High-voltage input and low-ripple output power supply applied to high-voltage optical storage system

Abstract

A power supply applied to high-voltage input and low-ripple output of a high-voltage optical storage system comprises a filtering unit and a power taking photovoltaic high-voltage input bus; a voltage division circuit divides the output of the filter unit to charge an energy storage capacitor so as to supply power to the drive circuit unit; the flyback circuit unit comprises a flyback transformer, MOS (Metal Oxide Semiconductor) tubes and multiple flyback transformer windings, the driving circuit unit outputs synchronous PWM (Pulse Width Modulation) signals to control the MOS tubes, each primary winding is bridged with the RCD absorption circuit and then is connected to the D pole of the MOS tube, the S pole of the MOS tube is connected with the next adjacent primary winding, and the flyback circuit unit inputs a voltage division circuit which is formed by bridged multiple resistors in series. The resistance is divided into equal parts corresponding to the number of windings, the S pole of each MOS tube is connected to a contact between two adjacent equal parts of series resistors, and the two ends of each equal part of series resistor are connected with a filter capacitor in parallel; the secondary output of the transformer is divided into multiple paths, one path forms first direct current output through the linear adjusting circuit unit, and the other path forms second direct current output through the rectifying and filtering circuit unit.

Description

Technical Field

[0001] The present invention relates to a high voltage input and low ripple output power supply device and a control method for a high voltage photovoltaic storage system. The power supply device designed by this scheme has high voltage input, a wide input voltage range, and different voltage outputs, and meets the characteristics of low ripple, high precision, low cost, high anti-interference ability, and high reliability. Background Art

[0002] High-voltage photovoltaic storage system refers to a system that uses solar energy to generate electricity and stores the electricity in energy storage equipment through high-voltage technology, so that the energy can be released to supply power when needed. At present, the photovoltaic storage system has the following problems and characteristics:

[0003] 1. Intermittent problem of renewable energy:

[0004] Solar power generation is intermittent, with power generation varying greatly between sunny and cloudy days. The high-voltage photovoltaic storage system stores excess solar power during the day and releases energy at night or on rainy days, thereby compensating for the unstable nature of solar power generation and providing stable power supply support to the grid.

[0005] 2. Power system operation flexibility requirements:

[0006] As the power system's requirements for flexibility and reliability continue to increase, high-voltage photovoltaic storage systems can store excess electricity generated by photovoltaic power generation and release it when needed, playing the role of energy storage and peak-filling, improving the flexibility of system scheduling and balancing the contradiction between supply and demand.

[0007] 3. Clean energy popularization trend:

[0008] The research and application of high-voltage photovoltaic storage systems will help alleviate the intermittent characteristics of renewable energy, improve the reliability and predictability of renewable energy, thereby promoting the large-scale application of clean energy and driving the transformation of the energy structure towards a clean and low-carbon direction.

[0009] Based on the above characteristics, low-voltage energy storage systems are currently developing towards high voltage, reducing losses by increasing voltage and improving the efficiency of the entire system. In the low-voltage energy storage solution, the DC side bus voltage has developed from the initial 600V to 1000V, and from 1000V to 1500V. Currently, the 1500V high-voltage energy storage system has become the mainstream solution in the market from 2023 to date. Not only that, the low-voltage energy storage solution is also moving towards a voltage level of more than 2000V. In this high-voltage energy storage system, it is particularly important to match the high-voltage power supply device of the system.

[0010] The current high-voltage energy storage system matching power supply usually adopts the method of direct voltage reduction by high-voltage transformer, which has the problems of large transformer volume, high voltage resistance requirements, complex manufacturing process, and high manufacturing cost; another solution is to combine different DC-DC topology solutions, such as Buck step-down plus LLC resonant conversion, but this solution requires a large number of MOS tubes, and the control logic is very complex, the manufacturing cost is high, and the software control algorithm is complex. If the existing topology solution is adopted, the input capacitor and switch tube of the high-voltage input power supply device require a very high voltage resistance level (for example, a 2000V photovoltaic energy storage system requires 2200V and above based on 1.1 times the voltage resistance), which greatly increases the cost of capacitors and switch devices. Due to the high voltage level (generally above 1000V) of the high-voltage photovoltaic storage system and the huge voltage difference with the control circuit voltage (generally around 3.3V), it is difficult for the control circuit to obtain power. At the same time, the existing design solutions generally have problems such as low efficiency due to the voltage difference problem, which is very unfavorable for photovoltaic systems with energy saving as the main indicator. Another solution is to add a 220V or 380V auxiliary power supply to the photovoltaic system, which undoubtedly increases the system cost. Therefore, it is necessary to design a power supply device that can meet the high voltage difference, high efficiency, and does not require external power supply for application in high-voltage photovoltaic storage systems. Summary of the invention

