A circuit for charging a rechargeable battery using a solar panel

Abstract

The invention discloses a circuit for charging a rechargeable battery with a solar panel. The circuit has a simple structure and is easy to implement. The circuit has an MPPT charging function and an LDO auxiliary charging function. When the sunlight illumination is good, the MPPT charging is performed, which is beneficial to daily charging. When the sunlight illumination is low, that is, when the input voltage is detected to be lower than a comparison threshold, the LDO auxiliary charging control is performed, which is beneficial to the utilization of low-illuminance solar energy and has good practicality.

Description

Technical Field

[0001] The invention relates to a circuit for charging a rechargeable battery using a solar panel. Background Art

[0002] At present, most of the existing solar panel charging circuits for rechargeable batteries use MPPT charging management circuits to perform trickle, constant current, and constant voltage charging control on the rechargeable batteries. The control is convenient, but the MPPT charging management circuit has the disadvantage of low energy conversion efficiency under low illumination conditions. The low energy conversion efficiency leads to low output power, which makes it impossible to charge the rechargeable battery, and is not conducive to the utilization of low illumination solar energy.

[0003] Therefore, how to overcome the above-mentioned defects has become an important issue to be solved urgently by those skilled in the art. Summary of the invention

[0004] The present invention overcomes the shortcomings of the above-mentioned technology and provides a circuit for charging a rechargeable battery using a solar panel.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A circuit for charging a rechargeable battery with a solar panel, comprising a solar panel electrical connection terminal 1 and a rechargeable battery electrical connection terminal 2, wherein the solar panel electrical connection terminal 1 is respectively connected with a first voltage detection module 3 and a first unidirectional conduction module 4 for cutting off when the positive and negative poles of the solar panel are reversely connected to the positive and negative poles of the solar panel electrical connection terminal 1, wherein an MPPT charging module 5 and a controlled LDO auxiliary charging module 6 are connected in parallel between the first unidirectional conduction module 4 and the rechargeable battery electrical connection terminal 2, and an output line of the MPPT charging module 5 is provided with a second unidirectional conduction circuit 51 for preventing the rechargeable battery and the controlled LDO auxiliary charging module 6 from reversely charging. The output line of the controlled LDO auxiliary charging module 6 is provided with a third unidirectional conduction circuit 61 for preventing the rechargeable battery and the MPPT charging module 5 from reversely charging. A second voltage detection circuit 7 is connected between the solar panel electrical connection terminal 1 and the MPPT detection pin of the MPPT charging module 5. The detection signal output terminal of the first voltage detection module 3 is connected to a main control module 8 for controlling the operation of the controlled LDO auxiliary charging module 6 when the detected input voltage is lower than the comparison threshold. The control signal input terminal of the MPPT charging module 5 and the control signal input terminal of the controlled LDO auxiliary charging module 6 are respectively connected to the main control module 8.

[0007] In the circuit for charging a rechargeable battery with a solar panel as described above, the first voltage detection module 3 and the second voltage detection circuit 7 respectively adopt resistance voltage division detection circuits.

[0008] As described above, a circuit for a solar panel to charge a rechargeable battery, the first unidirectional conduction module 4 includes a P-channel field effect transistor U2, a resistor R3, a resistor R4, a voltage-stabilizing diode D9, and a resistor R23, the D pole of the field effect transistor U2 is connected to the positive connection end of the solar panel electrical connection end 1, the S pole of the field effect transistor U2 is connected to one end of the resistor R23, one end of the resistor R3, and the positive pole of the voltage-stabilizing diode D9, the other end of the resistor R23 serves as the positive voltage output end of the first unidirectional conduction module 4, the G pole of the field effect transistor U2 is connected to the other end of the resistor R3, the negative pole of the voltage-stabilizing diode D9, and one end of the resistor R4, and the other end of the resistor R4 is connected to the negative connection end of the solar panel electrical connection end 1 as the negative voltage output end of the first unidirectional conduction module 4.

