Component-level fast turn-off device supporting SunSpec protocol

Abstract

The utility model provides a component-level rapid turn-off device supporting a SunSpec protocol, which is not easily interfered by external signals and external equipment, is more reliable than wireless networking connection, can realize connection or rapid turn-off of a PV component, conforms to NEC safety specifications, and comprises a power supply circuit, a power supply circuit, a wireless communication circuit, a wireless communication circuit, a wireless communication circuit and a wireless communication circuit, the open-circuit voltage conversion module is used for converting open-circuit voltage of the PV assembly into direct-current voltage for power supply; the PLC receiving circuit is connected with the power supply circuit, is provided with a PLC receiving one-way interface with a SunSpec protocol, and is used for receiving a PLC signal; the time-base circuit is connected with the PLC receiving circuit and is used for pressurizing the charge pump; and the quick turn-off circuit is connected with the PLC receiving circuit and is used for realizing quick turn-off of the PV assembly according to the signal output by the PLC receiving circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic power generation, in particular to a component-level fast shutdown device supporting the SunSpec protocol. Background Art

[0002] The concept of rapid shutdown of photovoltaic systems was proposed by the National Electrical Code (NEC) of the United States. In 2014, the NEC 2014 690.12 "Component-level Self-Shutdown Solution" standard was released, which made requirements for the rapid shutdown of photovoltaic systems. In the event of a short circuit or other fault, the RSD device (Rapid Shutdown Device) can quickly cut off the DC side high voltage, thereby avoiding further expansion of the fault and significantly improving system safety. The NEC RSD-related standards have undergone three revisions. The latest NEC 2020 690.12 has become a mandatory standard in North America. It requires that the distance to the photovoltaic matrix is ​​305mm as the boundary. Within 30 seconds after the rapid shutdown device is activated, the voltage outside the boundary range is reduced to below 30V, and the voltage within the boundary range is reduced to below 80V, so as to achieve component-level shutdown.

[0003] In recent years, in order to achieve the "dual carbon" goal, green and environmentally friendly solar photovoltaic power generation technology has been widely used, and the scale and investment of photovoltaic power generation have expanded year by year. In the photovoltaic power generation system, after multiple PV modules are connected in series and parallel, they can form a DC high-voltage grid-connected power generation system through the conversion of inverters and other equipment. However, high voltage electricity will endanger the safety of operators and firefighters. Based on electrical and fire safety considerations, if the photovoltaic power generation system is equipped with PV module-level fast shutdown equipment, in the event of an accident such as a fire, it can quickly reduce the PV module voltage and disconnect the photovoltaic power supply loop, so that operators and firefighters are in a safe working area, effectively protecting the safety of life and property.

[0004] Existing photovoltaic module shutdown devices with module-level shutdown functions include optimizers and rapid shutdown devices (RSDs). The optimizer can achieve the function of power point regulation (voltage regulation) through MMPT (maximum power point tracking), and can also achieve the module-level shutdown function by using its MOS-FET. However, the shutdown device still has the following defects:

[0005] 1. The architecture of the shutdown device includes large-capacity capacitors, high-current inductors, and high-power power chips, resulting in relatively high hardware costs;

[0006] 2. Traditional optimizers are large in size, complex in structure, and have high production costs, which are not conducive to popularization;

[0007] 3. The important protocol certification generally recognized by the North American market is the SunSpec protocol certification. SunSpec is an important protocol developed for communication between different devices in the rapid shutdown process. This is a communication (shutdown) protocol certification, but the current circuit breakers generally use Zigbee, BLE and other wireless networking methods to connect, which cannot achieve SunSpec protocol communication, and cannot achieve standardized intercommunication with inverters and other equipment. If you want to realize the RSD function, you must be equipped with gateway products.

[0008] Therefore, how to solve the above-mentioned deficiencies in the prior art has become a topic to be studied and solved in the present invention. Utility Model Content

[0009] The purpose of the utility model is to provide a component-level fast shutdown device supporting the SunSpec protocol to solve the problems raised in the above background technology.

[0010] The utility model adopts the following technical solution, a component-level fast shutdown device supporting the SunSpec protocol, comprising:

[0011] A power supply circuit, connected to the PV module, for converting the open circuit voltage of the PV module into a DC voltage for power supply;

[0012] A PLC receiving circuit is connected to the power supply circuit and is provided with a PLC receiving unidirectional interface with SunSpec protocol for receiving PLC signals;

[0013] A time base circuit, connected to the PLC receiving circuit, for implementing charge pump pressurization;

[0014] The fast shut-off circuit is connected to the PLC receiving circuit and is used to realize fast shut-off of the PV assembly according to the signal output by the PLC receiving circuit.

