A fast shutdown device capable of driving two series-connected MOS tubes through a single signal

Abstract

The present invention belongs to the field of power electronics technology, and specifically relates to a fast shut-off device that can drive two series-connected MOS tubes through a single-channel signal, including a switch tube S1, a switch tube S2, a control IC and a drive circuit; the PV+ end of a photovoltaic module is connected to an output end OUT+ through a switch tube S1 and a switch tube S2 connected in series in sequence; the PV-end of a photovoltaic module is connected to an output end OUT-; the control IC, the switch tube S1, and the switch tube S2 are respectively connected to the drive circuit, and the two signal ends of the control IC control the on-off of the switch tube S1 and the switch tube S2 through the drive circuit. The present invention uses two switch tubes connected in series to perform a switch operation, which greatly improves the reliability and safety of shutting down a photovoltaic power generation system, and does not cause high-voltage output due to failure of a single tube when shutting down is required, thereby avoiding potential safety hazards to people.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics, and in particular relates to a fast shut-down device capable of driving two series-connected MOS tubes through a single-channel signal. Background Art

[0002] As a renewable, pollution-free green energy, solar energy is increasingly valued by people. At the same time, with the advancement of power electronics technology, photovoltaic grid-connected power generation technology has developed rapidly. The photovoltaic power generation system is composed of multiple photovoltaic modules connected in series to form a photovoltaic string, and then the photovoltaic string is connected to the inverter to convert DC to AC for grid-connected power generation. Considering that the series-connected photovoltaic modules will form a DC high voltage, this high voltage will cause personal danger and fire accidents, so the photovoltaic power generation system is required to achieve rapid shutdown at the module level in an emergency.

[0003] The requirement for rapid shutdown is mainly for the protection of firefighters, photovoltaic power station installation and maintenance personnel. Generally, in photovoltaic power generation systems, as long as there is sunlight, there will be 600V to 1000V DC high voltage on the DC side. Once a fire occurs in the power station, firefighters will not be able to carry out firefighting and rescue work before the entire power station is burned down.

[0004] Based on the above reasons, it is very important to achieve rapid shutdown of each component in a photovoltaic power station. The current common practice is to connect a shutdown device to the outside of each component. In an emergency, the shutdown device can be used to shut down the connection between each photovoltaic component, thereby eliminating the DC high voltage in the photovoltaic power generation system, reducing the risk of electric shock, and solving the risk of rescue. However, the existing shutdown device uses a single tube for shutdown. If the single tube fails, it will cause high-voltage output, which will threaten the lives of firefighters. The control part of the existing shutdown device uses a control IC. For a dedicated control IC, the shutdown signal receiving function is integrated internally. At the same time, there is only a single-channel drive signal. If the single-channel signal is not processed, it is difficult to enter a safe shutdown mode when the control IC fails. Figure 1 As shown in the figure, when the single-channel drive signal pin of the control IC is short-circuited with its adjacent pin, if a constant high level state appears, the gate drive of the MOS switch tube will be constantly high level, entering the on state, and safe shutdown cannot be achieved. Summary of the invention

[0005] In view of the defects in the prior art, the present invention provides a fast shutdown device that can drive two series-connected MOS tubes through a single signal. Two series-connected switch tubes are used for switching operations, which greatly improves the reliability and safety of shutting down the photovoltaic power generation system. High-voltage output will not be caused by failure of a single tube when shutdown is required, thereby avoiding personal safety hazards.

[0006] The present invention provides a fast shut-down device capable of driving two series-connected MOS tubes through a single-channel signal, comprising a switch tube S1, a switch tube S2, a control IC and a drive circuit;

[0007] The PV+ end of the photovoltaic module is connected to the output end OUT+ through the switch tube S1 and the switch tube S2 connected in series; the PV- end of the photovoltaic module is connected to the output end OUT-;

[0008] The control IC, the switch tube S1 and the switch tube S2 are connected to the driving circuit respectively, and the two signal terminals of the control IC control the on and off of the switch tube S1 and the switch tube S2 through the driving circuit.

