CN100588077C - A complementary uninterruptible power supply system of solar energy and commercial power - Google Patents

Abstract

The invention discloses a solar energy and mains complementary uninterrupted power supply system, the system includes a mains and a solar photovoltaic power supply system, the mains system includes a 220V mains and a rectifier circuit connected to the mains, and the solar photovoltaic power supply system includes The solar panel, overcharge protection circuit, battery, undervoltage signal circuit, overdischarge protection circuit, PWM inverter circuit, rectifier circuit, and switching circuit are connected in series in sequence. The switching circuit is composed of a diode and a VMOS tube, wherein the input terminal of the diode is connected to the output terminal of the over-discharge protection circuit, the output terminal of the diode is connected to the G pole of the VMOS tube, and the D pole of the VMOS tube is connected to the electric load; The invention uses direct current to realize the fast on-off of the VMOS tube in the switching circuit, thereby realizing the fast switching between the mains and the solar photovoltaic power supply system, making the switching time reach the ms level, so as not to restart the load, and protecting various loads Safety.

Description

A complementary uninterruptible power supply system of solar energy and commercial power

technical field

The invention relates to a control system for switching power sources, in particular to a complementary uninterrupted power supply system of solar energy and commercial power.

Background technique

With the development of society, people pay more and more attention to energy saving. Solar energy has been widely used due to its non-polluting, renewable and inexhaustible advantages. Some areas have formed a dual mode of power supply using solar energy and mains power supply In this way, the solar power supply system mainly uses batteries to store electricity, but when the batteries are not charged in time due to weather or other reasons, the batteries will be in an over-discharged state due to low battery power and cannot supply power to the load. This requires a quick switch to the mains Power status.

A Chinese patent discloses a "complementary solar uninterruptible power supply controller" (patent number: 200620153408.3), including a multi-function control module, an inverter module, an AC switching control module, an embedded control module, a DC switching module, a rectifier module, Ethernet controller module and working status indicating module. This controller can realize three-way input of solar battery, storage battery and AC 220V mains, supply power for AC loads and/or DC loads, and realize solar battery/battery power supply priority, mains backup and switching between the two, but this control Devices are mostly used in the field of public lighting. For some existing load electrical appliances, especially computers, the switching speed between power supplies needs to be fast, otherwise the computer data will be lost. However, the existing dual power supply system and the above-mentioned The controller is AC switching between solar power and commercial power, and the switching speed is relatively slow, so that the computer will restart, which will not only cause the loss of unsaved data, but may even damage the computer.

Contents of the invention

The invention mainly solves the technical problem of slow switching speed of the existing solar power supply and mains power supply switching device, and provides a DC-driven vmos tube with fast switching speed, which does not restart the load and protects the safety of various loads. Solar energy and mains complementary uninterruptible power supply system.

The technical solution of the present invention is achieved in this way: a solar energy and mains complementary uninterrupted power supply system, the system includes:

City power and solar photovoltaic power supply system, the city power system includes 220V city power and a rectifier circuit connected to the city power, and the solar photovoltaic power supply system includes:

The solar panels connected in series, the overcharge protection circuit to prevent the battery from overcharging, the battery to store electric energy, the undervoltage signal circuit to output the control signal, and the overdischarge protection circuit to prevent the battery from overdischarging ;

The PWM inverter circuit is connected to the output end of the over-discharge protection circuit to realize DC-AC conversion;

The rectifier circuit is connected to the output terminal of the PWM inverter circuit to change the alternating current into direct current, and the output terminal of the rectifier circuit is connected to the electric load through the switching circuit;

The switch circuit is used to realize the millisecond-level fast switching between the power supply of the solar photovoltaic power supply system and the power supply of the mains power system. The output end of the circuit and the output end of the over-discharge protection circuit, the output end of the switching circuit is connected to the electric load, and the switching circuit is composed of a diode and a VMOS tube, wherein: the input end of the diode is connected to the output end of the over-discharge protection circuit , the output end of the diode is connected to the G pole of the VMOS transistor, and the D pole of the VMOS transistor is connected to the electric load.

Preferably, the system also includes a delay circuit and an alarm circuit, the input end of the delay circuit is connected to the output end of the undervoltage signal circuit, the output end of the delay circuit is connected to the input end of the over-discharge protection circuit, and the input end of the alarm circuit Connect the output terminal of the undervoltage signal circuit, the alarm circuit is used to generate an alarm signal when the battery is over-discharged, and the delay circuit is used to determine the alarm duration of the alarm circuit and the delay switching duration.

