Off-grid photovoltaic power generation device with energy storage function

Abstract

An off-grid photovoltaic power generation device with energy storage comprises an inverter main circuit, an isolation driving circuit used for isolating and amplifying a sine pulse width modulation (SPWM) signal to drive a power tube, an AC voltage sampling circuit used for collecting an output voltage, a true RMS conversion circuit used for converting an AC voltage effective value into a constant DC voltage value, and a power supply circuit used for supplying power to the inverter main circuit. The filter circuit is used for filtering high-frequency carrier signals; the auxiliary power supply circuit is used for supplying power to the isolation driving circuit, the alternating-current voltage sampling circuit and the true RMS conversion circuit; the inverter main circuit is respectively connected with the isolation drive circuit, the filter circuit and the photovoltaic cell and storage battery output circuit. According to the utility model, isolation inversion from low DC voltage to high AC voltage is realized, the true RMS conversion circuit and the isolation driving circuit are adopted, the anti-interference performance of the system is enhanced, and the safety and reliability of the system and the stability of the output voltage are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic power generation devices, in particular to an off-grid photovoltaic power generation device with energy storage. Background Art

[0002] The role of the inverter circuit in the photovoltaic system is to convert the direct current generated by the photovoltaic cell into the alternating current required by the household. There are three types of inverters commonly used in photovoltaic power generation systems: distributed, centralized, and string. The distributed inverter has a complex structure; the centralized inverter needs to adjust the tilt angle and position of the photovoltaic module when it is used; the string inverter has good matching, low loss, small size, light weight, and easy installation. It is currently widely used on curved roofs. In small household photovoltaic power generation systems, due to the small number of photovoltaic panels in household off-grid photovoltaic power generation devices, open-loop control is usually used, the structure is complex, the efficiency is generally low, and the output voltage is prone to large fluctuations with changes in light intensity and angle, resulting in electrical appliances not being able to work properly or even damaged. In addition, the price of the inverter is generally not low, and the maintenance cost is high. Summary of the invention

[0003] In order to overcome the defects of the prior art, the utility model provides an off-grid photovoltaic power generation device with energy storage, which realizes isolated inversion from low DC voltage to high AC voltage, and at the same time adopts a true effective value conversion circuit and an isolated drive circuit to enhance the system's anti-interference ability, improve the system's safety, reliability and output voltage stability.

[0004] The utility model solves the technical problem, and the technical solution adopted is:

[0005] An off-grid photovoltaic power generation device with energy storage comprises an inverter main circuit, an isolation drive circuit for isolating and amplifying a sinusoidal pulse width modulation (SPWM) signal to drive a power tube, an AC voltage sampling circuit for collecting output voltage, a true effective value conversion circuit for converting an AC voltage effective value into a constant DC voltage value, a filtering circuit for filtering high-frequency carrier signals, a photovoltaic cell and battery output circuit, an industrial frequency transformer, and an auxiliary power supply circuit for supplying power to the isolation drive circuit, the AC voltage sampling circuit, and the true effective value conversion circuit. The inverter main circuit is respectively connected to the isolation drive circuit, the filtering circuit, and the photovoltaic cell and battery output circuit, the isolation drive circuit is respectively connected to the auxiliary power supply circuit and four SPWM output ports of a microcontroller MCU, the auxiliary power supply circuit is respectively connected to the photovoltaic cell and battery output circuit, the AC voltage sampling circuit, and the true effective value conversion circuit, the filtering circuit is connected to the industrial frequency transformer, the industrial frequency transformer is respectively connected to the AC voltage sampling circuit and an external load, the AC voltage sampling circuit is connected to the true effective value conversion circuit, and the true effective value conversion circuit is connected to an AD input pin of the microcontroller MCU.

[0006] Further, the photovoltaic cell and battery output circuit includes a photovoltaic cell and a photovoltaic-specific colloidal battery;

[0007] Pin 1 of the photovoltaic cell is connected to pin 1 of the photovoltaic-specific colloidal battery and is led out as a power source VCC_POWER terminal, and pin 2 of the photovoltaic cell is connected to pin 2 of the photovoltaic-specific colloidal battery and is led out as a GND_POWER terminal.

[0008] Further, the isolation drive circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a high-speed optocoupler isolation chip, a first driver chip and a second driver chip;