[0009] The fast shutdown device capable of driving two series-connected MOS tubes through a single-channel signal also includes an input capacitor Cin, an output capacitor Cout, a bypass diode D1 and an output resistor Rx;

[0010] The input capacitor Cin is connected in parallel with the photovoltaic module, one end of the output capacitor Cout is connected to the output terminal OUT+, and the other end is connected to the output terminal OUT-, and the output capacitor Cout, the bypass diode D1 and the output resistor Rx are connected in parallel.

[0011] Preferably, the switch tube S1 is a MOS tube S1, and the switch tube S2 is a MOS tube S2;

[0012] The PV+ terminal of the photovoltaic module is connected to the drain of the MOS transistor S2, the source of the MOS transistor S2 is connected to the drain of the MOS transistor S1, and the source of the MOS transistor S1 is connected to the output terminal OUT+; the driving terminal Drv2 of the driving circuit is connected to the gate of the MOS transistor S2, and the driving terminal Drv1 of the driving circuit is connected to the gate of the MOS transistor S1;

[0013] The common terminal connecting the MOS transistor S2 and the MOS transistor S1 is a reference terminal S2GND.

[0014] Preferably, the driving circuit comprises a first driving module and a second driving module;

[0015] The control IC, the first driving module and the second driving module are electrically connected in sequence, the driving end Drv2 of the second driving module is connected to the gate of the MOS tube S2, and the driving end Drv1 of the second driving module is connected to the gate of the MOS tube S1.

[0016] Preferably, the first driving module includes an optical coupler OP1, a voltage regulator D3, a resistor R0, a resistor R1 and a resistor R2;

[0017] The first signal terminal of the control IC is connected to the input pin 2 of the optocoupler OP1 via the resistor R2 on the one hand, and to the output pin 4 of the optocoupler OP1 on the other hand. The second signal terminal of the control IC is connected to the input pin 1 of the optocoupler OP1 via the resistor R1 on the one hand, is grounded via the voltage regulator D3 on the one hand, and is connected to the power supply VCC via the resistor R0 on the other hand.

[0018] Preferably, the second driving module includes a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, a voltage regulator tube D4, a voltage regulator tube D2 and a plurality of resistors;

[0019] The output pin 3 of the optical coupler OP1 is connected to the base of the switch tube Q1 through the resistor R3, connected to the base of the switch tube Q2 through the resistor R4, and grounded through the resistor R5.

[0020] The emitter of the switch tube Q1 is grounded, and the collector of the switch tube Q1 is connected to the gate of the switch tube Q3 on one hand, and connected to the power supply VCC via the resistor R6 on the other hand;

[0021] The emitter of the switch tube Q2 is grounded, and the collector of the switch tube Q2 is connected to the gate of the switch tube Q4 on one hand, and connected to the power supply VCC via the resistor R7 on the other hand;

[0022] The source of the switch tube Q3 is grounded, and the drain of the switch tube Q3 is connected to the power supply VDD via the resistor R8 on one hand, and connected to the driving end Drv1 via the resistor R10 on the other hand;

[0023] The source of the switch tube Q4 is grounded, and the drain of the switch tube Q4 is connected to the power supply VDD via the resistor R9 on one hand, and connected to the driving end Drv2 via the resistor R11 on the other hand;

[0024] The anode of the voltage regulator tube D4 is connected to the output terminal OUT+, and the cathode of the voltage regulator tube D4 is connected to the driving terminal Drv1;

[0025] The anode of the voltage regulator tube D2 is connected to the reference terminal S2GND, and the cathode of the voltage regulator tube D2 is connected to the driving terminal Drv2.

