说明该保护电路的工作原理。
当回路未错接时，输入端的第二端口B连接直流电源103的正输出端，输入端的第一端口A连接直流电源103的负输出端。
进一步的，当错接检测单元101的输入电压小于过压电压值时，第四电阻R4的分压小于第二开关器件Q2的动作电压，第二开关器件Q2的漏极和源极维持闭合，第六电阻R6被短路。此时第一钳位二极管D1未导通，Q1的栅极的输入电压为第一电阻R2的分压，该电阻的分压值超过Q1的动作电压时，Q1的漏极和源极导通，此时机械连锁单元的第一端与Q1的漏极连接，机械连锁单元的第二端与第一电阻R1的第一端连接。电容C为机械连锁单元102供电以使机械连锁单元102解除对开关单元K的控制。可以理解的是，当不存在电容C时，机械连锁单元102并联在检测单元的两端，也可以由直流电源103进行供电。
而当错接检测单元101的输入电压大于过压电压值时，第四电阻R4的分压大于或等于第二开关器件Q2的动作电压，第二开关器件Q2的漏极和源极断开，此时第六电阻R6接入电路，第六电阻R6能够限流以保护电路。
在一些实施例中，可以将第六电阻R6的阻值设置较大，当第六电阻R6接入电路后使得Q1的控制端的电压小于Q1的动作电压，进而控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态。
当回路中出现错接时，具体为端口A、B与直流电源103之间的部分电路出现导线错接时，输入端的第一端口连接直流电源103的正输出端，输入端的第二端口连接直流电源103的负输出端。此时第二开关器件Q2的体二极管导通，以使第一钳位二极管D1导通，Q1栅极输入的电压为零，Q1的漏极和源极之间断开，此时机械连锁单元102失电以控制开关单元K维持断开状态。
关于机械连锁单元102和常闭开关104的说明可以参见以上实施例，本申请实施例在此不再赘述。
综上所述，该保护电路的错接检测单元当第一端口和第二端口连接的电压接反时，能够控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态，实现了回路接通前对错接回路的隔离与保护，以避免开关单元闭合后电路受到错接的危害。由于是在开关单元闭合前实现检测，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。并且当确定回路中无错接情况时，开关单元闭合后，常闭开关可以断开，以断开错接检测单元与输入端的连接，降低了功率损耗，实现错接检测单元和回路的隔离，因此可防止雷击、浪涌破坏保护电路，避免了额外增加使用防雷击和浪涌的器件，在保证安全性的同时降低了实现成本。
此外，该错接检测单元还包括过压保护电路，能够在过压时控制机械连锁单元失电以使开关单元的第二端保持断开状态，避免开关单元闭合后过压损坏回路。
保护电路实施例五：
下面结合错接检测单元的又一种实现方式说明该保护电路的工作原理。本申请实施例中通过检测第一端口和第二端口之间的阻抗来判断第一端口和第二端口连接是否存在接线 错接。
参见图8A，该图为本申请实施例提供的另一种防输入端错接的保护电路的示意图。
本实施例提供的防输入端错接的保护电路包括：输入端、错接检测单元101和外接电源106。
其中，输入端用于连接直流电源103的输出端，输入端包括第一端口和第二端口，图中分别以字母A、B表示。
错接检测单元101的第一输入端连接输入端的第一端口A，错接检测单元101的第二输入端连接输入端的第二端口B。
外接电源105与辅助开关J1先串联然后并联在第一端口A和第二端口B之间。其中，外接电源105的正输出端连接第一端口A。
错接检测单元105用于检测第一端口A和第二端口B的阻抗，当阻抗大于预设阈值时确定第一端口A和第二端口B接线错误，进而实现了回路接通前对错接回路的隔离与保护，以避免开关单元闭合后电路受到错接的危害。由于是在开关单元闭合前实现检测，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。
下面以外接电源105为直流源为例进行介绍，具体可以为隔离型直流源。
参见图8B，该图为本申请实施例提供的又一种防输入端错接的保护电路的示意图。
基于保护电路实施例五的以上说明，图8B对应的保护电路还包括机械连锁单元102和开关单元K。
其中，错接检测单元包括：阻抗网络单元106、阻抗检测单元101c和控制单元101b。