[0009] As described above, in a circuit for charging a rechargeable battery with a solar panel, the MPPT charging module 5 adopts an MPPT charging management circuit with a chip model of CN3791, and the second unidirectional conduction circuit 51 is a diode connected in series to the output line of the MPPT charging module 5.

[0010] As described above, a circuit for charging a rechargeable battery with a solar panel, the controlled LDO auxiliary charging module 6 includes a capacitor C6, a resistor R20, a P-channel field effect transistor U9, an NPN transistor Q1, a resistor R21, a resistor R22, an LDO linear voltage regulator chip HT7344, a resistor R24, a light emitting diode D8, a capacitor C7, a diode D6, and a resistor R9. One end of the capacitor C6 is connected to one end of the resistor R20, the S pole of the field effect transistor U9, and the positive voltage output end of the first unidirectional conduction module 4. The G pole of the field effect transistor U9 is connected to the other end of the resistor R20 and one end of the resistor R21. The D pole G of the field effect transistor U9 is connected to the DC voltage positive input terminal Vin of the LDO linear voltage regulator chip HT7344. The other end of the resistor R21 is connected to the collector of the NPN transistor Q1. The emitter of the NPN transistor Q1 is connected to the other end of the capacitor C6, the LDO linear voltage regulator, and the positive voltage output end of the first unidirectional conduction module 4. The ground end of the chip HT7344 is connected to the negative voltage output end of the first unidirectional conduction module 4, the base of the NPN transistor Q1 is connected to one end of the resistor R22, and the other end of the resistor R22 is connected to the main control module 8 as the control signal input end of the controlled LDO auxiliary charging module 6, the DC voltage positive output end of the LDO linear voltage regulator chip HT7344 is connected to one end of the resistor R24, one end of the capacitor C7, and the positive electrode of the diode D6, the other end of the resistor R24 ​​is connected to the positive electrode of the light-emitting diode D8, the negative electrode of the light-emitting diode D8 is connected to the ground end of the LDO linear voltage regulator chip HT7344, the other end of the capacitor C7, and the negative electrode connection end of the rechargeable battery electrical connection end 2, the negative electrode of the diode D6 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the positive electrode connection end of the rechargeable battery electrical connection end 2 as the DC voltage positive output end of the controlled LDO auxiliary charging module 6.

[0011] In the circuit for charging a rechargeable battery with a solar panel as described above, the third unidirectional conducting circuit 61 is a diode D6 arranged on the output line of the controlled LDO auxiliary charging module 6 .

[0012] In the circuit for charging a rechargeable battery using a solar panel as described above, the main control module 8 uses a single-chip microcomputer circuit with a chip model of STM8S001J3.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention has a simple structure and is easy to implement. It has MPPT charging function and LDO auxiliary charging function. MPPT charging is performed when the sunlight illumination is good, which is beneficial to daily charging. When the sunlight illumination is low, that is, when the input voltage is detected to be lower than the comparison threshold, LDO auxiliary charging control is performed, which is beneficial to the utilization of low-illuminance solar energy and has good practicality. In addition, due to the setting of the first unidirectional conduction module, it is convenient to perform cutoff protection when the positive and negative poles of the solar panel and the positive and negative poles of the solar panel electrical connection end are reversely connected during specific use, which can prevent the MPPT charging module and the controlled LDO auxiliary charging module from being damaged due to the reverse connection of the positive and negative poles of the voltage. The setting of the second unidirectional conduction circuit and the third unidirectional conduction circuit is beneficial to prevent reverse power injection to the output end of the MPPT charging module and the output end of the controlled LDO auxiliary charging module, and has good practicality. In addition, the voltage detection point of the second voltage detection circuit is set before the first unidirectional conduction module, which is beneficial to detect the real-time voltage of solar energy for MPPT tracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is one of the circuit diagrams in this case.

