Control circuit applied to photovoltaic disconnector, photovoltaic disconnector and photovoltaic system

Abstract

The application discloses a control circuit applied to a photovoltaic shutdown device, the photovoltaic shutdown device and a photovoltaic system, and belongs to the photovoltaic technical field.In the control circuit of the embodiment of the application, a switch module is connected with a photovoltaic module.A switch control module is connected with the switch module, and is used for outputting a control voltage according to a comparison result of a first voltage and a second voltage, and controlling the on-off state of the switch module.A hysteresis filtering module is connected between the switch control module and the switch module at one end, and is connected between a first voltage dividing unit and the switch control module at the other end, and is used for staggering the threshold points of the switch module in the on state and the off state when the control voltage is equal to an input voltage.In this way, the switch module is prevented from being repeatedly turned on and turned off due to the influence of voltage oscillation at the on time and the off time, accurate control of the switch module is achieved, the service life of the switch module is prolonged, and the reliability and safety of the photovoltaic system are improved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a control circuit for a photovoltaic shut-off device, a photovoltaic shut-off device, and a photovoltaic system. Background Technology

[0002] A photovoltaic (PV) fast shutdown device is a safety device installed in a photovoltaic system to quickly cut off the DC-side voltage of PV modules in emergency situations or when maintenance is required. High-power metal-oxide-semiconductor field-effect transistors (MOSFETs) are used in PV fast shutdown devices to control the switching between the PV modules and the inverter, enabling the PV modules to be disconnected in abnormal situations, reducing losses and ensuring the safety of property and personnel.

[0003] Currently, MOSFET drive control can be achieved through PWM signal control based on a digital MCU or through hardware control circuits. PWM signal control based on a digital MCU offers high precision but also suffers from higher costs and response delays. In the pure hardware control method, voltage oscillations during the turn-on and turn-off cycles of the MOSFETs can easily lead to repeated switching on and off, damaging the MOSFETs. Summary of the Invention

[0004] This application provides a control circuit, a photovoltaic switch, and a photovoltaic system for use in photovoltaic switch-off devices, in order to solve at least one of the aforementioned technical problems.

[0005] The present application discloses a control circuit for a photovoltaic (PV) shut-off device, wherein the PV shut-off device is applied to a photovoltaic system, the photovoltaic system includes photovoltaic modules, and the control circuit for the PV shut-off device includes:

[0006] A switching module, connected to a photovoltaic module, wherein the switching module is a field-effect transistor;

[0007] The voltage divider module includes a first voltage divider unit and a second voltage divider unit connected in parallel. The first voltage divider unit is used to output a first voltage according to the input voltage, and the second voltage divider unit is used to output a second voltage according to the input voltage.

[0008] A switch control module is connected to the first voltage divider unit, the second voltage divider unit, and the switch module, respectively. The switch control module is used to output a control voltage based on the comparison result of the first voltage and the second voltage. When the first voltage is greater than the second voltage, the control voltage is equal to the input voltage to turn on the switch module; when the first voltage is less than or equal to the second voltage, the control voltage is zero to turn off the switch module.

[0009] The hysteresis filter module has one end connected between the switch control module and the switch module, and the other end connected between the first voltage divider unit and the switch control module. When the control voltage is equal to the input voltage, the hysteresis filter module is used to stagger the threshold points for the switch module to turn on and off.

[0010] In some embodiments, the first voltage divider unit includes a first resistor and a second resistor, one end of the first resistor is connected to one end of the second resistor, the other end of the second resistor is grounded, and one end of the switch control module is connected between the first resistor and the second resistor;

[0011] The hysteresis filter module includes a hysteresis resistor, one end of which is connected between the switch control module and the switch module, and the other end is connected between the first resistor and the second resistor;

[0012] The resistance value of the hysteresis resistor is less than the resistance value of the first resistor.

[0013] In some embodiments, the hysteresis filter module further includes a hysteresis capacitor connected in parallel across the hysteresis resistor to form a low-pass filter with the hysteresis resistor.

[0014] In some embodiments, the second voltage divider unit includes a third resistor and a first Zener diode, the third resistor is connected to one end of the first Zener diode, the other end of the first Zener diode is grounded, and one end of the switch control module is connected between the third resistor and the first Zener diode;

[0015] The third resistor and the first Zener diode are used to divide the input voltage to obtain the second voltage, which is then input to the switch control module.

[0016] In some embodiments, the first voltage divider unit further includes a first capacitor, which is connected in parallel with the second resistor;

[0017] The first capacitor and the first resistor form a low-pass filter for filtering the input voltage.

[0018] The second voltage divider unit also includes a second capacitor, which is connected in parallel with the first Zener diode;

[0019] The second capacitor and the third resistor form a low-pass filter for filtering the input voltage.

[0020] In some embodiments, the first voltage divider unit further includes a third capacitor connected in parallel with the first resistor;

[0021] The third capacitor is used to filter the input voltage; and / or

[0022] The second voltage divider unit also includes a fourth capacitor, which is connected in parallel with the third resistor;

[0023] The fourth capacitor is used to filter the input voltage.

[0024] In some embodiments, the control circuit applied to the photovoltaic switch further includes a fourth resistor, a fifth capacitor, and a second Zener diode. The fourth resistor is connected to one end of the fifth capacitor, the other end of the fifth capacitor is grounded, the fifth capacitor is connected in parallel with the voltage divider module, and the second Zener diode is connected in parallel with the fifth capacitor.

[0025] The fourth resistor and the fifth capacitor are used to perform current limiting and filtering on the power supply voltage, and the second Zener diode is used to regulate the power supply voltage to obtain the input voltage.

