Photovoltaic new energy grid-connected and off-grid control circuit

Abstract

The invention discloses a photovoltaic new energy grid-connected and off-grid control circuit. The control circuit comprises a photovoltaic control module, a central control module, an on-grid and off-grid module, an anomaly detection module and a signal conversion module; the photovoltaic control module is used for generating electric energy according to light energy and outputting an alternating current signal according to a photovoltaic control signal output by the central control module; the grid-connected and off-grid module is used for transmitting an alternating current signal to an alternating current power grid during conduction; the anomaly detection module is used for detecting an AC signal of an AC power grid and outputting a detection signal when the AC signal is abnormal; the signal conversion module is used for forming a first control signal and a second control signal according to the detection signal, the central control module is used for forming a third control signal according to the first control signal, and the grid-connected and off-grid module is used for cutting off according to the second control signal and / or the third control signal. According to the invention, the grid-connected and off-grid module can be timely controlled to be off-grid, and the grid-connected and off-grid module is prevented from being damaged, so that the utilization rate of the electric energy of photovoltaic power generation can be improved.

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 has performed the best.

[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 the solar panel into alternating current that meets the requirements of the municipal power grid through the grid-connected inverter, and control the state of the alternating current connected to the public AC power grid. However, when there is a short voltage drop in the AC power grid, the current will increase, and then damage the components such as the grid-connected inverter. When there is a voltage drop, the photovoltaic new energy grid-connected and off-grid control circuit in the prior art will control the grid-connected inverter to go off-grid. However, since it is impossible to judge whether there is a voltage drop in the AC power grid in time, it will cause the problem of untimely off-grid, and the components such as the grid-connected inverter will be affected; and when there is a voltage drop in the AC power grid, not only the AC power grid is unstable, but also the photovoltaic power cannot 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, so as to timely control an on-grid and off-grid module to be off-grid when a sudden change occurs in an AC power grid, thereby improving the utilization rate of photovoltaic power generation electric energy.

[0005] The 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 cut off according to the second control signal and / or the third control signal.

[0008] The present invention provides a photovoltaic new energy grid-connected and off-grid control circuit, and the control circuit comprises 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 performs grid-connected power supply control on the photovoltaic control module 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 timely 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, 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 diagram of the structure 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 diagram of the structure of a signal conversion module provided in an embodiment of the present invention;

[0012] Figure 4 A schematic diagram of the structure 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 in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0014] 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 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-connecting 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-connecting and off-grid module 3 is used to cut off according to the second control signal and / or the third control signal.

[0017] Specifically, the photovoltaic control module 1 is used to convert light energy into electrical energy through photoelectric conversion, and when receiving the photovoltaic control signal output by the central control module 2, the DC power obtained after the light energy conversion is subjected to voltage regulation and inversion filtering to obtain AC power that meets the requirements of the mains power grid, and then the AC power is output as an AC signal to the on-grid and off-grid module 3. The on-grid and off-grid module 3 is controlled by the central control module 2 to conduct, thereby controlling the state of the AC signal accessing the public AC power grid, but when a short-term voltage drop occurs in the AC power grid, the current will increase, and then the components in the on-grid and off-grid module 3 will be damaged. The photovoltaic new energy grid-connected 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 timely determine whether the AC power grid has a voltage drop, the grid-connected inverter and other components 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 grid-connected and off-grid control circuit in the embodiment of the present invention can quickly detect abnormalities of the AC power grid 4 (power mutations in the AC power grid 4) through the abnormality detection module 5, and directly control the grid-connected 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 in which the central control module 2 controls the grid-connected and off-grid module 3 to be cut off, the grid-connected and off-grid module 3 can be disconnected in time to avoid damage to the grid-connected and off-grid module 3.

[0018] In the process of controlling the grid-connected and off-grid module 3 to go off-grid, firstly, the abnormality detection module 5 detects the AC signal of the AC power grid 4, and outputs the 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, and the central control module 2 also forms a third control signal according to the first control signal, and the grid-connected 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 grid-connected and off-grid module 3 to go off-grid and stop supplying power to the AC power grid 4 when detecting a sudden change in the AC power grid, thereby avoiding damage to the grid-connected 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 electric energy generated by photovoltaic power generation.