As preferably, the PWM inverter circuit is mainly composed of SG3525 pulse width modulator IC3, the over-discharge protection circuit is mainly composed of 555 time base integrated circuit IC2, the undervoltage signal circuit is composed of integrated circuit IC4, and the undervoltage signal circuit When pin 5 of integrated circuit IC4 detects that the battery voltage drops to a predetermined voltage value, pin 7 of integrated circuit IC4 outputs a control signal to the over-discharge protection circuit, and pin 3 of integrated circuit IC2 in the over-discharge protection circuit controls the output of the 555 time base The signal outputs a high level all the way to pin 10 of the SG3525 pulse width modulator IC3, so that the output voltage pulse width of the SG3525 pulse width modulator IC3 becomes zero, so that the output voltage is zero, and the PWM inverter circuit stops working to avoid Over-discharge of the storage battery; another control signal output by pin 3 of the 555 time-base integrated circuit IC2 drives the VMOS tube through the diode in the switching circuit, so that the VMOS tube is quickly turned on, and the mains is quickly connected, thus completing the solar power supply system and Quick switching between mains.

A solar energy and mains complementary uninterrupted power supply system, the system includes:

City power and solar photovoltaic power supply system, the city power system includes a city power and a rectifier circuit connected to the city power, and the solar photovoltaic power supply system includes:

The solar panels connected in series, the overcharge protection circuit to prevent the battery from overcharging, the battery to store electric energy, and the overdischarge protection circuit to prevent the battery from overdischarging;

The PWM inverter circuit is connected to the output end of the over-discharge protection circuit to realize DC-AC conversion;

The rectifier circuit is connected to the output terminal of the PWM inverter circuit to change the alternating current into direct current, and the output terminal of the rectifier circuit is connected to the electric load through the switching circuit;

The switch circuit is used to realize the millisecond-level fast switching between the power supply of the solar photovoltaic power supply system and the power supply of the mains power system. The output end of the circuit and the output end of the over-discharge protection circuit, the output end of the switching circuit is connected to the electric load, and the switching circuit is composed of a diode and a VMOS tube, wherein: the input end of the diode is connected to the output end of the over-discharge protection circuit , the output terminal of the diode is connected to the G pole of the VMOS tube, and the D pole of the VMOS tube is connected to the electric load;

The computer control system includes a computer, a computer interface circuit and a sampling circuit. The computer is respectively connected to the overcharge protection circuit and the sampling circuit through the computer interface circuit, and the other end of the sampling circuit is connected to the storage battery. The sampling circuit is used to realize the Acquisition of voltage data and data exchange with the computer through the computer interface circuit. There is an energy management system running on the computer. The electrical loads are controlled in real time, so that the electrical interface of each electrical load is interrupted or connected according to the change of the battery power.

Preferably, an overcurrent protection circuit is connected between the PWM inverter circuit and the rectifier circuit of the solar photovoltaic power supply system, and the overcurrent protection circuit is used to detect overload or short circuit to control the PWM inverter circuit so that its output voltage is zero, thereby Protect the rectification circuit of the solar photovoltaic power supply system.

As preferably, the system also includes a delay circuit and an alarm circuit, the input ends of the delay circuit and the alarm circuit are connected to the computer interface circuit, the output end of the delay circuit is connected to the input end of the over-discharge protection circuit, and the alarm circuit uses In order to generate an alarm signal when the storage battery is in an over-discharge state, the delay circuit is used to determine the alarm duration of the alarm circuit and the delay switching duration.

As a preference, the PWM inverter circuit is mainly composed of SG3525 pulse width modulator IC3, and the over-discharge protection circuit is mainly composed of integrated circuit IC4. When the sampling circuit detects that the battery voltage drops to a predetermined voltage value, the computer will output a control The signal is sent to the over-discharge protection circuit, and pin 7 of the integrated circuit IC4 in the over-discharge protection circuit outputs this control signal to pin 10 of the SG3525 pulse width modulator IC3, so that the PWM inverter circuit stops working. The power supply level of the system stops the power supply of the battery to the relevant electric load; at the same time, the buzzer in the alarm circuit sends out an alarm sound to remind the user to take measures to protect the electric load; the other channel of the control signal output by pin 7 of the integrated circuit IC4 The VMOS transistor T3 is driven by the diode D43, so that the VMOS transistor T3 is quickly turned on, and the mains power is quickly connected to the electric load that the battery is about to stop supplying, thus completing the fast switching between the solar power supply system and the mains power.

