A photovoltaic new energy on-grid and off-grid control circuit

Abstract

The present invention discloses a photovoltaic new energy on-grid and off-grid control circuit. The control circuit includes a photovoltaic control module, a central control module, an on-grid and off-grid module, an abnormality detection module and a signal conversion module; the photovoltaic control module is used to generate electrical energy according to light energy, and output an AC signal according to the photovoltaic control signal output by the central control module; the on-grid and off-grid module is used to transmit the AC signal to the AC power grid when it is turned on; the abnormality detection module is used to detect the AC signal of the AC power grid, and output a detection signal when the AC signal is abnormal; the signal conversion module is used to form a first control signal and a second control signal according to the detection signal, the central control module is used to form a third control signal according to the first control signal, and the on-grid and off-grid module is used to cut off according to the second control signal and / or the third control signal. The present invention can realize timely control of the on-grid and off-grid module to go off-grid, avoid damage to the on-grid and off-grid module, and thus improve the utilization rate of the electricity generated by photovoltaic power generation.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of photovoltaic control technology, and in particular to a photovoltaic new energy on-grid and off-grid control circuit. Background Art

[0002] As environmental pollution becomes increasingly prominent, new energy sources are developing rapidly, among which photovoltaic power generation is the most promising.

[0003] However, photovoltaic power generation is affected and limited by natural conditions and cannot provide electricity stably and continuously. The output power fluctuates violently, affecting the stability of the power grid and the quality of power supply. The existing photovoltaic new energy grid-connected and off-grid system can convert the direct current generated by solar panels into alternating current that meets the requirements of the mains power grid through a grid-connected inverter, and control the state of the alternating current connected to the public AC power grid. However, when a short voltage drop occurs in the AC power grid, the current will increase, which will in turn cause damage to components such as the grid-connected inverter. The photovoltaic new energy grid-connected and off-grid control circuit in the existing technology will control the grid-connected inverter to go off-grid when a voltage drop occurs. However, since it is impossible to judge whether the AC power grid has a voltage drop in time, it will lead to the problem of untimely off-grid operation, and components such as the grid-connected inverter will be affected. Moreover, when a voltage drop occurs in the AC power grid, not only will the AC power grid be unstable, but the photovoltaic power will not be fully utilized, resulting in low power supply efficiency. Summary of the Invention

[0004] The present invention provides a photovoltaic new energy on-grid and off-grid control circuit, which can timely control the on-grid and off-grid module to be off-grid when a sudden change occurs in the AC power grid, thereby improving the utilization rate of photovoltaic power generation.

[0005] An embodiment of the present invention provides a photovoltaic new energy on-grid and off-grid control circuit, the control circuit comprising a photovoltaic control module, a central control module, an on-grid and off-grid module, an abnormality detection module and a signal conversion module;

[0006] The output end of the photovoltaic control module is connected to the input end of the grid-connected and off-grid module, the output end of the grid-connected and off-grid module is connected to the AC power grid, the input end of the abnormality detection module is connected to the AC power grid, the input end of the signal conversion module is connected to the output end of the abnormality detection module, the first output end of the signal conversion module is connected to the input end of the central control module, the second output end of the signal conversion module is connected to the first control end of the grid-connected and off-grid module, the first output end of the central control module is connected to the control end of the photovoltaic control module, and the second output end of the central control module is connected to the control end of the grid-connected and off-grid module;

[0007] The photovoltaic control module is used to generate electrical energy based on light energy and output an AC signal based on the photovoltaic control signal output by the central control module; the grid-connected and off-grid module is used to transmit the AC signal to the AC power grid when it is turned on; the abnormality detection module is used to detect the AC signal of the AC power grid and output a detection signal when the AC signal is abnormal; the signal conversion module is used to form a first control signal and a second control signal based on the detection signal, the central control module is used to form a third control signal based on the first control signal, and the grid-connected and off-grid module is used to be cut off based on the second control signal and / or the third control signal.

[0008] The present invention provides a photovoltaic new energy on-grid and off-grid control circuit, which includes a photovoltaic control module, a central control module, an on-grid and off-grid module, an abnormality detection module and a signal conversion module; the photovoltaic control module can generate electric energy according to light energy, and output an AC signal according to the photovoltaic control signal output by the central control module, and the on-grid and off-grid module controls the photovoltaic control module to be on-grid and supply power to the AC power grid; the abnormality detection module detects the AC signal of the AC power grid and outputs a detection signal when the AC signal is abnormal; the signal conversion module forms a first control signal and a second control signal according to the detection signal, the central control module forms a third control signal according to the first control signal, and the on-grid and off-grid module is cut off according to the second control signal and / or the third control signal, so that when the abnormality detection module detects a sudden change in the AC power grid, it can promptly control the on-grid and off-grid module to go off-grid and stop supplying power to the AC power grid, thereby avoiding damage to the on-grid and off-grid module, thereby improving the utilization rate of the electric energy generated by photovoltaic power. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic diagram of a photovoltaic new energy on-grid and off-grid control circuit provided by an embodiment of the present invention;

[0010] Figure 2 A schematic structural diagram of another photovoltaic new energy on-grid and off-grid control circuit provided by an embodiment of the present invention;

[0011] Figure 3 A schematic structural diagram of a signal conversion module provided in an embodiment of the present invention;

[0012] Figure 4 This is a structural diagram of a compensation control module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0013] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0014] Figure 1 A schematic diagram of a photovoltaic new energy on-grid and off-grid control circuit according to an embodiment of the present invention is shown in FIG. Figure 1 As shown, the control circuit includes a photovoltaic control module 1, a central control module 2, a grid-connected and off-grid module 3, an abnormality detection module 5 and a signal conversion module 6.

