CN103647454B - Photovoltaic system self powered supply circuit - Google Patents

Abstract

The present invention provides a photovoltaic system self-power supply circuit, including: lightning protection circuit, rectification filter circuit, power change circuit, PWM controller circuit, output voltage feedback circuit, output rectification filter circuit, coupling power change circuit and output rectification filter circuit The transformer T1 of the circuit; the input voltage enters the rectification filter circuit after passing through the lightning protection circuit, the output end of the rectification filter circuit is connected to the power change circuit and the PWM controller circuit, and the PWM controller circuit is connected to and drives the power change circuit; the output rectification filter circuit Including a first output loop and a second output loop, the first output loop and the second output loop are isolated from each other; the output voltage feedback circuit is used to feed back the sampling voltage in the first output loop or the second output loop to the PWM controller circuit . The invention is mainly used to realize the isolation of multiple output voltages.

Description

Photovoltaic system self-powered power supply circuit

technical field

The invention relates to a photovoltaic system self-power supply circuit, which can be widely applied to the power supply of a combiner box self-power supply monitoring device of a centralized or distributed solar power generation system.

Background technique

With the development of society, the demand for energy is becoming increasingly tense. China is very rich in solar energy resources. Accelerating the construction of photovoltaic power plants is not only in line with my country's national conditions, but will also more effectively promote the transformation of my country's economic structure and the optimization of energy structure. With the development of computer technology, people have higher and higher requirements for the monitoring of photovoltaic power plants, and the application of intelligent monitoring devices is becoming more and more popular. In this way, it is necessary to provide self-power supply for intelligent monitoring devices.

The voltage of the battery panel in the photovoltaic power station is generally as high as hundreds of volts, or even thousands of volts. The power input of the intelligent monitoring device is generally 24V or 5V. This requires the use of a self-powered power conversion device that can convert hundreds of volts or even thousands of volts into a stable 24V or 5V DC voltage for the intelligent monitoring device. Generally speaking, the main control circuit part, the switching value acquisition part and the RS485 communication part are required inside the intelligent monitoring device. The circuits of each part need to be connected to the system, which requires the necessary power supply to be isolated from each other. At present, the commonly used photovoltaic monitoring device power supply circuit can only provide one voltage of 24V or 5V, so when in use, the monitoring device needs to perform secondary isolation on each part of the circuit system through DCDC, which increases the circuit complexity and complexity of the monitoring device circuit. cost.

Contents of the invention

The purpose of the present invention is to provide a photovoltaic system self-power supply circuit, which can provide stable output of three isolation voltages. The technical scheme adopted in the present invention is:

A self-powered power supply circuit for a photovoltaic system, comprising: a lightning protection circuit, a rectification filter circuit, a power change circuit, a PWM controller circuit, an output voltage feedback circuit, an output rectification filter circuit, and a transformer coupling the power change circuit and the output rectification filter circuit T1; the input voltage enters the rectification filter circuit after passing through the lightning protection circuit, the output terminal of the rectification filter circuit is connected to the power change circuit and the PWM controller circuit, and the PWM controller circuit is connected to and drives the power change circuit; the output rectification filter circuit includes a first The output loop and the second output loop, the first output loop and the second output loop are isolated from each other; the output voltage feedback circuit is used to feed back the sampling voltage in the first output loop or the second output loop to the PWM controller circuit.

The power changing circuit includes a primary winding of a transformer T1, a transient voltage suppression diode TVS1, a diode D7, a resistor R8, a capacitor C10, a switch tube, namely an NMOS transistor Q1, resistors R22 and R23; the anode of the transient voltage suppression diode TVS1, the resistor One end of R8 and one end of capacitor C10 are jointly connected to the output end of the rectifier filter circuit and one end of the primary winding of transformer T1; the other end of resistor R8 and capacitor C10 are connected to the cathode of transient voltage suppression diode TVS1 and the cathode of diode D7; the primary winding of transformer T1 The other end is connected to the anode of the diode D7 and the drain of the NMOS transistor Q1, the source of the NMOS transistor Q1 is connected to the input ground GND_H through two parallel resistors R22 and R23; the gate of the NMOS transistor Q1 is connected to the PWM controller circuit.

