CN211239409U

CN211239409U - Photovoltaic power generation's storage control circuit

Info

Publication number: CN211239409U
Application number: CN202020100155.3U
Authority: CN
Inventors: 刘洪恩; 王继凤; 陈银燕
Original assignee: Huaian Vocational College of Information Technology
Current assignee: Huaian Vocational College of Information Technology
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2020-08-11
Anticipated expiration: 2030-01-17

Abstract

The utility model discloses a photovoltaic power generation storage control circuit applied to a photovoltaic power generation storage system, which comprises a photovoltaic boosting part and a storage battery charging control part; when the output voltage of the photovoltaic module is lower than the voltage of the storage battery, the storage battery is charged by boosting, the magnitude of charging current and the magnitude of charging voltage are detected and controlled in the charging process, so that when the output voltage of the photovoltaic module changes in a large range due to the change of illumination intensity, electric energy can be stored and utilized, the safety of the storage battery is protected, and the photovoltaic module is suitable for a photovoltaic power generation storage system with rated output voltage of 12-60V (single-chip or 2-5 photovoltaic modules connected in series).

Description

Photovoltaic power generation's storage control circuit

Technical Field

The utility model relates to a photovoltaic power generation's storage control circuit is applied to among the photovoltaic power generation storage system to improve electric energy utilization and possess battery charging control function.

Background

In the photovoltaic power generation and storage system, the photovoltaic module generates direct current electric energy, and the storage battery stores the electric energy. The change range of the output voltage of the photovoltaic module is large due to the influence of the change of illumination intensity. When the illumination intensity is weaker, the output voltage is lower, when the output voltage is lower than the voltage of the storage battery, the storage battery cannot be charged, and the electric energy cannot be stored and utilized; on the contrary, when the illumination intensity is strong, the output voltage is high, and when the output voltage is higher than the voltage of the storage battery, the storage battery is damaged due to overlarge charging current or overlarge charging voltage.

Disclosure of Invention

The utility model aims to provide a: the utility model provides a photovoltaic power generation's storage control circuit is applied to photovoltaic power generation storage system, and when photovoltaic module arouses its output voltage to change on a large scale because of illumination intensity changes, the electric energy can both be stored and utilized, improves electric energy utilization ratio, possesses the battery charge control function to the safety of protection battery.

The principle of the utility model is that: the circuit comprises a booster circuit and a storage battery charging control circuit; the boosting circuit is used for charging the storage battery by boosting when the output voltage of the photovoltaic module is lower than the voltage of the storage battery, so that the electric energy at the moment is utilized; the storage battery charging control circuit is used for controlling the magnitude of charging current and the magnitude of charging voltage and protecting the storage battery.

The technical solution of the utility model is that: the storage control circuit of the photovoltaic power generation consists of a booster circuit and a storage battery charging control circuit; when the output voltage of the photovoltaic module is lower than the voltage required by the storage battery charging, the voltage is boosted by the DC-DC conversion circuit and is sent to the storage battery charging control circuit; when the output voltage of the photovoltaic module is higher than or equal to the voltage required by the storage battery charging, the boosting circuit does not boost the voltage and directly sends the voltage to the storage battery charging control circuit; the storage battery charging control circuit controls the charging current to avoid the damage of the storage battery due to overlarge charging current; and secondly, the charging stop voltage of the storage battery is limited, and the storage battery is prevented from being damaged by overcharge.

The utility model has the advantages of it is following:

1. when the illumination intensity is weak and the output voltage of the photovoltaic module is lower than the voltage of the storage battery, the electric energy is stored, and the electric energy utilization rate is improved;

2. the charging current and the charging termination voltage of the storage battery are accurately controlled, and the storage battery is prevented from being damaged due to overlarge charging current or overcharge;

3. compared with the traditional continuous analog charging mode (a triode is used for simulating a resistor to limit the charging current), the pulse width modulation charging mode has high efficiency and low power consumption.

3. The circuit of the utility model is suitable for a photovoltaic module and a storage battery with rated output voltage of 12-60V (single-chip or 2-5-chip series connection), and has good universality.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

Detailed Description

The technical solutions of the present invention are further described below with reference to the accompanying drawings, but the technical solutions are not construed as being limited thereto.