[0015] Furthermore, the power supply circuit includes a switching converter U1, capacitors C1-C4, resistors R1-R5, an inductor L1, and a diode D1. The switching converter U1 adopts a TI LM5007 step-down switching converter; one end of the capacitor C1 is connected to one end of the resistor R1 and pin 8 of the switching converter U1, the other end of the resistor R1 is connected to pin 6 of the switching converter U1, one end of the capacitor C2 is connected to pin 7 of the switching converter U1, the other end of the capacitor C2 is grounded, one end of the resistor R2 is connected to pin 3 of the switching converter U1, the other end of the resistor R2 is grounded, one end of the capacitor C3 is connected to one end of the inductor L1, the cathode of the diode D1, and pin 1 of the switching converter U1, the other end of the capacitor C3 is connected to pin 2 of the switching converter U1, the anode of the diode D1 is grounded, the other end of the inductor L1 is connected to one end of the resistors R3 and R5, the other end of the resistor R5 is grounded after being connected to the capacitor C4, the other end of the resistor R3 is connected to one end of the resistor R4 and pin 5 of the switching converter U1, the other end of the resistor R4 is grounded;

[0016] Further, the PLC receiving circuit includes a controller U2, a crystal oscillator Y1, capacitors C5-C11, resistors R6-R13, an inductor L2, a light-emitting diode LED1, MOS tubes Q1, Q2, interfaces J1, J2, and the controller U2 adopts a model TPS9361 control chip; the fast shutdown circuit includes a capacitor C12, resistors R14-R16, MOS tubes Q3, Q4, Q5, a diode D2, and a voltage regulator D3; pin 1 of the crystal oscillator Y1 is connected to pin 7 of the controller U2, one end of the resistor R6 is connected to one end of the resistor R14, one end of the resistor R10 is connected to the gate of the MOS tube Q1 and one end of the resistor R12, pin 4 of the controller U2 is connected to one end of the resistor R5, and the interfaces J1 and J2 are respectively connected to the positive terminal PV+ and the negative terminal PV- of the PV component;

[0017] Furthermore, the time base circuit includes a timer U3, capacitors C13-C17, resistors R17-R22, and diodes D4-D8. The timer U3 adopts a model NE555 time base chip; one end of the resistor R17 is connected to the cathode of the diodes D4 and D5, and then connected to the anode of the diode D7 and the 8th pin of the timer U3; the drain of the MOS tube Q3 is connected to one end of the resistors R16 and R18, the cathode of the voltage regulator tube D3, and the gates of the MOS tubes Q4 and Q5;

[0018] Furthermore, the open circuit voltage of the PV module is 45V to 70V.

[0019] The beneficial effect of the utility model is that the PLC receiving circuit is configured with a PLC receiving unidirectional interface with the SunSpec protocol, which can be conveniently interconnected with third-party devices such as inverters, receive the heartbeat signal sent by the inverter, is not easily interfered by external signals, and is not easy to interfere with external devices. It is more reliable than wireless networking connections, and can achieve connection or rapid shutdown of PV components through a fast shutdown circuit, which complies with NEC safety regulations, thereby ensuring the personal safety and property safety of firefighters and staff in specific emergency situations such as fire extinguishing, and has good economic use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural block diagram of the utility model;

[0021] Figure 2 It is a circuit schematic diagram of the power supply circuit in the utility model;

[0022] Figure 3 It is a circuit schematic diagram after the PLC receiving circuit and the fast shut-off circuit are connected in the utility model;

[0023] Figure 4 It is a circuit principle diagram of the time base circuit in the utility model. DETAILED DESCRIPTION

[0024] like Figure 1 to Figure 4 As shown, the utility model provides a component-level fast shutdown device supporting the SunSpec protocol, including:

[0025] A power supply circuit is connected to the PV module and is used to convert the open circuit voltage of the PV module into a DC voltage for power supply; the open circuit voltage of the PV module is 45V to 70V;

[0026] A PLC receiving circuit is connected to the power supply circuit and is provided with a PLC receiving unidirectional interface with SunSpec protocol for receiving PLC signals;

[0027] A time base circuit is connected to the PLC receiving circuit and is used to realize charge pump pressurization;

[0028] The fast shutdown circuit is connected to the PLC receiving circuit and is used to realize fast shutdown of the PV components according to the signal output by the PLC receiving circuit, that is, the PV components corresponding to the connected PV+ and PV- are shut down.