The PWM controller circuit includes a PWM controller chip U1, resistors R9, R10, R12, R15, R24, R30, R17, R25, and a capacitor C23; the starting input terminal VIN of the PWM controller chip U1 passes through serially connected resistors R15, R12, R10, R9 are connected to the output terminal of the rectifier filter circuit; the ground terminal of the PWM controller chip U1 is connected to the input ground GND_H, the feedback terminal FB is connected to the output voltage feedback circuit, and the reference setting terminal RI is connected to the input ground GND_H through the resistor R24; the PWM controller The drive output terminal GATE of the chip U1 is connected to the gate of the NMOS transistor Q1 in the power changing circuit through the resistor R30; the current monitoring terminal CS of the PWM controller chip U1 is connected to the source of the NMOS transistor Q1 in the power changing circuit through the resistor R17 and the resistor R22 , the node connected to R23; the current monitoring terminal CS of the PWM controller chip U1 is connected to the input ground GND_H through the capacitor C23, and the temperature detection terminal RT is connected to the input ground GND_H through the resistor R25; the power supply terminal of the PWM controller chip U1 is connected from an auxiliary of the transformer T1 The winding is powered.

Specifically, one end of the auxiliary winding of the transformer T1 is connected to the input ground GND_H, the other end is connected to the anode of the diode D9, the cathode of the diode D9 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the power supply end of the PWM controller chip U1; capacitors C24, C21 and C20 are connected in parallel between the other end of the resistor R13 and the input ground GND_H.

The first output circuit includes the first secondary winding of transformer T1, resistor R7, capacitors C7, C8 and C9, diode D5, integrated voltage regulator block U2, capacitors C25 and C26; one end of the first secondary winding of transformer T1 is connected to The anode of the diode D5, the other end is connected to the first output ground GND_1; the cathode of the diode D5 is connected to one end of the capacitor C8, the positive electrode of the capacitor C9, and the input end of the integrated voltage stabilizing block U2; the other end of the capacitor C8 is connected to the negative electrode of the capacitor C9 The first output ground GND_1; the resistor R7 and the capacitor C7 are connected in series and then connected in parallel between the anode and the cathode of the diode D5; the output terminal of the integrated voltage stabilizing block U2 is connected to the positive pole of the capacitor C26 and one end of the capacitor C25, and the negative pole of the capacitor C26 is connected to the capacitor C25 The other terminal of U2 is connected to the first output ground GND_1; the ground terminal of the integrated voltage regulator block U2 is connected to the first output ground GND_1.

The second output circuit comprises a second secondary winding of transformer T1 with center tap and two output sections.

An output section comprising diodes D6 and D11, resistor R11, capacitors C13, C14 and C15, inductor L1, capacitors C1, C12 and C16, resistor R38; taps of the second secondary winding of transformer T1 connected to the anodes of diodes D6 and D11, and One end of the resistor R11, the other end of the resistor R11 is connected to one end of the capacitor C13; the cathodes of the diode D6 and D11 are connected together and connected to the other end of the capacitor C13, the positive pole of the capacitor C14, one end of the capacitor C15 and one end of the inductor L1; the inductor L1 The other end of the output part is used as the output end of the output part, connecting the positive pole of the capacitor C1, one end of the capacitor C12, the positive pole of the capacitor C16 and one end of the resistor R38; the negative pole of the capacitor C14, the other end of the capacitor C15, the negative pole of the capacitor C1, and the capacitor C12 The other end of the capacitor C16 and the other end of the resistor R38 are all connected to the second output ground GND_2; one end of the second secondary winding of the transformer T1 is connected to the second output ground GND_2.