[0011] In view of the problems existing in the application of the power supply device of the above-mentioned high-voltage photovoltaic storage system, the patent of the present invention proposes a power supply device with an improved circuit topology scheme. By improving the existing high-voltage input power supply device, the power supply device is small in size, high in efficiency, good in stability, strong in anti-interference ability, low in output ripple, and low in manufacturing cost. By designing a high-voltage self-starting circuit, the problem that the high-voltage power supply needs an external auxiliary power supply is cleverly solved. At the same time, because the high-voltage self-starting circuit automatically shuts down after successful startup, the problem of long-term power consumption of the self-starting circuit is solved. Due to the high voltage of the photovoltaic storage high-voltage system, the voltage isolation between its input and output is a very important indicator. If the isolation effect is not good, it is easy to introduce interference on the high-voltage side, causing the control circuit to be damaged due to the high voltage. The topological structure and control method adopted by the present invention effectively solve the problem of electrical isolation between the high-voltage input side and the output side, and improve the anti-interference performance and save costs. The main topology of the patent of the present invention adopts a transformer with three or more windings connected in series to achieve voltage reduction processing for the high-voltage input power supply. The transformer itself is an inductive device with extremely small active power consumption. The traditional method of voltage division through series resistors causes great power loss to the resistor device itself and generates serious heat. It is not suitable for high-voltage photovoltaic storage systems that are sensitive to temperature because they contain batteries inside.

[0012] The purpose of the present invention is to address the above-mentioned deficiencies in the prior art and to provide a new power supply device and control method that meet the performance requirements of the high-voltage photovoltaic storage system power supply on volume, stability, efficiency and energy consumption, output progress, etc., and to design a high-voltage self-starting circuit to solve the problem of power supply of the control loop power supply system when the photovoltaic storage high-voltage power supply system has no auxiliary power supply, and to solve the problem of high-voltage electrical isolation between the input and output sides of the photovoltaic storage high-voltage system, while also being able to provide multiple high-precision power outputs.

[0013] To this end, a power supply with high voltage input and low ripple output for a high voltage photovoltaic storage system is provided, comprising a high voltage power input filter unit, a high voltage self-starting circuit unit, a driving circuit unit, a flyback circuit unit, a rectifier filter circuit unit, and a linear regulation circuit unit; the high voltage power input filter unit is connected to the photovoltaic high voltage input bus to take power; the high voltage self-starting circuit unit comprises a voltage divider circuit and an energy storage capacitor, the voltage divider circuit divides the electric energy provided by the high voltage power input filter unit to charge the energy storage capacitor, and the energy storage capacitor serves as an energy supply component of the driving circuit unit; the flyback circuit unit comprises a flyback transformer and a MOS tube, the flyback transformer has multiple windings, adjacent primary windings are connected in series through MOS tubes, and the driving circuit unit The PWM signal output by the element controls the on-off of each MOS tube, the two ends of each primary winding are connected across the RCD absorption circuit and then connected to the D pole of the MOS tube, the S pole of the MOS tube is connected to the next adjacent primary winding, the input end of the flyback circuit unit is connected across a voltage divider circuit formed by multiple resistors in series, the number of resistors is divided into equal parts corresponding to the number of windings, the S pole of each MOS tube is connected to the connection point between two adjacent equal parts of series resistors to form a series loop, and the two ends of each equal part of the series resistor are connected in parallel with a filter capacitor; the secondary output of the flyback transformer is divided into multiple paths, one path is formed through the linear regulation circuit unit to form a first DC output as a low-voltage power supply, and the other path is formed through the rectification and filtering circuit unit to form a second DC output as the output of the power supply.

[0014] Among them, a main filter capacitor is connected in parallel at both ends of each equal series resistor, and a secondary filter capacitor is connected in parallel with every two series resistors, and the filter capacitor serves as a component of the series loop.

[0015] The driving circuit unit includes a driving chip and a driving transformer. The driving chip generates PWM pulses to control the driving transformer to generate multiple synchronously output PWM signals.