[0015] The output end of the photovoltaic control module 1 is connected to the input end of the grid-connected and off-grid module 3, the output end of the grid-connected and off-grid module 3 is connected to the AC power grid 4, the input end of the abnormality detection module 5 is connected to the AC power grid 4, the input end of the signal conversion module 6 is connected to the output end of the abnormality detection module 5, the first output end of the signal conversion module 6 is connected to the input end of the central control module 2, the second output end of the signal conversion module 6 is connected to the first control end of the grid-connected and off-grid module 3, the first output end of the central control module 2 is connected to the control end of the photovoltaic control module 1, and the second output end of the central control module 2 is connected to the control end of the grid-connected and off-grid module 3.

[0016] The photovoltaic control module 1 is used to generate electrical energy based on light energy, and output an AC signal based on the photovoltaic control signal output by the central control module 2; the grid-connected and off-grid module 3 is used to transmit the AC signal to the AC power grid 4 when it is turned on; the abnormality detection module 5 is used to detect the AC signal of the AC power grid 4, and output a detection signal when the AC signal is abnormal; the signal conversion module 6 is used to form a first control signal and a second control signal based on the detection signal, the central control module 2 is used to form a third control signal based on the first control signal, and the grid-connected and off-grid module 3 is used to cut off based on the second control signal and / or the third control signal.

[0017] Specifically, photovoltaic control module 1 converts light energy into electrical energy through photoelectric conversion. Upon receiving a photovoltaic control signal from central control module 2, photovoltaic control module 1 performs voltage regulation and inversion filtering on the DC power generated after the light energy conversion to generate AC power that meets the requirements of the utility grid. This AC power is then output as an AC signal to on-grid and off-grid module 3. On-grid and off-grid module 3 is controlled by central control module 2 to control the state of the AC signal connected to the public AC grid. However, a brief voltage drop in the AC grid can increase the current, potentially damaging components in on-grid and off-grid module 3. The photovoltaic new energy on-grid and off-grid control circuit in the prior art will control the grid-connected inverter to go off-grid when a voltage drop occurs. However, since it is impossible to judge in time whether the AC power grid has a voltage drop, the off-grid operation is not timely, and components such as the grid-connected inverter will still be affected. In addition, when a voltage drop occurs, not only is the AC power grid unstable, but the photovoltaic power cannot be fully utilized, resulting in low power supply efficiency. The photovoltaic new energy on-grid and off-grid control circuit in the embodiment of the present invention can quickly detect abnormalities in the AC power grid 4 (power mutations in the AC power grid 4) through the abnormality detection module 5, and directly control the on-grid and off-grid module 3 to disconnect from the AC power grid 4 when an abnormality occurs in the AC power grid 4. Compared with the method of controlling the on-grid and off-grid module 3 to be cut off by the central control module 2, the on-grid and off-grid module 3 can be disconnected in time to avoid damage to the on-grid and off-grid module 3.

[0018] In the process of controlling the on-grid and off-grid module 3 to go off-grid, first, the abnormality detection module 5 detects the AC signal of the AC power grid 4 and outputs a detection signal when the AC signal is abnormal; secondly, the signal conversion module 6 forms a first control signal and a second control signal according to the detection signal, and the central control module 2 can stop outputting the photovoltaic control signal according to the first control signal. The central control module 2 also forms a third control signal according to the first control signal, and the on-grid and off-grid module 3 is cut off according to the second control signal and / or the third control signal, so that the abnormality detection module 5 can control the on-grid and off-grid module 3 to go off-grid when detecting a sudden change in the AC power grid, and stop supplying power to the AC power grid 4, thereby avoiding damage to the on-grid and off-grid module 3, so that the photovoltaic control module 1 can transmit electric energy when the AC power grid 4 is normal, and stop transmitting electric energy when the AC power grid 4 is abnormal, thereby improving the utilization rate of the electric energy generated by photovoltaic power.

[0019] The present invention provides a photovoltaic new energy grid-connected and off-grid control circuit, which includes a photovoltaic control module, a central control module, a grid-connected and off-grid module, an abnormality detection module and a signal conversion module; the photovoltaic control module can generate electric energy according to light energy, and output an AC signal according to the photovoltaic control signal output by the central control module, and the grid-connected and off-grid module controls the photovoltaic control module to perform grid-connected power supply control to supply power to the AC power grid; the abnormality detection module detects the AC signal of the AC power grid and outputs a detection signal when the AC signal is abnormal; the signal conversion module forms a first control signal and a second control signal according to the detection signal, the central control module forms a third control signal according to the first control signal, and the grid-connected and off-grid module is cut off according to the second control signal and / or the third control signal, so that when the abnormality detection module detects a sudden change in the AC power grid, it can control the grid-connected and off-grid module to go off-grid and stop supplying power to the AC power grid, thereby avoiding damage to the grid-connected and off-grid modules, thereby improving the utilization rate of the electric energy generated by photovoltaic power.