Another output part includes diodes D10 and D8, resistor R14, capacitors C17, C18 and C19, resistor R34, PNP transistor Q4, resistor R33, NPN transistor Q5, resistors R36, R37 and R35, reference regulator chip U4, capacitor C29 , resistors R31 and R32, capacitors C30 and C31, resistor R39; the other end of the second secondary winding of transformer T1 is connected to the anodes of diodes D10 and D8, one end of resistor R14, the other end of resistor R14 is connected to one end of capacitor C17, diode D10 Connect with the cathode of D8 and connect the other end of capacitor C17, the positive pole of capacitor C18, one end of capacitor C19, one end of resistor R34, the emitter of transistor Q4, and one end of resistor R35; the negative pole of capacitor C18 and the other end of capacitor C19 One end is connected to the second output ground GND_2; the other end of the resistor R34 is connected to the base of the transistor Q4 and one end of the resistor R33; the other end of the resistor R33 is connected to the collector of the transistor Q5, and the emitter of the transistor Q5 is connected to the second output ground GND_2. The base of Q5 is connected to one end of the resistor R37, and connected to the second output ground GND_2 through the resistor R36; the other end of the resistor R37 is connected to the other end of the resistor R35, one end of the capacitor C29, and the cathode of the reference voltage regulator chip U4; the reference voltage regulator The anode of the source chip U4 is grounded, and the reference electrode is connected to the other end of the capacitor C29; one end of the resistor R31 is connected to the collector of the transistor Q4, and the other end is connected to the second output ground GND_2 through the resistor R32; the resistors R31 and R32 form a voltage divider circuit, and the connected The node is connected to the reference pole of the reference voltage stabilizing source chip U4; the collector of the triode Q4 is used as the output end of the other output part, and is connected to the positive pole of the capacitor C30, one end of the capacitor C31 and one end of the resistor R39; the negative pole of the capacitor C30, the capacitor C31 The other end of the resistor R39 and the other end of the resistor R39 are both connected to the second output ground GND_2.

The output voltage feedback circuit includes a capacitor C22, a photocoupler T2, resistors R18, R19, R20 and R21, a capacitor C28, and a reference voltage source chip P4; one end of the resistor R19 and one end of R20 are connected together and connected to the second output circuit The cathode of the middle diode D6 is used to obtain the sampling voltage fed back to the PWM controller circuit; the other end of the resistor R19 is connected to one end of the resistor R18 and the anode of the photocoupler T2; the cathode of the photocoupler T2 is connected to the other end of the resistor R18, One end of the capacitor C28 and the cathode of the reference voltage source chip P4; the other end of the capacitor C28 is connected to the reference end of the reference voltage source chip P4, the other end of the resistor R20, and one end of the resistor R21; the other end of the resistor R21 is connected to the reference voltage source chip P4 The anode of the photocoupler T2 is connected to the second output ground GND_2; the emitter of the photocoupler T2 is connected to one end of the capacitor C22 and the input ground GND_H; the collector of the photocoupler T2 is connected to the other end of the capacitor C22 and the PWM controller chip in the PWM controller circuit The feedback terminal FB of U1.

The PWM controller chip U1 is a PWM controller chip OB2269.

The integrated voltage stabilizing block U2 adopts the integrated voltage stabilizing block 7805.

Both the reference voltage stabilizing source chips U4 and P4 use the reference voltage stabilizing source chip TL432.

The advantages of the present invention: the present invention can realize the effective isolation of the main control circuit system of the intelligent monitoring device in the photovoltaic power station, the switching value acquisition system and the RS485 communication system, and reduce the circuit design and cost of the monitoring device. Has the following advantages,

1) Realize the stable output of 3 voltages, the output voltage is two +5V, one +24V.

2) Realize the mutual isolation of +5V voltage output and +24V voltage output.

3) The circuit is exquisitely designed, with few components and easy to test and measure.

Description of drawings

Fig. 1 is a structural block diagram of the present invention.

Fig. 2 is a circuit diagram of the present invention.

detailed description

The present invention will be further described below in conjunction with specific drawings and embodiments.

As shown in Figure 1 and Figure 2:

The photovoltaic system self-power supply circuit provided by the present invention includes: a lightning protection circuit, a rectification filter circuit, a power change circuit, a PWM controller circuit, an output voltage feedback circuit, an output rectification filter circuit, and a coupling power change circuit and an output rectification filter circuit. circuit transformer T1. The input voltage enters the rectification and filtering circuit after passing through the lightning protection circuit, the output end of the rectification and filtering circuit is connected to the power changing circuit and the PWM controller circuit, and the PWM controller circuit is connected to and drives the power changing circuit. The output rectifying and filtering circuit includes a first output loop and a second output loop, and the first output loop and the second output loop are isolated from each other. The output voltage feedback circuit is used to feed back the sampling voltage in the first output loop or the second output loop to the PWM controller circuit.