[0016] Among them, the driving chip adopts the SF1565 PWM driver, which has 1 input port, 1 driving pulse output port, and 1 feedback control port; the output of the high-voltage power supply input filter unit is connected to the input port after multi-resistor current limiting, and the driving pulse output port is connected to the input terminal 1 of the driving transformer after the driving amplifier circuit composed of driving tubes Q5 and Q6. The driving transformer adopts three windings in parallel output to generate multiple synchronous output PWM signals.

[0017] The pin of the PWM signal output by each driving circuit unit is connected in parallel with an overvoltage absorption loop composed of a transistor Q7, a diode D22 and a diode D20.

[0018] Among them, it includes a flyback control circuit unit, which is used to control the driving circuit unit to generate a driving pulse signal. The flyback control circuit unit collects the output voltage and output current of the power supply. When the output voltage is greater than the designed output voltage, the pulse duty cycle of the driving circuit is reduced; when the output voltage is less than the designed output voltage, the duty cycle of the driving circuit output is increased.

[0019] Among them, the linear regulation circuit unit includes a half-wave rectifier circuit, a dual-tube push-pull linear conversion circuit, and a microprocessor; the inverting output end of the flyback transformer is rectified and filtered by the half-wave rectifier circuit and then provided with a first DC output by the dual-tube push-pull linear conversion circuit; the microprocessor samples the output voltage and output current of the first DC output, passes through an internal proportional integral differential regulator, and then generates an analog regulation amount for controlling the dual-tube push-pull linear conversion circuit by the analog-to-digital conversion unit. When the output voltage is less than the set voltage, the output of the analog quantity is increased; when the output voltage is greater than the required set voltage, the output of the analog quantity is reduced.

[0020] The update frequency of the analog quantity by the microprocessor is set to half of the sampling frequency.

[0021] Beneficial effects of the present invention:

[0022] The purpose of the present invention is to solve the problems of high voltage, high voltage rating, high device selection voltage resistance level, high device cost, low efficiency, and the need for additional auxiliary power supply to provide control power in the application of high-voltage photovoltaic storage system power supply devices. The present invention patent proposes a power supply device with an improved circuit topology scheme and a new control method. By improving the existing high-voltage input power supply device, a design topology and control method for a power supply device is proposed, which can achieve two-way or multi-way precise power output, adopt low voltage resistance level devices, and meet the requirements of high efficiency, good stability, strong anti-interference ability, low output ripple, and low manufacturing cost.

[0023] At the same time, by designing a high-voltage self-starting circuit, the problem that the high-voltage power supply needs an external auxiliary power supply is cleverly solved. At the same time, because the high-voltage self-starting circuit is automatically turned off after the high-voltage self-starting circuit is successfully started, the problem of long-term power consumption of the self-starting circuit is solved, and the energy consumption of the system is reduced. At the same time, due to the high voltage of the photovoltaic storage high-voltage system, the voltage isolation between its input and output is a very important indicator. If the isolation effect is not good, it is easy to introduce interference on the high-voltage side, causing the control loop to be damaged due to the high voltage. The topological structure and control method adopted by the present invention effectively solve the problem of electrical isolation between the high-voltage input side and the output side, and improve the anti-interference performance and save costs.

[0024] The main topology of the patent of the present invention adopts a transformer with three or more windings connected in series to achieve voltage reduction processing for the high-voltage input power supply. The transformer itself is an inductive device with extremely small active power consumption. Compared with the traditional method of dividing the voltage by series connection of resistors, the power loss of the resistor device itself is very large, and the heat is also very serious. It is not suitable for high-voltage photovoltaic storage systems that are sensitive to temperature because they contain batteries inside. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The block diagram of the high voltage input and low ripple output power supply device is shown;

[0026] Figure 2 A block diagram of a high voltage input and low ripple output power supply device control method 1 is shown;

[0027] Figure 3 A block diagram of a high voltage input and low ripple output power supply device control mode 2 is shown;

[0028] Figure 4 The working diagram of the self-starting circuit is shown;

[0029] Figure 5 The main topology circuit diagram of the power supply device is shown;

[0030] Figure 6 The main control circuit schematic diagram of the power supply device is shown;

[0031] Figure 7 The schematic diagram of the flyback control circuit and the isolation conversion circuit is shown;

[0032] Figure 8 The schematic diagram of the linear regulation circuit and the output circuit is shown;

[0033] Fig. 9 shows a schematic diagram of a driving circuit;

