Auxiliary power supply applied to wide voltage range input and optimization method

Abstract

The invention discloses an auxiliary power supply applied to wide voltage range input and an optimization method.The auxiliary power supply comprises a starting circuit and a flyback conversion circuit, the starting circuit comprises a starting resistor, a high-voltage switch and a control unit of the high-voltage switch, and the flyback conversion circuit at least comprises a transformer. Based on the voltage output by the secondary winding of the transformer, the starting resistor can be disconnected from the circuit through the high-voltage switch and the control unit of the high-voltage switch, so that the loss of the starting resistor is reduced. By optimizing the input starting circuit, the working voltage range of the auxiliary power supply can be enlarged, the conversion efficiency is improved under the wide-range working voltage, the temperature of a device is reduced, and the stability of a product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic energy storage inverter power supply, and in particular to an auxiliary power supply applied to wide voltage range input and an optimization method thereof. Background Art

[0002] Energy shortage and environmental degradation are global issues. Developing renewable energy, optimizing energy allocation, and developing a low-carbon economy are the common choices of countries around the world. Renewable resources are greatly affected by weather and time periods, and are obviously unstable, discontinuous, and uncontrollable. The development of energy storage technology has largely solved the problems of randomness and volatility in new energy power generation. With the rapid development of the new energy industry, in order to better utilize these renewable energy sources, high efficiency and high power density have become hot topics in industry research.

[0003] In conventional auxiliary power supply design, the input voltage fluctuation range generally does not exceed 50% of the rated voltage. When the input voltage variation range is large, high voltage input will cause greater losses in the startup circuit. When the requirements of high voltage input and low loss are met, the power supply startup voltage will become higher, that is, the voltage variation range cannot be too large. Summary of the invention

[0004] The technical problem to be solved by the present invention is that when the input voltage changes over a wide range, the loss of the starting resistor in the auxiliary power supply increases rapidly as the input voltage increases, and the power supply efficiency is significantly reduced. In order to solve the above problem, the present invention proposes an auxiliary power supply for wide voltage range input and an optimization method, which can take into account the requirements of low starting voltage and low starting circuit loss when the input voltage is low and high.

[0005] The technical solution adopted by the present invention is as follows:

[0006] An auxiliary power supply for wide voltage range input includes a starting circuit and a flyback conversion circuit. The starting circuit includes a starting resistor, a high voltage switch and a control unit thereof. The flyback conversion circuit includes at least a transformer. Based on the voltage output by the secondary winding of the transformer, the starting resistor can be disconnected from the circuit through the high voltage switch and the control unit thereof, thereby reducing the loss on the starting resistor.

[0007] Furthermore, the startup circuit includes a startup resistor, a first switch tube, a second switch tube, a first voltage regulator tube, a second voltage regulator tube, a diode, a capacitor, a second resistor, a third resistor and a fourth resistor, wherein: the drain of the first switch tube is connected to the input voltage through the startup resistor, the source is connected to the anode of the first voltage regulator tube, the cathode of the second voltage regulator tube and the first end of the capacitor, and the gate is connected to the second end of the second resistor, the anode of the diode and the drain of the second switch tube; the cathode of the first voltage regulator tube is connected to the cathode of the diode, the anode of the second voltage regulator tube and the second end of the capacitor are grounded, and the first end of the second resistor is connected to the input voltage; the gate of the second switch tube is grounded through the third resistor, and is connected to the flyback conversion circuit through the fourth resistor, and the source is grounded.

[0008] Furthermore, after being stabilized by the startup resistor, the first switch tube, the capacitor and the second voltage regulator tube, the input voltage provides an initial startup voltage and current for the target integrated circuit.

[0009] Furthermore, when the power supply is started, the second resistor, the diode and the first voltage regulator provide voltage to the first switch tube, so that the first switch tube is turned on; the input voltage charges the capacitor through the starting resistor and the first switch tube, and the second voltage regulator tube ensures that the starting voltage does not exceed the power supply range of the target integrated circuit.

[0010] Furthermore, in the flyback conversion circuit, the primary winding of the transformer is connected to the input voltage, and the voltage output by the first secondary winding is rectified and filtered to provide power for the target integrated circuit. At the same time, the second switch tube is controlled to be turned on after voltage division, and the gate of the first switch tube is pulled down to turn off the first switch tube, thereby disconnecting the starting resistor from the circuit.

[0011] An auxiliary power optimization method for wide voltage range input, comprising:

[0012] Optimize the startup circuit of the auxiliary power supply and add a high-voltage switch and its control unit;

[0013] When the auxiliary power supply starts normally, based on the voltage output by the secondary winding of the transformer of the flyback conversion circuit in the auxiliary power supply, the starting resistor of the starting circuit is disconnected from the circuit through the high-voltage switch and its control unit, thereby reducing the loss on the starting resistor.