[0026] In some embodiments, the control circuit applied to the photovoltaic switch further includes a diode, the negative terminal of which is connected to one end of the fourth resistor;

[0027] The diode is used to prevent the input voltage from being reversed.

[0028] The photovoltaic shut-off device according to the embodiments of this application includes the control circuit applied to the photovoltaic shut-off device according to any of the above embodiments.

[0029] The photovoltaic system of this application includes the photovoltaic shut-off device of the above-described embodiments.

[0030] The control circuit, photovoltaic switch, and photovoltaic system implemented in this application utilize a voltage divider module to divide the input voltage. A hysteresis filter module is also included. The switch control module determines the control voltage based on the input voltage after voltage division and the hysteresis width of the hysteresis filter module, thereby controlling the on / off state of the switch module according to the control voltage. This avoids repeated switching on and off due to voltage oscillations at the on and off times, achieving precise control of the switch module, improving its lifespan, and enhancing the reliability and safety of the photovoltaic system.

[0031] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort. Among them:

[0033] Figure 1 This is a schematic diagram of a control circuit applied to a photovoltaic switch in some embodiments of this application;

[0034] Figure 2 This is a circuit diagram of a control circuit applied to a photovoltaic switch in some embodiments of this application;

[0035] Figure 3 This is a schematic diagram of a photovoltaic system according to certain embodiments of this application;

[0036] Figure 4 This is a circuit diagram of a control circuit applied to a photovoltaic switch in some embodiments of this application;

[0037] Figure 5 This is a waveform diagram of the first voltage and the second voltage during the turn-off process of the control circuit applied to the photovoltaic turn-off device in some embodiments of this application;

[0038] Figure 6 This is a schematic diagram showing the change of control voltage with regulated voltage in a control circuit applied to a photovoltaic switch in certain embodiments of this application;

[0039] Figure 7 This is a circuit diagram of a control circuit applied to a photovoltaic switch in some embodiments of this application;

[0040] Figure 8This is a schematic diagram of a photovoltaic shut-off device according to certain embodiments of this application;

[0041] Figure 9 This is a schematic diagram of a photovoltaic system according to certain embodiments of this application.

[0042] Explanation of reference numerals in the attached figures:

[0043] Control circuit 100, switch module 10, switch control module 20, voltage divider module 30, voltage regulator module 40, hysteresis filter module 50, field-effect transistor Q1, operational amplifier op1, first resistor R1, second resistor R2, third resistor R3, fourth resistor R4, fifth resistor R5, first capacitor C1, second capacitor C2, third capacitor C3, fourth capacitor C4, fifth capacitor C5, hysteresis resistor R6, hysteresis capacitor C6, first Zener diode D1, second Zener diode D2, diode D3, photovoltaic shut-off circuit 101, photovoltaic system 200, photovoltaic module 210, inverter 220, transmitter 230. Detailed Implementation

[0044] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0045] Please see Figures 1 to 3This application provides a control circuit 100 for a photovoltaic (PV) switch 101. The PV switch 101 is applied to a photovoltaic system 200, which includes an inverter 220 and a photovoltaic module 210. The control circuit 100 for the PV switch 101 includes a switching module 10, a switching control module 20, a hysteresis filter module 50, and a voltage divider module 30. The switching module 10 is connected to the photovoltaic module 210. The switching module 10 is a field-effect transistor (FET) Q1. The voltage divider module 30 includes a first voltage divider unit and a second voltage divider unit connected in parallel. The first voltage divider unit outputs a first voltage based on the input voltage, and the second voltage divider unit outputs a second voltage based on the input voltage. The switching control module 20 is connected to the first voltage divider unit, the second voltage divider unit, and the switching module 10. The switching control module 20 outputs a control voltage based on a comparison between the first voltage and the second voltage. Specifically, when the first voltage is greater than the second voltage, the control voltage is equal to the input voltage, causing the switching module 10 to turn on; when the first voltage is less than or equal to the second voltage, the control voltage is zero, causing the switching module 10 to turn off. One end of the hysteresis filter module 50 is connected between the switch control module 20 and the switch module 10, and the other end is connected between the first voltage divider unit and the switch control module 20. When the control voltage is equal to the input voltage, the hysteresis filter module 50 is used to stagger the threshold points for the switch module 10 to turn on and off.

[0046] In the control circuit 100 of the photovoltaic switch 101 implemented in this application, the input voltage is divided by a voltage divider module 30, and a hysteresis filter module 50 is also provided. The switch control module 20 determines the control voltage based on the input voltage after voltage division and the hysteresis width of the hysteresis filter module 50, so as to control the on / off state of the switch module 10 according to the control voltage. In this way, the switch module 10 is avoided from repeatedly turning on and off due to voltage oscillations at the turn-on and turn-off times, realizing precise control of the switch module 10, improving the lifespan of the switch module 10, and also improving the reliability and safety of the photovoltaic system 200.

[0047] Specifically, the control circuit 100 is applied to the photovoltaic system 200, which includes an inverter 220 and photovoltaic modules 210. There are multiple photovoltaic modules 210, and multiple control circuits 100 can be set in each photovoltaic system 200. The control circuits 100 are used to control the on / off connection between the photovoltaic modules 210 and the inverter 220.

[0048] The control circuit 100 includes a circuit input terminal and a circuit output terminal. The circuit input terminal is used to connect to the control power supply, which can be an independent external power supply or the photovoltaic module 210 can be used directly as the control power supply. Between the circuit input terminal and the circuit output terminal of the control circuit 100, the voltage divider module 30, the switch control module 20, and the switch module 10 are connected in sequence.