[0016] Figure 2 This is the second circuit diagram of this case. DETAILED DESCRIPTION

[0017] The features of the present invention and other related features are further described in detail below through embodiments to facilitate understanding by those skilled in the art:

[0018] like Figure 1 to Figure 2As shown, a circuit for charging a rechargeable battery with a solar panel comprises a solar panel electrical connection terminal 1 and a rechargeable battery electrical connection terminal 2, the solar panel electrical connection terminal 1 is respectively connected with a first voltage detection module 3 and a first unidirectional conduction module 4 for cutting off when the positive and negative poles of the solar panel are reversely connected to the positive and negative poles of the solar panel electrical connection terminal 1, an MPPT charging module 5 and a controlled LDO auxiliary charging module 6 are connected in parallel between the first unidirectional conduction module 4 and the rechargeable battery electrical connection terminal 2, and an output line of the MPPT charging module 5 is provided with a second unidirectional conduction circuit 5 for preventing the rechargeable battery and the controlled LDO auxiliary charging module 6 from reversely charging. 1, a third unidirectional conduction circuit 61 is provided on the output line of the controlled LDO auxiliary charging module 6 for preventing the rechargeable battery and the MPPT charging module 5 from reversely charging, a second voltage detection circuit 7 is connected between the solar panel electrical connection terminal 1 and the MPPT detection pin of the MPPT charging module 5, the detection signal output terminal of the first voltage detection module 3 is connected to a main control module 8 for controlling the controlled LDO auxiliary charging module 6 to work when the detected input voltage is lower than the comparison threshold, and the control signal input terminal of the MPPT charging module 5 and the control signal input terminal of the controlled LDO auxiliary charging module 6 are respectively connected to the main control module 8.

[0019] As described above, the present invention has a simple structure and is easy to implement. It has an MPPT charging function and an LDO auxiliary charging function. When the sunlight illumination is good, MPPT charging is performed, which is beneficial to daily charging. When the sunlight illumination is low, that is, when the input voltage is detected to be lower than the comparison threshold, LDO auxiliary charging control is performed, which is beneficial to the utilization of low-illuminance solar energy and has good practicality. In addition, due to the setting of the first unidirectional conduction module 4, it is convenient to perform cutoff protection when the positive and negative poles of the solar panel are reversely connected to the positive and negative poles of the solar panel electrical connection terminal 1 during specific use, which can prevent the MPPT charging module 5 and the controlled LDO auxiliary charging module 6 from being damaged due to the reverse connection of the positive and negative poles of the voltage. The setting of the second unidirectional conduction circuit 51 and the third unidirectional conduction circuit 61 is beneficial to prevent reverse power injection to the output end of the MPPT charging module 5 and the output end of the controlled LDO auxiliary charging module 6, and has good practicality. In addition, the voltage detection point of the second voltage detection circuit 7 is set before the first unidirectional conduction module 4, which is beneficial to detect the real-time voltage of solar energy for MPPT tracking.

[0020] As described above, in specific implementation, the first voltage detection module 3 and the second voltage detection circuit 7 respectively adopt resistance voltage division detection circuits.

[0021] As described above, in a specific implementation, the first unidirectional conduction module 4 includes a P-channel field effect transistor U2, a resistor R3, a resistor R4, a voltage-stabilizing diode D9, and a resistor R23. The D pole of the field effect transistor U2 is connected to the positive connection end of the solar panel electrical connection end 1, the S pole of the field effect transistor U2 is connected to one end of the resistor R23, one end of the resistor R3, and the positive pole of the voltage-stabilizing diode D9, and the other end of the resistor R23 serves as the positive voltage output end of the first unidirectional conduction module 4, the G pole of the field effect transistor U2 is connected to the other end of the resistor R3, the negative pole of the voltage-stabilizing diode D9, and one end of the resistor R4, and the other end of the resistor R4 is connected to the negative connection end of the solar panel electrical connection end 1 as the negative voltage output end of the first unidirectional conduction module 4.

[0022] As described above, when a forward voltage is input between the positive and negative poles of the solar panel electrical connection terminal 1, the D pole and the S pole of the field effect transistor U2 are connected, otherwise when a reverse voltage is input between the positive and negative poles of the solar panel electrical connection terminal 1, the D pole and the S pole are cut off.