[0014] Furthermore, the startup circuit includes a startup resistor, a first switch tube, a second switch tube, a first voltage regulator tube, a second voltage regulator tube, a diode, a capacitor, a second resistor, a third resistor and a fourth resistor, wherein: the drain of the first switch tube is connected to the input voltage through the startup resistor, the source is connected to the anode of the first voltage regulator tube, the cathode of the second voltage regulator tube and the first end of the capacitor, and the gate is connected to the second end of the second resistor, the anode of the diode and the drain of the second switch tube; the cathode of the first voltage regulator tube is connected to the cathode of the diode, the anode of the second voltage regulator tube and the second end of the capacitor are grounded, and the first end of the second resistor is connected to the input voltage; the gate of the second switch tube is grounded through the third resistor, and is connected to the flyback conversion circuit through the fourth resistor, and the source is grounded.

[0015] Furthermore, after being stabilized by the startup resistor, the first switch tube, the capacitor and the second voltage regulator tube, the input voltage provides an initial startup voltage and current for the target integrated circuit.

[0016] Furthermore, when the power supply is started, the second resistor, the diode and the first voltage regulator provide voltage to the first switch tube, so that the first switch tube is turned on; the input voltage charges the capacitor through the starting resistor and the first switch tube, and the second voltage regulator tube ensures that the starting voltage does not exceed the power supply range of the target integrated circuit.

[0017] Furthermore, in the flyback conversion circuit, the primary winding of the transformer is connected to the input voltage, and the voltage output by the first secondary winding is rectified and filtered to provide power for the target integrated circuit. At the same time, the second switch tube is controlled to be turned on after voltage division, and the gate of the first switch tube is pulled down to turn off the first switch tube, thereby disconnecting the starting resistor from the circuit.

[0018] The beneficial effects of the present invention are:

[0019] The present invention is directed to a photovoltaic energy storage inverter, and by optimizing an input start-up circuit, the operating voltage range of an auxiliary power supply can be increased, and under a wide range of operating voltages, conversion efficiency can be improved, device temperature can be reduced, and product stability can be improved.

[0020] The auxiliary power supply of the present invention has an operating DC voltage range of up to 70V-1100V, and can take into account the requirements of low starting voltage and low starting circuit loss at high input voltage, and can overcome the disadvantage of excessive starting resistance loss of auxiliary power supplies in traditional industries when working under a wide range of input voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of a conventional power supply solution.

[0022] Figure 2 The present invention is a schematic diagram of a startup circuit for inputting a wide voltage range.

[0023] Figure 3 The invention is a schematic diagram of an auxiliary power supply circuit for inputting a wide voltage range. DETAILED DESCRIPTION

[0024] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0025] The startup circuit of the auxiliary power supply requires a certain startup current when the control IC (U1) starts. Figure 1 As shown, the conventional solution is to connect resistor Rs and voltage regulator Dvr1 in series between high voltage VH and VH_GND, where Dvr1 is used for voltage stabilization to ensure that the voltage Vdd provided to U1 is within the appropriate range. The resistance value of Rs needs to be determined based on the chip's startup current Istart, input voltage VH and voltage regulator voltage Vr1, and Rs≤(VH-Vr1) / Istart. For the selected control IC, the startup current Istart has been determined. When the input voltage VH changes between the lowest voltage VH1 and the highest voltage VH2, and the value of VH2 / VH1 is large (for example, VH2 / VH1≥5), the resistance value of Rs cannot be too large. At this time, the power consumption on Rs Prs=(VH2-Vr1) 2 / Rs, the power consumption on the startup resistor Rs will increase significantly at the highest voltage VH2.

[0026] Based on this, this embodiment provides an auxiliary power supply for wide voltage range input, including a startup circuit and a flyback conversion circuit. The startup circuit part is optimized based on the conventional power supply solution to adapt to the characteristics of a large input voltage range of a photovoltaic inverter, and the flyback conversion circuit maintains the conventional solution.

[0027] The startup circuit of this embodiment optimizes the connection circuit of the startup resistor Rs, adds a high-voltage switch and a corresponding control circuit, and can disconnect the startup resistor Rs from the circuit by using the secondary winding of the transformer T1 in the flyback conversion circuit (the windings at pins 1 and 3 of the transformer T1) after the power supply starts normally, thereby reducing the loss on the startup resistor Rs.