[0049] The input voltage to the voltage divider module 30 is denoted by Vcc. After being divided by the voltage divider module 30, the input voltage Vcc is input to the switch control module 20. The control circuit 100 also includes a hysteresis filter module 50, which is connected in parallel with the switch control module 20. The hysteresis filter module 50 can generate a hysteresis width. The existence of the hysteresis width can stagger the threshold points for the switch module 10 to turn on and off, thus preventing the switch module 10 from oscillating between turning on and off.

[0050] The switch control module 20 can determine the control voltage based on the input voltage Vcc after voltage division and the hysteresis width. The control voltage can be represented by Vout. The control voltage Vout is input to the switch module 10 to control the on / off state of the switch module 10.

[0051] The switch control module 20 can use an operational amplifier op1, which includes a non-inverting input, an inverting input, and an op-amp output. The non-inverting and inverting inputs of the operational amplifier op1 are also the inputs of the switch control module 20, and the op-amp output of the operational amplifier op1 is also the output of the switch control module 20.

[0052] The voltage divider module 30 includes a first voltage divider unit and a second voltage divider unit. The non-inverting input terminal is connected to the first voltage divider unit, the inverting input terminal is connected to the second voltage divider unit, and the operational amplifier output terminal is connected to the switching module 10. The first voltage divider unit performs a first voltage division on the input voltage Vcc to obtain a first voltage, denoted by VIN+, which can be input to the non-inverting input terminal. The second voltage divider unit performs a second voltage division on the input voltage Vcc to obtain a second voltage, denoted by VIN-, which can be input to the inverting input terminal.

[0053] The operational amplifier output is connected to the switching module 10. Operational amplifier op1 compares the input first voltage VIN+ and second voltage VIN- to determine the control voltage Vout, which is then output to the switching module 10. The switching module 10 is a field-effect transistor Q1. In one example, such as... Figure 2 As shown, the switching module 10 can use an N-channel field-effect transistor, and the gate of the field-effect transistor Q1 is connected to the switching control module 20. The turn-on and turn-off principle of the switching module 10 is as follows.

[0054] When the first voltage VIN+ is greater than the second voltage VIN-, the control voltage Vout output is high. At this time, Vout=Vcc, and the control voltage Vout drives the gate of the field-effect transistor Q1, thereby turning on the field-effect transistor Q1, that is, turning on the switching module 10.

[0055] When the first voltage VIN+ is less than the second voltage VIN-, the control voltage Vout outputs a low level of 0, and the gate of the field-effect transistor Q1 discharges to the operational amplifier op1's output terminal, thus turning off the field-effect transistor Q1, which is also turning off the switching module 10.

[0056] In addition to being connected to the switch control module 20, the switch module 10 is also connected in series or parallel to the photovoltaic module 210. Therefore, by controlling the on / off state of the switch module 10, the connection state between the photovoltaic module 210 and the inverter 220 can be controlled. When the switch module 10 is connected in series with the photovoltaic module 210, the source of the field-effect transistor Q1 is connected to one photovoltaic module 210, that is... Figure 2 The second interface P2 is used to connect one photovoltaic module 210; the drain of the field-effect transistor Q1 is connected to another photovoltaic module 210, that is... Figure 2 The first interface P1 is used to connect to another photovoltaic module 210.

[0057] When the switching module 10 is connected in parallel with the photovoltaic module 210, the source and drain of the field-effect transistor Q1 are connected to the two ends of the photovoltaic module 210, that is... Figure 2 The first interface P1 and the second interface P2 are connected to the two ends of the same photovoltaic module 210. When the control voltage Vout output by the switch control module 20 is high, the switch module 10 is turned on; when the control voltage Vout output by the switch control module 20 is low, the switch module 10 is turned off.

[0058] When the switch module 10 is turned on, the photovoltaic module 210 is connected to the inverter 220; when the switch module 10 is turned off, the connection between the photovoltaic module 210 and the inverter 220 is disconnected.

[0059] In this embodiment, a purely hardware-based control circuit 100 for turning on and off a photovoltaic switch module 10 is proposed for a photovoltaic switch 101. Considering the fluctuation of the input voltage Vcc during the on and off moments of the switch module 10, a voltage divider module 30 is used to divide the input voltage Vcc, and a hysteresis filter module 50 is also provided. The switch control module 20 determines the control voltage Vout based on the input voltage Vcc after voltage division and the hysteresis width, and controls the on / off state of the switch module 10 according to the control voltage Vout.

[0060] Thus, when the amplitude of voltage noise or disturbance is less than the hysteresis width, erroneous switching on and off will not occur. During the switching process of the switching module 10, the problem of repeated switching on and off caused by the jitter of the first voltage VIN+ and the second voltage VIN- and the oscillation of the control voltage can be avoided, thereby achieving precise and reliable switching on and off of the switching module 10. In addition, controlling the switching of the switching module 10 through pure hardware significantly reduces sensitivity to electromagnetic interference, has lower cost, and also improves the reliability and safety of the photovoltaic system 200.

[0061] Please see Figure 4 In some embodiments, the first voltage divider unit includes a first resistor R1 and a second resistor R2. One end of the first resistor R1 and one end of the second resistor R2 are connected, and the other end of the second resistor R2 is grounded. One end of the switch control module 20 is connected between the first resistor R1 and the second resistor R2. The hysteresis filter module 50 includes a hysteresis resistor R6. One end of the hysteresis resistor R6 is connected between the switch control module 20 and the switch module 10, and the other end is connected between the first resistor R1 and the second resistor R2. The resistance of the hysteresis resistor R6 is less than the resistance of the first resistor R1.