[0034] Fig.10 The schematic diagram of the self-starting circuit is shown;

[0035] Fig.11 The schematic diagram of the output current limiting protection circuit is shown;

[0036] Fig.12 shows the output overvoltage protection circuit schematic. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0038] The power supply device of the present invention includes a high-voltage power input filter unit, a high-voltage self-starting circuit unit, a driving circuit unit, a flyback circuit unit, a rectifier filter circuit unit, a linear regulator circuit unit, a voltage and current sampling circuit unit, a rectifier filter output circuit unit, and an MCU processor control unit. Figure 1 shown. Figure 1 The medium photovoltaic high-voltage energy storage bus is the input power supply end of the present invention and is not an internal component of the power supply device of the present invention.

[0039] The high-voltage power input filter unit is connected to the photovoltaic high-voltage input busbar to take power. It is composed of fuses, high-voltage common-mode inductors, varistors, high-voltage diodes, thermistors, other resistors and capacitors, etc. The high-voltage input filter circuit unit can effectively filter out and suppress voltage fluctuations caused by fluctuations at the high-voltage power input end and other interference. Varistors can protect the power supply device from damage to components due to overvoltage, and thermistors can achieve over-temperature protection.

[0040] When the power supply device is not started, the photovoltaic storage system has no low-voltage control power required by the control circuit except for the high-voltage power, and the entire system is in an inoperable state. The high-voltage self-starting circuit unit includes a voltage dividing circuit and an energy storage capacitor. The voltage dividing circuit divides the power provided by the high-voltage power input filter unit to charge the energy storage capacitor, and the energy storage capacitor serves as an energy supply component of the driving circuit unit. When the high-voltage self-starting circuit unit obtains the power provided by the high-voltage power input filter unit and is divided by the capacitor, the MOS tube and the transistor begin to charge the energy storage capacitor. When the energy storage capacitor is fully charged, it starts to drive the PWM driving chip to send pulses. When the output flyback conversion circuit and the output isolation transformer obtain the pulses sent by the driving chip, the entire power supply device starts to self-start and provide the system with stable low-voltage control power. When the output control power reaches a stable state, the MOS tube and the triode of the automatic circuit are turned off due to the pressure difference between the two ends of the self-starting circuit, and the self-starting circuit stops running, thereby realizing the function of reducing system losses.

[0041] The flyback control circuit unit is used to control the drive circuit unit to generate a drive pulse signal. It also collects the power supply output voltage and output current for the system feedback signal, which acts on the drive circuit to form a closed-loop negative feedback regulation control system. When the output voltage rises and is greater than the designed output voltage, the negative feedback system works to reduce the pulse duty cycle of the drive circuit to achieve step-down control. When the output voltage drops and is less than the designed output voltage, the negative feedback system increases the duty cycle of the drive circuit output to achieve step-up control, ensuring that the output voltage is always the voltage value required during design. The flyback control circuit unit can use hardware simulation (using devices such as MOS tubes and transistors) or digital (software PID regulator) to control the flyback circuit. Figure 2 Mode 1 and Figure 3Mode 2 is shown.

[0042] The drive circuit unit consists of a drive chip and a drive transformer. The drive chip can generate PWM pulses and generate three or more synchronously output PWM signals by controlling the drive transformer. At the same time, the drive chip also has a feedback adjustment input terminal, which can sample the voltage and current of the output circuit and add them to the feedback input terminal of the drive circuit to form a negative feedback closed-loop control system, controlling the drive circuit and the flyback circuit to form a stable output voltage.

[0043] The flyback circuit unit is the core of the power supply device, including a flyback transformer and a MOS tube. The flyback transformer has three or N windings. Adjacent primary windings are connected in series through MOS tubes. The PWM signal output by the driving circuit unit controls the on and off of each MOS tube. The two ends of each primary winding are connected across the RCD absorption circuit and then connected to the D pole of the MOS tube. The S pole of the MOS tube is connected to the next adjacent primary winding. The input end of the flyback circuit unit is connected across a voltage divider circuit formed by multiple resistors in series. The number of resistors is divided into equal parts corresponding to the number of windings. The S pole of each MOS tube is connected to the connection point between two adjacent equal series resistors to form a series loop. A main filter capacitor is connected in parallel to both ends of each equal series resistor, and a secondary filter capacitor is connected in parallel to every two series resistors. The filter capacitor is a component of the series loop. By connecting three windings (or multiple windings) of the transformer in series, the input voltage of the flyback transformer can be reduced to 1 / 3Vi n (input voltage) or 1 / N Vin. Firstly, the design difficulty and cost of the flyback transformer can be reduced. Secondly, since it is divided into three or more series circuits, the withstand voltage level of the components such as resistors, capacitors, diodes and MOS tubes is also reduced, thereby reducing the device cost. Thirdly, since the voltage is reduced, the interference effect on the control system will also be reduced, thereby improving the stability of the system.