Compared with the existing solar power supply and mains power supply switching system, the core design idea of the present invention is: the alternating current output by the mains power is converted into direct current through the rectifier circuit, and the direct current output by the solar photovoltaic power supply system is passed through the inverter and rectified After the circuit becomes the direct current of the voltage required by the load, the direct current is used to realize the fast on-off of the VMOS tube in the switching circuit, thereby realizing the fast switching between the mains and the solar photovoltaic power supply system, and the switching time reaches the ms level; when the solar battery is in In the state of over-discharge, it will quickly switch to the mains power supply mode. When the solar energy returns to normal power supply, it will automatically switch from the mains to the battery to provide power to the load, so as not to cause power failure of various loads such as computers. or restart, thereby protecting the safety of the load; in addition, when the DC output of the switching circuit is connected to a computer and other multiple electrical loads, the computer can also be used for energy management, that is, the computer can monitor and measure the consumption of each electrical load , according to the operating conditions of each load and the change of battery power, the real-time optimization control of the load is automatically carried out, so that the power interface of each load is interrupted or connected according to the change of the total battery power. In order to ensure that users can use solar power as evenly as possible in each time period of the day, so as to achieve reasonable and effective use of energy. The computer can automatically control the power consumption of some electric loads when the solar power supply is insufficient, so as to ensure the normal operation of the most urgently needed and most important loads.

Description of drawings

Fig. 1 is the flow block diagram of embodiment 1 of the present invention;

Fig. 2 is the circuit diagram of the whole power supply system of embodiment 1;

Fig. 3 is the flow block diagram of embodiment 2 of the present invention;

Fig. 4 is the circuit diagram of whole power supply system in embodiment 2;

Fig. 5 is the functional block diagram of computer interface circuit hardware part in embodiment 2;

Fig. 6 is the main program flowchart of computer interface circuit software in embodiment 2;

Fig. 7 is the flow chart of sending interrupt program of computer interface circuit software part in embodiment 2;

Fig. 8 is the flow chart of computer interface circuit software part receiving interrupt program in embodiment 2;

Fig. 9 is the flowchart of battery voltage real-time detection program in embodiment 2;

Fig. 10 is a flow chart of the electrical load disconnection program in Embodiment 2;

Fig. 11 is a flow chart of the procedure for connecting electric loads in Embodiment 2.

Detailed ways

The specific embodiment of the present invention is as follows:

Embodiment 1: As shown in Figure 1, according to a kind of solar energy and mains complementary uninterrupted power supply system of the present invention, this system comprises:

City power and solar photovoltaic power supply system, the city power system includes a city power and a rectifier circuit connected to the city power, and the solar photovoltaic power supply system includes:

The solar panels connected in series, the overcharge protection circuit to prevent the battery from overcharging, the battery to store electric energy, the undervoltage signal circuit to output the control signal, and the overdischarge protection circuit to prevent the battery from overdischarging The over-discharge protection circuit is connected with the storage battery to prevent the storage battery from over-discharging, and a diode D1 with an anti-reverse charging function is also connected between the solar panel and the storage battery; the undervoltage signal circuit is mainly composed of integrated circuits IC4 and Composed of resistor R43 and resistor R44, pin 5 of the integrated circuit IC4 is connected to the battery to sample the battery voltage. The overcharge protection circuit is mainly composed of the integrated circuit IC5 and peripheral circuits. The overdischarge protection circuit mainly includes 555 Base integrated circuit IC2 and peripheral circuits.

The PWM inverter circuit is connected to the output terminal of the over-discharge protection circuit to change the direct current into alternating current. It is mainly composed of SG3525 pulse width modulator IC3 and peripheral circuits.

The rectification circuit is connected with the output end of the PWM inverter circuit to change the alternating current into direct current, and the output end of the rectification circuit is connected with the electric load through the switching circuit.