[0062] Specifically, the first voltage divider unit includes a first resistor R1 and a second resistor R2. One end of the first resistor R1 is connected to the circuit input terminal, and the other end is connected to one end of the second resistor R2, with the other end of the second resistor R2 grounded. The non-inverting input terminal of the operational amplifier op1 is connected between the first resistor R1 and the second resistor R2.

[0063] The first resistor R1 and the second resistor R2 are used to divide the input voltage Vcc to obtain the first voltage VIN+, which is then input to the non-inverting input terminal. The stable voltage of the first voltage VIN+ is determined by the voltage division value of the first resistor R1 and the second resistor R2, denoted by K3.

[0064] The hysteresis filter module 50 includes a hysteresis resistor R6. One end of the hysteresis resistor R6 is connected to the non-inverting input of the operational amplifier op1, and the other end is connected between the op-amp output of the operational amplifier op1 and the switching module 10. The hysteresis resistor R6 is used to determine the first threshold and the second threshold corresponding to the hysteresis width.

[0065] The resistance of the hysteresis resistor R6 is less than that of the first resistor R1. During the turn-on process of the switching module 10, when the control voltage Vout equals the input voltage Vcc, the second resistor R2 and the hysteresis resistor R6 are connected in series, and the total resistance of the second resistor R2 and the hysteresis resistor R6 is less than the total resistance of the first resistor R1 and the second resistor R2. At this time, the current increases, and the voltage across the second resistor R2 increases instantaneously, that is, the first voltage VIN+ increases instantaneously, causing the fluctuation range of the first voltage VIN+ to be offset from the fluctuation range of the second voltage VIN-.

[0066] Similarly, such as Figure 5 As shown, during the turn-off process of the switching module 10, when the control voltage Vout equals zero, the voltage across the second resistor R2 decreases instantaneously, meaning the first voltage VIN+ decreases instantaneously as well. This causes the fluctuation range of the first voltage VIN+ to be offset from the fluctuation range of the second voltage VIN-. This avoids repeated switching on and off caused by voltage fluctuations in the second resistor R2.

[0067] The first threshold is denoted by K1, the second threshold by K2, and K1-K2 is the hysteresis width. Due to the existence of the hysteresis width, such as Figure 6 As shown, when the input voltage Vcc is greater than the first threshold K1, the field-effect transistor Q1 is turned on.

[0068] When the input voltage Vcc is less than the second threshold K2, the field-effect transistor Q1 is turned off. The stable value K0 of the input voltage Vcc is greater than the first threshold K1, and the first threshold K1 is greater than the second threshold K2. As long as the amplitude of the noise or disturbance of the input voltage Vcc is less than the hysteresis width, there will be no false turn-on or turn-off.

[0069] Please see Figure 2 In some embodiments, the hysteresis filter module 50 further includes a hysteresis capacitor C6, which is connected in parallel across the hysteresis resistor R6 to form a low-pass filter with the hysteresis resistor R6.

[0070] Specifically, the hysteresis capacitor C6 is connected in parallel across the hysteresis resistor R6. Together, the hysteresis capacitor C6 and the hysteresis resistor R6 form a low-pass filter, which enhances the anti-interference capability and stability of the control circuit 100 and prevents oscillation.

[0071] Please see Figure 4In some embodiments, the second voltage divider unit includes a third resistor R3 and a first Zener diode D1. The third resistor R3 is connected to one end of the first Zener diode D1, and the other end of the first Zener diode D1 is grounded. One end of the switch control module 20 is connected between the third resistor R3 and the first Zener diode D1. The third resistor R3 and the first Zener diode D1 are used to divide the input voltage to obtain a second voltage, which is then input to the switch control module 20. The resistance value of the first resistor R1 and the second resistor R2 connected in parallel is less than the resistance value of the third resistor R3.

[0072] Specifically, the second voltage divider unit includes a third resistor R3 and a first Zener diode D1. One end of the third resistor R3 is connected to the circuit input terminal, and the other end is connected to one end of the first Zener diode D1. The other end of the first Zener diode D1 is grounded, and the inverting input terminal is connected between the third resistor R3 and the first Zener diode D1.

[0073] The third resistor R3 and the first Zener diode D1 are used to divide the input voltage Vcc to obtain the second voltage VIN-, which is then input to the inverting input terminal. The stable voltage of the second voltage VIN- is determined by the regulated voltage values ​​of the third resistor R3 and the first Zener diode D1, denoted by K4.

[0074] Please see Figure 4 In some embodiments, the first voltage divider unit further includes a first capacitor C1, which is connected in parallel with a second resistor R2. The first capacitor C1 and the first resistor R1 form a low-pass filter for filtering the input voltage.

[0075] Specifically, the first voltage divider unit can be equipped with a first capacitor C1, which is connected in parallel with the second resistor R2. The first capacitor C1 and the first resistor R1 can form a first low-pass filter. The time constant τ1 of the first low-pass filter is R1 * C1. By adjusting the time constant τ1, the settling time of the first voltage VIN+ can be adjusted, that is, the time it takes for the first voltage VIN+ to reach a stable value K3 during the switching module 10's turn-on process, denoted as t3, where t3 = n2 * τ1, and n2 ≥ 5. In one example, n2 = 5.

[0076] Please see Figure 4 In some embodiments, the second voltage divider unit further includes a second capacitor C2, which is connected in parallel with the first Zener diode D1. The second capacitor C2 and the third resistor R3 form a low-pass filter for filtering the input voltage.

