CN203416011U - Solar charging control loop - Google Patents

Abstract

The utility model discloses a solar charging control circuit. At present, there is no mature and perfect battery charging protection circuit on the market. If the monitoring of the charging power of the battery is not timely, it is easy to cause the battery to be overcharged and shorten the service life. The utility model comprises a solar panel, a polarity protection diode D0, a voltage comparator, a current comparator, and a storage battery charging and discharging control switch circuit. The voltage comparator circuit is used to control the charging voltage. The current comparator circuit is used to control the size of the charging current. According to the strength of the solar panel and the charging demand of the battery, the charging control circuit controls the electronic switch field effect transistor Q1 to be frequently connected through the voltage comparator and current comparator to achieve the purpose of controlling the charging current and charging voltage. The utility model effectively avoids the overcharging problem of the storage battery, and greatly prolongs the service life of the storage battery.

Description

A solar charging control circuit

technical field

The utility model relates to a solar charging control circuit, in particular to a circuit, in particular to a control circuit for charging a storage battery with solar energy.

Background technique

The so-called solar battery application actually uses the unstable electric energy generated by the solar panel to charge the battery through complex current and voltage control, so that the battery can store energy relatively stably for the stable use of the load. Batteries are delicate devices, improper charging will shorten their service life, or even damage them. Therefore, the conventional constant voltage and constant current charging method cannot achieve the purpose of prolonging the service life of the lead-acid battery. At present, the monitoring device for solar energy charging the battery is not perfect and mature, and the charging detection of the battery is not timely. It is still necessary to manually judge whether the battery is fully charged regularly based on experience, which will easily cause the battery to be overcharged and reduce its service life. .

Contents of the invention

The purpose of this utility model is to provide a control circuit that automatically monitors solar energy for battery charging, which solves the cumbersome steps of manually detecting battery power. The circuit automatically detects battery power and controls the size of solar charging voltage and current. In this way, the conversion efficiency of electric energy is high, which avoids overcharging of the battery and greatly prolongs the service life of the battery.

The circuit of the utility model includes a solar panel U0, a polarity protection diode D0, a solar charging control circuit part, and a storage battery charging control circuit.

The positive pole of the polarity protection diode D0 is connected to the positive terminal of the solar panel U0, and the negative pole of the polarity protection diode D0 is connected to the positive pole "+" of the battery BT1.

The solar charging control loop part includes a voltage comparator circuit and a current comparator circuit, where:

The voltage comparator circuit includes a first operational amplifier U1A, a first resistor R1, a second resistor R2, a first boom sampling resistor RW1, a first diode D1, a first voltage stabilizing element DW1, and a first electrolytic capacitor C1. The Vin input terminal of the first voltage stabilizing element DW1 and one end of the first resistor R1 are both connected to the positive pole "+" of the storage battery BT1, the Gnd ground terminal of the first voltage stabilizing element DW1, the negative pole of the first electrolytic capacitor C1, and the second resistor One terminal of R2 is connected as a common terminal to the negative ground of the battery BT1, and the Vout output terminal of the first voltage stabilizing element DW1 and the positive terminal of the first electrolytic capacitor C1 are connected to the non-inverting input terminal of the first operational amplifier U1A. The other end of the first resistor R1 is connected to one end of the first boom sampling resistor RW1, the other end of the first boom sampling resistor RW1 is connected to the other end of the second resistor R2, and the boom end of the first boom sampling resistor RW1 The output serves as the inverting input of the first operational amplifier U1A. The output terminal of the first operational amplifier U1A is connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the gate terminal G of the field effect transistor Q1. The positive terminal voltage "+" of battery BT1 provides positive voltage for U1A, and the negative ground voltage of solar cell U0 provides negative voltage for U1A.

The current comparator circuit includes a second operational amplifier U1B, a third operational amplifier U1C, a second voltage stabilizing element DW2, a second electrolytic capacitor C2, a second diode D2, a third resistor R3 and a second boom sampling resistor RW2. The Vin input terminal of the second voltage stabilizing element DW2 is connected to the positive pole "+" of the battery BT1, the ground terminal Gnd of the second voltage stabilizing element DW2, the negative pole of the second electrolytic capacitor C2, one end of the third resistor R3 and the second swing arm One end of the sampling resistor RW2 is connected together as a common end to the negative ground end of the solar cell U0. The Vout output terminal of the second voltage stabilizing element DW2 is connected with the positive pole of the second electrolytic capacitor C2 as the non-inverting input terminal of the second operational amplifier U1B, and the output terminal of the second operational amplifier U1B is connected to the negative pole of the second diode D2, The positive end of the second diode D2 is connected to the control electrode G end of the field effect transistor Q1. The inverting input terminal of the second operational amplifier U1B, the output terminal of the third operational amplifier U1C, and the other terminal of the second boom sampling resistor RW2 are connected together. The non-inverting input terminal of the third operational amplifier U1C is connected with the negative terminal of the third electrolytic capacitor C3, the source terminal S of the field effect transistor Q1, and the other terminal of the third resistor R3. The inverting input terminal of the third operational amplifier U1C is connected to the swing arm end of the second swing arm sampling resistor RW2. The positive terminal voltage "+" of the battery BT1 provides positive voltages for the second operational amplifier U1B and the third operational amplifier U1C, and the negative ground voltage of the solar cell U0 provides negative voltages for the second operational amplifier U1B and the third operational amplifier U1C.