[0009] One end of the first resistor is connected to the SPWM1 output port of the microcontroller MCU, the other end of the first resistor is connected to pin 1 of the high-speed optocoupler isolation chip, one end of the second resistor is connected to the SPWM2 output port of the microcontroller MCU, the other end of the second resistor is connected to pin 3 of the high-speed optocoupler isolation chip, one end of the third resistor is connected to the SPWM3 output port of the microcontroller MCU, the other end of the third resistor is connected to pin 5 of the high-speed optocoupler isolation chip, one end of the fourth resistor is connected to the SPWM4 output port of the microcontroller MCU, the other end of the fourth resistor is connected to pin 7 of the high-speed optocoupler isolation chip The pins 2, 4, 6 and 8 of the high-speed optocoupler isolation chip are connected to GND_MCU, the pins 9, 11, 13 and 15 of the high-speed optocoupler isolation chip are connected to GND_POWER, the pin 10 of the high-speed optocoupler isolation chip is connected to the pin 12 of the second driver chip, the pin 12 of the high-speed optocoupler isolation chip is connected to the pin 10 of the second driver chip, the pin 14 of the high-speed optocoupler isolation chip is connected to the pin 12 of the first driver chip, the pin 16 of the high-speed optocoupler isolation chip is connected to the pin 10 of the first driver chip, one end of the first capacitor is connected to the pin 9 of the first driver chip The other end of the first capacitor is connected to the 13th pin of the first driver chip and to GND_POWER, the anode of the first diode is respectively connected to the 3rd pin of the first driver chip and one end of the third capacitor and to the power supply VCC_15V, the cathode of the first diode is respectively connected to the 6th pin of the first driver chip and one end of the second capacitor, the other end of the second capacitor is connected to the 5th pin of the first driver chip and to the inverter main circuit output terminal Q1-2, the other end of the third capacitor is connected to the 2nd pin of the first driver chip and to GND_POWER. D_POWER is connected, one end of the fifth resistor is connected to the anode of the second diode and the 7th pin of the first driver chip respectively, the other end of the fifth resistor is connected to the cathode of the second diode and is led out as SPWM1, one end of the sixth resistor is connected to the 1st pin of the first driver chip and the anode of the third diode, the other end of the sixth resistor is connected to the cathode of the third diode and is led out as SPWM2, the 4th pin, the 8th pin, the 11th pin and the 14th pin of the first driver chip are suspended, one end of the fourth capacitor is connected to the 9th pin of the second driver chip and is connected to the power supply VCC_15V,The other end of the fourth capacitor is connected to the 13th pin of the second driver chip and to GND_POWER, the anode of the fourth diode is respectively connected to the 3rd pin of the second driver chip and one end of the sixth capacitor and to the power supply VCC_15V, the cathode of the fourth diode is respectively connected to the 6th pin of the second driver chip and one end of the fifth capacitor, the other end of the fifth capacitor is connected to the 5th pin of the second driver chip and to the inverter main circuit output terminal Q3-4, the other end of the sixth capacitor is connected to the 2nd pin of the second driver chip and to GND_POWER, one end of the seventh resistor is respectively connected to the anode of the fifth diode and the 7th pin of the second driver chip, the other end of the seventh resistor is connected to the cathode of the fifth diode and is led out as SPWM3, one end of the eighth resistor is respectively connected to the 1st pin of the second driver chip and the anode of the sixth diode, the other end of the eighth resistor is connected to the cathode of the sixth diode and is led out as SPWM4, and the 4th, 8th, 11th and 14th pins of the second driver chip are suspended. ,

[0010] Furthermore, the inverter main circuit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a first power tube, a second power tube, a third power tube, a fourth power tube, a seventh diode, an eighth diode, a ninth diode and a tenth diode;

[0011] One end of the ninth resistor is connected to the gate of the first power tube and to SPWM1, the other end of the ninth resistor is respectively connected to the source of the first power tube, the drain of the second power tube, the anode of the seventh diode and the cathode of the eighth diode, and is led out as the output end Q1-2 of the inverter main circuit, the drain of the first power tube is respectively connected to the cathode of the seventh diode, the drain of the third power tube and the cathode of the ninth diode and is connected to the power supply VCC_POWER, one end of the tenth resistor is connected to the gate of the second power tube and to SPWM2, and the other end of the tenth resistor is connected to the gate of the second power tube and to SPWM2. They are respectively connected to the source of the second power tube, the anode of the eighth diode, one end of the twelfth resistor, the source of the fourth power tube and the anode of the tenth diode and are connected to GND_POWER, one end of the eleventh resistor is connected to the gate of the third power tube and is connected to SPWM3, the other end of the eleventh resistor is respectively connected to the source of the third power tube, the drain of the fourth power tube, the anode of the ninth diode and the cathode of the tenth diode, and are led out as the output terminal Q3-4 of the inverter main circuit, the other end of the twelfth resistor is connected to the gate of the fourth power tube and is connected to SPWM4.

[0012] Furthermore, the filter circuit includes a first inductor, a second inductor and a seventh capacitor;

[0013] One end of the first inductor is connected to the inverter main circuit output terminal Q3-4, the other end of the first inductor is connected to one end of the seventh capacitor and is led out as POWEROUT1, one end of the second inductor is connected to the inverter main circuit output terminal Q1-2, the other end of the second inductor is connected to the other end of the seventh capacitor and is led out as POWEROUT2.

[0014] Furthermore, pin 1 of the power frequency transformer is connected to POWEROUT1, pin 2 is connected to POWEROUT2, pin 3 is led out as an AC output 220VAC_OUT2 terminal, and pin 4 is led out as an AC output 220VAC_OUT1 terminal.

[0015] Furthermore, the AC voltage sampling circuit includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, an eighth capacitor, a ninth capacitor, a voltage transformer and an operational amplifier chip;

[0016] One end of the thirteenth resistor is connected to GND_MCU, the other end of the thirteenth resistor is respectively connected to the 4th pin of the voltage transformer, one end of the eighth capacitor and the 5th pin of the operational amplifier chip, one end of the fourteenth resistor is respectively connected to the other end of the eighth capacitor and the 1st pin of the operational amplifier chip, the other end of the fourteenth resistor is respectively connected to one end of the fifteenth resistor and the 2nd pin of the operational amplifier chip, the other end of the fifteenth resistor is connected to GND_MCU, one end of the sixteenth resistor is respectively connected to the 3rd pin of the voltage transformer and the 3rd pin of the operational amplifier chip, the other end of the sixteenth resistor is connected to the 4th pin of the operational amplifier chip and to GND_MCU U is connected, pin 1 of the voltage transformer is connected to 220VAC_OUT2, pin 2 of the voltage transformer is connected to 220VAC_OUT1, one end of the seventeenth resistor is connected to one end of the ninth capacitor and is led out as RMS_IN, the other end of the seventeenth resistor is respectively connected to pin 7 of the operational amplifier chip and pin 2 of the eighteenth resistor, pin 3 of the eighteenth resistor is respectively connected to pin 6 of the operational amplifier chip and one end of the nineteenth resistor, pin 1 of the eighteenth resistor is suspended, the other end of the nineteenth resistor is connected to GND_MCU, the other end of the ninth capacitor is connected to GND_MCU, and pin 8 of the operational amplifier chip is connected to a +5V power supply.