[0028] Preferably, if Figure 2As shown, the startup circuit includes a startup resistor Rs, a first switch tube Q5, a second switch tube Q6, a first voltage regulator tube D23, a second voltage regulator tube D24, a diode D2, a capacitor C49, a second resistor R53, a third resistor R50 and a fourth resistor R133, wherein: the drain of the first switch tube Q5 is connected to the input voltage HV through the startup resistor Rs, the source is connected to the anode of the first voltage regulator tube D23, the cathode of the second voltage regulator tube D24 and the first end of the capacitor C49, and the gate is connected to the second end of the second resistor R53, the anode of the diode D2 and the drain of the second switch tube Q6; the cathode of the first voltage regulator tube D23 is connected to the cathode of the diode D2, the anode of the second voltage regulator tube D24 and the second end of the capacitor C49 are grounded, and the first end of the second resistor R53 is connected to the input voltage HV; the gate of the second switch tube Q6 is grounded through the third resistor R50, and is connected to the flyback conversion circuit through the fourth resistor R133, and the source is grounded.

[0029] Among them, the input voltage HV is stabilized by the starting resistor Rs, the first switch tube Q5, the capacitor C49 and the second voltage regulator tube D24 to provide the target integrated circuit with the initial starting voltage and current. Specifically, when the power supply is started, the second resistor R53, the diode D2 and the first voltage regulator tube D23 provide voltage to the first switch tube Q5, so that the first switch tube Q5 is turned on; the input voltage HV charges the capacitor C49 through the starting resistor Rs and the first switch tube Q5, and the second voltage regulator tube D24 ensures that the starting voltage does not exceed the power supply range of the target integrated circuit.

[0030] Preferably, if Figure 3 As shown, in the flyback conversion circuit, the primary winding of the transformer T1 is connected to the input voltage HV, and the voltage output by the first secondary winding is rectified and filtered to provide power for the target integrated circuit. At the same time, after voltage division, the second switch tube Q6 is controlled to be turned on, the gate of the first switch tube Q5 is pulled down, and the first switch tube Q5 is turned off, thereby disconnecting the starting resistor Rs from the circuit.

[0031] Specifically, when the voltage Vr1 is higher than the working voltage required by U1, U1 starts, and the 6th foot outputs a PWM signal, the flyback conversion circuit works, and the high-frequency voltage output from the 1st and 3rd feet of the transformer T1 is rectified and filtered by the diode D38 and the capacitor C8, and then divided into two paths, one path is used to power the control IC U1, and the other path is sent to the gate of the second switch tube Q6, driving the second switch tube Q6 to turn on, thereby turning off the first switch tube Q5, disconnecting the starting resistor Rs from the circuit, and reducing the power consumption of the starting resistor Rs.

[0032] Preferably, the second resistor R53 is always in the circuit, but the resistance of the second resistor R53 is many times greater than that of the starting resistor Rs, for example, more than 5 times, so the loss on the second resistor R53 will be at least less than 1 / 5 of the loss on the starting resistor Rs in the conventional solution.

[0033] Accordingly, this embodiment also provides an auxiliary power optimization method for a wide voltage range input, including: optimizing the startup circuit of the auxiliary power supply, adding a high-voltage switch and a control unit thereof; when the auxiliary power supply is started normally, based on the voltage output by the secondary winding of the transformer T1 of the flyback conversion circuit in the auxiliary power supply, the startup resistor Rs of the startup circuit is disconnected from the circuit through the high-voltage switch and its control unit, thereby reducing the loss on the startup resistor Rs.

[0034] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

Claims

1. An auxiliary power supply for wide voltage range input, characterized in that: The invention comprises a starting circuit and a flyback conversion circuit, wherein the starting circuit comprises a starting resistor (Rs), a high-voltage switch and a control unit thereof, and the flyback conversion circuit comprises at least a transformer (T1). Based on the voltage output by the secondary winding of the transformer (T1), the starting resistor (Rs) can be disconnected from the circuit through the high-voltage switch and the control unit thereof, thereby reducing the loss on the starting resistor (Rs).

2. The auxiliary power supply for wide voltage range input according to claim 1, characterized in that: The startup circuit comprises a startup resistor (Rs), a first switch tube (Q5), a second switch tube (Q6), a first voltage regulator tube (D23), a second voltage regulator tube (D24), a diode (D2), a capacitor (C49), a second resistor (R53), a third resistor (R50) and a fourth resistor (R133), wherein: The drain of the first switch tube (Q5) is connected to the input voltage (HV) through a starting resistor (Rs), the source is connected to the anode of the first voltage regulator tube (D23), the cathode of the second voltage regulator tube (D24) and the first end of the capacitor (C49), and the gate is connected to the second end of the second resistor (R53), the anode of the diode (D2) and the drain of the second switch tube (Q6); the cathode of the first voltage regulator tube (D23) is connected to the cathode of the diode (D2), the anode of the second voltage regulator tube (D24) and the second end of the capacitor (C49) are grounded, and the first end of the second resistor (R53) is connected to the input voltage (HV); The gate of the second switch tube (Q6) is grounded via a third resistor (R50), is connected to the flyback conversion circuit via a fourth resistor (R133), and has a source connected to the ground.

