Photovoltaic panel anti-reverse circuit
By introducing sampling and comparison units into the photovoltaic energy storage system, and combining them with the switching unit to control the conduction state of the anti-reverse switch, the failure problem of the MOSFET anti-reverse connection circuit under residual voltage conditions is solved, and the reliability of the anti-reverse circuit is improved.
Patent Information
- Application Number
- CN202520154053.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-22
- Publication Date
- 2026-03-03
- Estimated Expiration
- 2035-01-22
AI Technical Summary
In existing photovoltaic energy storage systems, the reverse connection protection circuit of the MOSFET may directly turn on when the battery is powered on and there is residual voltage at the PV input, thus losing its reverse connection protection effect and resulting in poor reliability of the reverse connection protection circuit.
A photovoltaic panel anti-reverse circuit is adopted. The sampling unit collects the current between the photovoltaic panel and the battery, converts it into voltage, and compares it with the reference voltage by the comparison unit. The control unit switches the on and off states of the anti-reverse switch. The conduction state of the anti-reverse switch depends not only on the input voltage of the photovoltaic panel, but also on the negative current of the battery, thus increasing the current sampling judgment.
This improves the reliability of the anti-reverse circuit and prevents the anti-reverse switch from directly turning on and losing its anti-reverse effect when there is residual voltage at the negative input terminal of the photovoltaic panel.
Smart Images
Figure CN223967661U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of photovoltaic energy storage technology, specifically to a photovoltaic panel anti-reverse circuit. Background Technology
[0002] In photovoltaic (PV) energy storage systems, commonly used DC reverse connection protection circuits include diode reverse connection protection circuits and MOSFET reverse connection protection circuits. Diode reverse connection protection circuits utilize the unidirectional conductivity of diodes to achieve reverse connection protection. However, diodes have a forward voltage drop, which causes power loss across the diode, reducing PV charging efficiency. MOSFET reverse connection protection circuits utilize the switching characteristics of MOSFETs to achieve reverse connection protection. MOSFETs have very low on-resistance, resulting in virtually no voltage drop. Conventional MOSFET reverse connection protection circuits are simple, requiring few external components, consisting of a MOSFET, resistors, capacitors, and a Zener diode. However, in conventional MOSFET reverse connection protection circuits, when the battery is powered on and there is residual voltage at the PV input, the MOSFET may turn on directly, losing its reverse connection protection effect. Utility Model Content
[0003] In view of this, the present invention provides a photovoltaic panel anti-reverse circuit to solve the problem of poor reliability of existing anti-reverse connection circuits in photovoltaic energy storage systems.
[0004] This utility model provides a photovoltaic panel anti-reverse circuit, including: a sampling unit, a comparison unit, a switching unit, and an anti-reverse switch. The positive input terminal of the photovoltaic panel is connected to the first terminal of the switching unit and the positive terminal of the battery, and the negative input terminal of the photovoltaic panel is connected to the first terminal of the anti-reverse switch. The first terminal of the sampling unit is connected to the second terminal of the switching unit, and the second terminal of the sampling unit is connected to the negative terminal of the battery. The output terminal of the sampling unit is connected to the first input terminal of the comparison unit. The sampling unit is used to collect the negative current of the battery and convert the sampled current into a sampled voltage before outputting it. The second input terminal of the comparison unit receives a reference voltage, and the output terminal of the comparison unit is connected to the control terminal of the switching unit. The comparison unit is used to control the switching unit to switch on / off states based on the magnitude of the sampled voltage and the reference voltage. The output terminal of the switching unit is connected to the control terminal of the anti-reverse switch, and the third terminal of the switching unit is also connected to the second terminal of the anti-reverse switch. The anti-reverse switch operates based on the on / off state of the switching unit.
[0005] The photovoltaic panel anti-reverse circuit provided by this utility model has a sampling unit that collects the sampling current on the line between the negative input terminal of the photovoltaic panel and the negative terminal of the battery. After converting the sampling current into a sampling voltage, the comparison unit compares the sampling voltage with a preset reference voltage. Based on the comparison result, the on / off state of the switching unit controls the anti-reverse switch to conduct. That is, the on / off state of the anti-reverse switch depends not only on the input terminal voltage of the photovoltaic panel, but also on the current magnitude of the negative terminal of the battery. This adds current sampling judgment and avoids the anti-reverse switch from directly conducting based on a small residual voltage when there is residual voltage at the negative input terminal of the photovoltaic panel, thus losing the anti-reverse effect and improving the reliability of the anti-reverse circuit.
[0006] In one alternative implementation, the reverse protection switch is a MOSFET.