[0077] Specifically, the second voltage divider unit can be equipped with a second capacitor C2, which is connected in parallel with the first Zener diode D1. The second capacitor C2 can act as a bypass to prevent fluctuations in the regulated voltage of the first Zener diode D1 caused by interference. The second capacitor C2 can also form a second low-pass filter with the third resistor R3. The time constant τ2 of the second low-pass filter is R3*C2. By adjusting the time constant τ2, the stabilization time of the second voltage VIN- can be adjusted, that is, the time it takes for the second voltage VIN- to reach a stable value K4 during the switching module 10 is turned on, denoted by t1, where t1=n1*τ2, n1≥5. In one example, n1=5.

[0078] Please see Figure 4 In some embodiments, the first voltage divider unit further includes a third capacitor C3, which is connected in parallel with the first resistor R1. The third capacitor C3 and the first capacitor C1 are used to filter the input voltage.

[0079] Specifically, the first voltage divider unit can be equipped with a third capacitor C3, which is connected in parallel with the first resistor R1. The third capacitor C3 is used to filter and decouple the input voltage Vcc.

[0080] Please see Figure 4 In some embodiments, the second voltage divider unit further includes a fourth capacitor C4, which is connected in parallel with the third resistor R3. The fourth capacitor C4 and the second capacitor C2 are used to filter the input voltage.

[0081] Specifically, the second voltage divider unit can be equipped with a fourth capacitor C4, which is connected in parallel with the third resistor R3. The fourth capacitor C4 is used to filter and decouple the input voltage Vcc.

[0082] Please see Figure 7 In some embodiments, the control circuit 100 applied to the photovoltaic switch 101 further includes a voltage regulator module 40, which is connected to a voltage divider module 30. The voltage divider module 30 is used to divide the power supply voltage after passing through the voltage regulator module 40.

[0083] It is understandable that when the control power supply of the control circuit 100 is taken from an external power source, the large area of ​​the photovoltaic module 210 results in a relatively long power supply cable to the control circuit 100, with numerous power extraction points on the cable, leading to significant fluctuations in the output voltage Vin of the control power supply. Similarly, when the control power supply of the control circuit 100 is taken from the photovoltaic module 210, factors such as light intensity, ambient temperature, and the maximum power point tracking (MPPT) adjustment of the inverter 220 will also cause significant fluctuations in the output voltage Vin of the photovoltaic module 210.

[0084] Therefore, a voltage regulator module 40 is provided, which is connected to the voltage divider module 30. Specifically, it can be connected between the circuit input terminal of the control circuit 100 and the voltage divider module 30. The voltage regulator module 40 can regulate the power supply voltage Vin to obtain the input voltage Vcc, and the voltage divider module 30 can then divide the input voltage Vcc. In this way, the problem of unstable power supply voltage Vin can be solved, and overvoltage and other situations that could damage the components in the circuit can be avoided.

[0085] In addition to its voltage regulation function, the voltage regulator module 40 can also be equipped with other functions according to actual application requirements. The specific structure of the voltage regulator module 40 is described in detail below.

[0086] Please see Figure 7 In some embodiments, the voltage regulator module 40 includes a diode D3, a fourth resistor R4, a fifth capacitor C5, and a second Zener diode D2. The cathode of diode D3 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to one end of the fifth capacitor C5. The other end of the fifth capacitor C5 is grounded. The second Zener diode D2 is connected in parallel with the fifth capacitor C5. Diode D3 is used for reverse voltage protection of the power supply. The fourth resistor R4 and the fifth capacitor C5 are used for current limiting and filtering of the power supply voltage, and the second Zener diode D2 is used for voltage regulation of the power supply voltage to obtain the input voltage.

[0087] Specifically, in the voltage regulator module 40, the anode of diode D3 is connected to the circuit input terminal, the cathode of diode D3 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is connected to one end of the fifth capacitor C5, the other end of the fifth capacitor C5 is grounded, and the second Zener diode D2 is connected in parallel with the fifth capacitor C5. The voltage divider module 30 is connected in parallel with the fifth capacitor C5.

[0088] Diode D3 provides reverse bias protection for the power supply voltage Vin. When Vin experiences a non-forward voltage, diode D3's unidirectional conduction characteristic ensures effective reverse bias protection. Resistor R4 and capacitor C5 form a current-limiting filter. After passing through diode D3, the power supply voltage Vin flows to this filter, preventing large current surges in the downstream circuitry. A relatively large capacitance value for capacitor C5, such as 10-20µF, allows for the storage of more energy, ensuring sufficient power for the downstream circuitry during abnormal events.

[0089] The voltage regulation value of the second Zener diode D2 can be determined according to the actual application requirements. By selecting the voltage regulation value, the power supply voltage Vin is regulated. The power supply voltage Vin after being processed by the voltage regulation module 40 can be represented by the input voltage Vcc.

[0090] Thus, the voltage regulator module 40, composed of diode D3, fourth resistor R4, fifth capacitor C5, and second Zener diode D2, achieves four major functions: reverse protection, voltage regulation, current limiting, and energy storage.

[0091] A fifth resistor R5 is also connected between the switch control module 20 and the switch module 10. When the first voltage VIN+ is greater than the second voltage VIN-, the control voltage Vout drives the gate of the field-effect transistor Q1 through the fifth resistor R5; when the first voltage VIN+ is less than the second voltage VIN-, the gate of the field-effect transistor Q1 discharges to the output terminal of the operational amplifier op1 through the fifth resistor R5. The fifth resistor R5 can suppress the oscillation during the turn-on and turn-off process of the switch module 10, making the turn-on and turn-off of the switch module 10 smoother.