[0020] Continue to refer Figure 1 Optionally, the photovoltaic new energy grid-connected and off-grid control circuit further includes an energy storage power supply control module 7 and a compensation control module 8. The first input terminal of the energy storage power supply control module 7 is connected to the detection terminal of the compensation control module 8, the power input terminal of the energy storage power supply control module 7 is connected to the output terminal of the photovoltaic control module 1, the second input terminal of the energy storage power supply control module 7 is connected to the third output terminal of the central control module 2, the third input terminal of the energy storage power supply control module 7 is connected to the second output terminal of the signal conversion module 6, and the output terminal of the energy storage power supply control module 7 is electrically connected to the AC power grid 4; the first input terminal of the compensation control module 8 is connected to the fourth output terminal of the central control module 2, and the second input terminal of the compensation control module 8 is connected to the second output terminal of the signal conversion module 6.

[0021] The signal conversion module 6 is also used to output a second control signal to the energy storage power supply control module 7 and the compensation control module 8. The energy storage power supply control module 7 is used to store the electric energy output by the photovoltaic control module 1 when receiving the second control signal, and release the electric energy to the AC power grid 4 when receiving the compensation signal and the second pulse signal; the central control module 2 is also used to generate the second pulse signal after receiving the compensation signal; the compensation control module 8 is used to output the compensation signal to the central control module 2 and the energy storage power supply control module 7 when it detects that the electric amount in the energy storage power supply control module 7 is greater than the low power threshold and receives the second control signal.

[0022] Specifically, the compensation control module 8 is used to detect the power level of the energy storage power supply control module 7, and after the detected power level signal is greater than the set full power threshold, output a first power control signal and set a low power threshold; the compensation control module 8 is also used to continuously output the first power control signal when the detected power level signal is greater than the low power threshold, and during the output of the first power control signal, when the second control signal is received, the compensation signal will be output to the central control module 2 and the energy storage power supply control module 7.

[0023] The energy storage power supply control module 7 is connected to the signal conversion module 6, the photovoltaic control module 1, the central control module 2, and the compensation control module 8. When the energy storage power supply control module 7 receives the second control signal, it stores the electric energy output by the photovoltaic control module 1 at a stable voltage. When it receives the compensation signal and the second pulse signal output by the compensation control module 8, it releases the stored electric energy and inverts the released electric energy to output the compensation electric energy. The compensation control module 8 is connected to the signal conversion module 6, performs a power detection on the energy storage power supply control module 7, and outputs a first power control signal to the energy storage power supply control module 7 after the detected power signal is greater than the set full power threshold, and sets a low power threshold. When the detected power signal is greater than the low power threshold, the first power control signal is continuously output. During the output of the first power control signal, if the third control signal is received, the compensation signal is output to the central control module 2.

[0024] Specifically, the energy storage power supply control module 7 can adopt an energy storage power supply control circuit composed of a field effect transistor, an energy storage device and an inverter to perform energy storage and discharge control, and invert the released electric energy; the compensation control module 8 can adopt a compensation control circuit composed of a resistor, a transistor, a comparator, a logic chip, etc., and can detect the power level of the energy storage power supply control module 7, and set a full power threshold and a low power threshold. When the power level is greater than the full power threshold and the grid-connected and off-grid module 3 is in an off-grid state, the energy storage power supply control module 7 is controlled to perform discharge work until the grid-connected and off-grid module 3 is in a grid-connected state or the power level is lower than the low power threshold, and then the discharge work is stopped.

[0025] In addition, an AC busbar is provided between the on-grid and off-grid module 3 and the AC power grid 4; the energy storage power supply control module 7, the on-grid and off-grid module 3, and the anomaly detection module 5 are connected to the AC power grid 4 via the AC busbar. The central control module 2 is further configured to output a first regulation signal and a first pulse signal to the photovoltaic control module 1. The photovoltaic control module 1 is further configured to convert light energy into electrical energy through photoelectric conversion, perform voltage regulation on the electrical energy according to the first regulation signal, perform inversion filtering on the electrical energy according to the first pulse signal, and output the AC signal obtained after voltage regulation and inversion filtering on the electrical energy to the on-grid and off-grid module 3. The photovoltaic control signal includes the first regulation signal and the first pulse signal.

[0026] The on-grid and off-grid module 3 is specifically used to transmit the first electric energy to the AC grid 4 when receiving the third control signal; the on-grid and off-grid module 3 is also used to stop receiving the third control signal and stop transmitting the AC signal to the AC grid 4 when receiving the second control signal.