[0026] Preferably, the second driving module includes a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, an optocoupler OP2, an optocoupler OP3, a diode D4, a diode D2 and a plurality of resistors;

[0027] The output pin 3 of the optical coupler OP1 is connected to the ground via a resistor R5, connected to the input pin 1 of the optical coupler OP2 via a resistor R4, and connected to the input pin 1 of the optical coupler OP3 via a resistor R7.

[0028] The input pin 2 of the optical coupler OP2 is grounded via a resistor R3, the output pin 4 of the optical coupler OP2 is connected to the output terminal OUT+, the output pin 3 of the optical coupler OP2 is connected to the power supply VDD via resistors R9 and R10 connected in series, the common end of the resistors R9 and R10 is connected to the base of the switch tube Q1, the emitter of the switch tube Q1 is connected to the power supply VDD, the collector of the switch tube Q1 is connected to the base of the switch tube Q3 via a resistor R13, the base of the switch tube Q3 is connected to the collector of the transistor Q3 via a resistor R15 on the one hand, and to the emitter of the transistor Q3 via a diode D4 on the other hand, the collector of the transistor Q3 is connected to the output terminal OUT+, and the emitter of the transistor Q3 is connected to the driving terminal Drv1;

[0029] The input pin 2 of the optocoupler OP3 is grounded via a resistor R6, the output pin 4 of the optocoupler OP3 is connected to a reference terminal S2GND, the output pin 3 of the optocoupler OP3 is connected to a power supply VDD via resistors R11 and R12 connected in series, the common end of the resistors R11 and R12 is connected to the base of the switch tube Q2, the emitter of the switch tube Q2 is connected to the power supply VDD, the collector of the switch tube Q2 is connected to the base of the switch tube Q4 via a resistor R14, the base of the switch tube Q4 is connected to the collector of the transistor Q4 via a resistor R16 on the one hand, and to the emitter of the transistor Q4 via a diode D2 on the other hand, the collector of the transistor Q4 is connected to the reference terminal S2GND, and the emitter of the transistor Q4 is connected to the driving terminal Drv2.

[0030] The technical solution of the present invention adopts two switch tubes connected in series to perform switching operations, which greatly improves the reliability and safety of shutting down the photovoltaic power generation system, and does not cause high-voltage output due to failure of a single tube when shutdown is required, thereby avoiding potential safety hazards to personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0032] Figure 1 A schematic diagram of a control IC with a single-channel driving signal in the background art where adjacent pins are short-circuited;

[0033] Figure 2 This is a circuit structure diagram of a fast shutdown device capable of driving two series-connected MOS tubes through a single-channel signal in this embodiment;

[0034] Figure 3 The circuit structure of the driving circuit in this embodiment is Figure 1 ;

[0035] Figure 4 The circuit structure of the driving circuit in this embodiment is Figure 2 ;

[0036] Figure 5 This is a circuit structure diagram of the power supply reference ground in this embodiment. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0039] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0040] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0041] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0042] Embodiment 1:

[0043] This embodiment provides a fast shutdown device that can drive two series-connected MOS tubes through a single signal. Figure 2As shown, it includes a switch tube S1, a switch tube S2, an input capacitor Cin, an output capacitor Cout, a bypass diode D1, an output resistor Rx, a control IC and a drive circuit;

[0044] The PV+ end of the photovoltaic module is connected to the output end OUT+ through the switch tube S1 and the switch tube S2 connected in series; the PV- end (i.e., the ground end) of the photovoltaic module is connected to the output end OUT-;

[0045] The input capacitor Cin is connected in parallel with the photovoltaic module, one end of the output capacitor Cout is connected to the output terminal OUT+, and the other end is connected to the output terminal OUT-, and the output capacitor Cout, the bypass diode D1 and the output resistor Rx are connected in parallel;

[0046] The control IC, the switch tube S1 and the switch tube S2 are connected to the driving circuit respectively, and the two signal terminals of the control IC control the on and off of the switch tube S1 and the switch tube S2 through the driving circuit.