[0017] Further, the true effective value conversion circuit includes a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, a fifteenth capacitor, a sixteenth capacitor, a seventeenth capacitor and a true effective value chip;

[0018] The positive electrode of the tenth capacitor is connected to one end of the eleventh capacitor and to the +5V power supply of the auxiliary power supply circuit, the negative electrode of the tenth capacitor is connected to the other end of the eleventh capacitor and to GND_MCU, the negative electrode of the twelfth capacitor is connected to one end of the thirteenth capacitor and to the -5V power supply, the positive electrode of the twelfth capacitor is connected to the other end of the thirteenth capacitor and to GND_MCU, pin 1 of the twentieth resistor is connected to the -5V power supply, pin 3 of the twentieth resistor is connected to the +5V power supply, pin 2 of the twentieth resistor is connected to one end of the twenty-first resistor, the other end of the twenty-first resistor is connected to pin 4 of the true effective value chip, one end of the twenty-second resistor is connected to the +5V power supply, the other end of the twenty-second resistor is connected to pin 5 of the true effective value chip, pin 3 of the twenty-third resistor is connected to pin 6 of the true effective value chip, and pins 1 and 2 of the twenty-third resistor are simultaneously connected to the One end of the twenty-fifth resistor, the negative electrode of the fifteenth capacitor and pin 11 of the true effective value chip are connected and are led out as MCU_AD, one end of the twenty-fourth resistor is respectively connected to the positive electrode of the seventeenth capacitor and pin 1 of the true effective value chip, the other end of the twenty-fourth resistor is respectively connected to the other end of the twenty-fifth resistor and the negative electrode of the sixteenth capacitor, the positive electrode of the fourteenth capacitor is connected to pin 15 of the true effective value chip, the negative electrode of the fourteenth capacitor is connected to RMS_IN, the positive electrode of the fifteenth capacitor is connected to pin 10 of the true effective value chip, the positive electrode of the sixteenth capacitor is connected to pin 16 of the true effective value chip, the negative electrode of the seventeenth capacitor is connected to GND_MCU, pin 3 of the true effective value chip is connected to GND_MCU, pin 12 of the true effective value chip is connected to a -5V power supply, pin 13 of the true effective value chip is connected to a +5V power supply, and pins 2, 7, 8, 9 and 14 of the true effective value chip are suspended.

[0019] Furthermore, the auxiliary power supply circuit includes a first DC-DC power supply module and a second DC-DC power supply module;

[0020] Pin 1 of the first DC-DC power module is connected to VCC_POWER, pin 2 of the first DC-DC power module is connected to GND_POWER, pin 3 of the first DC-DC power module is connected to GND_POWER, pin 4 of the first DC-DC power module is suspended, pin 5 of the first DC-DC power module is led out as a power supply VCC_15V, pin 1 of the second DC-DC power module is connected to GND_POWER, pin 2 of the second DC-DC power module is connected to VCC_15V, pin 3 of the second DC-DC power module is led out as a +5V power supply, pin 4 of the second DC-DC power module is connected to GND_MCU, and pin 5 of the second DC-DC power module is led out as a -5V power supply.

[0021] The beneficial effects of the utility model are:

[0022] Take the example of converting the 24V DC voltage output by a photovoltaic cell (i.e., a storage battery) into a 220V AC voltage. The utility model adopts a single-phase full-bridge inverter circuit to realize the efficient conversion of the DC voltage into the AC voltage. After the AC voltage passes through the filter circuit, the high-frequency clutter is filtered out to obtain a high-quality industrial frequency sine wave with a very small harmonic distortion rate. This low-voltage sinusoidal AC power is boosted by the industrial frequency transformer to obtain a 220V sinusoidal AC power, which is supplied to the load. After the 220V AC voltage at both ends of the load is isolated and sampled by the AC voltage, a low-voltage AC power with an effective value of 0 to 5V is obtained. After passing through the true effective value conversion circuit, a constant DC power of 0 to 5V is further obtained. After conversion by the analog-to-digital AD converter of the microcontroller MCU, it is compared with the given voltage to obtain the voltage deviation. After proportional integral PI adjustment, a new sinusoidal pulse width modulation SPWM pulse signal is generated, thereby realizing the closed-loop control of the load voltage, ensuring that the output voltage 220V has a constant amplitude and is not affected by changes in light intensity and load. An auxiliary power supply circuit is used to realize the power supply of the feedback circuit (i.e., the AC voltage sampling circuit and the true effective value conversion circuit) and the isolated drive circuit. The first DC-DC power supply module provides a 15V auxiliary power supply VCC_15V, and the second DC-DC module power supply provides an isolated +5V, -5V auxiliary power supply, which provides a guarantee for the power isolation between the control side and the drive side. A high-speed optical coupler is used to realize the electrical isolation between the drive circuit and the control circuit, and a driver chip is used to realize the amplification of the SPWM signal. The use of the battery in this device makes the DC input voltage relatively stable, so that the AC output voltage of the device remains basically stable, while reducing the difficulty of controlling the output voltage amplitude. This device extends the service life of the battery. When the battery output voltage is less than the set warning value, the inverter is automatically turned off by the microcontroller MCU to prevent the battery from being damaged due to over-discharge, thereby protecting the battery and making it highly reliable and safe. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the electrical structure of the utility model.

[0024] Figure 2 It is a circuit diagram of the photovoltaic cell and battery output circuit.

[0025] Figure 3 It is a circuit diagram of the isolation drive circuit.

[0026] Figure 4 This is the circuit diagram of the inverter main circuit.

[0027] Figure 5 It is the circuit diagram of the filter circuit.

[0028] Figure 6 It is the circuit diagram of the industrial frequency transformer.

[0029] Figure 7 It is the circuit diagram of the AC voltage sampling circuit.

[0030] Figure 8 This is the circuit diagram of the true effective value conversion circuit.

[0031] Fig. 9 is a circuit diagram of the auxiliary power supply circuit. DETAILED DESCRIPTION

[0032] The utility model is further described below in conjunction with the accompanying drawings.