[0027] The abnormality detection module 5 samples and phase-shifts the AC signal in the AC grid 4, superimposes the phase-shifted signal with the sampled signal, and outputs a detection signal. The signal conversion module 6 receives the detection signal and, when the detection signal is positive, outputs a first-level signal. When the detection signal is negative, it performs absolute value processing and outputs a second-level signal. It controls the transmission of the first-level signal or the second-level signal and outputs a third-level signal, which serves as the second control signal. The first control signal includes the first-level signal and the second-level signal. Upon receiving the first-level signal and the second-level signal output by the signal conversion module 6, the central control module 2 determines the sudden change in the AC grid 4 and stops outputting the first pulse signal and the grid-connected signal. Upon receiving the compensation signal output by the compensation control module 8, the central control module 2 outputs the second pulse signal, allowing the photovoltaic control module 1 to perform normal voltage stabilization during the off-grid period.

[0028] Specifically, the abnormality detection module 5 can employ an abnormality detection circuit composed of resistors, capacitors, and operational amplifiers, and can perform voltage sampling on the AC grid 4. The sampled signal is then subjected to a 180-degree phase shift and superimposed with the phase-shifted signal. When the potential of the superimposed signal is 0, the AC power provided by the AC grid 4 is normal. When the potential of the superimposed signal is non-zero, the AC power in the AC grid 4 has undergone an AC mutation. The signal conversion module 6 can employ a signal conversion circuit composed of an absolute value device and a diode, capable of transmitting positive signals and performing absolute value processing on negative signals. The on-grid and off-grid module 3 is also configured to stop receiving the third control signal and stop transmitting the AC signal to the AC grid 4 upon receiving the second control signal. This ensures that when an abnormality occurs in the AC grid 4, the on-grid and off-grid module 3 can be quickly disconnected, allowing the photovoltaic control module 1 to disconnect from the grid in a timely manner, thereby avoiding damage to components in the on-grid and off-grid module 3 and the photovoltaic control module 1.

[0029] Optionally, the photovoltaic control module 1 includes a photoelectric conversion circuit, a voltage stabilizing circuit and an inverter circuit; the output end of the photoelectric conversion circuit is connected to the input end of the voltage stabilizing circuit, the output end of the voltage stabilizing circuit is connected to the input end of the inverter circuit, the control end of the voltage stabilizing circuit is connected to the first interface of the central control module 2, the output end of the inverter circuit is connected to the input end of the grid-connected and off-grid module 3, and the control end of the inverter circuit is connected to the second interface of the central control module 2; wherein, the first output end of the central control module 2 includes the second interface and the first interface of the central control module 2.

[0030] The photoelectric conversion circuit is used to convert light energy into electrical energy through photoelectric conversion; the voltage stabilizing circuit is used to regulate the voltage of the electrical energy according to the first regulation signal, and the inverter circuit is used to perform inversion filtering processing on the electrical energy according to the first pulse signal, and output the AC signal obtained after the voltage stabilizing and inversion filtering processing of the electrical energy to the on-grid and off-grid module 3.

[0031] In the embodiment of the present invention, when the abnormality detection module 5 detects a sudden change in the AC power grid 4, the grid-connected and off-grid module 3 is controlled to go off-grid. At the same time, the energy storage and power supply control module 7 stores the electric energy generated by the photovoltaic control module 1 during the off-grid period, thereby improving the utilization rate of electric energy. After the electric energy stored in the energy storage and power supply control module 7 reaches the set full-charge threshold, and when the AC power grid 4 suddenly changes again, the energy storage and power supply control module 7 will provide compensation electric energy to the AC power grid 4 to quickly control the stability of electric energy and then quickly restore the grid-connected power supply work of the photovoltaic control module 1.

[0032] In addition, by outputting the first adjustment signal and the first pulse signal to the photovoltaic control module 1 through the central control module 2, the voltage stabilization and inversion processes of the photovoltaic control module 1 can be controlled separately, so that when an abnormality occurs in the AC power grid 4, the photovoltaic control module 1 can be controlled to stop inverting the electric energy, but still perform voltage stabilization, and the stabilized electric energy can be transmitted to the energy storage power supply control module 7. The energy storage power supply control module 7 stores the electric energy generated by the photovoltaic control module 1 during the off-grid period, thereby improving the utilization rate of electric energy until the electric energy stored in the energy storage power supply control module 7 reaches the set full charge threshold, and when the AC power grid 4 mutates again, the energy storage power supply control module 7 will provide compensation electric energy to the AC power grid 4 module to quickly control the stability of electric energy, and then quickly restore the grid-connected power supply work of the photovoltaic control module 1.

[0033] Figure 2 This is a schematic diagram of another photovoltaic new energy on-grid and off-grid control circuit provided by an embodiment of the present invention, referring to Figure 2 An AC bus is provided between the grid-connected and off-grid module 3 and the AC grid 4. The energy storage power supply control module 7, the grid-connected and off-grid module 3 and the abnormality detection module 5 are connected to the AC grid 4 through the AC bus; the photovoltaic control module includes a first diode D1, a first capacitor C1, a first inductor L1, a first transistor Q3, a second capacitor C2, a first inverter T1, a second inductor L2 and a third capacitor C3.