As shown in fig. 1, the utility model comprises a booster circuit and a storage battery charging control circuit; the booster circuit is used for boosting the voltage of the photovoltaic module when the voltage output by the photovoltaic module is low so as to charge the storage battery; the function of the battery charging control circuit is to limit the magnitude of the charging current and the battery charging termination voltage.

The boost circuit is connected as follows: the negative electrode of the output voltage U1 of the photovoltaic module is Grounded (GND), the positive electrode of the output voltage U1 of the photovoltaic module is connected with the positive electrode of the energy storage capacitor C1, and the negative electrode of the capacitor C1 is grounded; the anode of the voltage U1 is connected with the synonym end of the N1 coil of the inductor L1, the synonym end of the N1 coil of the L1 is connected with the anode of a fast recovery diode D1 (model MUR 1620), the cathode of a diode D1 is connected with the anode of an energy storage capacitor C5, the cathode of the capacitor C5 is grounded, and the voltage at the two ends of the C5 is the boosted voltage U2; the anode of the voltage U2 is connected with the resistors R6 and R7 in series in sequence and then grounded; a pin 1 of an integrated circuit IC1 (model is LM 2577-ADJ) is sequentially connected with a resistor R3 and a capacitor C3 in series and then grounded, a pin 2 is connected with a connecting point of the resistor R6 and the resistor R7, a pin 3 is grounded, a pin 4 is connected with a different-name end of a primary coil N1 of a driving transformer TR, and a like-name end of N1 is connected with a pin 5 of an IC 1; the pin 5 of the IC1 is connected with the anode of the capacitor C2, and the cathode of the C2 is grounded; the anode of the voltage U1 is connected with a resistor R1 in series and then connected with the pin 5 of the IC 1; the synonym end of an auxiliary coil N2 on the inductor L1 is grounded, the homonymy end of a series resistor R2 is connected with the anode of a diode D2 (model UF 1004) in back, the cathode of the D2 is connected with the pin 5 of the IC1, the pin 5 of the IC1 is connected with the cathode of an 18V voltage stabilizing diode D3, and the anode of the D3 is grounded; the dotted terminal of a secondary coil N2 of the driving transformer TR is connected with a resistor R4 in series and then connected with the grid of a MOSFET switching tube V1 (model IRF 250), the two ends of the resistor R4 are respectively connected with a capacitor C4 and a diode D4 in parallel, and the anode of D4 is connected with the grid of a switching tube V1; the synonym end of a secondary coil N2 of the driving transformer TR is grounded, the source of a switching tube V1 is grounded, the drain is connected with the synonym end of a coil N1 of an inductor L1, and a resistor R5 and a bidirectional voltage stabilizing diode D5 (model P6KE15 CA) are connected between the grid and the source in parallel.

The working principle of the booster circuit is as follows: the IC1 is a boost type pulse width modulation switching regulator chip (model LM 2577-ADJ) with adjustable output voltage, a pin 5 (VDD) and a pin 3 (GND) of the chip are power supply ends, a pin 1 is a soft start control end, a pin 2 is an output voltage U2 sampling feedback end, and a pin 4 is a collector of an internal switching tube; after a power supply U1 is powered on, power is supplied to an IC1 through a starting resistor R1, a sawtooth wave oscillating circuit in the IC1 starts oscillating, a 4 pin outputs a low level of a certain duty ratio, pulse signals with the same duty ratio are obtained on a primary coil N1 and a secondary coil N2 of a driving transformer TR, a switching tube V1 is periodically switched on and off with the same duty ratio, when the switching tube V1 is switched on, the current in a coil N1 of an inductor L1 starts to increase and store energy, when the V1 is switched off, L1 releases energy, the N1 generates a left-negative-right-positive induced potential which is superposed on a voltage U1, and the current which is increased to the voltages U2 and N1 by the U1 is output through a diode D1; meanwhile, an N2 coil of the L1 generates right negative left positive induction potential, and current passes through a current-limiting resistor R2 and a rectifier diode D2 to supply power to the IC 1; the resistor R4 is a gate drive resistor of the switching tube V1 and plays a role in limiting current; when the driving pulse of the V1 is at a high level, the capacitor C4 can increase the charging speed of the grid of the V1 so as to reduce the turn-on loss of the V1; when the V1 driving pulse is low, the diode D4 can rapidly release the gate charge of V1, speeding up its turn-off, so as to reduce the turn-off loss of V1; the resistor R5 is a grid charge discharge resistor of the switch tube V1, and is prevented from being conducted mistakenly due to interference; the bidirectional voltage stabilizing diode D5 is used for protecting the switching tube V1 and preventing the grid and the source of the switching tube from being damaged due to overvoltage; resistors R6 and R7 are sampling resistors for outputting a voltage U2, a sampling signal is fed back through a pin 2 of the IC1, the duty ratio (pulse width modulation) of the pulse width output by the IC1 is controlled, the duty ratio is large when the voltage U2 is low, the duty ratio is small when the voltage U2 is high, the size of the voltage U2 is determined by the ratio of the resistors R6 and R7, that is, U2 = 1.23 (1 + R6/R7), and the U2 is stabilized at a set voltage value; the voltage U2 should be 2-3 volts higher than the required end-of-charge voltage of the battery pack (i.e., 1.2 times the rated voltage).