[0029] The power supply circuit includes a switching converter U1, capacitors C1 to C4, resistors R1 to R5, an inductor L1, and a diode D1. The switching converter U1 adopts a TI LM5007 step-down switching converter. The LM5007 step-down switching converter has all the functions required to realize a high-efficiency step-down regulator. Since the open-circuit voltage of a single photovoltaic PV module is generally between 45V and 70V, and the LM5007 chip integrates an 80V, 0.7AN channel step-down switch, it can operate within an input voltage range of 9V to 75V, which fully meets the photovoltaic PV module power supply scenario; one end of the capacitor C1 is connected to one end of the resistor R1 and the 8th pin of the switching converter U1, the other end of the resistor R1 is connected to the 6th pin of the switching converter U1, one end of the capacitor C2 is connected to the 7th pin of the switching converter U1, the other end of the capacitor C2 is grounded, and one end of the resistor R2 is grounded. It is connected to pin 3 of the switching converter U1, the other end of the resistor R2 is grounded, one end of the capacitor C3 is connected to one end of the inductor L1, the cathode of the diode D1, and pin 1 of the switching converter U1, the other end of the capacitor C3 is connected to pin 2 of the switching converter U1, the anode of the diode D1 is grounded, the other end of the inductor L1 is connected to one end of the resistors R3 and R5, the other end of the resistor R5 is grounded after being connected to the capacitor C4, the other end of the resistor R3 is connected to one end of the resistor R4 and pin 5 of the switching converter U1, and the other end of the resistor R4 is grounded; the power supply circuit can reliably convert the high voltage of a single PV component into the system power supply voltage required by the component-level fast shutdown device of the utility model.

[0030] The PLC receiving circuit includes a controller U2, a crystal oscillator Y1, capacitors C5-C11, resistors R6-R13, an inductor L2, a light-emitting diode LED1, MOS tubes Q1, Q2, and interfaces J1, J2. The controller U2 uses the TI model TPS9361 control chip, that is, the controller U2 has a built-in PLC receiving unidirectional interface with SunSpec protocol, which can realize the reception of PLC signals; the fast shutdown circuit includes a capacitor C12, resistors R14-R16, MOS tubes Q3, Q4, Q5, a diode D2, a voltage regulator tube D3, and interfaces J3, J4; the 1st pin of the crystal oscillator Y1 is connected to the 7th pin of the controller U2, and the One end of resistor R6 is connected to one end of resistor R14, one end of resistor R10 is connected to the gate of MOS tube Q1 and one end of resistor R12, pin 4 of controller U2 is connected to one end of resistor R5, interfaces J1 and J2 are respectively connected to the positive terminal PV+ and negative terminal PV- of the PV component, interfaces J3 and J4 are respectively connected to the positive terminal Vstring+ and negative terminal Vstring- of the component string formed by several PV components connected in series; when the PLC receiving circuit does not receive the heartbeat signal sent by the inverter, the fast shutdown circuit will send a shutdown signal through MOS tubes Q4 and Q5 to realize the fast shutdown of the PV component;

[0031] Among them, the TPS9361 control chip is a power line carrier (PLC) receiver with a SunSpec-compliant demodulator and an integrated fixed output regulator, which can be used to regulate the voltage of the photovoltaic module. The controller U2 can control the rapid shutdown circuit to connect or disconnect the PV module from the entire module string. The PLC receives the unidirectional interface and protocol in accordance with the standards set by the SunSpec Alliance ('Communication Signal for Rapid Shutdown', rev.34);

[0032] in, Figure 3 The pin end CP-out drives the external charge pump of MOS tubes Q4 and Q5 (equivalent to Figure 4 The timing circuit adopts the NE555 timing chip, and the NE555 timing circuit is a charge pump circuit. The pin end CP-out is about 10V higher than the positive terminal PV+ of the PV component, which can control the on and off of the MOS tubes Q4 and Q5; the charge pump voltage HS_G is connected to the gate terminals of the MOS tubes Q4 and Q5. When the controller U2 receives the heartbeat signal, the charge pump voltage HS_G is high level. If no heartbeat signal is received, HS_G is low level.

[0033] The time base circuit includes a timer U3, capacitors C13 to C17, resistors R17 to R22, and diodes D4 to D8. The timer U3 uses a model NE555 time base chip to achieve square wave output and realize the function of charge pump pressurization; one end of the resistor R17 is connected to the cathode of the diodes D4 and D5, and then connected to the anode of the diode D7 and the 8th pin of the timer U3. The drain of the MOS tube Q3 is connected to one end of the resistors R16 and R18, the cathode of the voltage regulator tube D3, and the gates of the MOS tubes Q4 and Q5.