[0034] A first end of the photovoltaic cell is connected to the anode of the first diode D1. The cathode of the first diode D1 is connected to one end of the first capacitor C1 and is connected to one end of the second capacitor C2, the drain of the first transistor Q3, and the first end of the first inverter T1 through the first inductor L1. The second end of the photovoltaic cell is connected to the other end of the first capacitor C1, the source of the first transistor Q3, the other end of the second capacitor C2, the second end of the first inverter T1, and ground. The third end of the first inverter T1 is connected to the first end of the second inductor L2 and the grid-connected / off-grid module 3. The second end of the second inductor L2 is connected to one end of the third capacitor C3. The other end of the third capacitor C3 is connected to the fourth end of the first inverter T1. The fifth end of the first inverter T1 is connected to the second interface IO2 of the central control module 2. The gate of the first transistor Q3 is connected to the first interface IO1 of the central control module 2. The first output end of the central control module 2 includes the second interface IO2 and the first interface IO1 of the central control module 2.

[0035] Among them, the first transistor Q3 can be an N-channel field-effect transistor, which cooperates with the first capacitor C1, the first inductor L1, the second capacitor C2 and the first diode D1 to perform voltage regulation. The conduction state of the first transistor Q3 is specifically controlled by the central control module 2 according to the MPPT algorithm. The first inverter T1 can be composed of four groups of IGBTs for inverter control; the central control module 2 can be an STM32 microcontroller.

[0036] Continue to refer Figure 2 The on-grid and off-grid module 3 includes a first thyristor S1, a second thyristor S2 and a first transistor V1; an AC bus is also provided between the on-grid and off-grid module 3 and the AC grid 4; one end of the first thyristor S1 is connected to the second end of the second inductor L2, the other end of the first thyristor S1 is connected to the first end of the AC bus and the first end of the AC grid, one end of the second thyristor S2 is connected to the fourth end of the first inverter T1, the other end of the second thyristor S2 is connected to the second end of the AC bus and the second end of the AC grid 4, the control end of the first thyristor S1 is connected to the control end of the second thyristor S2, the third interface IO3 of the central control module 2 and the collector of the first transistor V1, the emitter of the first transistor V1 is grounded, and the base of the first transistor V1 is connected to the second output end of the signal conversion module 6; the second output end of the central control module 2 is the third interface IO3 of the central control module 2.

[0037] Optionally, both the first thyristor S1 and the second thyristor S2 are bidirectional thyristors.

[0038] Continue to refer Figure 2The abnormality detection module 5 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fourth capacitor C4, a fifth capacitor C5, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an amplifier OP1.

[0039] A first end of the second resistor R2 is connected to a first end of the AC power grid, and is connected to one end of the fourth resistor R4 and the inverting end of the amplifier OP1 via the first resistor R1 and the fifth capacitor C5 in sequence. The other end of the fourth resistor R4 is connected to one end of the fifth resistor R5 and the ground via the fourth capacitor C4 and the third resistor R3 in sequence. The non-inverting end of the amplifier OP1 is connected to the other end of the fifth resistor R5 and is connected to the output end of the amplifier OP1 and one end of the seventh resistor R7 via the sixth resistor R6. The other end of the seventh resistor R7 is connected to the second end of the second resistor R2 and the second output end of the signal conversion module 6.

[0040] In a specific embodiment, the amplifier OP1 can select an OP07 operational amplifier, and cooperate with the first resistor R1, the fifth capacitor C5, the fourth capacitor C4, the fourth resistor R4, the third resistor R3, the fifth resistor R5, the sixth resistor R6 and the seventh resistor R7 to perform a 180-degree phase shift on the input signal, and then superimpose it with the signal transmitted by the second resistor R2.

[0041] Figure 3 The schematic diagram of the structure of the signal conversion module provided by the embodiment of the present invention is shown in FIG. Figure 3 The signal conversion module 6 includes an absolute value device, a second diode D2, a third diode D3 and a fourth diode D4.

[0042] The anode of the second diode D2 is connected to the input end of the absolute value device and the second end of the second resistor R2. The output end of the absolute value device is connected to the sixth interface IO6 of the central control module 2 and the anode of the fourth diode D4. The cathode of the second diode D2 is connected to the seventh interface IO7 of the central control module 2 and the anode of the third diode D3. The cathode of the third diode D3 is connected to the cathode of the fourth diode D4, the second input end of the compensation control module 8, and the first control end of the grid-connected and off-grid module 3. The absolute value processing device is used to perform absolute value processing on the input negative signal. The sixth interface and the seventh interface of the central control module are both input ends of the central control module.

[0043] The cathode of the third diode D3 is connected to the base of the first transistor V1 in the off-grid module 3 .

[0044] In a specific embodiment, the absolute value processing device may be composed of a resistor, an operational amplifier, and a diode, and performs absolute value processing on an input negative signal.

[0045] Continue to refer Figure 2 The energy storage power supply control module 7 includes a third transistor Q1, a second transistor Q2, an energy storage device and a second inverter T2.

[0046] The drain of the third transistor Q1 is connected to the photovoltaic control module 1, the source of the third transistor Q1 is connected to the first end of the energy storage device and the drain of the second transistor Q2, the source of the second transistor Q2 is connected to the first end of the second inverter T2, the second end of the second inverter T2 and the second end of the energy storage device are both grounded, the third end and the fourth end of the second inverter T2 are respectively connected to the first end and the second end of the AC bus, the gate of the second transistor Q2 is connected to the fifth interface IO5 of the central control module 2 and the compensation control module 8, and the fifth end of the second inverter T2 is connected to the fourth interface IO4 of the central control module 2; the third output end of the central control module 2 includes the fifth interface IO5 and the fourth interface IO4 of the central control module.