[0033] like Figure 1 As shown, the off-grid photovoltaic power generation device with energy storage includes an inverter main circuit, an isolation drive circuit for isolating and amplifying a sinusoidal pulse width modulation SPWM signal to drive a power tube, an AC voltage sampling circuit for collecting output voltage, a true effective value conversion circuit for converting the AC voltage effective value into a constant DC voltage value, a filtering circuit for filtering high-frequency carrier signals, a photovoltaic cell and battery output circuit, an industrial frequency transformer, and an auxiliary power supply circuit for powering the isolation drive circuit, the AC voltage sampling circuit, and the true effective value conversion circuit. The inverter main circuit is respectively connected to the isolation drive circuit, the filtering circuit, and the photovoltaic cell and battery output circuit, the isolation drive circuit is respectively connected to the auxiliary power supply circuit and the four-way SPWM output ports of the microcontroller MCU, the auxiliary power supply circuit is respectively connected to the photovoltaic cell and battery output circuit, the AC voltage sampling circuit, and the true effective value conversion circuit, the filtering circuit is connected to the industrial frequency transformer, the industrial frequency transformer is respectively connected to the AC voltage sampling circuit and an external load, the AC voltage sampling circuit is connected to the true effective value conversion circuit, and the true effective value conversion circuit is connected to the AD input pin of the microcontroller MCU. The inverter main circuit adopts a single-phase full-bridge inverter circuit.

[0034] This device adopts a single-phase full-bridge inverter circuit to convert the DC voltage output by photovoltaic cells and batteries into AC voltage. After the AC voltage passes through the filter circuit, high-frequency clutter is filtered out to obtain a high-quality industrial frequency sine wave with very small harmonic distortion rate. This low-voltage sinusoidal AC power is boosted by the industrial frequency transformer to obtain 220V sinusoidal AC power for load use.

[0035] like Figure 2 As shown, the photovoltaic cell and battery output circuit: Pin 1 of the photovoltaic cell U1 is connected to Pin 1 of the photovoltaic-specific colloidal battery U2 and is led out as the power supply VCC_POWER terminal, and Pin 2 of the photovoltaic cell U1 is connected to Pin 2 of the photovoltaic-specific colloidal battery U2 and is led out as the GND_POWER terminal.

[0036] like Figure 3As shown, the isolation drive circuit: one end of the first resistor R1 is connected to the SPWM1 output port of the microcontroller MCU, the other end of the first resistor R1 is connected to the 1st pin of the high-speed optical coupler isolation chip U3, one end of the second resistor R2 is connected to the SPWM2 output port of the microcontroller MCU, the other end of the second resistor R2 is connected to the 3rd pin of the high-speed optical coupler isolation chip U3, one end of the third resistor R3 is connected to the SPWM3 output port of the microcontroller MCU, the other end of the third resistor R3 is connected to the 5th pin of the high-speed optical coupler isolation chip U3, one end of the fourth resistor R4 is connected to the SPWM4 output port of the microcontroller MCU, the other end of the fourth resistor R4 is connected to the SPWM5 output port of the microcontroller MCU, The 7th pin of the isolation chip U3 is connected, the 2nd, 4th, 6th and 8th pins of the high-speed optocoupler isolation chip U3 are connected to GND_MCU, the 9th, 11th, 13th and 15th pins of the high-speed optocoupler isolation chip U3 are connected to GND_POWER, the 10th pin of the high-speed optocoupler isolation chip U3 is connected to the 12th pin of the second driver chip U5, the 12th pin of the high-speed optocoupler isolation chip U3 is connected to the 10th pin of the second driver chip U5, the 14th pin of the high-speed optocoupler isolation chip U3 is connected to the 12th pin of the first driver chip U4, the 16th pin of the high-speed optocoupler isolation chip U3 is connected to the 10th pin of the first driver chip U4, one end of the first capacitor C1 is connected to the 9th pin of the first driver chip U4 The other end of the first capacitor C1 is connected to the 13th pin of the first driver chip U4 and to GND_POWER, the anode of the first diode D1 is connected to the 3rd pin of the first driver chip U4 and one end of the third capacitor U3 and to the power supply VCC_15V, the cathode of the first diode D1 is connected to the 6th pin of the first driver chip U4 and one end of the second capacitor C2, the other end of the second capacitor C2 is connected to the 5th pin of the first driver chip U4 and to the inverter main circuit output terminal Q1-2, the other end of the third capacitor C3 is connected to the 2nd pin of the first driver chip U4 and to GND_POWER. ND_POWER is connected, one end of the fifth resistor R5 is connected to the anode of the second diode D2 and the 7th pin of the first driver chip U4 respectively, the other end of the fifth resistor R5 is connected to the cathode of the second diode D2 and is led out as SPWM1, one end of the sixth resistor R6 is connected to the 1st pin of the first driver chip U4 and the anode of the third diode D3 respectively, the other end of the sixth resistor R6 is connected to the cathode of the third diode D3 and is led out as SPWM2, the 4th pin, the 8th pin, the 11th pin and the 14th pin of the first driver chip U4 are suspended, one end of the fourth capacitor C4 is connected to the 9th pin of the second driver chip U5 and is connected to the power supply VCC_15V,The other end of the fourth capacitor C4 is connected to the 13th pin of the second driver chip U5 and to GND_POWER, the anode of the fourth diode D4 is respectively connected to the 3rd pin of the second driver chip U5 and one end of the sixth capacitor U6 and to the power supply VCC_15V, the cathode of the fourth diode D4 is respectively connected to the 6th pin of the second driver chip U5 and one end of the fifth capacitor C5, the other end of the fifth capacitor C5 is connected to the 5th pin of the second driver chip U4 and to the inverter main circuit output terminal Q3-4, the other end of the sixth capacitor C6 is connected to the second driver chip U 5 and connected to GND_POWER, one end of the seventh resistor R7 is connected to the anode of the fifth diode D5 and the 7th pin of the second driver chip U5, the other end of the seventh resistor R7 is connected to the cathode of the fifth diode D5, and is led out as SPWM3, one end of the eighth resistor R8 is connected to the 1st pin of the second driver chip U5 and the anode of the sixth diode D6, the other end of the eighth resistor R8 is connected to the cathode of the sixth diode D6, and is led out as SPWM4, and the 4th, 8th, 11th and 14th pins of the second driver chip U5 are suspended. The model of the high-speed optocoupler isolation chip U3 is TLP290-4, the model of the first driver chip U4 and the second driver chip U5 are both IR2110PBF, the model of the first diode D1 and the fourth diode D4 are both HER105, and the model of the second diode D2, the third diode D3, the fifth diode D5 and the sixth diode D6 are all 1N4148. ,