[0092] It is understandable that the field-effect transistor Q1 operating in the amplification region is highly susceptible to overheating and damage, and in severe cases, even explosion. Therefore, it is necessary to prevent the field-effect transistor Q1 from entering the amplification region; that is, when the field-effect transistor Q1 is turned on, the control voltage Vout must be greater than the amplification region threshold. The second threshold K2 is set to be greater than the amplification region threshold, meaning that the first threshold K1 is also greater than the amplification region threshold, thus ensuring that the control voltage Vout is greater than the amplification region threshold when the field-effect transistor Q1 is turned on. The voltage in the amplification region is a parameter of the field-effect transistor Q1 itself. In one example, the voltage range in the amplification region is 2.4V-3V, so 3V is taken as the amplification region threshold.

[0093] During the turn-on and turn-off process of the switch module 10, there is a problem with the setting of a comparison value. Since there is no digital MCU control, as the input voltage Vcc gradually increases from 0V to the set value K0, the first voltage VIN+ and the second voltage VIN- also gradually increase.

[0094] During this process, if the first voltage VIN+ and the second voltage VIN- cannot be well controlled, the first voltage VIN+ and the second voltage VIN- will fluctuate and cross multiple times. If a crossover occurs, there will inevitably be situations where the first voltage VIN+ is greater than the second voltage VIN-, the first voltage VIN+ is less than the second voltage VIN-, or the first voltage VIN+ is equal to the second voltage VIN-.

[0095] The alternation of these three situations causes the control voltage Vout to repeatedly fluctuate between high and low levels, corresponding to the repeated on / off switching of the switching module 10. Since the input voltage Vcc is still changing and has not reached a stable value K0, the gate voltage of the field-effect transistor Q1 needs to exceed a certain threshold to enter the saturation region. When the input voltage Vcc is high, the field-effect transistor Q1 can repeatedly turn on and off; however, when the input voltage Vcc is low, the field-effect transistor Q1 enters the amplification region, which needs to be avoided.

[0096] First, to prevent the control voltage Vout from outputting a high level during the rise of the input voltage Vcc, the first voltage VIN+ must remain stable as it is less than the second voltage VIN-. Once the input voltage Vcc reaches a certain threshold, the first voltage VIN+ becomes equal to and then greater than the second voltage VIN-, thus achieving a single flip of the control voltage Vout from a low level to an output high level. This prevents the field-effect transistor Q1 from entering the amplification region and repeatedly turning on and off during the turn-on process.

[0097] Secondly, during the decrease of the input voltage Vcc, the first voltage VIN+ should decrease rapidly. After reaching the flip point, the first voltage VIN+ should be less than the second voltage VIN-, so that the control voltage Vout can be flipped from high level to low level once, thus avoiding the field-effect transistor Q1 from entering the amplification region and repeatedly turning on and off during the turn-off process.

[0098] As the input voltage Vcc gradually increases from 0V, since Vcc is still changing and has not yet reached a stable value K0, the gate voltage of the field-effect transistor Q1 needs to exceed a certain threshold to enter the saturation region. When the input voltage Vcc is high, the field-effect transistor Q1 can be repeatedly turned on and off, but when the input voltage Vcc is low, the field-effect transistor Q1 enters the amplification region, which needs to be avoided.

[0099] Therefore, please refer to Figure 4 In some embodiments, both the first voltage and the second voltage increase with the increase of the input voltage, and before the first voltage is greater than the second voltage, the rate of increase of the first voltage is less than the rate of increase of the second voltage.

[0100] It can be understood that the first voltage VIN+ and the second voltage VIN- are both obtained by voltage division of the input voltage Vcc. The first voltage VIN+ and the second voltage VIN- both increase with the increase of the input voltage Vcc, and are maintained after reaching a stable value.

[0101] Due to the alternating fluctuations and cross processes of the first voltage VIN+ and the second voltage VIN, the switching module 10 may experience incorrect turn-on and turn-off, and will repeatedly turn on and off. Therefore, during the rising process of the input voltage Vcc, to avoid the control voltage Vout from outputting a high level, the first voltage VIN+ needs to be stable while being less than the second voltage VIN- during this period. After the input voltage Vcc reaches a certain threshold, the first voltage VIN+ becomes equal to and then greater than the second voltage VIN-, achieving a single flip of the control voltage Vout from a low level to a high level.

[0102] Therefore, it is set that before the first voltage VIN+ is greater than the second voltage VIN-, the increasing speed of the first voltage VIN+ is less than the increasing speed of the second voltage VIN-; after the second voltage VIN+ reaches a stable value, the first voltage VIN+ continues to increase until it is greater than the stable value of the second voltage VIN-, achieving the flip of the control voltage Vout. As Figure 4 shown, before the first voltage VIN+ is greater than the second voltage VIN-, the slope of the waveform curve corresponding to the first voltage VIN+ is always less than the slope of the waveform curve corresponding to the second voltage VIN-.

[0103] Please refer to Figure 4 , in some embodiments, the product of the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1 is greater than the product of the resistance value of the third resistor R3 and the capacitance value of the second capacitor C2.

[0104] The turn-on moment of the switching module 10 satisfies the first preset condition, and the first preset condition is t1 < t2 < t3. Wherein, t1 = n1 * τ2, n1 ≥ 5, τ2 = R3 * C4. t2 is the turn-on moment of the switching module 10. t3 is the stable time of the first voltage VIN+ at the non-inverting input terminal, t3 = n2 * τ1, n2 ≥ 5, τ1 = R1 * C2, then τ1 is greater than τ2, that is, the product of the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1 is greater than the product of the resistance value of the third resistor R3 and the capacitance value of the second capacitor C2.