阻抗网络单元106的第一端连接第一端口A，第二端连接第二端口B。
错接检测单元的输出端耦合于机械连锁单元102，机械连锁单元102连接开关单元K。
阻抗检测单元101c用于获取第一端口A和第二端口B之间的阻抗。
开关单元K的第一端用于连接输入端，即连接第一端口A和第二端口B，开关单元K的第二端连接后级电路，本申请实施例不具体限定后级电路的实现方式。
控制单元101b用于在第一端口A和第二端口B之间的阻抗大于预设阈值时控制机械连锁单元102失电，机械连锁单元102失电时使开关单元维持断开状态。
进一步的，下面具体说明阻抗网络单元106的具体实现方式。
参见图8C，该图为本申请实施例提供的再一种防输入端错接的保护电路的示意图。
其中，该阻抗网络单元包括：第一二极管D3和检测电阻R0。
直流源105与辅助开关J1先串联然后并联在输入端的第一端口A和第二端口B之间，其中，直流源105的正输出端连接所述输入端的第一端口A，负输出端连接输出端的第二端口B。其中，辅助开关J1可以为继电器。
第一二极管D3的阳极连接直流电源103的负输出端，阴极通过检测电阻R0连接直流电源103的正输出端。
阻抗检测单元101c用于获取输入端的第一端口A和第二端口B之间的阻抗。
控制单元101b用于在所述阻抗大于预设阈值时控制所述机械连锁单元102失电。
本申请实施例可以通过检测输入端的第一端口A和第二端口B之间的电压判断回路中的导线是否错接，下面具体说明。
当回路中导线接线正确时，直流源105接入电路后，第一二极管D3导通，第一端口A和第二端口B之间的阻抗为检测电阻R0的阻抗和第一二极管D3的导通阻抗之和，可以设置预设阈值略大于以上的阻抗之和，则此时检测单元检测得到的输入端的第一端口和第二端口之间的阻抗小于预设阈值，机械连锁单元102得电以解除对开关单元K的控制，开关单元K可以正常合闸。
如直流开关单元K前端导线错接时，可能存在以下的情况，下面分别说明。
参见图9A，该图为回路发生错接时的示意图一。
图9A示意出了单个回路内部出现错接时的示意图。此时，当直流源105接入后，第一二极管D3不导通，第一端口A和第二端口B之间的电压等于0，阻抗大于预设阈值，此时控制单元101b在所述阻抗大于预设阈值时控制机械连锁单元102失电，所述机械连锁单元102失电时使所述开关单元K维持断开状态。
一并参见图9B和图9C。其中，图9B为回路发生错接时的示意图二，图9C为回路发生错接时的示意图三。
对于9B和图9C所示的场景，即多个回路之间出现错接，此时当直流源105接入后，输入端的第一端口A和第二端口B之间的回路除了包括检测电阻R0和第一二极管D3，还会包括开关单元。具体而言，对于图9B所示的直流电源1所在的回路，当直流源105接入回路时，回路依次包括：第一端口A、第一二极管D3、检测电阻R0、开关单元K2、直流电源2所在回路中的第一二极管和检测电阻、第二端口B。此时由于回路处于断路状态，开关单元K2处于断开状态，因此阻抗检测单元获取的第一端口A和第二端口B之间的阻抗大于预设阈值，控制单元101b控制机械连锁单元失电，所述机械连锁单元失电时使所述开关单元维持断开状态。
对于图9C所示的直流电源1所在的回路，当直流源105接入回路时，回路依次包括：第一端口A、直流电源2所在回路中的第一二极管和检测电阻、开关单元K2、第一二极管D3、检测电阻R0、第二端口B。此时由于回路处于断路状态，阻抗检测单元获取的第一端口A和第二端口B之间的阻抗大于预设阈值，此时控制单元101b控制机械连锁单元失电，所述机械连锁单元失电时使所述开关单元维持断开状态。
当完成检测后，可以控制辅助开关断开，以使直流源105与回路隔离。
综上所述，该保护电路的错接检测单元当回路出现错接时，控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态，实现了回路接通前对错接回路的隔离与保护，以避免开关单元闭合后电路受到错接的危害。由于是在开关单元闭合前实现检测，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此具有更高的安全性和可靠性。
在另一些实施例中，该保护电路还包括告警单元。
此时错接检测单元101还用于在第一端口A和第二端口B接线错误时向告警单元发送告警指令，以使告警单元根据告警指令进行告警。