[0037] like Figure 4As shown, the inverter main circuit: one end of the ninth resistor R9 is connected to the gate of the first power tube Q1 and to SPWM1, the other end of the ninth resistor R9 is respectively connected to the source of the first power tube Q1, the drain of the second power tube Q2, the anode of the seventh diode D7 and the cathode of the eighth diode D8, and is led out as the inverter main circuit output end Q1-2, the drain of the first power tube Q1 is respectively connected to the cathode of the seventh diode D7, the drain of the third power tube Q3 and the cathode of the ninth diode D2 and is connected to the power supply VCC_POWER, one end of the tenth resistor R10 is connected to the gate of the second power tube D2 and to SPWM2, the tenth resistor R10 is connected to the gate of the second power tube D2 and to SPWM2, The other end is respectively connected to the source of the second power tube Q2, the anode of the eighth diode D8, one end of the twelfth resistor R12, the source of the fourth power tube Q4 and the anode of the tenth diode D10 and connected to GND_POWER, one end of the eleventh resistor R11 is connected to the gate of the third power tube Q3 and connected to SPWM3, the other end of the eleventh resistor R11 is respectively connected to the source of the third power tube Q3, the drain of the fourth power tube Q4, the anode of the ninth diode D9 and the cathode of the twelfth pole D10, and is led out as the output end Q3-4 of the inverter main circuit, the other end of the twelfth resistor R12 is connected to the gate of the fourth power tube Q4 and connected to SPWM4. The model of the seventh diode D7, the eighth diode D8, the ninth diode D9 and the tenth diode D10 are all HER105, and the model of the first power tube Q1, the second power tube Q2, the third power tube Q3 and the fourth power tube Q4 are all IRFP640.

[0038] like Figure 5 As shown, the filtering circuit: one end of the first inductor L1 is connected to the inverter main circuit output terminal Q3-4, the other end of the first inductor L1 is connected to one end of the seventh capacitor C7 and is led out as POWEROUT1, one end of the second inductor L2 is connected to the inverter main circuit output terminal Q1-2, the other end of the second inductor L2 is connected to the other end of the seventh capacitor C7 and is led out as POWEROUT2.

[0039] like Figure 6 As shown, the industrial frequency transformer: Pin 1 of the industrial frequency transformer T2 is connected to POWEROUT1, Pin 2 is connected to POWEROUT2, Pin 3 is led out as the AC output 220VAC_OUT2 end, and Pin 4 is led out as the AC output 220VAC_OUT1 end, and is connected to an external load after being led out.

[0040] like Figure 7As shown, the AC voltage sampling circuit: one end of the thirteenth resistor R13 is connected to GND_MCU, the other end of the thirteenth resistor R13 is respectively connected to the 4th pin of the voltage transformer T1, one end of the eighth capacitor C8 and the 5th pin of the operational amplifier chip U6, one end of the fourteenth resistor R14 is respectively connected to the other end of the eighth capacitor C8 and the 1st pin of the operational amplifier chip U6, the other end of the fourteenth resistor R14 is respectively connected to one end of the fifteenth resistor R15 and the 2nd pin of the operational amplifier chip U6, the other end of the fifteenth resistor R15 is connected to GND_MCU, one end of the sixteenth resistor R16 is respectively connected to the 3rd pin of the voltage transformer T1 and the 3rd pin of the operational amplifier chip U6, the other end of the sixteenth resistor R16 is connected to the 4th pin of the operational amplifier chip U6. The pin 1 of the voltage transformer T1 is connected to 220VAC_OUT2, the pin 2 of the voltage transformer T1 is connected to 220VAC_OUT1, one end of the seventeenth resistor R17 is connected to one end of the ninth capacitor C9 and is led out as RMS_IN, the other end of the seventeenth resistor R17 is respectively connected to the pin 7 of the operational amplifier chip U6 and the pin 2 of the eighteenth resistor R18, the pin 3 of the eighteenth resistor R18 is respectively connected to the pin 6 of the operational amplifier chip U6 and one end of the nineteenth resistor R19, the pin 1 of the eighteenth resistor R18 is suspended, the other end of the nineteenth resistor R19 is connected to GND_MCU, the other end of the ninth capacitor C9 is connected to GND_MCU, and the pin 8 of the operational amplifier chip U6 is connected to the +5V power supply. The model of the operational amplifier chip U6 is LMV358IDR.