[0047] The switch tube S1 of this embodiment is a MOS tube S1, and the switch tube S2 is a MOS tube S2; the PV+ end of the photovoltaic module is connected to the drain of the MOS tube S2, the source of the MOS tube S2 is connected to the drain of the MOS tube S1, and the source of the MOS tube S1 is connected to the output end OUT+; the driving end Drv2 of the driving circuit is connected to the gate of the MOS tube S2, and the driving end Drv1 of the driving circuit is connected to the gate of the MOS tube S1; the common end connected to the MOS tube S2 and the MOS tube S1 is the reference end S2GND.

[0048] The fast shutdown device of this embodiment is located between the photovoltaic module and the inverter, and uses MOS tubes connected in series for switching operations, which greatly improves reliability and safety. It will not cause high-voltage output due to failure of a single tube when shutdown is required, thereby preventing high voltage from threatening the lives of firefighters during a fire.

[0049] The rapid shutdown device of this embodiment also includes an auxiliary power supply, the input of the auxiliary power supply is connected to the PV+ of the photovoltaic module, and the output of the auxiliary power supply is connected to the control IC and the drive circuit. The auxiliary power supply is used to provide working voltage to the control IC and the drive circuit.

[0050] The driving circuit of this embodiment has two structures, as described below.

[0051] The first structure, such as Figure 3 As shown, the driving circuit includes a first driving module and a second driving module;

[0052] The control IC, the first driving module and the second driving module are electrically connected in sequence, the driving end Drv2 of the second driving module is connected to the gate of the MOS tube S2, and the driving end Drv1 of the second driving module is connected to the gate of the MOS tube S1.

[0053] Wherein, the first driving module includes an optical coupler OP1, a voltage regulator D3, a resistor R0, a resistor R1 and a resistor R2;

[0054] The first signal terminal of the control IC is connected to the input pin 2 of the optocoupler OP1 via the resistor R2 on the one hand, and to the output pin 4 of the optocoupler OP1 on the other hand. The second signal terminal of the control IC is connected to the input pin 1 of the optocoupler OP1 via the resistor R1 on the one hand, is grounded via the voltage regulator D3 on the one hand, and is connected to the power supply VCC via the resistor R0 on the other hand.

[0055] The second driving module includes a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, a voltage regulator tube D4, a voltage regulator tube D2 and a plurality of resistors;

[0056] The output pin 3 of the optical coupler OP1 is connected to the base of the switch tube Q1 through the resistor R3, connected to the base of the switch tube Q2 through the resistor R4, and grounded through the resistor R5.

[0057] The emitter of the switch tube Q1 is grounded, and the collector of the switch tube Q1 is connected to the gate of the switch tube Q3 on one hand, and connected to the power supply VCC via the resistor R6 on the other hand;

[0058] The emitter of the switch tube Q2 is grounded, and the collector of the switch tube Q2 is connected to the gate of the switch tube Q4 on one hand, and connected to the power supply VCC via the resistor R7 on the other hand;

[0059] The source of the switch tube Q3 is grounded, and the drain of the switch tube Q3 is connected to the power supply VDD via the resistor R8 on one hand, and connected to the driving end Drv1 via the resistor R10 on the other hand;

[0060] The source of the switch tube Q4 is grounded, and the drain of the switch tube Q4 is connected to the power supply VDD via the resistor R9 on one hand, and connected to the driving end Drv2 via the resistor R11 on the other hand;

[0061] The anode of the voltage regulator tube D4 is connected to the output terminal OUT+, and the cathode of the voltage regulator tube D4 is connected to the driving terminal Drv1;

[0062] The anode of the voltage regulator tube D2 is connected to the reference terminal S2GND, and the cathode of the voltage regulator tube D2 is connected to the driving terminal Drv2.