[0105] In such a case, it can be ensured that before the first voltage VIN+ is greater than the second voltage VIN-, the increasing speed of the first voltage VIN+ is less than the increasing speed of the second voltage VIN-, so that the second voltage VIN- is always higher than the first voltage VIN+ before the second voltage VIN- reaches the stable value K4. After the second voltage VIN- reaches the stable value K4 at the moment t2, the first voltage VIN+ continues to rise and exceeds K4 after the moment t2, driving the flip to output a high level. At the same time, the first voltage VIN+ continues to rise until it reaches the stable value K3. Thus, during the turn-on process, the field-effect transistor Q1 is effectively prevented from entering the amplification region and repeatedly turning on and off.

[0106] Please refer to Figure 4 The resistance of the first resistor R1 and the second resistor R2 connected in parallel is less than the resistance of the third resistor R3.

[0107] Specifically, in the process of the control circuit 100 from a stable on state to a complete off state, in order to achieve reliable shutdown, it is also necessary to prevent the field-effect transistor Q1 from entering the amplification region, and it must be shut down once to avoid repeated on and off.

[0108] During the turn-off process, the discharge rate of the first voltage VIN+ needs to be greater than the discharge rate of the second voltage VIN-. Therefore, the resistance value of the first resistor R1 and the second resistor R2 connected in parallel must be less than the resistance value of the third resistor R3. Taking into account the energy storage effect of the first capacitor C1, after determining the resistance values ​​of the first resistor R1, the second resistor R2 and the third resistor R3, the drop rate of the first voltage VIN+ can be made greater than the drop rate of the second voltage VIN-.

[0109] At time t3, the input voltage Vcc is turned off. At this time, the first voltage VIN+ begins to decrease. The rate of decrease of the first voltage VIN+ is greater than the rate of decrease of the second voltage VIN-, which avoids the phenomenon that the field-effect transistor Q1 cannot be turned off. At the same time, as the voltage decreases, the gate voltage of the field-effect transistor Q1 gradually enters the amplification region. If the current IDS is still present at this time, it will inevitably cause the field-effect transistor Q1 to be damaged during turn-off.

[0110] To prevent the field-effect transistor Q1 from entering the amplification region, the actual gate turn-off voltage K5 of the field-effect transistor Q1 (at time t4) must be greater than the minimum reliable turn-on voltage K6 of the field-effect transistor Q1. The minimum reliable turn-on voltage K6 can be obtained from the datasheet of the corresponding field-effect transistor Q1. Simultaneously, after the field-effect transistor Q1 is turned off, the first voltage VIN+ must always be less than the second voltage VIN-. This avoids secondary or multiple crossings of the first voltage VIN+ and the second voltage VIN-, thereby preventing erroneous turn-on and turn-off of the switching module 10 before and after turn-off, and preventing damage caused by frequent turn-on and turn-off of the field-effect transistor Q1 in the amplification region.

[0111] Please see Figure 4 In some embodiments, the switching module 10 is a field-effect transistor Q1, and the stable voltage value of the first Zener diode D1 is greater than the amplification threshold voltage of the field-effect transistor Q1.

[0112] Please see Figure 4 In some embodiments, the switching module 10 is a field-effect transistor Q1. When the voltage division value of the second resistor R2 is greater than the stable voltage value of the first Zener diode D1, the input voltage is greater than the amplifier threshold voltage of the field-effect transistor Q1.

[0113] Specifically, when the first voltage VIN+ is greater than the second voltage VIN-, the control voltage Vout = the input voltage Vcc, and the field-effect transistor Q1 is turned on. This can be divided into two cases:

[0114] In the first scenario: the stable voltage value of the first Zener diode D1 is greater than the amplification region threshold, and the stable value of the second voltage VIN- is determined by setting the parameters of the first Zener diode D1. It can be understood that if the input voltage Vcc is greater than the stable value of the second voltage VIN-, and the first voltage VIN+ is greater than the second voltage VIN-, then the input voltage Vcc is significantly greater than the amplification region threshold, and the field-effect transistor Q1 will not operate in the amplification region.

[0115] The second scenario: The stable voltage of the first Zener diode D1 is less than the amplification threshold. Since the input voltage Vcc is determined by the voltage divider between the first resistor R1 and the second resistor R2, the resistance values ​​of the first resistor R1 and the second resistor R2 need to be considered. Research has shown that when the voltage divider value of the second resistor R2 is greater than the stable voltage of the first Zener diode D1, it is possible to make the input voltage Vcc greater than the amplification threshold when the first voltage VIN+ is greater than the second voltage VIN-.

[0116] This ensures that the field-effect transistor Q1 will not enter the amplification region when the first voltage VIN+ is greater than the second voltage VIN-.

[0117] Please see Figure 8 This application also provides a photovoltaic shut-off device 101, including the control circuit 100 applied to the photovoltaic shut-off device 101 according to any of the above embodiments.

[0118] Please see Figure 3 This application also provides a photovoltaic system 200, which includes the photovoltaic switch 101 described in the above embodiments.

[0119] Specifically, the photovoltaic system 200 includes a photovoltaic switch 101, photovoltaic modules 210, an inverter 220, and a transmitter 230. A control circuit 100 is applied to the photovoltaic switch 101, and there are multiple photovoltaic modules 210. The photovoltaic switch 101 can be connected in series or in parallel with the photovoltaic modules 210 in the photovoltaic system 200. The transmitter 230 is used to transmit electromagnetic waves to power the photovoltaic switch 101, and in turn, power the control circuit 100 applied to the photovoltaic switch 101.