[0034] In the utility model, when the heartbeat signal of the inverter or gateway is continuously sent to the DC power line of the component string (i.e., the positive terminal Vstring+ and the negative terminal Vstring-) through the PLC transmitter, after the PLC receiving circuit receives and decodes the heartbeat signal, the controller U2 sets the operation permission flag, the KA_OUT terminal in the PLC receiving circuit is set, and the PV component works normally; when the PLC receiving circuit does not receive the heartbeat signal, the PLC receiving circuit cancels the setting of the KA_OUT terminal, and at the same time, the VOUT pin on the controller U2 is driven to the regulated 1V, and the corresponding PV component open-circuit voltage (i.e., the corresponding voltage between PV+ and PV-) is pulled down to within the safety threshold range, and the MOS tubes Q4 and Q5 are actuated to directly send a shutdown signal to achieve rapid shutdown of the PV component. At this time, the current will be bypassed by the diode D2, which provides a DC current path at this time.

[0035] In summary, the utility model adopts PLC signal for reception and shutdown, which is not easily interfered by external signals or external equipment, and is more reliable than wireless networking connection; and supports SunSpec communication protocol, which is convenient for interconnection with third-party equipment such as inverters; and can quickly shut down the output voltage path of photovoltaic PV modules, which complies with NEC safety regulations, thereby ensuring the personal safety and property safety of firefighters and staff in specific emergency situations such as fire extinguishing.

[0036] In the figure, VIN refers to the open circuit voltage of the PV module; PLC_TP is the PLC signal test point, which is only for testing.

[0037] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0038] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A component-level fast shutdown device supporting the SunSpec protocol, characterized in that: include: A power supply circuit, connected to the PV module, for converting the open circuit voltage of the PV module into a DC voltage for power supply; A PLC receiving circuit is connected to the power supply circuit and is provided with a PLC receiving unidirectional interface with SunSpec protocol for receiving PLC signals; A time base circuit, connected to the PLC receiving circuit, for implementing charge pump pressurization; The fast shut-off circuit is connected to the PLC receiving circuit and is used to realize fast shut-off of the PV assembly according to the signal output by the PLC receiving circuit.

2. A component-level fast shutdown device supporting the SunSpec protocol according to claim 1, characterized in that: The power supply circuit includes a switching converter U1, capacitors C1-C4, resistors R1-R5, an inductor L1, and a diode D1. The switching converter U1 adopts a TI LM5007 step-down switching converter; one end of the capacitor C1 is connected to one end of the resistor R1 and pin 8 of the switching converter U1, the other end of the resistor R1 is connected to pin 6 of the switching converter U1, one end of the capacitor C2 is connected to pin 7 of the switching converter U1, the other end of the capacitor C2 is grounded, one end of the resistor R2 is connected to pin 3 of the switching converter U1, the other end of the resistor R2 is grounded, one end of the capacitor C3 is connected to one end of the inductor L1, the cathode of the diode D1, and pin 1 of the switching converter U1, the other end of the capacitor C3 is connected to pin 2 of the switching converter U1, the anode of the diode D1 is grounded, the other end of the inductor L1 is connected to one end of the resistors R3 and R5, the other end of the resistor R5 is grounded after being connected to the capacitor C4, the other end of the resistor R3 is connected to one end of the resistor R4 and pin 5 of the switching converter U1, and the other end of the resistor R4 is grounded.

3. A component-level fast shutdown device supporting the SunSpec protocol according to claim 2, characterized in that: The PLC receiving circuit includes a controller U2, a crystal oscillator Y1, capacitors C5-C11, resistors R6-R13, an inductor L2, a light-emitting diode LED1, MOS tubes Q1, Q2, interfaces J1, J2, and the controller U2 adopts a model TPS9361 control chip; the fast shutdown circuit includes a capacitor C12, resistors R14-R16, MOS tubes Q3, Q4, Q5, a diode D2, and a voltage regulator D3; pin 1 of the crystal oscillator Y1 is connected to pin 7 of the controller U2, one end of the resistor R6 is connected to one end of the resistor R14, one end of the resistor R10 is connected to the gate of the MOS tube Q1 and one end of the resistor R12, pin 4 of the controller U2 is connected to one end of the resistor R5, and the interfaces J1 and J2 are respectively connected to the positive terminal PV+ and the negative terminal PV- of the PV component.

4. A component-level fast shutdown device supporting the SunSpec protocol according to claim 3, characterized in that: The time base circuit includes a timer U3, capacitors C13-C17, resistors R17-R22, and diodes D4-D8. The timer U3 adopts a model NE555 time base chip; one end of the resistor R17 is connected to the cathode of the diodes D4 and D5, and then connected to the anode of the diode D7 and the 8th pin of the timer U3; the drain of the MOS tube Q3 is connected to one end of the resistors R16 and R18, the cathode of the voltage regulator tube D3, and the gates of the MOS tubes Q4 and Q5.

5. The component-level fast shutdown device supporting the SunSpec protocol according to claim 1, characterized in that: The open circuit voltage of the PV module is 45V to 70V.

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