[0047] The third transistor Q1 , the second transistor Q2 and the first transistor Q3 are all field effect transistors. The drain of the third transistor Q1 is connected to the drain of the photovoltaic control module 1 .

[0048] Specifically, the third transistor Q1 and the second transistor Q2 can both be N-channel field effect transistors, the third transistor Q1 performs charging control, and the second transistor Q2 performs discharging control; the energy storage device can be a battery; the second inverter T2 can be composed of four groups of IGBTs.

[0049] Figure 4 This is a schematic diagram of the structure of the compensation control module provided by the embodiment of the present invention, refer to Figure 4 The compensation control module 8 includes an eighth resistor R8, a ninth resistor R9, a first power supply VCC1, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a second transistor V2, a first comparator A1 and a first logic chip U2.

[0050] One end of the eighth resistor R8 is connected to the first input end of the energy storage device, the other end of the eighth resistor R8 is connected to the non-inverting end of the first comparator A1 and is connected to the second end of the energy storage device through the ninth resistor R9. The inverting end of the first comparator A1 is connected to the collector of the second transistor V2 and one end of the eleventh resistor R11, and is connected to the first power supply VCC1 through the tenth resistor R10. The emitter of the second transistor V2 is connected to the other end of the eleventh resistor R11 and the ground through the twelfth resistor R12. The base of the second transistor V2 is connected to the output end of the first comparator A1 and the second input end B of the first logic chip U2. The first input end A of the first logic chip U2 is connected to the signal conversion module 6. The output end Y of the first logic chip U is connected to the fifth interface IO5 of the central control module 2 and the gate of the second transistor Q2. The fourth output end of the central control module 2 is the fifth interface IO5 of the central control module.

[0051] The A terminal of the first logic chip U2 is connected to the cathode of the fourth diode D4 in the signal conversion module 6 .

[0052] Specifically, the eighth resistor R8 and the ninth resistor R9 perform power sampling and processing on the energy storage device; the first power supply VCC1, the tenth resistor R10 and the eleventh resistor R11 set the full power threshold, and cooperate with the second transistor V2 and the twelfth resistor R12 to set the low power threshold. The second transistor V2 can be an NPN transistor; the first transistor V1 can be an LM358 comparator; the first logic chip U2 can be an AND gate chip.

[0053] In the photovoltaic new energy grid-connected and off-grid control circuit of the embodiment of the present invention, the photovoltaic cell performs photoelectric conversion, the IO1 terminal of the central control module 2 outputs a first adjustment signal to control the conduction state of the first transistor Q3, and cooperates with the first capacitor C1, the first diode D1, the first inductor L1 and the second capacitor C2 to perform voltage regulation. The IO2 terminal of the central control module 2 outputs a first pulse signal to control the first inverter T1 to invert the voltage-regulated electric energy, and the inverted electric energy is filtered through the second inductor L2 and the third capacitor C3. The IO3 terminal of the central control module 2 outputs a grid-connected signal to control the first thyristor S1 and the second The thyristor S2 is turned on, and then the filtered electric energy is transmitted to the AC bus, and then transmitted to the AC grid 4 by the AC bus. At the same time, the amplifier OP1 cooperates with the first resistor R1, the third resistor R3, the fourth capacitor C4, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6 and the seventh resistor R7 to perform a 180-degree phase shift on the AC signal of the AC grid 4. The phase-shifted signal is superimposed with the signal transmitted by the second resistor R2. When the potential of the superimposed signal is not zero, it indicates that an AC sudden change has occurred in the AC grid 4, that is, a voltage drop or a voltage boost may occur. The second diode D2 and the third diode D 3 transmits the positive state signal between the second resistor R2 and the seventh resistor R7, and the absolute value device performs absolute value processing on the negative state signal, and then transmits it through the fourth diode D4, triggering the first transistor V1 to turn on, controlling the first thyristor S1 and the second thyristor S2 to turn off, and performing off-grid control. At the same time, the third transistor Q1 is turned on, so that the electric energy provided by the photovoltaic cell is transmitted to the energy storage device after voltage stabilization and stored by the energy storage device. The eighth resistor R8 and the ninth resistor R9 sample the power of the energy storage device. When the sampled signal is greater than the full charge threshold set by the first power supply VCC1, the tenth resistor R10 and the eleventh resistor R11, , the first comparator A1 outputs a high level and triggers the second transistor V2 to turn on. The twelfth resistor R12 is connected in parallel with the eleventh resistor R11, and then the low electric threshold is set. At this time, the B terminal of the first logic chip U2 becomes a high level. When disconnecting from the grid, the A terminal of the first logic chip U2 is a high level. At this time, the first logic chip U2 will trigger the second transistor Q2 to turn on, and the energy storage device will discharge. The IO5 terminal of the central control module 2 outputs a second pulse signal to control the second inverter T2 to perform inverter regulation and provide compensation power to the AC bus to stabilize the power of the AC grid until the AC grid returns to normal or the power of the energy storage device is lower than the low electric threshold.