[0019] The present invention provides a photovoltaic new energy grid-connected and off-grid control circuit, the control circuit comprises 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, the grid-connected and off-grid module controls the photovoltaic control module to perform grid-connected power supply control, and supplies 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 module, 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 also includes an energy storage power supply control module 7 and a compensation control module 8. The first input end of the energy storage power supply control module 7 is connected to the detection end of the compensation control module 8, the electric energy input end of the energy storage power supply control module 7 is connected to the output end of the photovoltaic control module 1, the second input end of the energy storage power supply control module 7 is connected to the third output end of the central control module 2, the third input end of the energy storage power supply control module 7 is connected to the second output end of the signal conversion module 6, and the output end of the energy storage power supply control module 7 is electrically connected to the AC power grid 4; the first input end of the compensation control module 8 is connected to the fourth output end of the central control module 2, and the second input end of the compensation control module 8 is connected to the second output end 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 power 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] Among them, the energy storage power supply control module 7 is connected with 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 in a stable voltage. When receiving 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 with the signal conversion module 6, performs power detection on the energy storage power supply control module 7, and outputs the 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 the 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, the third control signal is received, and 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 triode, a comparator, a logic chip, etc., can detect the power of the energy storage power supply control module 7, and set a full power threshold and a low power threshold. When the power 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 is lower than the low power threshold, then the discharge work is stopped.

[0025] In addition, an AC bus is provided between the grid-connected and off-grid module 3 and the AC power 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 power grid 4 via the AC bus. The central control module 2 is also used to output a first adjustment signal and a first pulse signal to the photovoltaic control module 1; the photovoltaic control module 1 is also used to convert light energy into electrical energy through photoelectric conversion, perform voltage regulation on the electrical energy according to the first adjustment 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 grid-connected and off-grid module 3; wherein the photovoltaic control signal includes the first adjustment 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 power 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 power grid 4 when receiving the second control signal.

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

[0028] Specifically, the above-mentioned abnormality detection module 5 can adopt an abnormality detection circuit composed of a resistor, a capacitor and an operational amplifier, etc., can perform voltage sampling processing on the AC power grid 4, and then perform 180-degree phase shift processing on the sampled signal and superimpose the phase-shifted signal with the sampled signal. When the potential of the superimposed signal is 0, the AC power provided in the AC power grid 4 is normal. When the potential of the superimposed signal is not zero, the AC power in the AC power grid 4 undergoes an AC mutation; the signal conversion module 6 can adopt a signal conversion circuit composed of an absolute value device and a diode, can transmit a signal in a positive state, and perform absolute value processing on a signal in a negative state. The grid-connection and off-grid module 3 is also used to stop receiving the third control signal when receiving the second control signal, and stop transmitting the AC signal to the AC power grid 4, thereby ensuring that when an abnormality occurs in the AC power grid 4, the grid-connection and off-grid module 3 can be quickly cut off, so that the photovoltaic control module 1 is disconnected from the grid in time, and the damage of the components in the grid-connection and off-grid module 3 and the photovoltaic control module 1 is avoided.

[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 perform voltage stabilization and regulation on the electrical energy according to the first regulation signal; the inverter circuit is used to perform inversion and filtering processing on the electrical energy according to the first pulse signal, and output the AC signal obtained after voltage stabilization and inversion and filtering processing on 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, and at the same time, 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 power threshold, and when the AC power grid 4 suddenly changes again, the energy storage 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 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 respectively, 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, which 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 power threshold, and when the AC power grid 4 suddenly changes 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 of the photovoltaic control module 1.