[0041] like Figure 8As shown, the true effective value conversion circuit: the positive electrode of the tenth capacitor C10 is connected to one end of the eleventh capacitor C11 and is connected to the +5V power supply of the auxiliary power supply circuit, the negative electrode of the tenth capacitor C10 is connected to the other end of the eleventh capacitor C11 and is connected to GND_MCU, the negative electrode of the twelfth capacitor C12 is connected to one end of the thirteenth capacitor C13 and is connected to the -5V power supply, the positive electrode of the twelfth capacitor C12 is connected to the other end of the thirteenth capacitor C13 and is connected to GND_MCU, and the 1 of the twentieth resistor R20 is connected to the positive electrode of the twelfth capacitor C12 and is connected to the other end of the thirteenth capacitor C13 and is connected to GND_MCU. The pin of the 20th resistor R20 is connected to a -5V power supply, the 3rd pin of the 20th resistor R20 is connected to a +5V power supply, the 2nd pin of the 20th resistor R20 is connected to one end of the 21st resistor R21, the other end of the 21st resistor R21 is connected to the 4th pin of the true effective value chip U7, one end of the 22nd resistor R22 is connected to the +5V power supply, the other end of the 22nd resistor R22 is connected to the 5th pin of the true effective value chip U7, the 3rd pin of the 23rd resistor R23 is connected to the 6th pin of the true effective value chip U7, the 1st and 2nd pins of the 23rd resistor R23 are simultaneously connected to the 25th resistor One end of R25, the negative electrode of the fifteenth capacitor C15 and the 11th pin of the true effective value chip U7 are connected, and are led out as MCU_AD and connected to the AD input pin of the microcontroller MCU. One end of the twenty-fourth resistor R24 ​​is respectively connected to the positive electrode of the seventeenth capacitor C17 and the 1st pin of the true effective value chip U7. The other end of the twenty-fourth resistor R24 ​​is respectively connected to the other end of the twenty-fifth resistor R25 and the negative electrode of the sixteenth capacitor C16. The positive electrode of the fourteenth capacitor C14 is connected to the 15th pin of the true effective value chip U7. The negative electrode of capacitor C14 is connected to RMS_IN, the positive electrode of the fifteenth capacitor C15 is connected to the 10th pin of the true effective value chip U7, the positive electrode of the sixteenth capacitor C16 is connected to the 16th pin of the true effective value chip U7, the negative electrode of the seventeenth capacitor C17 is connected to GND_MCU, the 3rd pin of the true effective value chip U7 is connected to GND_MCU, the 12th pin of the true effective value chip U7 is connected to the -5V power supply, the 13th pin of the true effective value chip U7 is connected to the +5V power supply, and the 2nd, 7th, 8th, 9th and 14th pins of the true effective value chip U7 are suspended. The model of the true effective value chip U7 is AD637.

[0042] like Fig. 9As shown, the auxiliary power supply circuit: Pin 1 of the first DC-DC power module U8 is connected to VCC_POWER, Pin 2 of the first DC-DC power module U8 is connected to GND_POWER, Pin 3 of the first DC-DC power module U8 is connected to GND_POWER, Pin 4 of the first DC-DC power module U8 is suspended, Pin 5 of the first DC-DC power module U8 is led out as power VCC_15V, Pin 1 of the second DC-DC power module U9 is connected to GND_POWER, Pin 2 of the second DC-DC power module U9 is connected to VCC_15V, Pin 3 of the second DC-DC power module U9 is led out as +5V power, Pin 4 of the second DC-DC module U9 is connected to GND_MCU, and Pin 5 of the second DC-DC power module U9 is led out as -5V power. The model of the first DC-DC power module U8 is TD6-24S15W, and the model of the second DC-DC power module U9 is URA2405YMD-6WR3_C54821.

[0043] The working process of the utility model is as follows:

[0044] Take the example of photovoltaic cells (i.e., batteries) outputting 24V DC voltage converted into 220V AC voltage, and the power frequency transformer ratio of 1:13. When DC power is input, the auxiliary power supply circuit converts the input DC power into 15V DC power through the first DC-DC power module U8, and supplies it to the driver chip of the isolation drive circuit. The second DC-DC power module converts the 15V DC power into positive and negative 5V DC power with isolation, and supplies it to the feedback circuit, i.e., the AC voltage sampling circuit and the true effective value conversion circuit. If the DC input voltage is 24V, the microcontroller MCU outputs four SPWM signals, which are isolated and amplified by the isolation drive circuit to control the conduction and shutdown of the four power tubes in the inverter main circuit, and then filter out high-frequency clutter through the filter circuit, and finally step up the voltage through the power frequency transformer T2 to stably output 220V AC power. When the output voltage exceeds 220V, the feedback data of the true effective value chip U7 increases, that is, the feedback voltage is greater than the given voltage. At this time, the microcontroller MCU reduces the duty cycle of the output SPWM signal, thereby reducing the output voltage to 220V; when the output voltage is lower than 220V, the feedback data of the true effective value chip U7 decreases, that is, the feedback voltage is lower than the given voltage. At this time, the microcontroller MCU increases the duty cycle of the output SPWM signal, thereby raising the output voltage to 220V. Assume that when the battery output voltage is the critical over-discharge voltage, the microcontroller MCU outputs the SPWM signal with a duty cycle of 90%, and the AC output voltage is exactly 220V. When the microcontroller MCU outputs the SPWM signal with a duty cycle of 90%, the AC output voltage is still less than 220V. At this time, the battery is in a critical over-discharge state. The microcontroller MCU immediately stops outputting the SPWM signal, the power tube is cut off, and the load is stopped from being supplied, so as to ensure the safety of the battery and the load.

[0045] The utility model has stable output voltage, small waveform distortion rate, high reliability, strong safety and certain application value.

Claims

1. An off-grid photovoltaic power generation device with energy storage, characterized in that: The device comprises an inverter main circuit, an isolation drive circuit for isolating and amplifying a sinusoidal pulse width modulation (SPWM) signal to drive a power tube, an AC voltage sampling circuit for collecting output voltage, a true effective value conversion circuit for converting an AC voltage effective value into a constant DC voltage value, a filtering circuit for filtering high-frequency carrier signals, a photovoltaic cell and battery output circuit, an industrial frequency transformer, and an auxiliary power supply circuit for supplying power to the isolation drive circuit, the AC voltage sampling circuit, and the true effective value conversion circuit. The inverter main circuit is respectively connected to the isolation drive circuit, the filtering circuit, and the photovoltaic cell and battery output circuit; the isolation drive circuit is respectively connected to the auxiliary power supply circuit and four SPWM output ports of a microcontroller MCU; the auxiliary power supply circuit is respectively connected to the photovoltaic cell and battery output circuit, the AC voltage sampling circuit, and the true effective value conversion circuit; the filtering circuit is connected to the industrial frequency transformer; the industrial frequency transformer is respectively connected to the AC voltage sampling circuit and an external load; the AC voltage sampling circuit is connected to the true effective value conversion circuit; and the true effective value conversion circuit is connected to an AD input pin of the microcontroller MCU.

