A starting circuit and device for an auxiliary power supply for a photovoltaic inverter

Abstract

This application discloses a startup circuit for an auxiliary power supply of a photovoltaic inverter, including a voltage input terminal, a control chip, a first switching unit, and a second switching unit. The voltage input terminal is electrically connected to an external circuit and is used to receive an externally input startup voltage. The control chip is electrically connected to the voltage input terminal and the external auxiliary power supply, and is used to receive the startup voltage from the voltage input terminal to control the startup of the external auxiliary power supply. The first switching unit is electrically connected between the voltage input terminal and the control chip, and is used to control the conduction or disconnection between the voltage input terminal and the control chip. The second switching unit is electrically connected to both the control chip and the first switching unit, and is used to disconnect the first switching unit according to the control signal output by the control chip, so that the control chip stops working. This design can effectively reduce the loss of the auxiliary power supply, thereby improving the light-load and no-load efficiency of the auxiliary power supply.

Description

Technical Field

[0001] This application relates to the field of photovoltaic inverter technology, and in particular to a starting circuit and device for an auxiliary power supply of a photovoltaic inverter. Background Technology

[0002] In the context of the country's strong advocacy for energy conservation and emission reduction, photovoltaic inverters are widely used. In the actual use of photovoltaic inverters, in order to improve the utilization rate of battery energy and reduce the overall loss of solar photovoltaic inverters, it is necessary to improve the utilization rate of battery energy and reduce the overall loss of solar photovoltaic inverters. During the light load or no load operation of the system, multiple auxiliary power modules provide stable power supply to the entire system and keep running. Therefore, auxiliary power loss will occur, and the efficiency is low under light load and no load.

[0003] Therefore, how to reduce the losses of the auxiliary power supply, thereby improving the efficiency of the auxiliary power supply under light load and no-load conditions, is a problem that urgently needs to be solved by those in the field. Utility Model Content

[0004] To address the technical deficiencies mentioned in the background section, this application provides a starting circuit and device for an auxiliary power supply of a photovoltaic inverter, which can effectively reduce the loss of the auxiliary power supply, thereby improving the light-load and no-load efficiency of the auxiliary power supply.

[0005] The present invention adopts the following technical solution:

[0006] In a first aspect, a startup circuit for an auxiliary power supply of a photovoltaic inverter includes:

[0007] The voltage input terminal is electrically connected to an external circuit and is used to receive an externally input start-up voltage.

[0008] The control chip is electrically connected to the voltage input terminal and the external auxiliary power supply. The control chip is used to receive the start-up voltage from the voltage input terminal to control the external auxiliary power supply to start.

[0009] The switching module includes a first switching unit and a second switching unit. The first switching unit is electrically connected between the voltage input terminal and the control chip. The first switching unit is used to control the conduction or disconnection between the voltage input terminal and the control chip.

[0010] The second switching unit is electrically connected to both the control chip and the first switching unit. The second switching unit is used to turn off the first switching unit according to the control signal output by the control chip, so that the control chip stops working.

[0011] Optionally, the control terminal of the second switching unit is electrically connected to the control terminal of the control chip, and the voltage input terminal of the second switching unit is electrically connected to the control terminal of the first switching unit. When the control chip sends a control signal, the second switching unit is turned on and pulls down the high level of the first switching unit to turn off, thereby disconnecting the voltage input terminal from the control chip and stopping the control chip from working.

[0012] Optionally, it also includes a first voltage divider unit and a second voltage divider unit. The first end of the first voltage divider unit is electrically connected to the voltage input terminal, and the second end of the first voltage divider unit is electrically connected to the control terminal of the first switching unit. The first voltage divider unit is used to provide a high level to the first switching unit to control the first switching unit to conduct.

[0013] Optionally, the first voltage divider unit includes a first voltage divider resistor, a second voltage divider resistor, and a Zener diode. The first voltage divider resistor and the second voltage divider resistor are connected in series. The first end of the first voltage divider resistor is electrically connected to the voltage input terminal. The second end of the first voltage divider resistor is electrically connected to the first end of the second voltage divider resistor. The second end of the second voltage divider resistor is electrically connected to one end of the first switching unit and the Zener diode. The other end of the Zener diode is grounded.

[0014] Optionally, the second voltage divider unit includes a third voltage divider resistor, a fourth voltage divider resistor, and a first capacitor. The first end of the third voltage divider is electrically connected to the control chip, the second end of the third voltage divider resistor is electrically connected to the control terminal of the second switching unit, the first end of the fourth voltage divider resistor is electrically connected between the third voltage divider resistor and the control terminal of the second switching unit, the other end of the fourth voltage divider resistor is grounded, and the first capacitor is connected in parallel with the fourth voltage divider resistor.

[0015] Optionally, a diode is also electrically connected between the second voltage divider resistor and the first switching unit. The anode of the diode is electrically connected to the second terminal of the second voltage divider resistor, and the cathode is electrically connected to the control terminal of the second switching unit.