[0063] The VCC power supply of this embodiment is converted by the power supply reference ground conversion circuit to obtain the VDD power supply. Figure 5As shown, in this embodiment, the control IC controls the working state of the conversion circuit through the two pins QD1 and QD2. The driving circuit of the first structure of this embodiment is constructed by electronic components such as switch tubes, optocouplers, voltage regulator tubes, resistors, etc. Only these simple electronic components are needed to achieve safe driving of a single-channel signal. It has a simple structure and does not require a special floating power drive chip. It has low cost and high reliability.

[0064] The driving circuit of the first structure of this embodiment has two working modes: an on mode and an off mode. The specific working process is as follows.

[0065] On mode: the first signal terminal of the control IC outputs a low level (3.3V), and the voltage regulator D3 connected to the second signal terminal of the control IC uses a 5V voltage regulator. There is a light-emitting diode between the two input pins of the optocoupler OP1. The voltage difference causes the light-emitting diode to be turned on, so that the output end of the optocoupler OP1 will be turned on, and the output pins 3 and 4 of the optocoupler OP1 keep consistent and output a high level. At this time, the switch tubes Q1 and Q2 are turned on, and the gate voltages of the switch tubes Q3 and Q4 are pulled to 0V respectively. The switch tubes Q3 and Q4 are turned off, and the power supply VDD is connected to the gates of the MOS tubes S1 and S2 through resistors respectively. The MOS tubes S1 and S2 are in the on state, and the fast shutdown device has an output to keep working in the on mode.

[0066] Shutdown mode: The first signal terminal of the control IC outputs a low voltage (0V). Since the voltage at the input terminal 1 of the optocoupler OP1 is stable at 5V, the voltage difference causes the light-emitting diode to be turned on, so that the output terminal of the optocoupler OP1 will be turned on, and the output pins 3 and 4 of the optocoupler OP1 keep consistent and output a low level. At this time, the switch tubes Q1 and Q2 are turned off, and the power supply VCC is connected to the gates of the switch tubes Q3 and Q4 through resistors respectively. The switch tubes Q3 and Q4 are turned on, and the gate voltages of the MOS tubes S1 and S2 are pulled to 0V respectively. The MOS tubes S1 and S2 are in the off state, and the fast shutdown device has no output, and keeps working in the off mode.

[0067] This embodiment can effectively solve the problem that the control IC cannot be safely shut down when the first signal terminal and the adjacent second signal terminal are short-circuited. When the first signal terminal and the adjacent second signal terminal are short-circuited, the voltages of the two input pins of the optocoupler OP1 are the same, there is no voltage difference, and the light-emitting diode between the two input pins will not be turned on, so that the output end of the optocoupler OP1 will be turned off, and no matter what the state of the output pin 4 of the optocoupler OP1 is, the output pin 3 is 0V low level. According to the above working mode analysis, the fast shutdown device enters the shutdown mode, which can achieve safe shutdown.

[0068] The second structure, such as Figure 4As shown, the driving circuit includes a first driving module and a second driving module; compared with the first structure, the first driving module of the second structure is the same, and the second driving module is different.

[0069] The control IC, the first driving module and the second driving module are electrically connected in sequence, the driving end Drv2 of the second driving module is connected to the gate of the MOS tube S2, and the driving end Drv1 of the second driving module is connected to the gate of the MOS tube S1.

[0070] Wherein, the first driving module includes an optical coupler OP1, a voltage regulator D3, a resistor R0, a resistor R1 and a resistor R2;

[0071] The first signal terminal of the control IC is connected to the input pin 2 of the optocoupler OP1 via the resistor R2 on the one hand, and to the output pin 4 of the optocoupler OP1 on the other hand. The second signal terminal of the control IC is connected to the input pin 1 of the optocoupler OP1 via the resistor R1 on the one hand, is grounded via the voltage regulator D3 on the one hand, and is connected to the power supply VCC via the resistor R0 on the other hand.