When the voltage U1 is greater than 5V and less than the set voltage U2, the boost circuit raises U1 to U2; when U1 is more than or equal to U2, the booster circuit does not boost the voltage (the duty ratio is 0 by pulse width modulation), and then U2 = U1; when the voltage U1 is less than 5V, the circuit stops working.

The utility model uses the external high-power MOSFET switch tube as a switch element and is driven by a transformer to increase the output power; the voltage U2 supplies power to the subsequent battery pack and its charge control circuit.

The storage battery charging control circuit is connected as follows: the 2-pin 18V voltage stabilizing diode D11 cathode of IC2 (model SG6858 DZ), the D11 anode are grounded, the 2-pin filter capacitor C11 is grounded, and the resistor R11 is connected to the voltage U2 anode; a 5-pin connection resistor R12 is connected to the ground, an 8-pin is grounded, a 7-pin is connected to a capacitor C12 to the ground, a 1-pin series resistor R13 is connected to the grid of a MOSFET switching tube V2 (model IRF 250), the source of V2 is respectively connected to resistors R14, R15 to the ground and the 4-pin of IC2, the drain of V2 is connected to the anode of a freewheeling diode D12, the cathode of D12 is connected to the anode of a voltage U2, the drain of V2 is additionally connected to one end of an inductor L2, the other end of L2 is connected to the cathode of a storage battery BT, and the anode of the storage battery BT is connected to the anode of a voltage U89; sampling resistors R16 and R17 of the BT voltage UB of the storage battery are connected in series and then are connected in parallel at two ends of the storage battery; one end of the resistor R18 is connected with the anode of the storage battery, the other end of the resistor R18 is respectively connected with the cathode of an 18V voltage stabilizing diode D13 and the anode of a light emitting diode in an optocoupler LP (model PC 817), and the anode of the D13 is connected with the cathode of the storage battery; the anode of a 2.5V reference voltage stabilizer IC3 (model TL 431) is connected with the cathode of a storage battery, the reference electrode is connected with the connection point of resistors R16 and R17, the cathode is connected with the cathode of a light-emitting diode in an optical coupler LP, and the resistor R19 and a capacitor C13 are connected in series and then connected in parallel to the cathode and the reference electrode of the IC 3; the emitter of the triode in the optocoupler LP is grounded, and the collector is connected with the pin 7 of the IC 2.