进一步的，在另一些实现方式中，该保护电路还可以包括常闭开关，即以上实施例中的常闭开关104，常闭开关与开关单元K连锁，开关单元K断开时，常闭开关闭合，开关单元闭合时，常闭开关断开。关于常闭开关的具体说明参见以上实施例，本申请实施例在此不再赘述。
当保护电路包括常闭开关时，还可以实现错接检测单元和直流回路的隔离，因此可防止雷击、浪涌破坏保护电路，避免了额外增加使用防雷击和浪涌的器件，在保证安全性的同时降低了实现成本。
保护电路实施例六：
以上实施例以一个回路为例进行说明，实际应用场景中直流回路的数量还可以为多个，下面说明至少包括两个直流回路时该保护电路实现方式与工作原理。
参见图10，该图为本申请实施例提供的另一种防输入端错接的保护电路的示意图。
在一种实现方式中，每路回路包括一个直流电源和一个独立的防输入端错接的保护电路。每个回路中包括的保护电路均包括错接检测单元101、机械连锁单元102和开关单元K。
此时错接检测单元101可以采用以上任意保护电路实施例中的实现方式，本申请实施例在此不再赘述。
参见图11，该图为本申请实施例提供的又一种防输入端错接的保护电路的示意图。
在另一种可能的实现方式中，多个直流回路共用一个错接检测单元101，该错接检测单元101同时检测多路回路的第一端口和所述第二端口连接的电压是否接反，并同时控制多路回路的机械连锁单元102。错接检测单元101控制第一端口和所述第二端口连接的电压接反的回路的机械连锁单元102以使该回路的开关单元K保持断开状态。此时的错接检测单元101可以采用保护电路实施例六中记载的方式，下面以两个直流回路为例结合附图具体说明，当直流回路数量大于两个时的原理类似。
参见图12，该图为本申请实施例提供的再一种防输入端错接的保护电路的示意图。
其中，直流电源至少包括第一直流电源103a和第二直流电源103b。开关单元至少包括：第一开关单元K1和第二开关单元K2，所述输入端至少包括第一电源输入端和第二电源输入端(图中未示意出)。
错接检测单元101包括：第一检测单元101c1、第二检测单元101c2和控制器101d。
其中，第一电源输入端用于连接第一直流电源103a，第二电源输入端用于连接第二直流电源101c2。
第一开关单元K1的第一端用于连接第一电源输入端，第二开关单元K2的第一端用于连接第二电源输入端，第一开关单元K1的第二端和第二开关单元K2的第二端均用于连接后级电路。
第一检测单元101c1用于检测第一电源输入端的第一端口和第二端口的电压。
第二检测单元101c2用于检测第二电源输入端的第一端口和第二端口的电压。
控制器101d用于在第一电源输入端的第一端口和第二端口错接时，控制机械连锁单元(即图中的第一机械连锁单元102a)使第一开关单元的第一端和第二端保持断开状态；还用 于在所述第二电源输入端的第一端口和第二端口错接时，控制所述机械连锁单元(即图中的第二机械连锁单元102b)使所述第二开关单元的第一端和第二端保持断开状态。
在一些实施例中，控制器101d可以为专用集成电路(Application-specific Integrated Circuit，ASIC)、可编程逻辑器件(Programmable Logic Device，PLD)、数字信号处理器(Digital Signal Processor，DSP)或其组合。上述PLD可以是复杂可编程逻辑器件(Complex Programmable Logic Device，CPLD)、现场可编程逻辑门阵列(Field-programmable Gate Array，FPGA)、通用阵列逻辑(Generic Array Logic,GAL)或其任意组合，本申请实施例不作具体限定。
采用图12所示的方案，当回路数量较多时，可以采用一套错接检测单元实现对多个机械连锁单元进行控制，能够节省成本并缩小防输入端错接的保护电路的体积。
下面以该保护电路具体应用于光伏发电系统为例进行说明。
继续参见图12，以光伏发电系统至少包括两路直流回路：第一回路和第二回路为例进行说明，则直流电源可以为光伏单元，也可以为直流变换器或储能单元，所述开关单元至少包括：第一开关单元和第二开关单元，输入端至少包括第一电源输入端和第二电源输入端。下面以直流电源为PV阵列为例，包括第一PV阵列和第二PV阵列。
