CN104052085A - A solar controller drive circuit with short circuit protection - Google Patents

Abstract

The invention discloses a solar-energy controller drive circuit with a short-circuit protection function. The solar-energy controller drive circuit includes a level conversion circuit, a bootstrap boost-up circuit, an MOS tube drive circuit and a short-circuit protection circuit. The level conversion circuit is connected with the bootstrap boost-up circuit. The bootstrap boost-up circuit is connected with the MOS tube drive circuit. The level conversion circuit converts square-wave signals output by an MCU in the solar-energy controller and uses the converted square-wave signals as input signals of the bootstrap boost-up circuit. A task of the bootstrap boost-up circuit is to use voltage bootstrap at a solar panel end as a drive voltage of the MOS tube drive circuit. The short-circuit protection circuit is connected with the MOS tube drive circuit. Drives signals of the MOS tube drive circuit are generated by the MCU and the low level is effective. The short-circuit protection circuit cuts off MOS tube drive signals when a solar panel is in a short circuit in a charging process so as to generate MOS tube switch-off signals and charging can be restored automatically when the short circuit is removed. The solar-energy controller drive circuit is simple in structure and has the advantages of protecting electronic elements, reducing product repair rate and reducing subsequent cost investment.

Description

A solar controller drive circuit with short circuit protection

technical field

The invention relates to the technical field of solar controllers, in particular to a solar controller drive circuit with short-circuit protection that can control the solar panel to charge the storage battery during normal operation and protect the entire system from being damaged when the solar panel is short-circuited during the charging process. .

Background technique

At present, most of the solar charge controllers on the market do not consider the damage of the battery to other auxiliary circuits such as charging MOS tubes and insurance tubes when the solar panel is short-circuited during charging. When a traditional solar controller short-circuits the solar panel during charging, the charging MOS tube and the fuse at the battery end will be burned, disconnecting the circuit between the battery and the solar panel. The disadvantage is that once the solar panel is short-circuited during charging, the MOS tube and fuse need to be replaced, which is extremely inconvenient to use. If it is made into a waterproof controller, this method is even more undesirable. If a short circuit occurs and the components are burned, the entire controller will be scrapped, which will increase the investment in the later stage of the project.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned defects in the prior art, and to provide a solar controller drive circuit with short-circuit protection with fast protection speed and high reliability, that is, the drive circuit can control the solar panel to charge the battery during normal operation, and the short-circuit When it happens, it can quickly protect electronic components, and it can automatically resume charging after the short circuit is removed.

The present invention is specifically realized through the following technical solutions.