[0120] like Figure 3 As shown, multiple photovoltaic modules 210 are connected in series with the inverter 220, and a photovoltaic switch 101 is connected between every two photovoltaic modules 210. Figure 9As shown, in parallel configuration, each photovoltaic switch 101 is connected in parallel with a photovoltaic module 210, and multiple photovoltaic switches 101 are then connected in series with an inverter 220.

[0121] In the control circuit 100 of the photovoltaic switch 101, the photovoltaic switch 101, and the photovoltaic system 200 implemented in this application, the input voltage Vcc is divided by a voltage divider module 30, and a hysteresis filter module 50 is also provided. The switch control module 20 determines the control voltage Vout based on the input voltage Vcc after voltage division and the hysteresis width of the hysteresis filter module 50, and controls the on / off state of the switch module 10 according to the control voltage Vout. In this way, the switch module 10 is prevented from repeatedly turning on and off due to voltage oscillations at the turn-on and turn-off times, achieving precise control of the switch module 10, improving the lifespan of the switch module 10, and also improving the reliability and safety of the photovoltaic system 200.

[0122] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0123] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0124] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0125] The foregoing disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described above. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0126] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," and "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with an embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0127] Although embodiments of this application have been shown and described above, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A control circuit for a photovoltaic switch, characterized in that, The photovoltaic shut-off device is applied to a photovoltaic system, the photovoltaic system including photovoltaic modules, and the control circuit applied to the photovoltaic shut-off device includes: A switching module, connected to a photovoltaic module, wherein the switching module is a field-effect transistor; The voltage divider module includes a first voltage divider unit and a second voltage divider unit connected in parallel. The first voltage divider unit is used to output a first voltage according to the input voltage, and the second voltage divider unit is used to output a second voltage according to the input voltage. A switch control module is connected to the first voltage divider unit, the second voltage divider unit, and the switch module, respectively. The switch control module is used to output a control voltage based on the comparison result of the first voltage and the second voltage. When the first voltage is greater than the second voltage, the control voltage is equal to the input voltage to turn on the switch module; when the first voltage is less than or equal to the second voltage, the control voltage is zero to turn off the switch module. The hysteresis filter module has one end connected between the switch control module and the switch module, and the other end connected between the first voltage divider unit and the switch control module. When the control voltage is equal to the input voltage, the hysteresis filter module is used to stagger the threshold points for the switch module to turn on and off. The first voltage divider unit includes a first resistor and a second resistor. One end of the first resistor is connected to one end of the second resistor, and the other end of the second resistor is grounded. One end of the switch control module is connected between the first resistor and the second resistor. The hysteresis filter module includes a hysteresis resistor, one end of which is connected between the switch control module and the switch module, and the other end is connected between the first resistor and the second resistor; The resistance value of the hysteresis resistor is less than the resistance value of the first resistor.

2. The control circuit for a photovoltaic switch as described in claim 1, characterized in that, The hysteresis filter module also includes a hysteresis capacitor, which is connected in parallel across the hysteresis resistor to form a low-pass filter with the hysteresis resistor.

3. The control circuit applied to a photovoltaic switch as described in claim 1, characterized in that, The second voltage divider unit includes a third resistor and a first Zener diode. The third resistor is connected to one end of the first Zener diode, and the other end of the first Zener diode is grounded. One end of the switch control module is connected between the third resistor and the first Zener diode. The third resistor and the first Zener diode are used to divide the input voltage to obtain the second voltage, which is then input to the switch control module.

4. The control circuit for a photovoltaic switch as described in claim 3, characterized in that, The first voltage divider unit further includes a first capacitor, which is connected in parallel with the second resistor; The first capacitor and the first resistor form a low-pass filter for filtering the input voltage; The second voltage divider unit also includes a second capacitor, which is connected in parallel with the first Zener diode; The second capacitor and the third resistor form a low-pass filter for filtering the input voltage.

5. The control circuit for a photovoltaic switch as described in claim 4, characterized in that, The first voltage divider unit further includes a third capacitor, which is connected in parallel with the first resistor; The third capacitor is used to filter the input voltage; and / or The second voltage divider unit also includes a fourth capacitor, which is connected in parallel with the third resistor; The fourth capacitor is used to filter the input voltage.

6. The control circuit for a photovoltaic switchgear according to claim 5, characterized in that, The control circuit applied to the photovoltaic switch also includes a fourth resistor, a fifth capacitor, and a second Zener diode. The fourth resistor is connected to one end of the fifth capacitor, the other end of the fifth capacitor is grounded, the fifth capacitor is connected in parallel with the voltage divider module, and the second Zener diode is connected in parallel with the fifth capacitor. The fourth resistor and the fifth capacitor are used to perform current limiting and filtering on the power supply voltage, and the second Zener diode is used to regulate the power supply voltage to obtain the input voltage.

7. The control circuit for a photovoltaic switchgear according to claim 6, characterized in that, The control circuit applied to the photovoltaic switch also includes a diode, the negative terminal of which is connected to one end of the fourth resistor; The diode is used to prevent the power supply voltage from being reversed.

8. A photovoltaic switch, characterized in that, Includes the control circuit applied to a photovoltaic shut-off device as described in any one of claims 1-7.

9. A photovoltaic system, characterized in that, Includes the photovoltaic shut-off device as described in claim 8.

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