[0023] As described above, in a specific implementation, the MPPT charging module 5 adopts an MPPT charging management circuit with a chip model of CN3791, and the second unidirectional conduction circuit 51 is a diode connected in series to the output line of the MPPT charging module 5 .

[0024] As described above, in a specific implementation, the controlled LDO auxiliary charging module 6 includes a capacitor C6, a resistor R20, a P-channel field effect transistor U9, an NPN transistor Q1, a resistor R21, a resistor R22, an LDO linear voltage regulator chip HT7344, a resistor R24, a light-emitting diode D8, a capacitor C7, a diode D6, and a resistor R9. One end of the capacitor C6 is connected to one end of the resistor R20, the S pole of the field effect transistor U9, and the positive voltage output end of the first unidirectional conduction module 4. The G pole of the field effect transistor U9 is connected to the other end of the resistor R20 and one end of the resistor R21. The D pole G of the field effect transistor U9 is connected to the DC voltage positive input terminal Vin of the LDO linear voltage regulator chip HT7344. The other end of the resistor R21 is connected to the collector of the NPN transistor Q1, and the emitter of the NPN transistor Q1 is connected to the other end of the capacitor C6 and the LDO linear voltage regulator chip HT73 The ground terminal of 44 and the voltage negative output terminal of the first unidirectional conduction module 4 are connected, the base of the NPN transistor Q1 is connected to one end of the resistor R22, and the other end of the resistor R22 is connected to the main control module 8 as the control signal input terminal of the controlled LDO auxiliary charging module 6, the DC voltage positive output terminal of the LDO linear voltage regulator chip HT7344 is connected to one end of the resistor R24, one end of the capacitor C7, and the positive electrode of the diode D6, the other end of the resistor R24 ​​is connected to the positive electrode of the light-emitting diode D8, the negative electrode of the light-emitting diode D8 is connected to the ground terminal of the LDO linear voltage regulator chip HT7344, the other end of the capacitor C7, and the negative electrode connection terminal of the rechargeable battery electrical connection terminal 2, the negative electrode of the diode D6 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the positive electrode connection terminal of the rechargeable battery electrical connection terminal 2 as the DC voltage positive output terminal of the controlled LDO auxiliary charging module 6.

[0025] As described above, the main control module 8 controls whether the D pole and the S pole of the field effect transistor U9 on the controlled LDO auxiliary charging module 6 are turned on according to the voltage detected by the first voltage detection module 3, thereby controlling whether the controlled LDO auxiliary charging module 6 works.

[0026] As described above, in a specific implementation, the third unidirectional conducting circuit 61 is a diode D6 arranged on the output line of the controlled LDO auxiliary charging module 6 .

[0027] As described above, in specific implementation, the main control module 8 uses a single-chip microcomputer circuit with a chip model of STM8S001J3.

[0028] As mentioned above, this case protects a circuit used for solar panels to charge rechargeable batteries. All technical solutions that are the same or similar to this case should be deemed to fall within the scope of protection of this case.