第一PV阵列、第一开关单元和第一电源输入端位于第一回路，第二PV阵列、第二开关单元和第二电源输入端位于第二回路。
第一电源输入端用于连接第一PV阵列，第二电源输入端用于连接第二PV阵列；
第一开关单元的第一端用于连接第一电源输入端，第二开关单元的第一端用于连接第二电源输入端；第一开关单元的第二端和第二开关单元的第二端均用于连接后级电路。
第一检测单元101c1用于检测第一电源输入端的第一端口和第二端口的电压。第二检测单元101c2用于检测第二电源输入端的第一端口和第二端口的电压。
控制器101d用于在第一电源输入端的第一端口和第二端口的连接的电压接反时，控制第一回路的机械连锁单元使第一开关单元的第一端和第二端保持断开状态；还用于在第二电源输入端的第一端口和第二端口的连接的电压接反时，控制第二回路的机械连锁单元使第二开关单元的第一端和第二端保持断开状态。
该错接检测单元可以单独设置于开关单元内，也可以设置于光伏发电系统的直流汇流箱内，本申请实施例对此不作具体限定，当错接检测单元设置于直流汇流箱内时，错接检测单元的控制器的功能可以由直流汇流箱的控制器实现，即错接检测单元的控制器可以集成于直流汇流箱的控制器，错接检测单元的控制器也可以单独设置，本申请实施例不作具体限定。
光伏发电系统实施例：
基于以上实施例提供的防输入端错接的保护电路，本申请实施例还提供了一种应用该保护电路的光伏发电系统，下面结合附图具体说明。
参见图13，该图为本申请实施例提供的一种光伏发电系统的示意图。
本实施例中以直流电源为PV阵列为例进行介绍，直流电源可以为其他直流供电装置， 例如直流变换器或储能单元等。
如图13所示，该光伏系统包括PV阵列203和防输入端错接的保护电路。
PV阵列203用于将太阳能转换为电能进行输出，即起到直流电源的作用。
其中，防输入端错接的保护电路包括错接检测单元101和机械连锁单元102。关于防输入端错接的保护电路的具体实现方式和工作原理可以参见以上实施例中的说明，本申请实施例在此不再赘述。
在一些实施例中，防输入端错接的保护电路可以设置于光伏发电系统的汇流箱中，以便于进行管理和维护。
综上所述，本申请实施例提供的光伏发电系统包括了防输入端错接的保护电路，该保护电路的错接检测单元当第一端口和第二端口连接的电压接反时，控制机械连锁单元使开关单元的第一端和开关单元的第二端保持断开状态，实现了回路接通前对错接回路的隔离与保护，以避免开关单元闭合后电路受到错接的危害。由于是在开关单元闭合前实现检测，即在回路接通之前实现检测，而不是在回路接通后检测到电路错接再断开回路，因此提升了光伏发电系统的安全性和可靠性。
进一步的，该保护电路还可以具有以上实施例所述的常闭开关，当确定回路中无错接情况时，开关单元闭合后，常闭开关可以断开，以断开错接检测单元与输入端的连接，降低了光伏发电系统的功率损耗，实现错接检测单元和回路的隔离，因此可防止雷击、浪涌破坏保护电路，避免了额外增加使用防雷击和浪涌的器件，在保证安全性的同时降低了光伏发电系统的成本。
并且在一些实施例中，机械连锁单元失电时具有手动解锁功能，因此在回路线路连接正确且PV阵列不进行直流电输出时，通过手动解锁的方式解除机械连锁单元对开关单元的锁定，以使开关单元能够正常闭合。
应当理解，在本申请中，“至少一个(项)”是指一个或者多个，“多个”是指两个或两个以上。“和/或”，用于描述关联对象的关联关系，表示可以存在三种关系，例如，“A和/或B”可以表示：只存在A，只存在B以及同时存在A和B三种情况，其中A，B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。“以下至少一项(个)”或其类似表达，是指这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，a，b或c中的至少一项(个)，可以表示：a，b，c，“a和b”，“a和c”，“b和c”，或“a和b和c”，其中a，b，c可以是单个，也可以是多个。
以上所述，以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围。

Claims (21)

  1. 一种防输入端错接的保护电路，其特征在于，该保护电路包括：输入端、错接检测单元、机械连锁单元和开关单元；所述输入端，用于连接直流电源的输出端；