[0044] The secondary output of the flyback transformer is divided into two or more paths to meet the requirements of different voltages and different output precisions. One path forms a first DC output through a linear regulation circuit unit, and the linear regulation circuit unit includes a half-wave rectifier circuit and a double-tube push-pull linear conversion circuit. The inverting output end of the flyback transformer is rectified and filtered by the half-wave rectifier circuit and then provided with a first DC output through a double-tube push-pull linear conversion circuit. The push-pull linear conversion circuit includes an operational amplifier, a double-tube push-pull linear regulation circuit, and a microprocessor MCU control circuit. The microprocessor MCU collects the output voltage and output current, passes through an internal proportional integral differential regulator (PID regulator), and then generates an analog regulation amount through an analog-to-digital conversion unit (DA unit), and then controls the push-pull circuit for linear output by the operational amplifier. The use of the push-pull circuit further isolates the input and output ends and improves the stability of the system. Due to the introduction of the linear regulation circuit, the output voltage can be accurately linearly regulated, which can meet the output requirements of high-precision power supplies in different occasions.

[0045] The other path forms a second DC output through a rectifier filter circuit unit. The rectifier filter circuit unit performs filtering after flyback conversion, and can use a half-wave rectifier circuit and a full-bridge rectifier circuit. The half-wave rectifier circuit has a lower cost and uses fewer components, so it is more applicable. The full-bridge rectifier circuit can improve the rectification effect and further reduce the system ripple, thereby improving the accuracy of the output voltage of the power supply device. An example of the patent of this invention selects a half-wave rectifier circuit.

[0046] Diversified power output is achieved through different circuit combinations. The example of the patent of this invention adopts two output units, one of which directly provides power output after rectification and filtering, meeting the power supply requirements of most applications. The other is rectified and filtered and then output through a linear adjustable circuit as a low-voltage power supply to meet the power supply requirements of precision devices such as control chips and sensors with higher output accuracy.

[0047] The voltage and current sampling circuit unit can use the ADC sampling chip inside the microprocessor MCU, or an external high-precision ADC sampling chip. In the specific embodiment of this patent, the internal sampling of the microprocessor is sampled, which reduces the system cost of the power supply device while meeting the accuracy requirements.

[0048] The rectifier filter output circuit unit is composed of output filter capacitors and inductors. By adding a filter circuit at the output end, the accuracy and temperature performance of the system can be further improved.

[0049] The MCU processor control unit acts as the central control and couples various sub-control systems.

[0050] like Figure 4 , Figure 5 As shown, the control method and steps are as follows:

[0051] After the self-starting circuit obtains the electric energy from the high-voltage photovoltaic storage system, it controls the MOS tubes M1, M2, and M3 through C13, C23, C29 and the voltage-dividing driving resistor R46 to control the transistor Q9 to turn on and charge the capacitor CD12. When the capacitor is fully charged, the transistor Q1 is controlled to turn on, thereby obtaining the voltage VDD of the control system (generally 3.3V or 5V, and the specific voltage is obtained by the resistor voltage divider mentioned above). At this time, VDD supplies power to the startup chip. After the driver chip is powered, it starts to send a driving pulse. The driving pulse generates a driving signal through the driving transformer, controls the secondary output voltage of the transformer, and then undergoes rectification, filtering, and linear regulation to make the output voltage reach a stable VDD voltage. When the secondary side output voltage reaches the stable VDD voltage, the transistor Q1 is turned off because the base and emitter voltages of the Q1 transistor are the same. This makes the self-starting circuit enter the closed state. The loss of the power supply system is reduced and the system efficiency is improved. Figure 6, Fig.10 shown.