The switching circuit is used to realize the millisecond-level fast switching between the power supply of the solar photovoltaic power supply system and the power supply of the mains power system. The output terminal of the rectifier circuit and the output terminal of the over-discharge protection circuit in the power supply system, the output terminal of the switching circuit is connected to the electric load, and the switching circuit includes a diode D3, a VMOS transistor T2, a resistor R9 and a resistor R10, wherein: 555 The output terminal of pin 3 of the time-base integrated circuit IC2 is connected to the pin 10 of the SG3525 pulse width modulator IC3 via diode D2, and the other is connected to the input terminal of diode D3, that is, connected to the anode of diode D3, and the output terminal of diode D3 is connected via resistor R9 One end of the resistor R10 is respectively connected to the G pole of the VMOS transistor T2, and the other end of the resistor R10 is respectively connected to the S pole of the VMOS transistor T2 and the AC power provided by the mains.

The system also includes an alarm circuit and a delay circuit. The input terminal of the alarm circuit is connected to the output terminal of the undervoltage signal circuit, and the output terminal of the delay circuit is connected to the input terminal of the switching circuit. The alarm signal is generated by the buzzer, and the delay circuit is used to determine the alarm duration and the delay switching duration of the alarm circuit. The alarm duration and the delay switching duration are determined by the 555 time base integrated circuit IC2.

In case of overload or accidental open circuit, in order to ensure the safety of the power system, an overcurrent protection circuit is connected between the PWM inverter circuit and the rectifier circuit. The overcurrent protection circuit is used to detect overload or short circuit to control The PWM inverter circuit makes its output voltage zero, thus protecting the power system. The overcurrent protection circuit mainly includes integrated circuit IC4, and pin 1 of integrated circuit IC4 is connected to the output terminal of diode D2 and pin 10 of SG3525 pulse width modulator IC3 via diode D52.

The working process of this system is as follows: the battery voltage is measured by pin 5 of the integrated circuit IC4 in the sampling circuit, that is, the undervoltage signal circuit, and the battery voltage is measured by the integrated circuit IC5 and the overcharge protection circuit in the overcharge protection circuit. In the over-discharge protection circuit, the 555 time-base integrated circuit IC2 performs processing, that is, compares them with their respective reference voltages. When the storage battery reaches the preset charging protection voltage threshold, the integrated circuit IC5 will output the control signal to automatically cut off the charging circuit to stop charging the battery. When the battery voltage drops to the recovery charging voltage threshold, the integrated circuit IC5 will output the control signal to automatically connect The charging circuit resumes charging the battery.

When the PWM inverter circuit is in the inverter working state, and the 5 pin of the integrated circuit IC4 in the undervoltage signal circuit measures that the battery voltage drops to a predetermined voltage value, the 7 pin of the integrated circuit IC4 outputs a control signal to the over-discharge protection circuit, In the over-discharge protection circuit, pin 3 of the 555 time-base integrated circuit IC2 outputs the received control signal to pin 10 of the SG3525 pulse width modulator IC3, so that the output voltage pulse width of the SG3525 pulse width modulator IC3 becomes Zero, so that the output voltage is zero, so that the PWM inverter circuit stops working to avoid over-discharge of the battery; at the same time, the buzzer in the alarm circuit sounds an alarm to remind the user to take measures to protect the electrical load; 555 time base integrated The other control signal output by pin 3 of circuit IC2 drives the VMOS tube T2 through the diode D3, so that the VMOS tube T2 is quickly turned on, and the mains is quickly connected, thus completing the fast switching between the solar power supply system and the mains, and the buzzer The device stops alarming.

When the battery is fully charged, when the battery voltage measured by the pin 5 of the integrated circuit IC4 in the undervoltage signal circuit reaches the voltage value that can be discharged, the pin 7 of the integrated circuit IC4 outputs a control signal to the over-discharge protection circuit, and the over-discharge protection circuit The control signal output by pin 3 of the 555 time base integrated circuit IC2 outputs a low level all the way to pin 10 of the SG3525 pulse width modulator IC3, so that the SG3525 pulse width modulator IC3 starts to work and supplies power for the load. The 555 time base integration Another control signal output by pin 3 of circuit IC2 drives VMOS tube T2 through diode D3, so that VMOS tube T2 is cut off quickly, and the solar power supply system is quickly connected to supply power for the load, thus completing the connection between the mains power supply and the solar power supply system. Quick switch.

The switching time of the above switching process is less than 20ms, so the computer and other loads will not be powered off or restarted. Therefore, this system is applicable to all electric loads, which greatly enhances the practicability.