The input of this circuit is 150V-1200V, the output is 2 +5V, and 1 24V.

The lightning protection circuit is composed of resettable fuses PTC1, PTC2 and varistor RV1. They are there to prevent damage to circuits from lightning strikes.

The rectification filter circuit is composed of diodes D1~D4, capacitors C1~C3, and resistors R1~R6. Diodes D1~D4 constitute a full-wave rectification circuit, the cathodes of diodes D2 and D3 serve as the output terminals of the rectification and filtering circuit, and the anodes of diodes D1 and D4 are connected to the input ground GND_H. Capacitors C1~C3 and resistors R1~R6 form a filter circuit. After the AC voltage or DC voltage is rectified by D1~D4, relatively pure DC voltage is obtained through capacitors C1~C3 and resistors R1~R6. It should be noted that the VCC100V in the figure does not mean that the voltage at the changed point must be 1000v, but that it is a relatively high DC voltage, and it acts as a connection symbol.

The power changing circuit includes the primary winding of the transformer T1, the transient voltage suppression diode TVS1, the diode D7, the resistor R8, the capacitor C10, the switch tube, namely the NMOS tube Q1, the resistors R22 and R23; the anode of the transient voltage suppression diode TVS1, the resistor R8 One end and one end of capacitor C10 are jointly connected to the output end of the rectifier filter circuit and one end of the primary winding of transformer T1; the other end of resistor R8 and capacitor C10 are connected to the cathode of transient voltage suppression diode TVS1 and the cathode of diode D7; the other end of the primary winding of transformer T1 The anode of the diode D7 is connected to the drain of the NMOS transistor Q1, and the source of the NMOS transistor Q1 is connected to the input ground GND_H through two parallel resistors R22 and R23; the gate of the NMOS transistor Q1 is connected to the PWM controller circuit.

The PWM controller circuit includes a PWM controller chip U1, resistors R9, R10, R12, R15, R24, R30, R17, R25 and a capacitor C23. The start-up input terminal VIN of the PWM controller chip U1 is connected to the output terminal of the rectification and filtering circuit through serially connected resistors R15, R12, R10, and R9; the ground terminal of the PWM controller chip U1 is connected to the input ground GND_H, and the feedback terminal FB is connected to the output voltage feedback In the circuit, the reference setting terminal RI is connected to the input ground GND_H through the resistor R24. The drive output terminal GATE of the PWM controller chip U1 is connected to the gate of the NMOS transistor Q1 in the power changing circuit through the resistor R30; the current monitoring terminal CS of the PWM controller chip U1 is connected to the source of the NMOS transistor Q1 in the power changing circuit through the resistor R17 The node connected to the resistors R22 and R23; the current monitoring terminal CS of the PWM controller chip U1 is connected to the input ground GND_H through the capacitor C23, and the temperature detection terminal RT is connected to the input ground GND_H through the resistor R25.

The power terminal of the PWM controller chip U1 takes power from an auxiliary winding of the transformer T1. Specifically, one end of the auxiliary winding of the transformer T1 is connected to the input ground GND_H, the other end is connected to the anode of the diode D9, the cathode of the diode D9 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the power supply end of the PWM controller chip U1; capacitors C24, C21 and C20 are connected in parallel between the other end of the resistor R13 and the input ground GND_H.

The PWM controller chip U1 is a PWM controller chip OB2269. The pins are as follows:

1 pin: GND ground terminal;

Pin 2: FB feedback terminal;

Pin 3: VIN start input terminal;

Pin 4: RI reference setting terminal;

Pin 5: RT temperature detection terminal;

Pin 6: CS current monitoring terminal;

Pin 7: VDD power supply terminal;

Pin 8: GATE drive output.

The output rectifying and filtering circuit includes a first output loop and a second output loop.