The principle of the storage battery charging control circuit is as follows: IC2 (model SG6858 DZ) is current control type pulse width modulation switch power supply control chip, its 2 feet and 8 feet are the power ends, obtain 18V voltage by voltage U2 through current-limiting resistance R11, zener diode D11 steady voltage, electric capacity C11 filtering and supply power for it, 5 feet of IC2 are the oscillation frequency setting end of its internal oscillator, 7 feet are the voltage feedback input end, 4 feet are the current sampling input end, 1 foot is the external switch tube drive pulse output end, the utility model discloses use 4 feet voltage to implement cycle control to the pulse width of 1 foot output; after electrification, an internal circuit of the IC2 starts oscillation, a pin 1 outputs driving pulses, a switching tube V2 is conducted, current starts to increase from 0 through a storage battery, an inductor L, V2 leakage source electrode and a current detection resistor R14, and the storage battery is charged; the current flows through a current detection resistor R14 and is converted into a voltage signal which is applied to a 4 pin of the IC2, when the current is increased to enable the voltage of the 4 pin of the IC2 to be 0.9V, an internal circuit of the IC2 enables a driving pulse to be changed into a low level, and the V2 is turned off; when the next pulse comes, V2 is conducted again, and the process is repeated; the charging current is a sawtooth wave, the maximum value is 0.9/R14, and the current detection resistor R14 determines the magnitude of the charging current; d12 is a freewheeling diode to prevent the breakdown of the V2 due to overvoltage generated at the drain when the diode is turned off; r16 and R17 are storage battery voltage UB sampling resistors, UB continuously rises along with the charging, when UB reaches 1.2 times of the rated voltage of the storage battery, the reference voltage of IC3 (model TL 431) approaches 2.5V, the cathode of IC3 is conducted with the anode slightly, the light emitting diode in the optical coupler LP emits light slightly, the triode is conducted slightly, the potential of the 7 pin of IC2 is pulled down, the output pulse width of the 1 pin of IC2 is reduced, the voltage on the current detection resistor does not reach 0.9V at the moment, V2 is turned off, the charging current is reduced, the state is switched into a trickle charging state, trickle charging reaches a certain time, the reference voltage of IC3 reaches 2.5V, the cathode of IC3 is conducted with the anode deeply, the light emitting diode in the optical coupler LP is enhanced, the triode is conducted deeply, the potential of the 7 pin of IC2 is pulled into a low level, the output pulse width of the 1 pin of IC2 is 0, and the charging is stopped to prevent overcharg; the resistor R19 and the capacitor C13 are connected in series and then are connected with the cathode and the reference electrode of the IC3 to form negative feedback, so that the cathode and the anode are prevented from being alternately switched on and off to generate oscillation when the reference voltage of the IC3 is close to 2.5V; the resistor R18 and the zener diode D14 reduce the battery voltage UB to 18V to prevent the IC3 from breaking down (the cathode withstand voltage of IC3 is 36V).

Claims

1. Photovoltaic power generation's storage control circuit, characterized by: the charging control circuit consists of a boosting circuit and a storage battery charging control circuit; the booster circuit boosts the voltage through the DC-DC conversion circuit and sends the boosted voltage to the storage battery charging control circuit when the output voltage of the photovoltaic module is lower than the voltage required by the storage battery charging; when the output voltage of the photovoltaic module is higher than or equal to the voltage required by the storage battery charging, the boosting circuit does not boost the voltage and directly sends the voltage to the storage battery charging control circuit; the storage battery charging control circuit controls the magnitude of charging current to avoid the damage of the storage battery due to overlarge charging current; and secondly, the charging stop voltage of the storage battery is limited, and the storage battery is prevented from being damaged by overcharge.