    所述错接检测单元的第一输入端连接所述输入端的第一端口，所述错接检测单元的第二输入端连接所述输入端的第二端口；所述错接检测单元的输出端耦合于所述机械连锁单元；
    所述机械连锁单元连接所述开关单元；
    所述开关单元的第一端用于连接所述输入端，所述开关单元的第二端用于连接后级电路；
    所述错接检测单元，用于当所述第一端口和所述第二端口接线错误时，控制所述机械连锁单元使所述开关单元的第一端和所述开关单元的第二端保持断开状态。
  2. 根据权利要求1所述的电路，其特征在于，还包括：常闭开关；
    所述常闭开关与所述开关单元互锁，所述开关单元断开时，所述常闭开关闭合；所述开关单元闭合时，所述常闭开关断开；
    所述常闭开关包括：第一常闭触点和第二常闭触点；
    所述错接检测单元的第一输入端通过所述第一常闭触点连接所述输入端的第一端口，所述错接检测单元的第二输入端通过所述第二常闭触点连接所述输入端的第二端口。
  3. 根据权利要求1所述的电路，其特征在于，所述错接检测单元包括：检测单元和控制单元；
    所述检测单元，用于检测所述第一端口和所述第二端口之间的电气参量，所述电气参量包括以下至少一种：电压、电流和阻抗；
    所述控制单元，用于将所述电气参量与对应的预设阈值进行比较，根据比较结果确定所述第一端口和所述第二端口的接线错误时，控制所述机械连锁单元使所述开关单元的第一端和所述开关单元的第二端保持断开状态。
  4. 根据权利要求3所述的电路，其特征在于，所述错接检测单元包括：检测单元和控制单元；
    所述检测单元，用于将所述第一端口和所述第二端口之间的电压进行分压，将分压后的电压发送给控制单元；
    所述控制单元，用于在所述分压后的电压小于所述预设阈值时断开，以使所述机械连锁单元失电，所述机械连锁单元失电时使所述开关单元维持断开状态。
  5. 根据权利要求4所述的电路，其特征在于，所述控制单元的控制端连接所述检测单元的输出端，所述控制单元的第一端连接所述机械连锁单元的第一端。
  6. 根据权利要求5所述的电路，其特征在于，所述错接检测单元还包括：第一箝位二极管；
    所述第一箝位二极管的阴极连接所述控制单元的控制端；
    所述第一箝位二极管的阳极连接所述控制单元的第二端。
  7. 根据权利要求4-6任一项所述的电路，其特征在于，所述控制单元为第一开关器件；
    所述第一开关器件为IGBT器件或MOS器件；
    所述检测单元包括：第一电阻和第二电阻；
    所述第一电阻的第一端连接所述输入端的第二端口，所述第一电阻的第二端通过所述第二电阻连接所述输入端的第一端口，所述第一电阻和所述第二电阻的公共端连接所述第一开关器件的控制端。
  8. 根据权利要求7所述的电路，其特征在于，所述错接检测单元还包括：过压保护电路；
    所述过压保护电路串联于所述输入端和所述控制单元的第二端之间；
    所述过压保护电路，用于在所述输入端的第一端口和第二端口之间的电压大于过压阈值时，断开所述输入端与所述控制单元的第二端之间的连接。
  9. 根据权利要求8所述的电路，其特征在于，所述过压保护电路包括：第三电阻、第四电阻、第六电阻和第二开关器件；
    所述第三电阻的第一端连接所述输入端的第二端口，所述第三电阻的第二端连接所述第二开关器件的控制端；所述第二开关器件的第二端连接所述输入端的第一端口，所述第二开关器件的第一端连接所述第一开关器件的第二端；所述第四电阻连接在所述第二开关器件的控制端和所述第二开关器件的第二端之间；所述第六电阻并联在所述第二开关器件的第一端和第二端。
  10. 根据权利要求7-9任一项所述的电路，其特征在于，所述错接检测单元还包括：限流电阻；
    所述限流电阻的第一端连接所述输入端的第二端口，所述限流电阻的第二端连接所述第一电阻的第一端。
  11. 根据权利要求7-9任一项所述的电路，其特征在于，所述错接检测单元还包括：电容和第二箝位二极管；
    所述电容并联在串联的第一电阻和第二电阻的两端；
    所述第二箝位二极管的阳极连接所述控制单元的第二端，所述第二箝位二极管的阴极连接所述第一电阻的第一端。
  12. 根据权利要求1-11任一项所述的电路，其特征在于，所述机械连锁单元包括电磁铁，所述电磁铁失电时控制所述开关单元维持断开状态。