And when the output short circuit occurs due to overload or careless use, the current value of the sampling resistor in the overcurrent protection circuit exceeds the predetermined value, and the integrated circuit IC4 in the overcurrent protection circuit will output a high level to the SG3525 through pin 1 Pin 10 of the pulse width modulator IC3 makes the output voltage zero, thereby protecting the rectifier circuit and sending out an alarm indication signal.

Therefore, the main design concept of the present invention is to convert the AC output from the mains into DC through the rectifier circuit, and convert the DC output from the storage battery in the solar photovoltaic power supply system into the voltage required by the electrical load after passing through the PWM inverter circuit and the rectifier circuit. The direct current, mains power and solar power supply system are respectively rectified by the rectifier circuit, and the direct current is used to realize the fast switching of the VMOS tube in the switching circuit, thus realizing the fast switching between the mains power and the solar photovoltaic power supply system, and the switching time reaches ms level; when the solar battery is in an over-discharge state, it will quickly switch to the mains power supply mode, and when the solar energy returns to normal power supply, it will automatically switch from the mains to the battery to provide power to the load, so as not to cause computers and other various The load is powered off or restarted, thus protecting the safety of the load.

Embodiment 2: As shown in Figure 3, a kind of solar energy and mains complementary uninterrupted power supply system according to the present invention, this system comprises:

City power and solar photovoltaic power supply system, the city power system includes a city power and a rectifier circuit connected to the city power, and the solar photovoltaic power supply system includes:

The solar panels connected in series, the overcharge protection circuit to prevent the battery from overcharging, the battery to store electric energy, and the overdischarge protection circuit to prevent the battery from overdischarging, between the solar panel and the overdischarge circuit A diode D31 for anti-reverse charging is also connected. As shown in Figure 4, the overcharge protection circuit includes a VMOS transistor T31, a triode T32 and a diode D31, the D pole and the S pole of the VMOS transistor T31 are connected to the solar panel, and the other side of the D pole of the VMOS transistor T31 The diode D31 is connected to the storage battery with the other side of the S pole, the G pole of the VMOS tube T31 is connected to one end of the resistor R31 and the collector of the transistor T32 through the resistor R32, and the other side of the G pole of the VMOS tube T31 is grounded through the resistor R33. The emitter of the triode T32 is grounded, one of the bases of the triode T32 is grounded via the resistor R36, the other of the base of the triode T32 is connected to one end of the resistor R35, the other end of the resistor R35 is connected to the computer interface circuit, and the other end of the resistor R35 The other end of the resistor R34 is connected to one end of the resistor R34, and the other end of the resistor R31 and the other end of the resistor R34 are connected to the cathode of the diode D31.

The PWM inverter circuit is connected to the output terminal of the over-discharge protection circuit to change the direct current into alternating current. It is mainly composed of SG3525 pulse width modulator IC3 and peripheral circuits.

The rectification circuit is connected with the output end of the PWM inverter circuit to change the alternating current into direct current, and the output end of the rectification circuit is connected with the electric load through the switching circuit.

The switching circuit is used to realize the millisecond-level fast switching between the power supply of the solar photovoltaic power supply system and the power supply of the mains power system. The switching circuit is composed of discrete components, and the input ends of the switching circuit are respectively connected to the rectifier circuit in the mains power system The output terminal of the solar photovoltaic power supply system, the output terminal of the rectifier circuit and the output terminal of the over-discharge protection circuit, the output terminal of the switching circuit is connected to the electric load, and the switching circuit is composed of a diode D43 and a VMOS tube T3, wherein : The input end of the diode D43 is connected to pin 7 of the integrated circuit IC4 in the over-discharge protection circuit, the output end of the diode D43 is connected to the G pole of the VMOS transistor T3, and the S pole of the VMOS transistor T3 is connected to the output end of the rectifier circuit in the mains system. The D pole of the tube T3 is connected to the output terminal of the rectifier circuit in the solar photovoltaic power supply system.

The system also includes a delay circuit and an alarm circuit, the input terminals of the delay circuit and the alarm circuit are connected to the computer interface circuit, the output terminal of the delay circuit is connected to the input terminal of the over-discharge protection circuit, and the alarm circuit is used as a storage battery When an over-discharge state occurs, an alarm signal is generated, and the delay circuit is used to determine the alarm duration of the alarm circuit and the delay switching duration.