[0052] The invention adopts the method of using three or more (N) transformer windings in series to divide the high input voltage into a low input voltage, and its working voltage is 1 / 3 or 1 / N of the traditional power supply voltage. The example of this patent adopts the method of three windings in series. The input voltage of the photovoltaic storage high-voltage power supply is input through the 6th pin of the flyback transformer TR1, and the 5th pin is connected to the MOS tube M5. The gate of the MOS tube is controlled by the driving signal G1 of the driving circuit. At the same time, D18, D19 and D39, capacitor C5 and resistor R8 form an RCD absorption circuit for the peak voltage generated during the switching process of the MOS tube; capacitors CD1 and CD2 are connected in parallel with the winding, resistors R5 and R6 are first connected in series and then in parallel to CD1, and resistors R7 and R8 are first connected in series in parallel with CD2, and their negative ends are connected to the S pole of the MOS tube M5. This circuit forms an automatic voltage equalization circuit for three windings. The 4th pin of the transformer TR1 is connected to the S pole of the MOS tube M5. Similarly, the 4-pin input and 3-pin output of transformer TR1 are connected to MOS tube M6, and the base of the MOS tube is controlled by the driving signal G2 of the driving circuit. At the same time, D23, D25, D40 and C17 form an RCD absorption circuit. The 2-pin input and 1-pin output of transformer TR1 are connected to MOS tube M7, and M7 is controlled by the driving signal G3 of the driving circuit. The RCD absorption circuit and automatic equalization circuit are also designed. Through the above design, the voltage of each group of transformers and resistors and capacitors is changed from the original input voltage Vin to only 1 / 3 Vin after the three windings are connected in series. This example uses a 2000V photovoltaic storage system. According to the traditional design scheme, the transformer needs to withstand a voltage of at least 2000V, and the corresponding filter capacitor and MOS tube need to withstand a minimum voltage of 2000V; while the minimum input voltage of the power transformer designed by the present invention is 2000 / 3=667V, the minimum voltage of the MOS tube used is also 667V, and the minimum design voltage of the matching resistor and capacitor is also reduced to 667V. Therefore, the use of this patent design will greatly reduce the difficulty of device selection. Figure 7 shown.

[0053] The output end of the isolation transformer can realize the output of multiple windings and multiple power supplies. A two-way output method is adopted, and the inverting output end of the isolation transformer is used as the positive end after isolation transformation. After rectification and filtering by the half-wave rectifier circuit, it is passed through the switch tubes Q3 and Q4 of the push-pull linear conversion circuit, and the power output is provided through the current sampling circuit and the output filter circuit. The digital analog output port of the microprocessor MCU controls the conduction of the switch tube Q3 through the DA input end after the linear adjustment after the operational amplifier. The microprocessor MCU samples the voltage and current of the first DC output. When the output voltage is less than the set voltage, the microprocessor MCU increases the output of the analog quantity, thereby increasing the output voltage; when the output voltage is greater than the required set voltage, the microprocessor MCU reduces the output of the analog quantity, thereby causing the output voltage to decrease. Through the continuous control of the closed-loop control system, a stable voltage output can be achieved. The sampling frequency of the microprocessor can be set to 20KHz, and the update frequency of the analog quantity of the microprocessor can be set to half of the sampling frequency, that is, 10KHz. The closed-loop regulation system designed in this way can achieve accurate voltage and current output. This output is generally used for the power supply of microprocessors and high-precision sensors and other chips. The other output directly samples the half-wave rectifier filter and then directly outputs after common-mode inductor filtering, which can provide power supply for most control system components. Figure 8 shown.

[0054] The driving circuit unit is composed of a driving chip and a driving transformer. The driving chip can generate PWM pulses and generate three or more synchronously output PWM signals by controlling the driving transformer. At the same time, the driving chip has a feedback adjustment input terminal, which can sample the voltage and current output by the power supply and add them to the feedback input terminal of the driving circuit to form a negative feedback closed-loop control system, which controls the driving circuit and the flyback circuit to form a stable output voltage. The driving chip of this patent example adopts the SF1565 PWM driver, which can generate reliable PWM pulse output signals and has 1 input port, 1 driving pulse output port, 1 feedback control port, etc. The output of the high-voltage power supply input filter unit is connected to the input port after current limiting by resistors R52, R64, R72, R78 and R138. The drive pulse output port is connected to the input terminal 1 of the drive transformer TR2 after the drive amplifier circuit composed of drive tubes Q5 and Q6. At the same time, the drive transformer TR2 adopts three windings in parallel to output, and generates drive pulse signals G1, G2 and G3 for driving the flyback transformer TR1; because these three signals are all generated by the transformer, the synchronous triggering performance of the pulses of the three series winding loops of the flyback transformer is guaranteed during operation. This has better driving performance than the traditional solution of sampling multiple pulse ports to generate drive pulses separately, and ensures that the flyback transformer will not be uneven due to the difference in drive pulses when connected in series, resulting in damage to resistors, capacitors and switching devices. The drive signal pin G1 is connected in parallel with an overvoltage absorption circuit consisting of transistor Q7, diodes D22 and D20. When the drive voltage is suddenly too high, the base and emitter of Q7 are turned on due to positive bias, thereby releasing excess energy to the GND section; when the energy release voltage decreases, the base and emitter voltage difference is the same, and transistor Q7 is turned off to continue to ensure the normal output of the drive signal. Fig. 9 shown.