Claims

1. A circuit for charging a rechargeable battery using a solar panel, characterized in that The invention comprises a solar panel electrical connection end (1) and a rechargeable battery electrical connection end (2), wherein the solar panel electrical connection end (1) is respectively connected with a first voltage detection module (3) and a first unidirectional conduction module (4) for cutting off when the positive and negative poles of the solar panel are reversely connected to the positive and negative poles of the solar panel electrical connection end (1), an MPPT charging module (5) and a controlled LDO auxiliary charging module (6) are connected in parallel between the first unidirectional conduction module (4) and the rechargeable battery electrical connection end (2), an output line of the MPPT charging module (5) is provided with a second unidirectional conduction circuit (51) for preventing the rechargeable battery and the controlled LDO auxiliary charging module (6) from reversely charging, and the controlled LDO auxiliary charging module (6) is connected in parallel with the first unidirectional conduction module (4) and the rechargeable battery electrical connection end (2). A third unidirectional conduction circuit (61) is provided on the output line of the auxiliary charging module (6) for preventing the rechargeable battery and the MPPT charging module (5) from reversely charging. A second voltage detection circuit (7) is connected between the solar panel electrical connection end (1) and the MPPT detection pin of the MPPT charging module (5). The detection signal output end of the first voltage detection module (3) is connected to a main control module (8) for controlling the operation of the controlled LDO auxiliary charging module (6) when the detected input voltage is lower than a comparison threshold. The control signal input end of the MPPT charging module (5) and the control signal input end of the controlled LDO auxiliary charging module (6) are respectively connected to the main control module (8). The first unidirectional conduction module (4) comprises a P-channel field effect transistor U2, a resistor R3, a resistor R4, a voltage-stabilizing diode D9, and a resistor R23; the D pole of the field effect transistor U2 is connected to the positive connection end of the solar panel electrical connection end (1); the S pole of the field effect transistor U2 is connected to one end of the resistor R23, one end of the resistor R3, and the positive pole of the voltage-stabilizing diode D9; the other end of the resistor R23 serves as the positive voltage output end of the first unidirectional conduction module (4); the G pole of the field effect transistor U2 is connected to the other end of the resistor R3, the negative pole of the voltage-stabilizing diode D9, and one end of the resistor R4; the other end of the resistor R4 is connected to the negative connection end of the solar panel electrical connection end (1) and serves as the negative voltage output end of the first unidirectional conduction module (4); The controlled LDO auxiliary charging module (6) comprises a capacitor C6, a resistor R20, a P-channel field effect transistor U9, an NPN transistor Q1, a resistor R21, a resistor R22, an LDO linear voltage regulator chip HT7344, a resistor R24, a light emitting diode D8, a capacitor C7, a diode D6, and a resistor R9, one end of the capacitor C6 is connected to one end of the resistor R20, an S pole of the field effect transistor U9, and a voltage positive output end of the first unidirectional conduction module (4), a G pole of the field effect transistor U9 is connected to the other end of the resistor R20 and one end of the resistor R21, a D pole G of the field effect transistor U9 is connected to a DC voltage positive input end Vin of the LDO linear voltage regulator chip HT7344, the other end of the resistor R21 is connected to the collector of the NPN transistor Q1, and an emitter of the NPN transistor Q1 is connected to the other end of the capacitor C6, a ground end of the LDO linear voltage regulator chip HT7344, and the first The negative electrode of the voltage of the unidirectional conduction module (4) is connected, the base of the NPN transistor Q1 is connected to one end of the resistor R22, the other end of the resistor R22 is connected to the main control module (8) as the control signal input end of the controlled LDO auxiliary charging module (6), the DC voltage positive electrode output end of the LDO linear voltage regulator chip HT7344 is connected to one end of the resistor R24, one end of the capacitor C7, and the positive electrode of the diode D6, the other end of the resistor R24 ​​is connected to the positive electrode of the light-emitting diode D8, the negative electrode of the light-emitting diode D8 is connected to the ground end of the LDO linear voltage regulator chip HT7344, the other end of the capacitor C7, and the negative electrode connection end of the rechargeable battery electrical connection end (2), the negative electrode of the diode D6 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the positive electrode connection end of the rechargeable battery electrical connection end (2) as the DC voltage positive electrode output end of the controlled LDO auxiliary charging module (6).

2. A circuit for charging a rechargeable battery using a solar panel according to claim 1, characterized in that The first voltage detection module (3) and the second voltage detection circuit (7) respectively adopt resistance voltage division detection circuits.

3. A circuit for charging a rechargeable battery using a solar panel according to claim 1, characterized in that The MPPT charging module (5) adopts an MPPT charging management circuit with a chip model of CN3791, and the second unidirectional conduction circuit (51) is a diode connected in series on the output line of the MPPT charging module (5).

4. A circuit for charging a rechargeable battery using a solar panel according to claim 1, characterized in that The third unidirectional conducting circuit (61) is a diode D6 arranged on the output line of the controlled LDO auxiliary charging module (6).

5. A circuit for charging a rechargeable battery using a solar panel according to any one of claims 1 to 4, characterized in that The main control module (8) adopts a single-chip microcomputer circuit with a chip model of STM8S001J3.

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