[0007] In one optional embodiment, the sampling unit includes a sampling circuit and an amplification circuit, wherein a first terminal of the sampling circuit is connected to a first input terminal of the amplification circuit and a second terminal of the switching unit, and a second terminal of the sampling circuit is connected to a second input terminal of the amplification circuit and the negative terminal of the battery; the output terminal of the amplification circuit is connected to a first input terminal of the comparison unit.
[0008] In one alternative implementation, the sampling circuit includes a sampling resistor.
[0009] In one alternative implementation, the amplifier circuit includes a differential amplifier.
[0010] In one optional embodiment, the switching unit includes: a switching circuit, an isolation circuit, and a driving circuit, wherein the control terminal of the switching circuit is connected to the output terminal of the comparator unit, the first terminal of the switching circuit is connected to an external power supply, and the second terminal of the switching circuit is connected to the first terminal of the isolation circuit; the second terminal of the isolation circuit is connected to the first terminal of the driving circuit, and the third terminal of the isolation circuit is connected to the control terminal of the reverse protection switch; the second terminal of the driving circuit is connected to the positive input terminal of the photovoltaic panel, and the third terminal of the driving circuit is connected to the second terminal of the reverse protection switch.
[0011] In one optional embodiment, the switching circuit includes a transistor and a first resistor, wherein the control terminal of the transistor is connected to the output terminal of the comparator unit, the first terminal of the transistor is connected to the first terminal of the first resistor and the first terminal of the isolation circuit, and the second terminal of the transistor is grounded; the second terminal of the first resistor is connected to an external power supply.
[0012] In one alternative implementation, the isolation circuit includes an optocoupler isolation chip.
[0013] In one optional embodiment, the driving circuit includes: a second resistor, a third resistor, and a Zener diode, wherein the first end of the second resistor is connected to the positive input terminal of the photovoltaic panel, the second end of the second resistor is connected to the first end of the third resistor, the first end of the Zener diode, and the second end of the isolation circuit; and the second end of the third resistor is connected to the second end of the Zener diode and the second end of the reverse protection switch. Attached Figure Description
[0014] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0015] Figure 1 This is a schematic diagram of a photovoltaic panel anti-reverse circuit according to an embodiment of the present invention;
[0016] Figure 2 This is another schematic diagram of the photovoltaic panel anti-reverse circuit according to an embodiment of the present utility model;
[0017] Figure 3 This is a circuit structure diagram of a photovoltaic panel anti-reverse circuit according to an embodiment of the present utility model. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0019] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model 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 utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly 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 also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0021] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.
[0022] This embodiment provides a photovoltaic panel anti-reverse circuit, such as... Figure 1 As shown, the system includes: a sampling unit 1, a comparison unit 2, a switching unit 3, and a reverse protection switch 4. The positive input terminal PV+ of the photovoltaic panel is connected to the first terminal of the switching unit 3 and the positive terminal of the battery; the negative input terminal PV- of the photovoltaic panel is connected to the first terminal of the reverse protection switch 4. The first terminal of the sampling unit 1 is connected to the second terminal of the reverse protection switch 4, and the second terminal of the sampling unit 1 is connected to the negative terminal of the battery. The output terminal of the sampling unit 1 is connected to the first input terminal of the comparison unit 2. The second input terminal of the comparison unit 2 receives a reference voltage, and the output terminal of the comparison unit 2 is connected to the control terminal of the switching unit 3. The output terminal of the switching unit 3 is connected to the control terminal of the reverse protection switch 4, and the third terminal of the switching unit 3 is connected to the second terminal of the reverse protection switch 4.
[0023] Specifically, Figure 1 In the sample unit 1, the negative current of the battery is collected and the sampled current is converted into a sampled voltage and output. When the magnitude of the current flowing through the sample unit 1 changes, the voltage across the sample unit 1 changes accordingly. The sample unit 1 can be a resistor network.
[0024] Specifically, Figure 1In this circuit, comparator unit 2 controls switch unit 3 to switch on / off states based on the magnitude of the sampled voltage and the reference voltage, while anti-reverse switch 4 operates based on the on / off state of switch unit 3. For example, when comparator unit 2 determines that the sampled voltage is less than the reference voltage, it indicates that there is residual voltage in the circuit, the current between the photovoltaic panel and the battery is small, and the photovoltaic panel is in a non-working state. At this time, anti-reverse switch 4 should remain off and not function. In this case, comparator unit 2 controls switch unit 3 to conduct, causing anti-reverse switch 4 to turn off. When comparator unit 2 determines that the sampled voltage is greater than or equal to the reference voltage, it indicates that the current between the photovoltaic panel and the battery is large, and the photovoltaic panel is in a working state. In this case, anti-reverse switch 4 should remain on, so that it can promptly disconnect the line between the photovoltaic panel and the battery when the battery is reverse-connected. In this case, comparator unit 2 controls switch unit 3 to turn off, causing anti-reverse switch 4 to conduct.