A solar controller driving circuit with short-circuit protection, characterized in that: the solar controller driving circuit with short-circuit protection is composed of a level conversion circuit, a bootstrap boost circuit, a MOS tube driving circuit, and a short-circuit protection circuit. The level conversion circuit is connected with the bootstrap boost circuit, and the bootstrap boost circuit is connected with the MOS drive circuit. The level conversion circuit converts the square wave signal output by the MCU in the solar controller with a frequency of 50KHZ and an amplitude of 5V into a frequency It is a 50KHZ square wave signal with an amplitude of 12V. This signal is used as the input signal of the bootstrap booster circuit. The task of the bootstrap booster circuit is to boost the voltage of the solar panel terminal by 12V as the driving voltage of the MOS tube drive circuit. , the short-circuit protection circuit is connected to the MOS tube drive circuit, the drive signal of the MOS tube drive circuit is generated by the MCU, and the low level is effective, and the short-circuit protection circuit can act quickly when the solar panel is short-circuited during the charging process, Cut off the driving signal of the MOS tube, and generate a signal to turn off the MOS tube. When the short circuit is removed, the charging can be resumed automatically. The short circuit protection circuit is composed of a resistor R12, a resistor R13, a transistor Q7 and a diode D6. The anode of the diode D6 and the transistor Q7 The base is connected, the resistor R13 is directly connected in series with the cathode of the diode D6, one end of the resistor R12 is connected to the emitter of the transistor Q7, and the other end is connected to the base of the transistor Q7 and simultaneously connected to the anode of the diode D6, the MOS drive The circuit is composed of resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, transistor Q4, transistor Q5, transistor Q6, diode D3, diode D4, and diode D5. The collectors of the transistor Q4 are connected in series Connect diode D4 and resistor R6 to the base of transistor Q6, the anode of diode D4 is connected to the collector of transistor Q4, the emitter of transistor Q4 is connected to the output of the bootstrap booster circuit, the collector of transistor Q5 is connected to the anode of diode D3 connection, the cathode of the diode D3 is connected to the base of the transistor Q4, one end of the resistor R5 is connected to the base of the transistor Q4, and the other end is connected to the emitter of the transistor Q4, and the base of the transistor Q5 is connected in series with the resistor R8 to the short-circuit protection circuit The emitter of the transistor Q7 is connected, the emitter of the transistor Q5 is connected to the collector of the transistor Q7 in the short-circuit protection circuit after being connected in series with the resistor R9, and then connected to the MOS tube drive signal PWM_PV through the resistor R11, wherein one end of the resistor R11 is connected to the transistor The collector of Q7 is connected to the resistor R9, the other end is connected to the MOS tube drive signal PWM_PV, the base of the transistor Q6 is connected to the anode of the diode D5, the cathode of the diode D5 is connected to the emitter of the transistor Q6 after being connected in series with the resistor R7, and the diode D5 The anode of the resistor R10 is connected to the base of the transistor Q6, one end of the resistor R10 is connected to the collector of the transistor Q6, and the other end is connected to the base of the transistor Q6.

The level conversion circuit is composed of resistor R1, resistor R2, resistor R3, resistor R4 and transistor Q1, transistor Q2, and transistor Q3, the collector of transistor Q1 is connected to the collector of transistor Q3, the emitter of transistor Q3 is grounded, and the transistor Q3 The collector-emitter of the transistor is the signal output terminal, the resistor R2 is directly connected in series with the collector of the transistor Q1, the emitter of the transistor Q2 is connected with the base of the transistor Q3, the collector of the transistor Q2 is connected with the base of the transistor Q1, and the base of the transistor Q3 pole and the signal input terminal, the resistor R4 is directly connected in series with the base of the transistor Q3, the resistor R3 is directly connected in series with the emitter of the transistor Q2, and the resistor R1 is connected between the emitter and the base of the transistor Q1, the self-lift The piezoelectric circuit is composed of diode D1, diode D2, capacitor C1, and capacitor C2. The cathode of diode D1 is connected to the anode of diode D2 and then connected to capacitor C1. Capacitor C2 is connected between the anode of diode D1 and the cathode of diode D2. Capacitor C1 Choose low ESR capacitors, choose fast recovery diodes for diode D1 and diode D2, and connect the emitter of transistor Q4 to the cathode of diode D2 and capacitor C2.

Compared with the prior art, the present invention has the following advantages: the circuit structure of the present invention is simple, and when a short circuit occurs at the solar panel end during charging, the MOS tube drive circuit can be quickly activated to cut off the charging circuit between the solar panel end and the storage battery end, and protect electronic components. Reduce the product repair rate and reduce the later cost investment.

Description of drawings

Fig. 1 is the principle block diagram block diagram of the solar controller driving circuit with short-circuit protection of the present invention;

Fig. 2 is a schematic block diagram of the circuit structure of the solar controller driving circuit with short circuit protection in the present invention.

specific embodiment

The solar controller driving circuit with short circuit protection of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Fig. 1 and Fig. 2, the solar controller drive circuit with short-circuit protection of the present invention is composed of a level shift circuit, a bootstrap boost circuit, a MOS tube drive circuit, and a short-circuit protection circuit. The level shift circuit and the bootstrap boost The circuit is connected, the bootstrap boost circuit is connected with the MOS drive circuit, and the level conversion circuit converts the square wave signal output by the MCU in the solar controller with a frequency of 50KHZ and an amplitude of 5V into a square wave signal with a frequency of 50KHZ and an amplitude of 12V. Wave signal, this signal is used as the input signal of the bootstrap boost circuit, the task of the bootstrap boost circuit is to boost the voltage of the solar panel terminal to 12V, which is used as the driving voltage of the MOS tube drive circuit.