The first output circuit includes the first secondary winding of the transformer T1, the resistor R7, the capacitors C7, C8 and C9, the diode D5, the integrated voltage stabilizing block U2, and the capacitors C25 and C26. One end of the first secondary winding of the transformer T1 is connected to the anode of the diode D5, and the other end is connected to the first output ground GND_1; the cathode of the diode D5 is connected to one end of the capacitor C8 and the positive electrode of the capacitor C9, and the input end of the integrated voltage stabilizing block U2; the capacitor The other end of C8 and the cathode of the capacitor C9 are connected to the first output ground GND_1; the resistor R7 and the capacitor C7 are connected in series and then connected in parallel between the anode and the cathode of the diode D5. The output terminal of the integrated voltage stabilizing block U2 is connected to the positive pole of the capacitor C26 and one end of the capacitor C25, the negative pole of the capacitor C26 and the other end of the capacitor C25 are connected to the first output ground GND_1; the ground terminal of the integrated voltage stabilizing block U2 is connected to the first output ground GND_1 . The output end of the integrated voltage stabilizing block U2 outputs the first +5V voltage. The integrated voltage regulator block U2 can use the integrated voltage regulator block 7805.

The second output loop consists of a second secondary winding of transformer T1 with center tap and two output sections.

An output section includes diodes D6 and D11, resistor R11, capacitors C13, C14 and C15, inductor L1, capacitors C1, C12 and C16, and resistor R38. The tap of the second secondary winding of transformer T1 is connected to the anodes of diodes D6 and D11, and one end of resistor R11, and the other end of resistor R11 is connected to one end of capacitor C13; the cathodes of diodes D6 and D11 are connected together and connected to the other end of capacitor C13 , the positive pole of capacitor C14, one end of capacitor C15 and one end of inductance L1; the other end of inductance L1 is used as the output end of the output part, connected to the positive pole of capacitor C1, one end of capacitor C12, the positive pole of capacitor C16 and one end of resistor R38; The negative pole of capacitor C14, the other end of capacitor C15, the negative pole of capacitor C1, the other end of capacitor C12, the negative pole of capacitor C16 and the other end of resistor R38 are all connected to the second output ground GND_2; one end of the second secondary winding of transformer T1 is connected to The second output ground GND_2. This output part outputs the second +5v voltage.

Another output part includes diodes D10 and D8, resistor R14, capacitors C17, C18 and C19, resistor R34, PNP transistor Q4, resistor R33, NPN transistor Q5, resistors R36, R37 and R35, reference regulator chip U4, capacitor C29 , resistors R31 and R32, capacitors C30 and C31, resistor R39. The other end of the second secondary winding of transformer T1 is connected to the anodes of diodes D10 and D8, one end of resistor R14, the other end of resistor R14 is connected to one end of capacitor C17, the cathodes of diodes D10 and D8 are connected together and connected to the other end of capacitor C17 , the positive pole of capacitor C18, one end of capacitor C19, one end of resistor R34, the emitter of transistor Q4, and one end of resistor R35; the negative pole of capacitor C18 and the other end of capacitor C19 are connected to the second output ground GND_2; the other end of resistor R34 is connected to The base of the transistor Q4 and one end of the resistor R33; the other end of the resistor R33 is connected to the collector of the transistor Q5, the emitter of the transistor Q5 is connected to the second output ground GND_2, the base of the transistor Q5 is connected to one end of the resistor R37, and passes through the resistor R36 Connect to the second output ground GND_2; the other end of the resistor R37 is connected to the other end of the resistor R35, one end of the capacitor C29, and the cathode of the reference voltage regulator chip U4; the anode of the reference voltage regulator chip U4 is grounded, and the reference electrode is connected to the other end of the capacitor C29 one end. One end of the resistor R31 is connected to the collector of the triode Q4, and the other end is connected to the second output ground GND_2 through the resistor R32; the resistors R31 and R32 form a voltage divider circuit, and the connected node is connected to the reference pole of the reference voltage regulator chip U4. The collector of the triode Q4 is used as the output terminal of the other output part, connected to the positive pole of the capacitor C30, one end of the capacitor C31 and one end of the resistor R39; the negative pole of the capacitor C30, the other end of the capacitor C31 and the other end of the resistor R39 are all connected to the first The second output ground is GND_2. This output part outputs the second +24v voltage.