[0025] Optionally, Figure 1 In this circuit, the positive input terminal PV+ of the photovoltaic panel is connected to the battery to form a power conversion circuit for boosting or bucking the voltage. Those skilled in the art can design the specific structure and connection relationship of the power conversion circuit themselves.
[0026] Optionally, Figure 1 In the middle, the reverse protection switch is a MOSFET.
[0027] The photovoltaic panel anti-reverse circuit provided in this embodiment has a sampling unit that collects the sampling current on the line between the negative input terminal of the photovoltaic panel and the negative terminal of the battery. After converting the sampling current into a sampling voltage, the comparison unit compares the sampling voltage with a preset reference voltage. Based on the comparison result, the on / off state of the switching unit controls the anti-reverse switch to be turned on. That is, the on / off state of the anti-reverse switch depends not only on the input voltage of the photovoltaic panel, but also on the current magnitude of the negative terminal of the battery. This adds current sampling judgment and avoids the anti-reverse switch from directly turning on based on a small residual voltage when there is residual voltage at the negative input terminal of the photovoltaic panel, thus losing the anti-reverse effect and improving the reliability of the anti-reverse circuit.
[0028] In some alternative implementations, such as Figure 2 As shown, the sampling unit 1 includes a sampling circuit 11 and an amplifier circuit 12. The first terminal of the sampling circuit 11 is connected to the first input terminal of the amplifier circuit 12 and the second terminal of the switching unit 3. The second terminal of the sampling circuit 11 is connected to the second input terminal of the amplifier circuit 12 and the negative terminal of the battery. The output terminal of the amplifier circuit 12 is connected to the first input terminal of the comparison unit 2.
[0029] Specifically, Figure 2 When current flows through the sampling circuit 11, the voltage across the sampling circuit 11 changes, thereby converting the sampling current in the circuit into a sampling voltage, which is then input to the amplifier circuit 12 for amplification.
[0030] Specifically, Figure 3 In the circuit, the sampling circuit includes a sampling resistor R0, and the amplification circuit includes a differential amplifier U1. When current flows through the sampling resistor R0, the voltage PV_I- at the first terminal of the sampling resistor R0 is input to the first input terminal of the differential amplifier U1, and the voltage PV_I+ at the second terminal of the sampling resistor R0 is input to the second input terminal of the differential amplifier U1. The differential amplifier U1 amplifies the voltage difference between the two input terminals and outputs an electrical signal to control the switching unit 3 to switch the state.
[0031] In some alternative implementations, such as Figure 3 As shown, the switching unit 3 includes a switching circuit 31, an isolation circuit 32, and a driving circuit 33. The control terminal of the switching circuit 31 (i.e., the base of Q1) is connected to the output terminal of the comparator unit 2. The first terminal of the switching circuit 31 is connected to an external power supply. The second terminal of the switching circuit 31 (i.e., the collector of Q1) is connected to the first terminal of the isolation circuit 32. The second terminal of the isolation circuit 32 is connected to the first terminal of the driving circuit 33 (i.e., the intersection of R2 and R3). The third terminal of the isolation circuit 32 is connected to the control terminal of the anti-reverse switch 4. The second terminal of the driving circuit 33 is connected to the positive input terminal PV+ of the photovoltaic panel. The third terminal of the driving circuit 33 is connected to the second terminal of the anti-reverse switch 4.
[0032] Specifically, Figure 3 In the process, when the comparison unit 2 determines that the sampled voltage is less than the reference voltage, the control switch circuit 31 is turned on and the isolation circuit 32 is turned off, so that the control terminal of the anti-reverse switch 4 is not turned off by a control signal; when the comparison unit 2 determines that the sampled voltage is greater than or equal to the reference voltage, the control switch unit 3 is turned off and the anti-reverse switch 4 is turned on, so that the control terminal of the anti-reverse switch 4 receives a control signal and is turned on.
[0033] Specifically, Figure 3 In the circuit, the switching circuit 31 includes a transistor Q1 and a first resistor R1. The control terminal of the transistor Q1 is connected to the output terminal of the comparator unit 2. The first terminal of the transistor Q1 is connected to the first terminal of the first resistor R1 and the first terminal of the isolation circuit 32. The second terminal of the transistor Q1 is grounded. The second terminal of the first resistor R1 is connected to an external power supply. The isolation circuit 32 includes an optocoupler isolation chip U3.