The short-circuit protection circuit is connected with the MOS tube drive circuit. The drive signal of the MOS tube drive circuit is generated by the MCU, which is active at low level. When the short-circuit protection circuit is short-circuited by the solar panel during charging, the circuit can quickly act and cut off the MOS tube drive. signal, and generate a signal to turn off the MOS tube, and it can automatically resume charging when the short circuit is removed.

The short-circuit protection circuit is composed of resistor R12, resistor R13, transistor Q7 and diode D6. The anode of diode D6 is connected to the base of transistor Q7. Resistor R13 is directly connected in series with the cathode of diode D6. One end of resistor R12 is connected to the emitter of transistor Q7. pole, and the other end is connected to the base of the transistor Q7 and simultaneously connected to the anode of the diode D6. If a short circuit occurs at the solar panel side during charging, the PV+ terminal is pulled down to GND, the transistor Q7 is turned on, the voltage at point D is pulled up, Q5 is turned off, Q4 is turned off, and the MOS tube Q8 is turned off. The charging circuit is disconnected; when the short circuit is removed, Q7 is turned off, and the control of the MOS is determined by the drive signal PWM_PV.

The MOS drive circuit is composed of resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, transistor Q4, transistor Q5, transistor Q6, diode D3, diode D4, and diode D5. The collector of the transistor Q4 Connect the diode D4 and the resistor R6 in series and then connect it to the base of the transistor Q6, the anode of the diode D4 is connected to the collector of the transistor Q4, the emitter of the transistor Q4 is connected to the output of the bootstrap booster circuit, the collector of the transistor Q5 is connected to the diode D3 The cathode of the diode D3 is connected to the base of the transistor Q4, one end of the resistor R5 is connected to the base of the transistor Q4, and the other end is connected to the emitter of the transistor Q4, and the base of the transistor Q5 is connected in series with the resistor R8 and short-circuited The emitter of the transistor Q7 in the protection circuit is connected, the emitter of the transistor Q5 is connected in series with the resistor R9, and then connected to the collector of the transistor Q7 in the short-circuit protection circuit, and then connected to the MOS tube drive signal PWM_PV through the resistor R11, wherein one end of the resistor R11 It is connected with the collector of the transistor Q7 and the resistor R9, and the other end is connected with the driving signal PWM_PV of the MOS tube, the base of the transistor Q6 is connected with the anode of the diode D5, and the cathode of the diode D5 is connected with the emitter of the transistor Q6 after being connected in series with the resistor R7, The anode of the diode D5 is connected to the base of the transistor Q6, one end of the resistor R10 is connected to the collector of the transistor Q6, and the other end is connected to the base of the transistor Q6. The MOS drive signal PWM_PV is generated by the MCU and is active at low level. When PWM_PV is low level, Q4 and Q5 are turned on, Q6 is turned off, and the MOS tube is turned on; when PWM_PV is high level, Q4 and Q5 are turned off, Q6 is turned on, and the MOS tube is turned off. D5, R7, R10, and Q6 are used to accelerate the turn-off of the MOS tube.

The level conversion circuit is composed of resistor R1, resistor R2, resistor R3, resistor R4 and transistor Q1, transistor Q2, and transistor Q3. The collector of transistor Q1 is connected to the collector of transistor Q3, the emitter of transistor Q3 is grounded, and the collector of transistor Q3 The emitter is the signal output terminal, the resistor R2 is directly connected in series with the collector of the transistor Q1, the emitter of the transistor Q2 is connected with the base of the transistor Q3, the collector of the transistor Q2 is connected with the base of the transistor Q1, and the base of the transistor Q3 is connected with the base of the transistor Q3. At the signal input end, the resistor R4 is directly connected in series with the base of the transistor Q3, the resistor R3 is directly connected in series with the emitter of the transistor Q2, and the resistor R1 is connected between the emitter and the base of the transistor Q1. The square wave signal PN_BOOST output by the MCU has a frequency of 50KHZ and an amplitude of 5V. It enters the level conversion circuit from point A. After conversion, the signal at point B has a frequency of 50KHZ and an amplitude of 12V.