2. An off-grid photovoltaic power generation device with energy storage as claimed in claim 1, characterized in that: The photovoltaic cell and battery output circuit includes a photovoltaic cell and a photovoltaic-specific colloidal battery; Pin 1 of the photovoltaic cell is connected to pin 1 of the photovoltaic-specific colloidal battery and is led out as a power source VCC_POWER terminal, and pin 2 of the photovoltaic cell is connected to pin 2 of the photovoltaic-specific colloidal battery and is led out as a GND_POWER terminal.

3. An off-grid photovoltaic power generation device with energy storage as claimed in claim 2, characterized in that: The isolation driving circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a high-speed optocoupler isolation chip, a first driving chip and a second driving chip; One end of the first resistor is connected to the SPWM1 output port of the microcontroller MCU, the other end of the first resistor is connected to pin 1 of the high-speed optocoupler isolation chip, one end of the second resistor is connected to the SPWM2 output port of the microcontroller MCU, the other end of the second resistor is connected to pin 3 of the high-speed optocoupler isolation chip, one end of the third resistor is connected to the SPWM3 output port of the microcontroller MCU, the other end of the third resistor is connected to pin 5 of the high-speed optocoupler isolation chip, one end of the fourth resistor is connected to the SPWM4 output port of the microcontroller MCU, the other end of the fourth resistor is connected to pin 7 of the high-speed optocoupler isolation chip The pins 2, 4, 6 and 8 of the high-speed optocoupler isolation chip are connected to GND_MCU, the pins 9, 11, 13 and 15 of the high-speed optocoupler isolation chip are connected to GND_POWER, the pin 10 of the high-speed optocoupler isolation chip is connected to the pin 12 of the second driver chip, the pin 12 of the high-speed optocoupler isolation chip is connected to the pin 10 of the second driver chip, the pin 14 of the high-speed optocoupler isolation chip is connected to the pin 12 of the first driver chip, the pin 16 of the high-speed optocoupler isolation chip is connected to the pin 10 of the first driver chip, one end of the first capacitor is connected to the pin 9 of the first driver chip The other end of the first capacitor is connected to the 13th pin of the first driver chip and to GND_POWER, the anode of the first diode is respectively connected to the 3rd pin of the first driver chip and one end of the third capacitor and to the power supply VCC_15V, the cathode of the first diode is respectively connected to the 6th pin of the first driver chip and one end of the second capacitor, the other end of the second capacitor is connected to the 5th pin of the first driver chip and to the inverter main circuit output terminal Q1-2, the other end of the third capacitor is connected to the 2nd pin of the first driver chip and to GND_POWER. D_POWER is connected, one end of the fifth resistor is connected to the anode of the second diode and the 7th pin of the first driver chip respectively, the other end of the fifth resistor is connected to the cathode of the second diode and is led out as SPWM1, one end of the sixth resistor is connected to the 1st pin of the first driver chip and the anode of the third diode, the other end of the sixth resistor is connected to the cathode of the third diode and is led out as SPWM2, the 4th pin, the 8th pin, the 11th pin and the 14th pin of the first driver chip are suspended, one end of the fourth capacitor is connected to the 9th pin of the second driver chip and is connected to the power supply VCC_15V,The other end of the fourth capacitor is connected to the 13th pin of the second driver chip and to GND_POWER, the anode of the fourth diode is respectively connected to the 3rd pin of the second driver chip and one end of the sixth capacitor and to the power supply VCC_15V, the cathode of the fourth diode is respectively connected to the 6th pin of the second driver chip and one end of the fifth capacitor, the other end of the fifth capacitor is connected to the 5th pin of the second driver chip and to the inverter main circuit output terminal Q3-4, the other end of the sixth capacitor is connected to the 2nd pin of the second driver chip and to GND_POWER, one end of the seventh resistor is respectively connected to the anode of the fifth diode and the 7th pin of the second driver chip, the other end of the seventh resistor is connected to the cathode of the fifth diode and is led out as SPWM3, one end of the eighth resistor is respectively connected to the 1st pin of the second driver chip and the anode of the sixth diode, the other end of the eighth resistor is connected to the cathode of the sixth diode and is led out as SPWM4, and the 4th, 8th, 11th and 14th pins of the second driver chip are suspended. , 4. An off-grid photovoltaic power generation device with energy storage as claimed in claim 3, characterized in that: The inverter main circuit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a first power tube, a second power tube, a third power tube, a fourth power tube, a seventh diode, an eighth diode, a ninth diode and a tenth diode; One end of the ninth resistor is connected to the gate of the first power tube and to SPWM1, the other end of the ninth resistor is respectively connected to the source of the first power tube, the drain of the second power tube, the anode of the seventh diode and the cathode of the eighth diode, and is led out as the output end Q1-2 of the inverter main circuit, the drain of the first power tube is respectively connected to the cathode of the seventh diode, the drain of the third power tube and the cathode of the ninth diode and is connected to the power supply VCC_POWER, one end of the tenth resistor is connected to the gate of the second power tube and to SPWM2, and the other end of the tenth resistor is connected to the gate of the second power tube and to SPWM2. They are respectively connected to the source of the second power tube, the anode of the eighth diode, one end of the twelfth resistor, the source of the fourth power tube and the anode of the tenth diode and are connected to GND_POWER, one end of the eleventh resistor is connected to the gate of the third power tube and is connected to SPWM3, the other end of the eleventh resistor is respectively connected to the source of the third power tube, the drain of the fourth power tube, the anode of the ninth diode and the cathode of the tenth diode, and are led out as the output terminal Q3-4 of the inverter main circuit, the other end of the twelfth resistor is connected to the gate of the fourth power tube and is connected to SPWM4.