[0054] The embodiment of the present invention provides a photovoltaic new energy grid-connected and off-grid control circuit. Compared with the prior art, the beneficial effect of the embodiment of the present invention is that the photovoltaic new energy grid-connected and off-grid control circuit of the embodiment of the present invention can control the photovoltaic control module to perform grid-connected power supply control by the grid-connected and off-grid module to supply power to the AC power grid. When the abnormality detection module detects a sudden change in the AC power grid module, it will control the grid-connected and off-grid module to go off-grid. At the same time, the energy storage power supply control module stores the electric energy generated by the photovoltaic control module during the off-grid period, thereby improving the utilization rate of electric energy. After the electric energy stored in the energy storage power supply control module reaches the set full charge threshold, and when the AC power grid suddenly changes again, the energy storage power supply control module will provide compensation electric energy to the AC power grid to quickly control the electric energy stability and then quickly restore the grid-connected power supply of the photovoltaic control module. In addition, when the abnormality detection module detects a sudden change in the AC power grid, it can promptly control the grid-connected and off-grid module to go off-grid and stop supplying power to the AC power grid, thereby avoiding damage to the grid-connected and off-grid module.

[0055] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments, and substitutions are possible for those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A photovoltaic new energy on-grid and off-grid control circuit, characterized in that: The control circuit includes a photovoltaic control module, a central control module, a grid-connected and off-grid module, an abnormality detection module and a signal conversion module; The output end of the photovoltaic control module is connected to the input end of the grid-connected and off-grid module, the output end of the grid-connected and off-grid module is connected to the AC power grid, the input end of the abnormality detection module is connected to the AC power grid, the input end of the signal conversion module is connected to the output end of the abnormality detection module, the first output end of the signal conversion module is connected to the input end of the central control module, the second output end of the signal conversion module is connected to the first control end of the grid-connected and off-grid module, the first output end of the central control module is connected to the control end of the photovoltaic control module, and the second output end of the central control module is connected to the control end of the grid-connected and off-grid module; The photovoltaic control module is used to generate electrical energy based on light energy and output an AC signal based on the photovoltaic control signal output by the central control module; the grid-connected and off-grid module is used to transmit the AC signal to the AC power grid when it is turned on; the abnormality detection module is used to detect the AC signal of the AC power grid and output a detection signal when the AC signal is abnormal; the signal conversion module is used to form a first control signal and a second control signal based on the detection signal, the central control module is used to form a third control signal based on the first control signal, and the grid-connected and off-grid module is used to cut off based on the second control signal and / or the third control signal; The control circuit also includes an energy storage power supply control module and a compensation control module; The first input end of the energy storage power supply control module is connected to the detection end of the compensation control module, the electric energy input end of the energy storage power supply control module is connected to the output end of the photovoltaic control module, the second input end of the energy storage power supply control module is connected to the third output end of the central control module, the third input end of the energy storage power supply control module is connected to the second output end of the signal conversion module, and the output end of the energy storage power supply control module is electrically connected to the AC power grid; the first input end of the compensation control module is connected to the fourth output end of the central control module, and the second input end of the compensation control module is connected to the second output end of the signal conversion module; The signal conversion module is further configured to output the second control signal to the energy storage and power supply control module and the compensation control module. The energy storage and power supply control module is configured to store the electric energy output by the photovoltaic control module upon receiving the second control signal, and release the electric energy to the AC power grid module upon receiving the compensation signal and the second pulse signal. The central control module is further configured to generate the second pulse signal after receiving the compensation signal; The compensation control module is configured to output the compensation signal to the central control module and the energy storage power supply control module when detecting that the power in the energy storage power supply control module is greater than a low power threshold and receiving the second control signal; The abnormality detection module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fourth capacitor, a fifth capacitor, a fifth resistor, a sixth resistor, a seventh resistor and an amplifier; A first end of the second resistor is connected to a first end of the AC power grid, and is connected to one end of the fourth resistor and the inverting end of the amplifier via the first resistor and the fifth capacitor in sequence. The other end of the fourth resistor is connected to one end of the fifth resistor and the ground via the fourth capacitor and the third resistor in sequence. The non-inverting end of the amplifier is connected to the other end of the fifth resistor and is connected to the output end of the amplifier and one end of the seventh resistor via the sixth resistor. The other end of the seventh resistor is connected to the second end of the second resistor and the second output end of the signal conversion module.

2. The photovoltaic new energy on-grid and off-grid control circuit according to claim 1, characterized in that: The photovoltaic control module includes a photoelectric conversion circuit, a voltage stabilizing circuit, and an inverter circuit; the output end of the photoelectric conversion circuit is connected to the input end of the voltage stabilizing circuit, the output end of the voltage stabilizing circuit is connected to the input end of the inverter circuit, the control end of the voltage stabilizing circuit is connected to the first interface of the central control module, the output end of the inverter circuit is connected to the input end of the grid-connected and off-grid module, and the control end of the inverter circuit is connected to the second interface of the central control module; wherein the first output end of the central control module includes the second interface and the first interface of the central control module; The photoelectric conversion circuit is used to convert light energy into electrical energy through photoelectric conversion; the voltage stabilization circuit is used to regulate the voltage of the electrical energy according to the first regulation signal, and the inverter circuit is used to perform inversion filtering processing on the electrical energy according to the first pulse signal, and output the AC signal obtained after the voltage stabilization and inversion filtering processing of the electrical energy to the on-grid and off-grid module; The photovoltaic control signal includes a first adjustment signal and a first pulse signal.