The bootstrap boost circuit is composed of diode D1, diode D2, capacitor C1, and capacitor C2. The cathode of diode D1 is connected to the anode of diode D2 and then connected to capacitor C1. Capacitor C2 is connected between the anode of diode D1 and the cathode of diode D2. The capacitor C1 is selected as a low ESR capacitor, the diode D1 and the diode D2 are selected as fast recovery diodes, and the emitter of the transistor Q4 is connected to the cathode of the diode D2 and the capacitor C2. When point B is at a low level, PV+ charges capacitor C1 to V _PV+ through a diode, and the function of D2 at this time is to prevent PV+ from charging C2; when point B is at a high level, since the charge of the capacitor cannot change suddenly, there are: Vpv ₊ ×C=(VDD_PV-V _Bm )×C, then VDD_PV=Vpv ₊ +V _Bm , where V _Bm is the voltage corresponding to the high level of point B. At this time, D1 can prevent the capacitor C1 from discharging to the PV+ terminal. In this way, the voltage at point C after passing through the level conversion circuit and the bootstrap boost circuit is: VDD_PV=Vpv ₊ +V _{CC_12V} . The bootstrap capacitor C1 should choose a low ESR capacitor, and the bootstrap diode should choose a fast recovery diode.

The following is the specific working process as follows:

Situation 1. When the solar panel is not short-circuited during the charging process: the square wave signal with a frequency of 50KHZ and an amplitude of 5V generated by the MCU passes through a level conversion circuit and a bootstrap boost circuit to obtain a VDD-PV voltage of (Vpv ₊ +V _{Cz_12V} ). When the MOS tube drive signal PWM_PV is at low level, the triode Q5 is turned on, Q4 is turned on, the voltage between the MOS tube GS is about 12V, and the MOS tube Q8 is turned on, the solar panel can charge the battery normally; when the MOS tube drive signal When the PWM-PV is at a high level, the triode Q5 and Q4 are cut off, the voltage between the MOS transistor GS is 0V, and the MOS transistor Q8 is turned off. In this case, the charging process is controlled by PWM_PV.

Situation 2: When the solar panel is short-circuited during charging: When the system is charging, the solar panel is short-circuited, the PV+ voltage is pulled down to GND, the transistor Q7 is turned on, the D voltage is pulled up to about 5V, and the transistor Q5 and Q4 are turned off. The voltage between the MOS tubes GS is 0V, the MOS tube Q8 is turned off, the short-circuit path at both ends of the battery is cut off, and other components such as the MOS tube and the fuse are protected.

Situation 3: The short circuit is removed after the short circuit protection: When the short circuit is removed, the PV+ voltage rises to a normal high voltage, and the transistor Q7 is cut off. Since the PWM_PV is at low level before the short circuit, the transistor Q5 is turned on, Q4 is turned on, and the MOS The voltage between the tubes GS is about 12V, the MOS tube Q8 is turned on, and the normal charging is automatically resumed.

The solar controller is an important bridge in the photovoltaic system. It connects solar modules to charge and discharge the battery, and provides reliable and effective protection for abnormal situations that may occur at any time. The invention provides a solar controller drive circuit with short-circuit protection. In the charging process, once the solar panel is short-circuited, the loop between the solar panel and the storage battery will be quickly blocked to implement reliable protection.