[0033] Figure 2 A schematic diagram of another photovoltaic new energy grid-connected 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 power grid 4, and 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 power 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] The 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 the ground, the third end of the first inverter T1 is connected to the first end of the second inductor L2 and the grid-connected 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, and the gate of the first transistor Q3 is connected to the first interface IO1 of the central control module 2; wherein, 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 grid-connected 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 grid-connected and off-grid module 3 and the AC power 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 power 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 power 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 through 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 through the fourth capacitor C4 and the third resistor R3 in sequence. The in-phase 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 through 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 in 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 value signal; wherein, 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 A schematic diagram of the structure of the compensation control module provided in an embodiment of the present invention, referring 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 in-phase 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 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 end 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 end of the central control module 2 outputs a first pulse signal to control the first inverter T1 to invert the electric energy after voltage regulation, the inverted electric energy is filtered through the second inductor L2 and the third capacitor C3, and the IO3 end 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 power 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 power 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 mutation occurs in the AC power 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, 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 triode 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 is stored by the energy storage device. The eighth resistor R8 and the ninth resistor R9 sample the electric quantity of the energy storage device. When the sampled signal is greater than the full power 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 electrical 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 for the AC bus to stabilize the power of the AC power grid until the AC power grid is normal or the power of the energy storage device is lower than the low electrical 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 abnormal detection module detects a sudden change in the AC power grid module, it will control the grid-connected and off-grid module to be 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, until the electric energy stored in the energy storage power supply control module reaches the set full power threshold, and when the AC power grid mutates 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 abnormal detection module detects a sudden change in the AC power grid, it can timely control the grid-connected and off-grid module to be off-grid, stop supplying power to the AC power grid, and avoid 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 used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by 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 more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and 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 according to the second control signal and / or the third control signal.

2. The photovoltaic new energy on-grid and off-grid control circuit according to claim 1, characterized in that: It 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 also used to output the second control signal to the energy storage power supply control module and the compensation control module. The energy storage power supply control module is used to store the electric energy output by the photovoltaic control module when receiving the second control signal, and release the electric energy to the AC power grid module when receiving the compensation signal and the second pulse signal; The central control module is further used to generate the second pulse signal after receiving the compensation signal; The compensation control module is used to output the compensation signal to the central control module and the energy storage power supply control module when it detects that the power in the energy storage power supply control module is greater than the low power threshold and receives the second control signal.

3. The photovoltaic new energy on-grid and off-grid control circuit according to claim 2, 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 perform voltage stabilization and regulation on the electrical energy according to the first regulation signal, and the inverter circuit is used to perform inversion and filtering processing on the electrical energy according to the first pulse signal, and output the AC signal obtained after voltage stabilization and inversion and filtering processing on the electrical energy to the on-grid and off-grid module; Wherein, the photovoltaic control signal includes a first adjustment signal and a first pulse signal.

4. 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; The first end of the photovoltaic cell is connected to the anode of the first diode, the 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, the 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, the third end of the first inverter is connected to the first end of the second inductor and the grid-connected module, the second end of the second inductor is connected to one end of the third capacitor, the other end of the third capacitor is connected to the fourth end of the first inverter, the 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; wherein the first output end of the central control module includes the second interface and the first 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 grid-connected and off-grid module includes a first thyristor, a second thyristor and a first triode; an AC bus is also provided between the grid-connected and off-grid module and the AC power 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 power 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 power 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 triode, the emitter of the first triode is grounded, and the base of the first triode 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.

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

7. The photovoltaic new energy on-grid and off-grid control circuit according to claim 2, characterized in that: 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; The first end of the second resistor is connected to the first end of the AC power grid, and is connected to one end of the fourth resistor and the inverting end of the amplifier through 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 through the fourth capacitor and the third resistor in sequence. The in-phase 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 through 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.

8. The photovoltaic new energy on-grid and off-grid control circuit according to claim 7, 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 processing device is used to perform absolute value processing on the input negative value signal; wherein the sixth interface and the seventh interface of the central control module are both input ends of the central control module.

9. The photovoltaic new energy on-grid and off-grid control circuit according to claim 2, 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.

10. The photovoltaic new energy on-grid and off-grid control circuit according to claim 9, 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 triode, 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 in-phase end of the first comparator and is connected to the second end of the energy storage device through the ninth resistor, the inverting end 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 end of the first comparator and the second input end of the first logic chip, the first input end of the first logic chip is connected to the second input end of the signal conversion module, and the output end 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 end of the central control module is the fifth interface of the central control module.

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