In order to perform energy management and control on the load, the system also includes a computer, a computer interface circuit and a sampling circuit, and the computer is respectively connected to the connection terminal b of the overcharge protection circuit, the connection terminal d of the sampling circuit, and the alarm circuit through the computer interface circuit The connection end c of the delay circuit and the connection end a of the delay circuit, the other end of the sampling circuit is connected to the storage battery, the sampling circuit is used to realize the collection of battery voltage data and exchange data with the computer through the computer interface circuit, in the computer There is an energy management system running on the network. The energy management system can automatically control the power loads in real time according to the operating conditions of each power load and the change of battery power, so that the power interface of each power load can be controlled according to the change of battery power. Instead take an interrupt or connect.

The over-discharge protection circuit is based on computer control, and the output terminals of the 7 pins of the integrated circuit IC4 in the over-discharge protection circuit are respectively connected to the input terminals of the diode D42 and the diode D43, and one of the output terminals of the diode D42 is connected to the overcurrent protection circuit. The output end of the diode D52 in the circuit, the other of the output end of the diode D42 is connected to pin 10 of the integrated circuit IC3 in the PWM inverter circuit via the resistor R5.

The computer interface circuit is divided into a hardware part and a software part, and realizes the collection of battery voltage data and data exchange with the computer. The functional block diagram of the hardware part of the computer interface circuit is shown in Figure 5. The CPU of the hardware part uses STC89LE516AD as the main chip. This chip has 3 UART interfaces and 8 channels of A/D. It mainly has the functions of completing AD sampling, upper and lower communication and load control. Real-time control to realize energy management and battery protection. The flowchart of the computer interface circuit software part is shown in Fig. 6, Fig. 7 and Fig. 8. The system can be connected with multiple loads, and there is an energy management system running on the computer. The energy management system can automatically control the loads in real time according to the operating conditions of each load and the change of the battery power. The power consumption interface of each power consumption load is interrupted or connected according to the change of battery power.

The design of the energy management system is mainly based on the following considerations, that is, in the current situation where the price of solar cell components and storage batteries is relatively expensive, it cannot meet the unrestrained requirements of users. Therefore, when the rated capacity of the battery in this system is constant, the energy management system needs to issue an interruption command to the electrical load according to the remaining capacity of the battery and the priority of the interruption of the electrical load, and control the switching of the VMOS tube T3 in the switching circuit. power supply to the load. With the reduction of the remaining capacity of the storage battery, each electric load will be cut off step by step, and when the terminal voltage of the storage battery drops to the over-discharge protection threshold level, the work of the host computer will be stopped. When the solar panel starts to charge the battery, the energy management system will automatically restore the power supply to the load according to the energy storage of the battery.

As shown in Fig. 9, Fig. 10, and Fig. 11, the energy management program consists of a real-time detection program for battery voltage, a disconnection program for electric loads and a connection program for electric loads.

When the battery voltage real-time detection program detects that the terminal voltage of the battery has dropped, the equipment disconnection program will control the disconnection of each connected load according to the priority, and disconnect all loads when the voltage drops to the battery over-discharge protection threshold. When the solar cell module is charging the battery, the battery voltage real-time detection program controls the connection of each device according to the priority according to the voltage rise. At the same time, the administrator can also control the disconnection and connection of the device as needed.

In the case of overload or accidental open circuit, in order to ensure the safety of the power system, an overcurrent protection circuit is connected between the rectifier circuit and the PWM inverter circuit. The overcurrent protection circuit is used to detect overload or short circuit to control PWM. The inverter circuit makes its output voltage zero, thus protecting the power system. That is, when the current value of the sampling resistor in the over-current protection circuit exceeds the predetermined value, the integrated circuit IC4 will output a high level to the 10-pin of the SG3525 pulse width modulator IC3 through pin 1, so that the output voltage is zero, thus protecting the rectifier circuit and send out an alarm indication signal.

The PWM inverter circuit is usually powered by the battery. When the PWM inverter circuit is in the inverter working state and the sampling circuit detects that the battery voltage drops to a predetermined voltage value, the signal will be fed back to the computer through the computer interface circuit, and the computer will output a control signal. For the over-discharge protection circuit, the over-discharge protection circuit outputs a high level to pin 10 of the SG3525, so that the output voltage pulse width of the SG3525 pulse width modulator becomes zero, so that the output voltage is zero, and the power amplifier circuit stops working to avoid When the battery is over-discharged, an alarm indication signal is sent at the same time to remind the user to shut down the machine.