[0034] Specifically, Figure 3In the process, when the comparison unit 2 determines that the sampled voltage is less than the reference voltage VREF, it controls the transistor Q1 to turn on, causing the voltage at the first terminal of the optocoupler isolation chip U3 to drop to ground. The primary current of the optocoupler isolation chip U3 is 0, and the secondary side is not conducting, thereby turning off the reverse protection switch 4. When the comparison unit 2 determines that the sampled voltage is greater than or equal to the reference voltage VREF, it controls the transistor Q1 to turn off, causing the voltage at the first terminal of the optocoupler isolation chip U3 to rise to the external power supply voltage VCC. The primary side of the optocoupler isolation chip U3 has current, and the secondary side is conducting, thereby turning on the reverse protection switch 4.
[0035] Specifically, Figure 3 In the driving circuit 33, there are: a second resistor R2, a third resistor R3, and a Zener diode U4. The first end of the second resistor R2 is connected to the positive input terminal PV+ of the photovoltaic panel. The second end of the second resistor R2 is connected to the first end of the third resistor R3, the first end of the Zener diode U4, and the second end of the isolation circuit 32. The second end of the third resistor R3 is connected to the second end of the Zener diode U4 and the second end of the reverse protection switch 4. The second resistor R2 and the third resistor R3 are used to adjust the current and voltage division between the positive and negative terminals of the battery. The Zener diode U4 is used to prevent excessively high driving voltage of the reverse protection switch 4 caused by voltage fluctuations at the input terminal of the photovoltaic panel, ensuring the safety and reliability of the reverse protection switch 4, thereby guaranteeing power quality and stability, and improving the reliability and durability of the photovoltaic system.
[0036] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. A photovoltaic panel anti-reverse circuit, characterized by, The application relates to a battery protection circuit. The positive input end of the photovoltaic panel is connected with the first end of the switch unit and the positive pole of the storage battery, and the negative input end of the photovoltaic panel is connected with the first end of the anti-reverse switch. The first end of the sampling unit is connected with the second end of the switch unit, the second end of the sampling unit is connected with the negative pole of the storage battery, the output end of the sampling unit is connected with the first input end of the comparison unit, and the sampling unit is used for collecting the negative pole current of the storage battery and converting the sampling current into a sampling voltage and then outputting. The second input end of the comparison unit inputs a reference voltage, the output end of the comparison unit is connected with the control end of the switch unit, and the comparison unit is used for controlling the switch unit to switch the on-off state based on the size of the sampling voltage and the reference voltage. The output end of the switch unit is connected with the control end of the anti-reverse switch, the third end of the switch unit is connected with the second end of the anti-reverse switch, and the anti-reverse switch is used for acting based on the on-off state of the switch unit. The anti-reverse switch is a MOS tube.
2. The photovoltaic panel anti-reverse circuit according to claim 1, characterized in that, The sampling unit comprises a sampling circuit and an amplification circuit.
3. The photovoltaic panel anti-reverse circuit according to claim 1, characterized in that, The first end of the sampling circuit is connected with the first input end of the amplification circuit and the second end of the switch unit, and the second end of the sampling circuit is connected with the second input end of the amplification circuit and the negative pole of the storage battery. The output end of the amplification circuit is connected with the first input end of the comparison unit. The sampling circuit comprises a sampling resistor.
4. The photovoltaic panel anti-reverse circuit according to claim 3, characterized in that, The amplification circuit comprises a differential amplifier.
5. The photovoltaic panel anti-reverse circuit according to claim 3, characterized in that, The switch unit comprises a switch circuit, an isolation circuit and a driving circuit.
6. The photovoltaic panel anti-reverse circuit according to claim 1, characterized in that, The control end of the switch circuit is connected with the output end of the comparison unit, the first end of the switch circuit is connected with an external power supply, and the second end of the switch circuit is connected with the first end of the isolation circuit. The second end of the isolation circuit is connected with the first end of the driving circuit, and the third end of the isolation circuit is connected with the control end of the anti-reverse switch. The second end of the driving circuit is connected with the positive input end of the photovoltaic panel, and the third end of the driving circuit is connected with the second end of the anti-reverse switch. The switch circuit comprises a triode and a first resistor.
7. The photovoltaic panel anti-reverse circuit according to claim 6, characterized in that, The control end of the triode is connected with the output end of the comparison unit, the first end of the triode is connected with the first end of the first resistor and the first end of the isolation circuit, and the second end of the triode is grounded. The second end of the first resistor is connected with the external power supply. The isolation circuit comprises an optical coupling isolation chip.
8. The photovoltaic panel anti-reverse circuit according to claim 6, characterized in that, The driving circuit comprises a second resistor, a third resistor and a stabilizing tube.
9. The photovoltaic panel anti-reverse circuit according to claim 6, characterized in that, The first end of the second resistor is connected with the positive input end of the photovoltaic panel, the second end of the second resistor is connected with the first end of the third resistor, the first end of the stabilizing tube and the second end of the isolation circuit. The second end of the third resistor is connected with the second end of the stabilizing tube and the second end of the anti-reverse switch.