5. An off-grid photovoltaic power generation device with energy storage as claimed in claim 4, characterized in that: The filter circuit includes a first inductor, a second inductor and a seventh capacitor; One end of the first inductor is connected to the inverter main circuit output terminal Q3-4, the other end of the first inductor is connected to one end of the seventh capacitor and is led out as POWEROUT1, one end of the second inductor is connected to the inverter main circuit output terminal Q1-2, the other end of the second inductor is connected to the other end of the seventh capacitor and is led out as POWEROUT2.

6. An off-grid photovoltaic power generation device with energy storage as claimed in claim 5, characterized in that: Pin 1 of the power frequency transformer is connected to POWEROUT1, pin 2 is connected to POWEROUT2, pin 3 is led out as an AC output 220VAC_OUT2 terminal, and pin 4 is led out as an AC output 220VAC_OUT1 terminal.

7. An off-grid photovoltaic power generation device with energy storage as claimed in claim 6, characterized in that: The AC voltage sampling circuit includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, an eighth capacitor, a ninth capacitor, a voltage transformer and an operational amplifier chip; One end of the thirteenth resistor is connected to GND_MCU, the other end of the thirteenth resistor is respectively connected to the 4th pin of the voltage transformer, one end of the eighth capacitor and the 5th pin of the operational amplifier chip, one end of the fourteenth resistor is respectively connected to the other end of the eighth capacitor and the 1st pin of the operational amplifier chip, the other end of the fourteenth resistor is respectively connected to one end of the fifteenth resistor and the 2nd pin of the operational amplifier chip, the other end of the fifteenth resistor is connected to GND_MCU, one end of the sixteenth resistor is respectively connected to the 3rd pin of the voltage transformer and the 3rd pin of the operational amplifier chip, the other end of the sixteenth resistor is connected to the 4th pin of the operational amplifier chip and to GND_MCU U is connected, pin 1 of the voltage transformer is connected to 220VAC_OUT2, pin 2 of the voltage transformer is connected to 220VAC_OUT1, one end of the seventeenth resistor is connected to one end of the ninth capacitor and is led out as RMS_IN, the other end of the seventeenth resistor is respectively connected to pin 7 of the operational amplifier chip and pin 2 of the eighteenth resistor, pin 3 of the eighteenth resistor is respectively connected to pin 6 of the operational amplifier chip and one end of the nineteenth resistor, pin 1 of the eighteenth resistor is suspended, the other end of the nineteenth resistor is connected to GND_MCU, the other end of the ninth capacitor is connected to GND_MCU, and pin 8 of the operational amplifier chip is connected to a +5V power supply.

8. An off-grid photovoltaic power generation device with energy storage as claimed in claim 7, characterized in that: The true effective value conversion circuit includes a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, a fifteenth capacitor, a sixteenth capacitor, a seventeenth capacitor and a true effective value chip; The positive electrode of the tenth capacitor is connected to one end of the eleventh capacitor and to the +5V power supply of the auxiliary power supply circuit, the negative electrode of the tenth capacitor is connected to the other end of the eleventh capacitor and to GND_MCU, the negative electrode of the twelfth capacitor is connected to one end of the thirteenth capacitor and to the -5V power supply, the positive electrode of the twelfth capacitor is connected to the other end of the thirteenth capacitor and to GND_MCU, pin 1 of the twentieth resistor is connected to the -5V power supply, pin 3 of the twentieth resistor is connected to the +5V power supply, pin 2 of the twentieth resistor is connected to one end of the twenty-first resistor, the other end of the twenty-first resistor is connected to pin 4 of the true effective value chip, one end of the twenty-second resistor is connected to the +5V power supply, the other end of the twenty-second resistor is connected to pin 5 of the true effective value chip, pin 3 of the twenty-third resistor is connected to pin 6 of the true effective value chip, and pins 1 and 2 of the twenty-third resistor are simultaneously connected to the One end of the twenty-fifth resistor, the negative electrode of the fifteenth capacitor and pin 11 of the true effective value chip are connected and are led out as MCU_AD, one end of the twenty-fourth resistor is respectively connected to the positive electrode of the seventeenth capacitor and pin 1 of the true effective value chip, the other end of the twenty-fourth resistor is respectively connected to the other end of the twenty-fifth resistor and the negative electrode of the sixteenth capacitor, the positive electrode of the fourteenth capacitor is connected to pin 15 of the true effective value chip, the negative electrode of the fourteenth capacitor is connected to RMS_IN, the positive electrode of the fifteenth capacitor is connected to pin 10 of the true effective value chip, the positive electrode of the sixteenth capacitor is connected to pin 16 of the true effective value chip, the negative electrode of the seventeenth capacitor is connected to GND_MCU, pin 3 of the true effective value chip is connected to GND_MCU, pin 12 of the true effective value chip is connected to a -5V power supply, pin 13 of the true effective value chip is connected to a +5V power supply, and pins 2, 7, 8, 9 and 14 of the true effective value chip are suspended.

9. An off-grid photovoltaic power generation device with energy storage as claimed in claim 8, characterized in that: The auxiliary power supply circuit includes a first DC-DC power supply module and a second DC-DC power supply module; Pin 1 of the first DC-DC power module is connected to VCC_POWER, pin 2 of the first DC-DC power module is connected to GND_POWER, pin 3 of the first DC-DC power module is connected to GND_POWER, pin 4 of the first DC-DC power module is suspended, pin 5 of the first DC-DC power module is led out as a power supply VCC_15V, pin 1 of the second DC-DC power module is connected to GND_POWER, pin 2 of the second DC-DC power module is connected to VCC_15V, pin 3 of the second DC-DC power module is led out as a +5V power supply, pin 4 of the second DC-DC power module is connected to GND_MCU, and pin 5 of the second DC-DC power module is led out as a -5V power supply.

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