The battery charging control circuit includes a battery BT1, a field effect transistor Q1, a third electrolytic capacitor C3 and a fourth resistor R4. The drain D terminal of the field effect transistor Q1 is connected to the negative ground terminal of the battery BT1. One end of the fourth resistor R4 and the positive pole of the third electrolytic capacitor C3 are both connected to the positive terminal "+" of the battery BT1, and the other end of the fourth resistor R4 is connected to the control terminal G of the field effect transistor Q1.

The beneficial effects of the utility model are: the circuit of the utility model has the advantages of building an analog circuit to automatically monitor the remaining power of the storage battery, and automatically controlling the floating charging of the solar battery to the storage battery through an electronic switch. The redundant steps of manually checking the battery power are avoided, because the hardware circuit is used for real-time monitoring, and the response to the battery circuit is very fast, which can effectively compare the remaining power of the battery in real time, avoid overcharging of the battery, and greatly delay the service life of the battery. The components and parts adopted by the utility model are mature and reliable, with low cost and abundant sources.

Description of drawings

Fig. 1 is a concrete circuit diagram of the utility model.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

As shown in Figure 1, the solar charging control circuit includes a solar panel U0, a polarity protection diode D0, a part of the solar charging control circuit, and a battery charging control circuit.

The positive pole of the solar battery U0 is connected to the positive pole of the polarity protection diode D0, and the negative pole of D0 is connected to the positive pole "+" of the storage battery BT1. The polarity protection diode D0 is used as polarity protection for the entire circuit to prevent damage to circuit components when the input polarity is reversed. In case the input circuit is short-circuited, D0 will also prevent the battery BT1 from short-circuiting and discharging due to the reverse voltage at both ends. Since ordinary rectifier diodes have a voltage drop of 0.50~1V, this is a large voltage drop loss for the solar panel U0. Therefore, the polarity protection diode D0 of this device uses an IN5822 rectifier diode with low power consumption and low voltage drop to overcome the defects of ordinary diodes.

The solar charging control loop part includes a voltage comparator circuit and a current comparator circuit.

The voltage comparator circuit includes a first operational amplifier U1A, a first resistor R1, a second resistor R2, a first boom sampling resistor RW1, a first diode D1, a first voltage stabilizing element DW1, and a first electrolytic capacitor C1. The voltage comparator circuit is used to control the charging voltage. The first operational amplifier U1A is the core device of the voltage comparator circuit. U1A is used in an open-loop mode here to achieve a fast comparison function. In the open-loop state of the operational amplifier, as long as the positive input voltage is slightly higher than the negative input, the output will be positive, otherwise the output will be negative, and the response is extremely fast. The Vout output terminal of the first voltage stabilizing element DW1 and the positive pole of the first electrolytic capacitor C1 are connected to the positive input terminal of U1A together as a reference reference voltage input. Here, DW1 adopts the HT series of voltage stabilizing elements with low power consumption and high stability. To provide a reference reference voltage, the Vin input terminal of DW1 is connected to the positive pole "+" of battery BT1. The addition of the first electrolytic capacitor C1 can make the output of DW1 more stable. One end of the first resistor R1 is connected to the positive pole of the battery BT1, the other end is connected to one end of the first boom sampling resistor RW1, one end of the second resistor R2 is connected to the other end of RW1, RW1 is the sampling resistor of the battery voltage, and the The feedback voltage is obtained from both ends of BT1, and the sampling and divided voltage is obtained from the boom end of RW1 as the inverting input voltage of the first operational amplifier U1A. Since the voltage comparator is used to monitor the voltage of the battery BT1, the Gnd terminal of the first voltage stabilizing element DW1, the negative terminal of the first electrolytic capacitor C1 and the other terminal of the second resistor R2 are all connected to the negative terminal of the battery BT1. The output terminal of U1A is connected to the cathode of the first diode D1, and the anode of D1 is connected to the control terminal G of the electronic switch field effect transistor Q1. In Figure 1, an N-channel field effect transistor Q1 is used as an electronic switch. When the voltage between the control terminal G of Q1 and the source S terminal is >3V, Q1 is turned on and the battery is in a charged state. On the contrary Q1 ends, the storage battery stops charging. Controlling the potential of the control terminal G of the electronic switch Q1 can control whether the storage battery BT1 is charged or not. When the sampling divided voltage at the sampling resistor RW1 of the first boom arm is higher than the reference voltage of the positive input terminal of the first operational amplifier U1A, the output of U1A is quickly low, and the control electrode of the electronic switch Q1 is pulled down by the first diode D1 Also low, Q1 cuts off quickly, at this time the charging circuit is disconnected, and the battery BT1 stops charging. Afterwards, the battery voltage will drop slowly due to discharge, and the sampling partial pressure of RW1 will also drop proportionally. When the sampling voltage is lower than the reference voltage of the positive input terminal of U1A, the output of U1A is quickly high, and the electronic switch Q1 is quickly turned on due to the extremely high control. At this time, the power supply circuit is closed, and the battery starts to be charged again, and the voltage of the battery gradually rising, the sampling voltage divider of the first boom sampling resistor RW1 also boosts. When the sampling divided voltage of RW1 is higher than the reference voltage of the positive input terminal of U1A, the output of U1A jumps down quickly, the electronic switch Q1 is also quickly cut off, and the charging circuit is disconnected again. In this way, the charging voltage of the battery BT1 will be accurately controlled. controlled at a set value.