The output voltage feedback circuit includes capacitor C22, photocoupler T2, resistors R18, R19, R20 and R21, capacitor C28, and reference voltage source chip P4. One end of resistor R19 and one end of R20 are connected together and connected to the cathode of diode D6 in the second output loop to obtain the sampling voltage fed back to the PWM controller circuit; (in this example, the sampling voltage is +5v, ie VCC5V in). The other end of resistor R19 is connected to one end of resistor R18 and the anode of photocoupler T2; the cathode of photocoupler T2 is connected to the other end of resistor R18, one end of capacitor C28 and the cathode of reference voltage source chip P4; the other end of capacitor C28 is connected to The reference terminal of the reference voltage source chip P4, the other end of the resistor R20, and one end of the resistor R21; the other end of the resistor R21 and the anode of the reference voltage source chip P4 are all connected to the second output ground GND_2. The emitter of the photocoupler T2 is connected to one end of the capacitor C22 and the input ground GND_H; the collector of the photocoupler T2 is connected to the other end of the capacitor C22 and the feedback terminal FB of the PWM controller chip U1 in the PWM controller circuit.

The reference voltage regulator chips U4 and P4 both use the reference voltage regulator chip TL432.

The working principles of the above-mentioned main circuits are analyzed below.

In the power changing circuit, D7, TVS1, R8, and C10 form a buffer, and are connected in parallel with the switch tube Q1, so that the voltage stress of the switch tube is reduced, EMI is reduced, and secondary breakdown does not occur. When the switch tube Q1 is turned off, the primary coil (primary winding) of the transformer is prone to generate peak voltage and peak current. The combination of these components can absorb the peak voltage and current well. The current peak signal measured from R22 and R23 participates in the duty ratio control of the current working cycle. When the voltage on R22 and R23 reaches 1V, U1 stops working, and the switch tube Q1 is turned off immediately. The controlled voltage of Q1 is a PWM waveform with a variable duty cycle. When the duty cycle is larger, the longer the on-time of Q1 is, the more energy stored in the transformer will be; when Q1 is cut off, the transformer will pass through D7 and R8 , C10, and TVS1 release energy, and at the same time achieve the purpose of resetting the magnetic field, making preparations for the next energy storage and transmission of the transformer. U1 constantly adjusts the duty cycle of the PWM waveform according to the output voltage and current, thereby stabilizing the output current and voltage of the whole machine.

The PWM controller circuit receives the signal from the output voltage feedback circuit, generates a PWM signal, controls the conduction and closure of the MOS tube, and realizes the purpose of stabilizing the output voltage.

The output voltage feedback circuit is mainly composed of C22, T2, R18, R19, R20, R21, C28, and P4. When the sampling voltage is higher than 5V, the optocoupler T2 is turned on, and the phototransistor inside the optocoupler is turned on. At this time, the voltage of the feedback terminal FB is low, and the PWM waveform output is low at this time. When the sampling voltage is lower than 5V, the optocoupler is disconnected, and the phototransistor inside the optocoupler is disconnected. At this time, the voltage of the feedback terminal FB is high, and the PWM waveform output is high at this time. Through sampling voltage feedback, the purpose of output voltage stability is finally achieved.

The output rectifying and filtering circuit includes a first output loop and a second output loop. The first output circuit is used to output one channel of +5V, and the second output circuit is used to output another channel of +5V and +24V, and the two channels are isolated from each other. The first output loop includes R7, C7, C8, C9, D5, U2, C25, and C26; the output voltage is filtered by R7, C7, C8, and C9, and then a stable +5V voltage output is achieved through the integrated voltage regulator block 7805. The maximum output power is 2.5W.

The second output loop includes two output sections. The output +5V part includes D6, D11, R11, C13, C14, C15, L1, C1, C12, C16, R38, and the output +5V is used as the input feedback voltage. The circuit forms a π-type filter network, which mainly filters the output voltage signal. Output +24V part, including D10, D8, R14, C17, C18, C19, R34, Q4, R33, Q5, R36, R37, R35, U4, C29, R31, R32, C30, C31, R39, to generate stable The +24V voltage.

The invention adopts a switching power supply circuit with multiple outputs. By controlling the PWM duty of the MOS switch tube and the feedback of the output voltage signal, as well as the mutual isolation of the output circuits, the stable output and isolation of multiple voltages are realized.