  13. 根据权利要求1-12任一项所述的电路，其特征在于，当所述第一端口和所述第二端口接线错误时，所述机械连锁单元失电，所述机械连锁单元失电时具有手动解锁功能。
  14. 根据权利要求1-13任一项所述的电路，其特征在于，所述直流电源为以下至少一种：光伏单元、直流变换器和储能单元；
    所述输入端的第一端口用于连接所述直流电源的负输出端，所述输入端的第二端口用于连接所述直流电源的正输出端。
  15. 根据权利要求14所述的电路，其特征在于，所述直流电源为至少两个，每个所述直流电源对应一个所述防输入端错接的保护电路。
  16. 根据权利要求15所述的电路，其特征在于，所述直流电源至少包括第一直流电源 和第二直流电源；所述开关单元至少包括：第一开关单元和第二开关单元，所述输入端至少包括第一电源输入端和第二电源输入端；所述错接检测单元包括：第一检测单元、第二检测单元和控制器；
    所述第一电源输入端用于连接所述第一直流电源，所述第二电源输入端用于连接所述第二直流电源；
    所述第一开关单元的第一端用于连接所述第一电源输入端，所述第二开关单元的第一端用于连接所述第二电源输入端；所述第一开关单元的第二端和所述第二开关单元的第二端均用于连接所述后级电路；
    所述第一检测单元，用于检测所述第一电源输入端的第一端口和第二端口的电压；
    所述第二检测单元，用于检测所述第二电源输入端的第一端口和第二端口的电压；
    所述控制器，用于在所述第一电源输入端的第一端口和第二端口错接时，控制所述机械连锁单元使所述第一开关单元的第一端和第二端保持断开状态；还用于在所述第二电源输入端的第一端口和第二端口错接时，控制所述机械连锁单元使所述第二开关单元的第一端和第二端保持断开状态。
  17. 一种防输入端错接的保护电路，其特征在于，该保护电路包括：输入端、错接检测单元和外接电源；所述输入端，用于连接直流电源的输出端；所述输入端包括第一端口和第二端口；
    所述错接检测单元的第一输入端连接所述输入端的第一端口，所述错接检测单元的第二输入端连接所述输入端的第二端口；
    所述外接电源与辅助开关先串联然后并联在所述第一端口和所述第二端口之间，其中，所述外接电源的正输出端连接所述第一端口；
    所述错接检测单元，用于检测所述第一端口和所述第二端口的阻抗，当所述阻抗大于预设阈值时确定所述第一端口和所述第二端口接线错误。
  18. 根据权利要求17所述的保护电路，其特征在于，还包括：机械连锁单元和开关单元；
    所述错接检测单元包括：阻抗网络单元、阻抗检测单元和控制单元；
    所述阻抗网络单元的第一端连接所述第一端口，所述阻抗网络单元的第二端连接所述第二端口；
    所述错接检测单元的输出端耦合于所述机械连锁单元；所述机械连锁单元连接所述开关单元；
    所述阻抗检测单元，用于获取所述第一端口和所述第二端口之间的阻抗；
    所述开关单元的第一端用于连接所述输入端，所述开关单元的第二端用于连接后级电路；
    所述控制单元，用于在所述阻抗大于预设阈值时控制所述机械连锁单元失电，所述机械连锁单元失电时使所述开关单元维持断开状态。
  19. 根据权利要求18所述的保护电路，其特征在于，所述阻抗网络单元至少包括：检测电阻和第一二极管；
    所述第一二极管的阳极连接所述直流电源的负输出端，阴极通过所述检测电阻连接所述直流电源的正输出端。
  20. 根据权利要求17-19任一项所述的保护电路，其特征在于，还包括：告警单元；
    所述错接检测单元，用于在所述第一端口和所述第二端口接线错误时向所述告警单元发送告警指令；
    所述告警单元，用于根据所述告警指令进行告警；
    所述外接电源为隔离型直流源。
  21. 一种光伏发电系统，其特征在于，包括：直流电源和权利要求1-20任一项所述的防输入端错接的保护电路；所述直流电源为以下至少一种：光伏单元、直流变换器和储能单元；
    所述输入端的第一端口用于连接所述直流电源的负输出端，所述输入端的第二端口用于连接所述直流电源的正输出端；
    所述保护电路，用于在所述直流电源的正输出端和负输出端错接时，断开所述直流电源与所述后级电路的连接。
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