[0072] The second driving module includes a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, an optocoupler OP2, an optocoupler OP3, a diode D4, a diode D2 and a plurality of resistors;

[0073] The output pin 3 of the optical coupler OP1 is connected to the ground via a resistor R5, connected to the input pin 1 of the optical coupler OP2 via a resistor R4, and connected to the input pin 1 of the optical coupler OP3 via a resistor R7.

[0074] The input pin 2 of the optical coupler OP2 is grounded via a resistor R3, the output pin 4 of the optical coupler OP2 is connected to the output terminal OUT+, the output pin 3 of the optical coupler OP2 is connected to the power supply VDD via resistors R9 and R10 connected in series, the common end of the resistors R9 and R10 is connected to the base of the switch tube Q1, the emitter of the switch tube Q1 is connected to the power supply VDD, the collector of the switch tube Q1 is connected to the base of the switch tube Q3 via a resistor R13, the base of the switch tube Q3 is connected to the collector of the transistor Q3 via a resistor R15 on the one hand, and to the emitter of the transistor Q3 via a diode D4 on the other hand, the collector of the transistor Q3 is connected to the output terminal OUT+, and the emitter of the transistor Q3 is connected to the driving terminal Drv1;

[0075] The input pin 2 of the optocoupler OP3 is grounded via a resistor R6, the output pin 4 of the optocoupler OP3 is connected to a reference terminal S2GND, the output pin 3 of the optocoupler OP3 is connected to a power supply VDD via resistors R11 and R12 connected in series, the common end of the resistors R11 and R12 is connected to the base of the switch tube Q2, the emitter of the switch tube Q2 is connected to the power supply VDD, the collector of the switch tube Q2 is connected to the base of the switch tube Q4 via a resistor R14, the base of the switch tube Q4 is connected to the collector of the transistor Q4 via a resistor R16 on the one hand, and to the emitter of the transistor Q4 via a diode D2 on the other hand, the collector of the transistor Q4 is connected to the reference terminal S2GND, and the emitter of the transistor Q4 is connected to the driving terminal Drv2.

[0076] The second driving circuit of the present embodiment is also constructed by electronic components such as switch tubes, optocouplers, voltage regulator tubes, resistors, etc., and can also achieve safe driving of single-channel signals, with simple structure, low cost and high reliability. Among them, the switch tubes Q1, Q2, Q3 and Q4 are all PNP triodes.

[0077] The driving circuit of the second structure of this embodiment has two working modes: an on mode and an off mode. The specific working process is as follows.

[0078] On mode: The first signal terminal of the control IC outputs a high level (3.3V). Since the voltage of the input pin 1 of the optocoupler OP1 is stable at 5V, the voltage difference causes the light-emitting diode to turn on, so that the output terminal of the optocoupler OP1 will be turned on, and the output pins 3 and 4 of the optocoupler OP1 will be consistent and output a high level. The output terminals of the optocouplers OP2 and OP3 are turned on, and the resistor R11 is connected to the reference terminal S2GND, and the resistor R9 is connected to the output terminal OUT+. The base and emitter of the switch tube Q1 form a negative voltage for turning on, and the base of the switch tube Q2 The base and emitter form a turn-on negative voltage, the switch tubes Q1 and Q2 are turned on, the diodes D4 and D2 are turned on, the base and emitter of the switch tube Q3 form a turn-off zero voltage, the base and emitter of the switch tube Q4 form a turn-off zero voltage, the switch tubes Q3 and Q4 are turned off, the driving voltage of the driving end Drv1 is connected to the gate of the MOS tube S1, the driving voltage of the driving end Drv2 is connected to the gate of the MOS tube S2, the MOS tubes S1 and S2 are in the on state, the fast shutdown device has an output, and keeps working in the on mode.