Claims (5)

1. a photovoltaic system self powered supply circuit, it is characterized in that, comprise: lightning protection circuit, current rectifying and wave filtering circuit, power-varying circuitry, PWM controller circuit, output voltage feedback circuit, output rectifier and filter, and the transformer T1 of coupled power varying circuit and output rectifier and filter;

Input voltage is by entering current rectifying and wave filtering circuit after lightning protection circuit, and the output of current rectifying and wave filtering circuit connects power-varying circuitry and PWM controller circuit, and PWM controller circuit connects and driving power varying circuit;

Described output rectifier and filter comprises the first output loop and the second output loop, the first output loop and the second output loop mutually isolated;

Described output voltage feedback circuit is for feeding back sampling voltage in the first output loop or the second output loop to PWM controller circuit;

Described power-varying circuitry comprises the armature winding of transformer T1, transient voltage suppressor TVS1, diode D7, resistance R8, electric capacity C10, switching tube and NMOS tube Q1, resistance R22 and R23;

One end of the anode of transient voltage suppressor TVS1, one end of resistance R8 and electric capacity C10 connects output and transformer T1 armature winding one end of current rectifying and wave filtering circuit jointly; The negative electrode of another termination transient voltage suppressor TVS1 of resistance R8 and electric capacity C10 and the negative electrode of diode D7; The anode of another terminating diode of transformer T1 armature winding D7 and the drain electrode of NMOS tube Q1, the source electrode of NMOS tube Q1 meets input ground GND_H by two resistance R22 and R23 in parallel; The grid of NMOS tube Q1 connects PWM controller circuit;

Described PWM controller circuit comprises PWM controller chip U1, resistance R9, R10, R12, R15, R24, R30, R17, R25 and electric capacity C23;

The startup input VIN of PWM controller chip U1 connects the output of current rectifying and wave filtering circuit by resistance R15, R12, R10, the R9 connected successively; The ground connection termination input ground GND_H of PWM controller chip U1, feedback end FB connects output voltage feedback circuit, meets input ground GND_H with reference to arranging end RI by resistance R24;

The drive output GATE of PWM controller chip U1 connects the grid of the NMOS tube Q1 in power-varying circuitry by resistance R30; The node that the current monitoring end CS of PWM controller chip U1 meets NMOS tube Q1 in power-varying circuitry source electrode by resistance R17 is connected with resistance R22, R23; The current monitoring end CS of PWM controller chip U1 meets input ground GND_H, temperature detection end RT by electric capacity C23 and meets input ground GND_H by resistance R25;

The power end of PWM controller chip U1 is from an auxiliary winding power taking of transformer T1;

The auxiliary winding one termination input ground GND_H of transformer T1, the anode of another terminating diode D9, one end of the negative electrode connecting resistance R13 of diode D9, the power end of another termination PWM controller chip U1 of resistance R13; Electric capacity C24, C21 and C20 are connected in parallel between the other end of resistance R13 and input ground GND_H;

First output loop comprises the first secondary winding, the resistance R7 of transformer T1, electric capacity C7, C8 and C9, diode D5, integrated voltage stabilizer U2, electric capacity C25 and C26;

The anode of one terminating diode D5 of transformer T1 first secondary winding, another termination first exports ground GND_1; The negative electrode of diode D5 connects one end of electric capacity C8 and the positive pole of electric capacity C9, and the input of integrated voltage stabilizer U2; The other end of electric capacity C8 and the negative pole of electric capacity C9 meet the first output ground GND_1; Between the anode that resistance R7 and electric capacity C7 is connected in parallel on diode D5 after connecting again and negative electrode;

The positive pole of the output termination capacitor C26 of integrated voltage stabilizer U2 and one end of electric capacity C25, the negative pole of electric capacity C26 and another termination first of electric capacity C25 export ground GND_1; The ground connection termination first of integrated voltage stabilizer U2 exports ground GND_1;

Second output loop comprises the tapped transformer T1 second subprime winding of band and two outputs;

An output comprises diode D6 and D11, resistance R11, electric capacity C13, C14 and C15, inductance L 1, electric capacity C1, C12 and C16, resistance R38;