Claims (2)

1. A solar controller drive circuit with short-circuit protection, characterized in that: the solar controller drive circuit with short-circuit protection is made up of a level conversion circuit, a bootstrap boost circuit, a MOS tube drive circuit, and a short-circuit protection circuit , the level conversion circuit is connected with the bootstrap boost circuit, the bootstrap boost circuit is connected with the MOS drive circuit, and the level conversion circuit converts the square wave signal output by the MCU in the solar controller with a frequency of 50KHZ and an amplitude of 5V It is a square wave signal with a frequency of 50KHZ and an amplitude of 12V. This signal is used as the input signal of the bootstrap booster circuit. The task of the bootstrap booster circuit is to boost the voltage of the solar panel terminal by 12V. driving voltage, The short-circuit protection circuit is connected with the MOS tube drive circuit. The drive signal of the MOS tube drive circuit is generated by the MCU, and the low level is effective. When the short-circuit protection circuit short-circuits the solar panel during the charging process, the circuit can quickly act to cut off the MOS tube. Drive signal, and generate off MOS tube signal, when the short circuit is removed, it can automatically resume charging, The short-circuit protection circuit is composed of a resistor R12, a resistor R13, a transistor Q7 and a diode D6, the anode of the diode D6 is connected to the base of the transistor Q7, the resistor R13 is directly connected in series with the cathode of the diode D6, and one end of the resistor R12 is connected to the transistor Q7 The emitter, the other end is connected to the base of the transistor Q7 and at the same time connected to the anode of the diode D6, The MOS driving circuit is composed of resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, transistor Q4, transistor Q5, transistor Q6, diode D3, diode D4, and diode D5, wherein the transistor Q4 The collector is connected in series with the diode D4 and the resistor R6 in series and then connected to the base of the transistor Q6, the anode of the diode D4 is connected to the collector of the transistor Q4, the emitter of the transistor Q4 is connected to the output of the bootstrap booster circuit, the collector of the transistor Q5 is connected to the The anode of the diode D3 is connected, the cathode of the diode D3 is connected to the base of the transistor Q4, one end of the resistor R5 is connected to the base of the transistor Q4, and the other end is connected to the emitter of the transistor Q4, and the base of the transistor Q5 is connected in series with the resistor R8 It is connected with the emitter of the transistor Q7 in the short-circuit protection circuit, the emitter of the transistor Q5 is connected in series with the resistor R9, and then connected with the collector of the transistor Q7 in the short-circuit protection circuit, and then connected with the MOS tube drive signal PWM-PV through the resistor R11, wherein One end of the resistor R11 is connected to the collector of the transistor Q7 and the resistor R9, the other end is connected to the drive signal PWM_PV of the MOS tube, the base of the transistor Q6 is connected to the anode of the diode D5, and the cathode of the diode D5 is connected in series with the resistor R7 to the transistor Q6 The emitter is connected, the anode of the diode D5 is connected to the base of the transistor Q6, one end of the resistor R10 is connected to the collector of the transistor Q6, and the other end is connected to the base of the transistor Q6. 2. The solar controller drive circuit with short circuit protection according to claim 1, characterized in that: said level conversion circuit consists of resistor R1, resistor R2, resistor R3, resistor R4 and triode Q1, triode Q2, and triode Q3, The collector of the transistor Q1 is connected to the collector of the transistor Q3, the emitter of the transistor Q3 is grounded, the collector of the transistor Q3 is the signal output terminal, the resistor R2 is directly connected in series with the collector of the transistor Q1, the emitter of the transistor Q2 is connected to the transistor Q3 The base of the transistor Q2 is connected to the base of the transistor Q1, the base of the transistor Q3 is connected to the signal input terminal, the resistor R4 is directly connected in series with the base of the transistor Q3, and the resistor R3 is directly connected in series with the emitter of the transistor Q2 On, the resistor R1 is connected between the emitter and the base of the transistor Q1, The bootstrap boost circuit is composed of diode D1, diode D2, capacitor C1, and capacitor C2. The cathode of diode D1 is connected to the anode of diode D2 and then connected to capacitor C1. Capacitor C2 is connected between the anode of diode D1 and the cathode of diode D2. The capacitor C1 is selected as a low ESR capacitor, the diode D1 and the diode D2 are selected as fast recovery diodes, and the emitter of the transistor Q4 is connected to the cathode of the diode D2 and the capacitor C2.