3. The auxiliary power supply for wide voltage range input according to claim 2, characterized in that: The input voltage (HV) is stabilized by a starting resistor (Rs), a first switch tube (Q5), a capacitor (C49) and a second voltage regulator tube (D24), thereby providing an initial starting voltage and current for a target integrated circuit.

4. The auxiliary power supply for wide voltage range input according to claim 2, characterized in that: When the power supply is started, the second resistor (R53), the diode (D2) and the first voltage regulator tube (D23) provide voltage for the first switch tube (Q5), so that the first switch tube (Q5) is turned on; the input voltage (HV) charges the capacitor (C49) through the starting resistor (Rs) and the first switch tube (Q5), and the second voltage regulator tube (D24) ensures that the starting voltage does not exceed the power supply range of the target integrated circuit.

5. The auxiliary power supply for wide voltage range input according to claim 2, characterized in that: In the flyback conversion circuit, the primary winding of the transformer (T1) is connected to the input voltage (HV), and the voltage output by the first secondary winding is rectified and filtered to provide power for the target integrated circuit, and at the same time, after voltage division, the second switch tube (Q6) is controlled to be turned on, the gate of the first switch tube (Q5) is pulled down, and the first switch tube (Q5) is turned off, thereby disconnecting the starting resistor (Rs) from the circuit.

6. An auxiliary power optimization method for wide voltage range input, characterized in that: include: Optimize the startup circuit of the auxiliary power supply and add a high-voltage switch and its control unit; When the auxiliary power supply starts normally, based on the voltage output by the secondary winding of the transformer (T1) of the flyback conversion circuit in the auxiliary power supply, the starting resistor (Rs) of the starting circuit is disconnected from the circuit through the high-voltage switch and its control unit, thereby reducing the loss on the starting resistor (Rs).

7. The auxiliary power optimization method for wide voltage range input according to claim 6, characterized in that: The startup circuit comprises a startup resistor (Rs), a first switch tube (Q5), a second switch tube (Q6), a first voltage regulator tube (D23), a second voltage regulator tube (D24), a diode (D2), a capacitor (C49), a second resistor (R53), a third resistor (R50) and a fourth resistor (R133), wherein: The drain of the first switch tube (Q5) is connected to the input voltage (HV) through a starting resistor (Rs), the source is connected to the anode of the first voltage regulator tube (D23), the cathode of the second voltage regulator tube (D24) and the first end of the capacitor (C49), and the gate is connected to the second end of the second resistor (R53), the anode of the diode (D2) and the drain of the second switch tube (Q6); the cathode of the first voltage regulator tube (D23) is connected to the cathode of the diode (D2), the anode of the second voltage regulator tube (D24) and the second end of the capacitor (C49) are grounded, and the first end of the second resistor (R53) is connected to the input voltage (HV); The gate of the second switch tube (Q6) is grounded via a third resistor (R50), is connected to the flyback conversion circuit via a fourth resistor (R133), and has a source connected to the ground.

8. The auxiliary power optimization method for wide voltage range input according to claim 7, characterized in that: The input voltage (HV) is stabilized by a starting resistor (Rs), a first switch tube (Q5), a capacitor (C49) and a second voltage regulator tube (D24), thereby providing an initial starting voltage and current for a target integrated circuit.

9. The auxiliary power optimization method for wide voltage range input according to claim 7, characterized in that: When the power supply is started, the second resistor (R53), the diode (D2) and the first voltage regulator tube (D23) provide voltage for the first switch tube (Q5), so that the first switch tube (Q5) is turned on; the input voltage (HV) charges the capacitor (C49) through the starting resistor (Rs) and the first switch tube (Q5), and the second voltage regulator tube (D24) ensures that the starting voltage does not exceed the power supply range of the target integrated circuit.

10. The auxiliary power optimization method for wide voltage range input according to claim 7, characterized in that: In the flyback conversion circuit, the primary winding of the transformer (T1) is connected to the input voltage (HV), and the voltage output by the first secondary winding is rectified and filtered to provide power for the target integrated circuit, and at the same time, after voltage division, the second switch tube (Q6) is controlled to be turned on, the gate of the first switch tube (Q5) is pulled down, and the first switch tube (Q5) is turned off, thereby disconnecting the starting resistor (Rs) from the circuit.

Images