The current comparator circuit includes a second operational amplifier U1B, a third operational amplifier U1C, a second voltage stabilizing element DW2, a second electrolytic capacitor C2, a second diode D2, a third resistor R3 and a second boom sampling resistor RW2. The current comparator circuit is used to control the size of the charging current. In this circuit, the second operational amplifier U1B is used as a comparator. The Vin input terminal of the second voltage stabilizing element DW2 is connected to the positive pole "+" of the battery BT1, and the Vout output terminal of DW2 is connected with the positive pole of the second electrolytic capacitor C2 as the non-inverting input terminal of U1B, and the non-inverting input terminal is used as a current comparator The circuit's reference reference potential. Wherein C2 is used as a filter of the second voltage stabilizing element DW2. Since this current comparator monitors the charging current with the negative terminal of the solar panel U0 as a reference point, the Gnd terminal of the second voltage stabilizing element DW2, the negative terminal of the second electrolytic capacitor C2, and one terminal of the third resistor R3 and one end of the second swing arm sampling resistor RW2 are both connected to the negative ground terminal of the solar panel U0. The inverting input terminal of the second operational amplifier U1B, the output terminal of the third operational amplifier U1C, and one terminal of the second boom sampling resistor RW2 are connected together. The non-inverting input terminal of U1C is connected with the negative terminal of the third electrolytic capacitor C3, the source terminal S of the field effect transistor Q1 and one terminal of the third resistor R3. The inverting input of U1C is connected to the boom end of RW2. The current negative feedback signal is taken from the third resistor R3, the charging current of the solar panel U0 to the battery BT1 is sent to the ground through R3, and the voltage drop across R3 is proportional to the magnitude of the charging current. The third operational amplifier U1C is connected as an ordinary negative feedback forward linear amplifier, and the voltage at both ends of R3 is amplified, and then transmitted to the negative input terminal of the second operational amplifier U1B. When the voltage at the negative input terminal of U1B is higher than the reference voltage at the positive terminal, the output of U1B quickly becomes negative, the field effect transistor Q1 is cut off immediately, the battery BT1 stops charging, the voltage at both ends of R3 immediately loses, and the output of the third operational amplifier U1C immediately returns to 0. Because the voltage of the positive input terminal of U1B is higher than that of the negative input terminal, the output of U1B immediately becomes high, and the field effect transistor Q1 is turned on immediately, and the battery BT1 starts to charge again, but the output of U1B becomes low rapidly after charging, and Q1 is cut off again. With such frequent oscillations, the battery BT1 obtains a certain amount of average charging current. The current size is determined by the magnification of the third operational amplifier U1C. Adjusting the sampling resistor RW2 of the second boom can change the magnification of U1C, thereby achieving the control of the charging current. . The resistance value of the third resistor R3 should not be too large, otherwise the internal power consumption of the circuit will be excessively increased and the efficiency of the solar panel will be affected.