2. The photovoltaic power generation storage control circuit of claim 1, wherein the boost circuit is connected to: the negative electrode of the output voltage U1 of the photovoltaic module is grounded GND, the positive electrode of the output voltage U1 of the photovoltaic module is connected with the positive electrode of the energy storage capacitor C1, and the negative electrode of the capacitor C1 is grounded; the positive pole of the voltage U1 is connected with the synonym end of the N1 coil of the inductor L1, the synonym end of the N1 coil of the L1 is connected with the positive pole of a fast recovery diode D1 model MUR1620, the cathode of the diode D1 is connected with the positive pole of an energy storage capacitor C5, the negative pole of the capacitor C5 is grounded, and the voltage at the two ends of the C5 is the boosted voltage U2; the anode of the voltage U2 is connected with the resistors R6 and R7 in series in sequence and then grounded; the 1 pin of an integrated circuit IC1 with the model number LM2577-ADJ is sequentially connected with a resistor R3 and a capacitor C3 in series and then grounded, the 2 pin is connected with the connection point of the resistor R6 and the resistor R7, the 3 pin is grounded, the 4 pin is connected with the different-name end of a primary coil N1 of a driving transformer TR, and the same-name end of N1 is connected with the 5 pin of an IC 1; the pin 5 of the IC1 is connected with the anode of the capacitor C2, and the cathode of the C2 is grounded; the anode of the voltage U1 is connected with a resistor R1 in series and then connected with the pin 5 of the IC 1; the synonym end of an auxiliary coil N2 on the inductor L1 is grounded, the homonymy end of a series resistor R2 is connected with the anode of a diode D2 model UF1004, the cathode of the D2 is connected with the pin 5 of the IC1, the pin 5 of the IC1 is connected with the cathode of an 18V voltage stabilizing diode D3, and the anode of the D3 is grounded; the dotted terminal of a secondary coil N2 of the driving transformer TR is connected with a resistor R4 in series and then connected with the grid of a MOSFET switching tube V1 model IRF250, two ends of the resistor R4 are respectively connected with a capacitor C4 and a diode D4 in parallel, and the anode of D4 is connected with the grid of a switching tube V1; the synonym end of a secondary coil N2 of the driving transformer TR is grounded, the source electrode of the switching tube V1 is grounded, the drain electrode is connected with the synonym end of a coil N1 of the inductor L1, and a resistor R5 and a bidirectional voltage stabilizing diode D5, model P6KE15CA are connected between the grid electrode and the source electrode in parallel.

3. The photovoltaic power generation storage control circuit as claimed in claim 1, wherein the battery charging control circuit is connected as follows: the 2-pin 18V voltage stabilizing diode D11 cathode of IC2 model SG6858DZ, the D11 anode are grounded, the 2-pin filter capacitor C11 is grounded, and the resistor R11 is connected to the voltage U2 anode; a 5-pin connection resistor R12 is connected to the ground, an 8-pin is grounded, a 7-pin is connected to a capacitor C12 to the ground, a 1-pin series resistor R13 is connected to the grid electrode of a MOSFET switching tube V2 model IRF250, the source electrode of V2 is respectively connected to resistors R14 and R15 to the ground and the 4-pin of IC2, the drain electrode of V2 is connected to the anode electrode of a freewheeling diode D12, the cathode electrode of D12 is connected to the anode electrode of a voltage U2, the drain electrode of V2 is additionally connected to one end of an inductor L2, the other end of L2 is connected to the cathode electrode of a storage battery BT, and the anode electrode of the storage battery BT; sampling resistors R16 and R17 of the BT voltage UB of the storage battery are connected in series and then are connected in parallel at two ends of the storage battery; one end of the resistor R18 is connected with the anode of the storage battery, the other end of the resistor R18 is respectively connected with the cathode of an 18V voltage stabilizing diode D13 and the anode of a light emitting diode in an optocoupler LP model PC817, and the anode of the resistor D13 is connected with the cathode of the storage battery; the anode of a 2.5V reference voltage stabilizer IC3 model TL431 is connected with the cathode of a storage battery, the reference electrode is connected with the connection point of resistors R16 and R17, the cathode is connected with the cathode of a light-emitting diode in an optical coupler LP, and the resistor R19 and a capacitor C13 are connected in series and then connected in parallel to the cathode and the reference electrode of the IC 3; the emitter of the triode in the optocoupler LP is grounded, and the collector is connected with the pin 7 of the IC 2.

4. The photovoltaic power generation storage control circuit of claim 2, wherein: a boost control circuit is formed by a DC-DC conversion chip LM2577-ADJ with adjustable output voltage, power is supplied to the boost control circuit by electric energy generated by an auxiliary coil N2 on an inductor L1, and an externally connected MOSFET switching tube is used as a switching element and is driven by a transformer TR to increase the output power.

5. The photovoltaic power generation storage control circuit of claim 3, wherein: the current control type switching power supply control chip SG6858DZ forms a pulse width modulation type current-limiting charging circuit, and the voltage reference control chip TL431 forms a voltage detection control chip of the storage battery pack.