[0079] Shutdown mode: The first signal terminal of the control IC outputs a low level (0V). Since the voltage of the input pin 1 of the optocoupler OP1 is stable at 5V, the voltage difference causes the light-emitting diode to turn on, so that the output terminal of the optocoupler OP1 will be turned on, and the output pins 3 and 4 of the optocoupler OP1 will be consistent and output a low level. The input terminals of the optocouplers OP2 and OP3 are cut off, and the output terminals of the optocouplers OP2 and OP3 are cut off. The resistor R11 is disconnected from the reference terminal S2GND, and the resistor R9 is disconnected from the output terminal OUT+. The switch tube The base and emitter of Q1 form a turn-off zero voltage, the base and emitter of the switch tube Q2 form a turn-off zero voltage, the switch tubes Q1 and Q2 are turned off, the diodes D4 and D2 are turned off, the base and emitter of the switch tube Q3 form a turn-on negative voltage, the base and emitter of the switch tube Q4 form a turn-on negative voltage, the switch tubes Q3 and Q4 are turned on, the gates of the MOS tubes S1 and S2 are discharged, the MOS tubes S1 and S2 are in the turn-off state, the fast shutdown device has no output, and keeps working in the shutdown mode.

[0080] In summary, the fast shutdown device of this embodiment has good safety, high reliability and low cost. This embodiment is aimed at a dedicated control IC with only a single-channel drive signal output, and uses a simple optocoupler to solve the problem that when the signal end of the control IC fails and has been outputting a high level, the fast shutdown device can still enter the shutdown mode to achieve safe shutdown. At the same time, because the single-channel signal is processed through safety protection, it can be achieved that the single-channel signal is used to drive two MOS tubes in series, which will not increase the complexity of the control software. The two MOS tubes are connected in series as a shutdown switch, which can effectively improve the reliability and safety of the system, and will not cause high-voltage output due to damage to a single switch tube S1 or S2, thereby avoiding personal safety hazards.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A fast shutdown device capable of driving two series-connected MOS tubes through a single-channel signal, characterized in that: It includes a switch tube S1, a switch tube S2, a control IC and a drive circuit; The PV+ end of the photovoltaic module is connected to the output end OUT+ through the switch tube S1 and the switch tube S2 connected in series; the PV- end of the photovoltaic module is connected to the output end OUT-; The control IC, the switch tube S1, and the switch tube S2 are respectively connected to the driving circuit, and the two signal terminals of the control IC control the switching of the switch tube S1 and the switch tube S2 through the driving circuit; It also includes an auxiliary power supply, the input of the auxiliary power supply is connected to the PV+ of the photovoltaic module, the output of the auxiliary power supply is connected to the control IC and the drive circuit, and the auxiliary power supply is used to provide working voltage to the control IC and the drive circuit; It also includes an input capacitor Cin, an output capacitor Cout, a bypass diode D1 and an output resistor Rx; The input capacitor Cin is connected in parallel with the photovoltaic module, one end of the output capacitor Cout is connected to the output terminal OUT+, and the other end is connected to the output terminal OUT-, and the output capacitor Cout, the bypass diode D1 and the output resistor Rx are connected in parallel; The switch tube S1 is a MOS tube S1, and the switch tube S2 is a MOS tube S2; The PV+ terminal of the photovoltaic module is connected to the drain of the MOS transistor S2, the source of the MOS transistor S2 is connected to the drain of the MOS transistor S1, and the source of the MOS transistor S1 is connected to the output terminal OUT+; the driving terminal Drv2 of the driving circuit is connected to the gate of the MOS transistor S2, and the driving terminal Drv1 of the driving circuit is connected to the gate of the MOS transistor S1; The common end of the MOS transistor S2 and the MOS transistor S1 is connected to the reference end S2GND; The driving circuit includes a first driving module and a second driving module; The control IC, the first driving module and the second driving module are electrically connected in sequence, the driving end Drv2 of the second driving module is connected to the gate of the MOS tube S2, and the driving end Drv1 of the second driving module is connected to the gate of the MOS tube S1; The first driving module includes an optical coupler OP1, a voltage regulator D3, a resistor R0, a resistor R1 and a resistor R2; The first signal terminal of the control IC is connected to the input pin 2 of the optocoupler OP1 via the resistor R2 on one hand, and to the output pin 4 of the optocoupler OP1 on the other hand. The second signal terminal of the control IC is connected to the input pin 1 of the optocoupler OP1 via the resistor R1 on one hand, to the ground via the voltage regulator D3 on one hand, and to the power supply VCC via the resistor R0 on the other hand. The second driving module includes a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, a voltage regulator tube D4, a voltage regulator tube D2 and a plurality of resistors; The output pin 3 of the optical coupler OP1 is connected to the base of the switch tube Q1 through the resistor R3, connected to the base of the switch tube Q2 through the resistor R4, and grounded through the resistor R5. The emitter of the switch tube Q1 is grounded, and the collector of the switch tube Q1 is connected to the gate of the switch tube Q3 on one hand, and connected to the power supply VCC via the resistor R6 on the other hand; The emitter of the switch tube Q2 is grounded, and the collector of the switch tube Q2 is connected to the gate of the switch tube Q4 on one hand, and connected to the power supply VCC via the resistor R7 on the other hand; The source of the switch tube Q3 is grounded, and the drain of the switch tube Q3 is connected to the power supply VDD via the resistor R8 on one hand, and connected to the driving end Drv1 via the resistor R10 on the other hand; The source of the switch tube Q4 is grounded, and the drain of the switch tube Q4 is connected to the power supply VDD via the resistor R9 on one hand, and connected to the driving end Drv2 via the resistor R11 on the other hand; The anode of the voltage regulator tube D4 is connected to the output terminal OUT+, and the cathode of the voltage regulator tube D4 is connected to the driving terminal Drv1; The anode of the voltage regulator tube D2 is connected to the reference terminal S2GND, and the cathode of the voltage regulator tube D2 is connected to the driving terminal Drv2.