[0055] The output overvoltage protection is designed by connecting the voltage output terminal Vout1+ to the overvoltage protection input terminal OUT+, and controlling the control pin of the photocoupler U6 after voltage division through multi-stage voltage regulator tubes DW1, DW2, DW13 and resistors R91 and R95. The output pin of the photocoupler controls the enable pin RT of the driver chip through transistor Q10; when the output terminal is overvoltage, the output voltage passes through the voltage regulator tube and the photocoupler U6 is turned on, controlling the transistor Q10 to output a high level, so that the driver chip turns off the output pulse signal, the flyback circuit stops working, and thus stops the power output. Fig.12 shown.

[0056] An output current limiting protection circuit is designed. The sampling resistor R19 between the power supply voltage output terminals SW1-12 and SW1-13 is connected to the output current sampling circuit. The power supply voltage output terminals SW1-12 and SW1-13 are connected to the overcurrent protection input terminal. The parallel capacitor C3 is used for filtering. The resistors R21, R25, R26, R27, R34 and the comparator U2A form a comparison circuit. The positive end of U2A is connected to the 2.5V comparison reference voltage, and the negative end of U2A is connected to the 2.5V reference voltage and the adjustable resistor U1, and connected to SW1-13; the output current limit value is set by adjusting the resistance value of U1. The comparator U2A is connected to the feedback terminal FB of the drive circuit after being isolated by a diode and a photocoupler U3. When the output current is too large, the output voltage of the comparator U2A decreases, the energy output by the photocoupler decreases, and the voltage of the output feedback FB decreases. The PWM pulse width output by the driver chip decreases, thereby reducing the output current. Thus, the purpose of output current limiting is achieved. Fig.11 shown.

[0057] Flyback control can be realized by using a digital circuit to generate a PWM pulse signal by a microprocessor, or by using an analog circuit to control a transistor and a driver chip. The digital circuit microprocessor samples the voltage and current through the internal sampling circuit unit, and then uses the internal digital proportional integral differential (PID) controller, and then the internal pulse generating PWM unit of the microprocessor controls the flyback circuit to perform closed-loop operation. This example uses an analog circuit and a startup chip to achieve this. The driver chip U10 uses the SF1565SGPWM driver.

[0058] 1. The power supply device of the present invention comprises a high-voltage power supply input filter unit, a high-voltage self-starting circuit unit, a flyback circuit unit, an isolation conversion circuit unit, a driving circuit unit, a rectifier filter circuit unit, a linear regulation circuit unit, a voltage and current sampling circuit unit, a rectifier filter output circuit unit, an MCU processor control unit and a multi-channel output circuit unit, which is very different from the existing high-voltage power supply design. Figure 1 shown.

[0059] 2. The invention adopts the method of using three or more (N) transformer windings in series to divide the high input voltage into a low input voltage, and its working voltage is 1 / 3 or 1 / N of the traditional power supply voltage. The voltage level of the input voltage is reduced, and the withstand voltage level of switching devices, capacitors, transformers, resistors and other devices is greatly reduced. The cost of these devices is greatly reduced due to the reduced withstand voltage. At the same time, the system stability is greatly improved after the input voltage is divided.

[0060] 3. The present invention realizes the power supply to the system processor MCU and control devices such as sampling and driving chips without external auxiliary power supply by applying high voltage into the self-starting circuit. Compared with the existing system that requires additional auxiliary power supply, it has great advantages and realizes the function that both the main circuit and the control circuit can be powered by the main circuit input.

[0061] 4. The topology of the present invention solves the problem of voltage imbalance between different windings due to input voltage through the design of a flyback control circuit, and realizes the automatic voltage and current equalization control function between different windings through the improvement of the circuit topology.