The battery charging control circuit includes a battery BT1, a field effect transistor Q1, a fourth resistor R4 and a third electrolytic capacitor C3. The drain D terminal of the field effect transistor Q1 is connected to the negative ground terminal of the battery BT1. One terminal of the fourth resistor R4 and the positive terminal of the third electrolytic capacitor C3 are connected to the positive terminal "+" of the battery BT1. Since the first operational amplifier U1A is used in an open-loop mode, its sensitivity is extremely high, and the subtle output ripple of the electronic switch Q1 will be regulated by U1A, coupled with the filtering of the third electrolytic capacitor C3, the battery can obtain a very stable supply voltage. Even if the battery is removed, the output of Q1 is still stable.

Claims (1)

1. a solar charging electric control loop, comprises solar panel U0, polarity protection diode D0, solar charging electric control loop part, storage battery charge control circuit, it is characterized in that:

The positive pole of polarity protection diode D0 connects the positive terminal of solar panel U0, and the negative pole of polarity protection diode D0 is connected with the positive pole "+" of storage battery BT1;

Solar charging electric control loop partly comprises voltage comparator circuit and current comparator circuit, wherein:

Voltage comparator circuit comprises the first operational amplifier U1A, the first resistance R 1, the second resistance R 2, the first swing arm sample resistance RW1, the first diode D1, the first voltage stabilizing element DW1, the first electrochemical capacitor C1; The Vin input of the first voltage stabilizing element DW1 is all connected with the positive pole "+" of storage battery BT1 with one end of the first resistance R 1, the Gnd ground end of the first voltage stabilizing element DW1, the negative pole of the first electrochemical capacitor C1, one end of the second resistance R 2 connect into common port and storage battery BT1 negative pole be connected, the Vout output of the first voltage stabilizing element DW1 and the positive pole of the first electrochemical capacitor C1 are connected to the in-phase input end of the first operational amplifier U1A; The other end of the first resistance R 1 is connected to one end of the first swing arm sample resistance RW1, the other end of the first swing arm sample resistance RW1 is connected with the other end of the second resistance R 2, and the swing arm end output of the first swing arm sample resistance RW1 is as the inverting input of the first operational amplifier U1A; The output of the first operational amplifier U1A is linked the negative pole of the first diode D1, and the positive pole of the first diode D1 is connected to the control utmost point G end of field effect transistor Q1; The positive terminal voltage "+" of storage battery BT1 provides positive voltage for U1A, and the negative pole ground voltage of solar cell U0 provides negative voltage for U1A;

Current comparator circuit comprises the second operational amplifier U1B, the 3rd operational amplifier U1C, the second voltage stabilizing element DW2, the second electrochemical capacitor C2, the second diode D2, the 3rd resistance R 3 and the second swing arm sample resistance RW2; The Vin input of the second voltage stabilizing element DW2 is connected to the positive pole "+" of storage battery BT1, the negative pole of ground end Gnd, the second electrochemical capacitor C2 of the second voltage stabilizing element DW2, one end of one end of the 3rd resistance R 3 and the second swing arm sample resistance RW2 be connected together as common port be connected to solar cell U0 negative pole hold; The Vout output of the second voltage stabilizing element DW2 connects the in-phase input end as the second operational amplifier U1B together with the positive pole of the second electrochemical capacitor C2, the output of the second operational amplifier U1B is connected to the negative pole of the second diode D2, and the positive terminal of the second diode D2 is connected to the control utmost point G end of field effect transistor Q1; The other end of the output of the inverting input of the second operational amplifier U1B, the 3rd operational amplifier U1C, the second swing arm sample resistance RW2 connects together; The source S end of the negative pole of the in-phase input end of the 3rd operational amplifier U1C and the 3rd electrochemical capacitor C3, field effect transistor Q1, the other end of the 3rd resistance R 3 couple together; The inverting input of the 3rd operational amplifier U1C is connected with the swing arm end of the second swing arm sample resistance RW2; The positive terminal voltage "+" of storage battery BT1 provides positive voltage for the second operational amplifier U1B, the 3rd operational amplifier U1C, and the negative pole ground voltage of solar cell U0 provides negative voltage for the second operational amplifier U1B, the 3rd operational amplifier U1C;

Storage battery charge control circuit comprises a storage battery BT1, field effect transistor Q1, a 3rd electrochemical capacitor C3 and the 4th resistance R 4; The drain D end of field effect transistor Q1 is connected with the negative pole of storage battery BT1 ground end; The positive pole of one end of the 4th resistance R 4 and the 3rd electrochemical capacitor C3 is all connected with the positive terminal "+" of storage battery BT1, and the other end of the 4th resistance R 4 is received the control utmost point G end of field effect transistor Q1.

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