When the storage battery is charged to a predetermined voltage value, the overcharge protection circuit operates to automatically cut off the charging circuit; when the battery voltage drops to the recovery charging control threshold, the overcharge protection circuit automatically connects the charging circuit to resume charging the battery.

When the PWM inverter circuit is in the inverter working state and the battery voltage drops to a predetermined voltage value, the computer will output a control signal to the over-discharge protection circuit through the connection terminal 1 of the computer interface circuit, and the integrated circuit IC4 in the over-discharge protection circuit Pin 7 of pin 1 outputs this control signal at a high level to pin 10 of SG3525 pulse width modulator IC3, so that the PWM inverter circuit stops working, and the computer stops the battery from supplying power to the relevant loads according to the power supply level of the energy management system. ; At the same time, the buzzer in the alarm circuit sends out an alarm sound to remind the user to take measures to protect the electrical load; the other channel of the control signal output by pin 7 of the integrated circuit IC4 drives the VMOS tube T3 through the diode D43, so that the VMOS tube T3 is quickly turned on , the mains power is quickly connected to the electric load that the battery is about to stop supplying, thus completing the fast switch between the solar power supply system and the mains, and the buzzer stops alarming.

When the battery is fully charged, the computer will output a control signal to the over-discharge protection circuit. The control signal output by pin 7 of the integrated circuit IC4 outputs a low level all the way to pin 10 of the SG3525 pulse width modulator IC3, so that the SG3525 pulse width modulation IC3 starts to work to make the battery output voltage for the electric load, another control signal output by pin 3 of the 555 time base integrated circuit IC2 drives the VMOS tube T2 through the diode D3, so that the VMOS tube T2 is quickly cut off, and the solar power supply system is quickly connected. The electric load is used to supply power, thereby completing the fast switching between the mains power and the solar power supply system.

The switching time of the above-mentioned switching process reaches the millisecond level, so it will not cause the computer and other loads to be powered off or restarted. Therefore, this system is especially suitable for electrical equipment that needs to be switched quickly.

Claims (7)