The tap of transformer T1 second subprime winding connects the anode of diode D6 and D11 and one end of resistance R11, one end of another termination capacitor C13 of resistance R11; The negative electrode of diode D6 with D11 links together and is connected one end of the other end of electric capacity C13, the positive pole of electric capacity C14, one end of electric capacity C15 and inductance L 1; The other end of inductance L 1, as the output of this output, connects one end of the positive pole of electric capacity C1, one end of electric capacity C12, the positive pole of electric capacity C16 and resistance R38; The other end of the negative pole of the negative pole of electric capacity C14, the other end of electric capacity C15, electric capacity C1, the other end of electric capacity C12, the negative pole of electric capacity C16 and resistance R38 all meets the second output ground GND_2; One termination second of transformer T1 second subprime winding exports ground GND_2;

Another output comprises diode D10 and D8, resistance R14, electric capacity C17, C18 and C19, resistance R34, PNP triode Q4, resistance R33, NPN triode Q5, resistance R36, R37 and R35, reference voltage stabilizing source chip U4, electric capacity C29, resistance R31 and R32, electric capacity C30 and C31, resistance R39;

The anode of another terminating diode D10 and D8 of transformer T1 second subprime winding, one end of resistance R14, one end of another termination capacitor C17 of resistance R14, the negative electrode of diode D10 with D8 links together and is connected the other end of electric capacity C17, the positive pole of electric capacity C18, one end of electric capacity C19, one end of resistance R34, the emitter of triode Q4, one end of resistance R35; The negative pole of electric capacity C18 and another termination second of electric capacity C19 export ground GND_2; The base stage of another termination triode Q4 of resistance R34 and one end of resistance R33; The collector electrode of another termination triode Q5 of resistance R33, the emitter of triode Q5 connects one end of the base stage connecting resistance R37 of the second output ground GND_2, triode Q5, and meets the second output ground GND_2 by resistance R36; The negative electrode of the other end of the other end connecting resistance R35 of resistance R37, one end of electric capacity C29, reference voltage stabilizing source chip U4; The plus earth of reference voltage stabilizing source chip U4, connects the other end of electric capacity C29 with reference to pole;

The collector electrode of the one termination triode Q4 of resistance R31, the other end meets the second output ground GND_2 by resistance R32; Resistance R31 and R32 forms bleeder circuit, and the node of connection connects the reference pole of reference voltage stabilizing source chip U4;

The collector electrode of triode Q4, as the output of this another output, connects the positive pole of electric capacity C30, one end of electric capacity C31 and one end of resistance R39; The other end of the negative pole of electric capacity C30, the other end of electric capacity C31 and resistance R39 all meets the second output ground GND_2.

2. photovoltaic system self powered supply circuit as claimed in claim 1, is characterized in that:

Described output voltage feedback circuit comprises electric capacity C22, photoelectrical coupler T2, resistance R18, R19, R20 and R21, electric capacity C28, reference voltage stabilizing source chip P4;

One end of resistance R19 links together with one end of R20 and is connected the negative electrode of diode D6 in the second output loop, for obtaining the sampling voltage feeding back to PWM controller circuit;

One end of other end connecting resistance R18 of resistance R19 and the anode of photoelectrical coupler T2; The negative electrode of the other end of negative electrode connecting resistance R18 of photoelectrical coupler T2, one end of electric capacity C28 and reference voltage stabilizing source chip P4; The reference edge of another termination reference voltage stabilizing source chip P4 of electric capacity C28, the other end of resistance R20, one end of resistance R21; The other end of resistance R21 and the anode of reference voltage stabilizing source chip P4 all meet the second output ground GND_2;

The emitter of photoelectrical coupler T2 meets one end and the input ground GND_H of electric capacity C22; The collector electrode of photoelectrical coupler T2 meets the feedback end FB of PWM controller chip U1 in the other end of electric capacity C22 and PWM controller circuit.

3. the photovoltaic system self powered supply circuit according to any one of claim 1 ~ 2, is characterized in that: described PWM controller chip U1 adopts PWM controller chip OB2269.

4. the photovoltaic system self powered supply circuit according to any one of claim 1 ~ 2, is characterized in that:

Described integrated voltage stabilizer U2 adopts integrated voltage stabilizer 7805.

5. photovoltaic system self powered supply circuit as claimed in claim 1, is characterized in that:

Described reference voltage stabilizing source chip U4 and P4 all adopts reference voltage stabilizing source chip TL432.