2. A fast shutdown device capable of driving two series-connected MOS tubes by a single-channel signal according to claim 1, characterized in that: The second driving module includes a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, an optocoupler OP2, an optocoupler OP3, a diode D4, a diode D2 and a plurality of resistors; The output pin 3 of the optical coupler OP1 is connected to the ground via a resistor R5, connected to the input pin 1 of the optical coupler OP2 via a resistor R4, and connected to the input pin 1 of the optical coupler OP3 via a resistor R7. The input pin 2 of the optical coupler OP2 is grounded via a resistor R3, the output pin 4 of the optical coupler OP2 is connected to the output terminal OUT+, the output pin 3 of the optical coupler OP2 is connected to the power supply VDD via resistors R9 and R10 connected in series, the common end of the resistors R9 and R10 is connected to the base of the switch tube Q1, the emitter of the switch tube Q1 is connected to the power supply VDD, the collector of the switch tube Q1 is connected to the base of the switch tube Q3 via a resistor R13, the base of the switch tube Q3 is connected to the collector of the transistor Q3 via a resistor R15 on the one hand, and to the emitter of the transistor Q3 via a diode D4 on the other hand, the collector of the transistor Q3 is connected to the output terminal OUT+, and the emitter of the transistor Q3 is connected to the driving terminal Drv1; The input pin 2 of the optocoupler OP3 is grounded via a resistor R6, the output pin 4 of the optocoupler OP3 is connected to a reference terminal S2GND, the output pin 3 of the optocoupler OP3 is connected to a power supply VDD via resistors R11 and R12 connected in series, the common end of the resistors R11 and R12 is connected to the base of the switch tube Q2, the emitter of the switch tube Q2 is connected to the power supply VDD, the collector of the switch tube Q2 is connected to the base of the switch tube Q4 via a resistor R14, the base of the switch tube Q4 is connected to the collector of the transistor Q4 via a resistor R16 on the one hand, and to the emitter of the transistor Q4 via a diode D2 on the other hand, the collector of the transistor Q4 is connected to the reference terminal S2GND, and the emitter of the transistor Q4 is connected to the driving terminal Drv2.

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