[0062] 5. The present invention realizes the overvoltage and overcurrent protection functions triggered by hardware design.

[0063] 6. The present invention adopts a transformer isolation method to isolate the input high voltage from the output side, thereby improving the stability of the system.

[0064] 7. The present invention adds a linear adjustable circuit to achieve further isolation between input and output, and adopts a linear adjustable control method to provide a linear adjustable output voltage.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A power supply with high voltage input and low ripple output applied to high voltage photovoltaic storage system, characterized by: It includes a high-voltage power supply input filter unit, a high-voltage self-starting circuit unit, a driving circuit unit, a flyback circuit unit, a rectifier filter circuit unit, and a linear regulation circuit unit; The high-voltage power input filter unit is connected to the photovoltaic high-voltage input bus to draw power; The high-voltage self-starting circuit unit includes a voltage-dividing circuit and an energy storage capacitor. The voltage-dividing circuit divides the electric energy provided by the high-voltage power supply input filter unit to charge the energy storage capacitor, and the energy storage capacitor serves as an energy supply component of the driving circuit unit. A flyback circuit unit includes a flyback transformer and a MOS tube. The flyback transformer has multiple windings. Adjacent primary windings are connected in series through MOS tubes. The PWM signal output by the driving circuit unit controls the on and off of each MOS tube. Both ends of each primary winding are connected across an RCD absorption circuit and then connected to the D pole of the MOS tube. The S pole of the MOS tube is connected to the next adjacent primary winding. The input end of the flyback circuit unit is connected across a voltage divider circuit formed by multiple resistors connected in series. The number of resistors is divided into equal parts corresponding to the number of windings. The S pole of each MOS tube is connected to the connection point between two adjacent equal parts of series resistors to form a series loop. Both ends of each equal part of the series resistor are connected in parallel with a filter capacitor. The secondary output of the flyback transformer is divided into multiple paths, one of which is formed into a first DC output through a linear regulation circuit unit as a low-voltage power supply, and the other is formed into a second DC output through a rectification and filtering circuit unit as the output of the power supply.

2. The power supply according to claim 1, characterized in that: A main filter capacitor is connected in parallel across each equal series resistor, and a secondary filter capacitor is connected in parallel across every two series resistors. The filter capacitor serves as a component of the series loop.

3. The power supply according to claim 1, characterized in that: The driving circuit unit includes a driving chip and a driving transformer. The driving chip generates PWM pulses to control the driving transformer to generate multi-channel synchronous output PWM signals.

4. The power supply according to claim 3, characterized in that: The driver chip uses the SF1565 PWM driver, which has 1 input port, 1 drive pulse output port, and 1 feedback control port; The output of the high-voltage power supply input filter unit is connected to the input port after being limited by multiple resistors. The drive pulse output port is connected to the input terminal 1 of the drive transformer after passing through the drive amplifier circuit composed of drive tubes Q5 and Q6. The drive transformer adopts three-winding parallel output to generate multi-channel synchronous output PWM signals.

5. The power supply according to claim 4, characterized in that: The pin of the PWM signal output by each driving circuit unit is connected in parallel with an overvoltage absorption circuit composed of a transistor Q7, a diode D22 and a diode D20.

6. The power supply according to claim 4, characterized in that: It includes a flyback control circuit unit, which is used to control the driving circuit unit to generate a driving pulse signal. The flyback control circuit unit collects the output voltage and output current of the power supply. When the output voltage is greater than the designed output voltage, the pulse duty cycle of the drive circuit is reduced; when the output voltage is less than the designed output voltage, the duty cycle of the drive circuit output is increased.

7. The power supply according to claim 4, characterized in that: The linear regulation circuit unit includes a half-wave rectification circuit, a double-tube push-pull linear conversion circuit, and a microprocessor; The inverting output end of the flyback transformer is rectified and filtered by a half-wave rectifier circuit and then provided with a first DC output by a double-tube push-pull linear conversion circuit; The microprocessor samples the output voltage and output current of the first DC output, passes through the internal proportional integral differential regulator, and then the analog digital conversion unit generates an analog adjustment amount for controlling the double-tube push-pull linear conversion circuit. When the output voltage is less than the set voltage, the output of the analog quantity is increased; when the output voltage is greater than the required set voltage, the output of the analog quantity is reduced.

8. The power supply according to claim 7, characterized in that: The microprocessor sets the update frequency of analog quantity to half of the sampling frequency.

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