1. A solar energy and mains complementary uninterrupted power supply system, characterized in that the system includes: City power and solar photovoltaic power supply system, the city power system includes a city power and a rectifier circuit connected to the city power, and the solar photovoltaic power supply system includes: The solar panels connected in series, the overcharge protection circuit to prevent the battery from overcharging, the battery to store electric energy, the undervoltage signal circuit to output the control signal, and the overdischarge protection circuit to prevent the battery from overdischarging ; The PWM inverter circuit is connected to the output terminal of the over-discharge protection circuit to convert direct current into alternating current; The rectifier circuit is connected to the output terminal of the PWM inverter circuit to change the alternating current into direct current, and the output terminal of the rectifier circuit is connected to the electric load through the switching circuit; The switch circuit is used to realize the millisecond-level fast switching between the power supply of the solar photovoltaic power supply system and the power supply of the mains power system. The output end of the circuit and the output end of the over-discharge protection circuit, the output end of the switching circuit is connected to the electric load, and the switching circuit is composed of a diode and a VMOS tube, wherein: the input end of the diode is connected to the output end of the over-discharge protection circuit , the output end of the diode is connected to the G pole of the VMOS transistor, and the D pole of the VMOS transistor is connected to the electric load. 2. A complementary uninterruptible power supply system based on solar energy and commercial electricity according to claim 1, characterized in that: the system also includes a delay circuit and an alarm circuit, and the input end of the delay circuit is connected to the undervoltage signal circuit Output terminal, the output terminal of the delay circuit is connected to the input terminal of the over-discharge protection circuit, the input terminal of the alarm circuit is connected to the output terminal of the undervoltage signal circuit, the alarm circuit is used to generate an alarm signal when the battery is in an over-discharge state, and the delay time The circuit is used to determine the alarm duration and the delay switching duration of the alarm circuit. 3. A complementary uninterruptible power supply system based on solar energy and commercial electricity according to claim 1, characterized in that: the PWM inverter circuit is mainly composed of SG3525 pulse width modulator IC3, and the over-discharge protection circuit is mainly composed of 555 The time-base integrated circuit IC2 is composed, and the undervoltage signal circuit is composed of integrated circuit IC4. When the 5 pin of the integrated circuit IC4 in the undervoltage signal circuit detects that the battery voltage drops to a predetermined voltage value, the 7 pin of the integrated circuit IC4 outputs a control signal To the over-discharge protection circuit, the control signal output by pin 3 of the 555 time-base integrated circuit IC2 in the over-discharge protection circuit outputs a high level all the way to pin 10 of the SG3525 pulse width modulator IC3, so that the output voltage of the SG3525 pulse width modulator IC3 The pulse width becomes zero, so that the output voltage is zero, and the PWM inverter circuit stops working to avoid over-discharge of the battery; another control signal output by pin 3 of the 555 time-base integrated circuit IC2 is driven by a diode in the switching circuit The VMOS tube makes the VMOS tube turn on quickly, and the mains power is quickly connected, thus completing the fast switching between the solar power supply system and the mains power. 4. A complementary uninterrupted power supply system for solar energy and commercial power, characterized in that the system includes: City power and solar photovoltaic power supply system, the city power system includes a city power and a rectifier circuit connected to the city power, and the solar photovoltaic power supply system includes: The solar panels connected in series, the overcharge protection circuit to prevent the battery from overcharging, the battery to store electric energy, and the overdischarge protection circuit to prevent the battery from overdischarging; The PWM inverter circuit is connected to the output end of the over-discharge protection circuit to realize DC-AC conversion; The rectifier circuit is connected to the output terminal of the PWM inverter circuit to change the alternating current into direct current, and the output terminal of the rectifier circuit is connected to the electric load through the switching circuit; The switch circuit is used to realize the millisecond-level fast switching between the power supply of the solar photovoltaic power supply system and the power supply of the mains power system. The output end of the circuit and the output end of the over-discharge protection circuit, the output end of the switching circuit is connected to the electric load, and the switching circuit is composed of a diode and a VMOS tube, wherein: the input end of the diode is connected to the output end of the over-discharge protection circuit , the output terminal of the diode is connected to the G pole of the VMOS tube, and the D pole of the VMOS tube is connected to the electric load; The computer control system includes a computer, a computer interface circuit and a sampling circuit. The computer is respectively connected to the overcharge protection circuit and the sampling circuit through the computer interface circuit, and the other end of the sampling circuit is connected to the storage battery. The sampling circuit is used to realize the Acquisition of voltage data and data exchange with the computer through the computer interface circuit. There is an energy management system running on the computer. The electrical loads are controlled in real time, so that the electrical interface of each electrical load is interrupted or connected according to the change of the battery power. 5. A complementary uninterruptible power supply system between solar energy and commercial electricity according to claim 1 or 4, characterized in that: an overcurrent protection circuit is connected between the PWM inverter circuit and the rectifier circuit of the solar photovoltaic power supply system, The overcurrent protection circuit is used to detect overload or short circuit to control the PWM inverter circuit so that the output voltage is zero, thereby protecting the rectification circuit of the solar photovoltaic power supply system. 6. A complementary uninterruptible power supply system based on solar energy and mains power according to claim 4, characterized in that: the system also includes a delay circuit and an alarm circuit, and the input terminals of the delay circuit and the alarm circuit Connect the computer interface circuit, the output end of the delay circuit is connected to the input end of the over-discharge protection circuit, the alarm circuit is used to generate an alarm signal when the battery is over-discharged, and the delay circuit is used to determine the alarm duration and delay of the alarm circuit The duration of the switch. 7. A complementary uninterruptible power supply system for solar energy and mains power according to claim 6, characterized in that: said PWM inverter circuit is mainly composed of SG3525 pulse width modulator IC3, and the over-discharge protection circuit is mainly composed of integrated The circuit IC4 is composed. When the battery voltage measured by the sampling circuit drops to a predetermined voltage value, the computer will output a control signal to the over-discharge protection circuit, and pin 7 of the integrated circuit IC4 in the over-discharge protection circuit will output this control signal to a high level all the way. Connect to pin 10 of SG3525 pulse width modulator IC3 to stop the PWM inverter circuit, and the computer stops the power supply of the battery to the relevant electric load according to the power supply level of the energy management system; at the same time, the buzzer in the alarm circuit emits an alarm sound , to remind the user to take measures to protect the electrical load; the other way of the control signal output by pin 7 of the integrated circuit IC4 drives the VMOS tube (T3) through the diode (D43), so that the VMOS tube (T3) is quickly turned on, and the mains power is quickly connected The electric load that the storage battery is about to stop supplying power to complete the fast switching between the solar power supply system and the mains.

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