3. The photovoltaic new energy on-grid and off-grid control circuit according to claim 1, characterized in that: The photovoltaic control module includes a photovoltaic cell, a first diode, a first capacitor, a first inductor, a first transistor, a second capacitor, a first inverter, a second inductor and a third capacitor; A first end of the photovoltaic cell is connected to the anode of the first diode, a cathode of the first diode is connected to one end of the first capacitor and is connected to one end of the second capacitor, the drain of the first transistor, and the first end of the first inverter through the first inductor. A second end of the photovoltaic cell is connected to the other end of the first capacitor, the source of the first transistor, the other end of the second capacitor, the second end of the first inverter, and the ground. A third end of the first inverter is connected to the first end of the second inductor and the grid-connected and off-grid module. A second end of the second inductor is connected to one end of the third capacitor, and the other end of the third capacitor is connected to the fourth end of the first inverter. A fifth end of the first inverter is connected to the second interface of the central control module, and the gate of the first transistor is connected to the first interface of the central control module. The first output end of the central control module includes the second interface and the first interface of the central control module.

4. The photovoltaic new energy on-grid and off-grid control circuit according to claim 3, characterized in that: The grid-connected and off-grid module includes a first thyristor, a second thyristor and a first transistor; an AC bus is also provided between the grid-connected and off-grid module and the AC grid; one end of the first thyristor is connected to the second end of the second inductor, the other end of the first thyristor is connected to the first end of the AC bus and the first end of the AC grid, one end of the second thyristor is connected to the fourth end of the first inverter, the other end of the second thyristor is connected to the second end of the AC bus and the second end of the AC grid, the control end of the first thyristor is connected to the control end of the second thyristor, the third interface of the central control module and the collector of the first transistor, the emitter of the first transistor is grounded, and the base of the first transistor is connected to the second output end of the signal conversion module; the second output end of the central control module is the third interface of the central control module.

5. The photovoltaic new energy on-grid and off-grid control circuit according to claim 4, characterized in that: The first thyristor and the second thyristor are both bidirectional thyristors.

6. The photovoltaic new energy on-grid and off-grid control circuit according to claim 1, characterized in that: The signal conversion module includes an absolute value device, a second diode, a third diode and a fourth diode; The anode of the second diode is connected to the input end of the absolute value device and the second end of the second resistor, the output end of the absolute value device is connected to the sixth interface of the central control module and the anode of the fourth diode, the cathode of the second diode is connected to the seventh interface of the central control module and the anode of the third diode, and the cathode of the third diode is connected to the cathode of the fourth diode, the second input end of the compensation control module, and the first control end of the grid-connected and off-grid module; the absolute value device is used to perform absolute value processing on the input negative signal; wherein the sixth interface and the seventh interface of the central control module are both input ends of the central control module.

7. The photovoltaic new energy on-grid and off-grid control circuit according to claim 1, characterized in that: The energy storage power supply control module includes a second transistor, a third transistor, an energy storage device and a second inverter; The drain of the third transistor is connected to the photovoltaic control module, the source of the third transistor is connected to the first end of the energy storage device and the drain of the second transistor, the source of the second transistor is connected to the first end of the second inverter, the second end of the second inverter and the second end of the energy storage device are both grounded, the third end and the fourth end of the second inverter are respectively connected to the first end and the second end of the AC power grid, the gate of the second transistor is connected to the fifth interface of the central control module and the compensation control module, and the fifth end of the second inverter is connected to the fourth interface of the central control module; the third output end of the central control module includes the fifth interface and the fourth interface of the central control module.

8. The photovoltaic new energy on-grid and off-grid control circuit according to claim 7, characterized in that: The compensation control module includes an eighth resistor, a ninth resistor, a first power supply, a tenth resistor, an eleventh resistor, a twelfth resistor, a second transistor, a first comparator and a first logic chip; One end of the eighth resistor is connected to the first input terminal of the energy storage device, the other end of the eighth resistor is connected to the non-inverting terminal of the first comparator and is connected to the second end of the energy storage device through the ninth resistor, the inverting terminal of the first comparator is connected to the collector of the second transistor and one end of the eleventh resistor and is connected to the first power supply through the tenth resistor, the emitter of the second transistor is connected to the other end of the eleventh resistor and the ground through the twelfth resistor, the base of the second transistor is connected to the output terminal of the first comparator and the second input terminal of the first logic chip, the first input terminal of the first logic chip is connected to the second input terminal of the signal conversion module, and the output terminal of the first logic chip is connected to the fifth interface of the central control module and the gate of the second transistor; the fourth output terminal of the central control module is the fifth interface of the central control module.

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