[0016] Optionally, it also includes a first current-limiting resistor and a second current-limiting resistor, which are connected in series. The first end of the first current-limiting resistor is electrically connected to the voltage input terminal, the second end of the first current-limiting resistor is electrically connected to the first end of the second current-limiting resistor, and the second end of the second current-limiting resistor is electrically connected to the drain of the first switching unit.

[0017] Optionally, it also includes a charging and discharging unit, one end of which is electrically connected to the source of the first switching unit and the other end is grounded. The charging and discharging unit is used to charge the voltage delivered by the first switching unit and to supply power to the power pin of the control chip.

[0018] Optionally, the charging and discharging unit includes a first charging capacitor and a second charging capacitor connected in parallel. One end of the first charging capacitor is electrically connected to the source of the second switching unit, and the other end is grounded. One end of the second charging capacitor is electrically connected to the source of the second switching unit, and the other end is grounded.

[0019] Secondly, a starting device for a photovoltaic inverter auxiliary power supply includes the starting circuit for the photovoltaic inverter auxiliary power supply as described above; and

[0020] The starting circuit of the photovoltaic inverter auxiliary power supply is etched onto the circuit board.

[0021] In summary, the beneficial effects of this utility model are as follows:

[0022] By providing a startup voltage to the control chip through a voltage input terminal and placing a first switching unit between the voltage input terminal and the control chip, the connection between the control voltage input terminal and the control chip can be switched on and off. After the control chip starts up, it sends a startup signal to the auxiliary power supply. After the auxiliary power supply starts up, the control chip sends a control signal. By setting a second switching unit, the control signal output by the control chip is received, which enables the second switching unit to conduct. When the second switching unit is conducting, it pulls down the control voltage of the first switching unit, thereby turning off the first switching unit. This cuts off the voltage between the voltage input terminal and the power supply pin of the control chip, allowing the control chip to stop working. The entire circuit then stops working, improving the efficiency of the auxiliary power supply under no-load and load conditions and reducing the power consumption of the auxiliary power supply circuit. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the architecture of an embodiment of the present utility model;

[0025] Figure 2 This is a circuit diagram of an embodiment of the present invention. Attached image description:

[0027] 100. Voltage input terminal;

[0028] 200. Control chip;

[0029] 300. Switch module; 310. First switch unit; 320. Second switch unit;

[0030] 400, First voltage divider unit; R1, First voltage divider resistor; R2, Second voltage divider resistor; ZD1, Zener diode;

[0031] 500, second voltage divider unit; R3, third voltage divider resistor; R4, fourth voltage divider resistor; C1, first capacitor;

[0032] D1, diode; R5, first current-limiting resistor; R6, second current-limiting resistor;

[0033] 600, charging and discharging unit; C2, first charging capacitor; C3, second charging capacitor. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0035] like Figure 1 As shown in the figure, this application embodiment provides a startup circuit for an auxiliary power supply of a photovoltaic inverter, including a voltage input terminal 100, a control chip 200, and a switching module 300. The switching module 300 includes a first switching unit 310 and a second switching unit 320. The voltage input terminal 100 is electrically connected to an external circuit and is used to receive an externally input startup voltage. The control chip 200 is electrically connected to the voltage input terminal 100 and the external auxiliary power supply. The control chip 200 is used to receive the startup voltage from the voltage input terminal 100 and operate to control the startup of the external auxiliary power supply. The first switching unit 310 is electrically connected between the voltage input terminal 100 and the control chip 200 and is used to control the conduction or disconnection between the voltage input terminal 100 and the control chip 200.

[0036] The second switch unit 320 is electrically connected to the control chip 200 and the first switch unit 310 respectively. The second switch unit 320 is used to disconnect the first switch unit 310 according to the control signal output by the control chip 200, so that the control chip 200 stops working.

[0037] In this embodiment, the voltage input terminal 100 is used to connect an external voltage source, typically a high voltage, which is the starting voltage of the photovoltaic inverter auxiliary power supply. Since the external auxiliary power supply circuit is started by the control chip 200, the starting voltage is input to the control chip 200 through the voltage input terminal 100, enabling the auxiliary power supply to be started by the control chip 200. Furthermore, by setting a first switching unit 310 between the voltage input terminal 100 and the control chip, the starting voltage supplied by the voltage input terminal 100 can be controlled to be supplied to the control chip 200 through the first switching unit 310. When the control chip 200 receives the starting voltage, the control chip 200 starts working and sends a start signal to the auxiliary power supply circuit to start the auxiliary power supply circuit to work. Once the auxiliary power supply circuit has started, to avoid power loss caused by the continuous operation of the control chip 200, the control chip 200 will send a control signal to the second switching unit 320. After receiving the control signal, the second switching unit 320 will turn on and pull down the high level of the first switching unit 310, thereby turning off the first switching unit 310. In this way, the circuit between the voltage input terminal 100 and the control chip 200 is cut off, and the control chip 200 stops working. This realizes automatic power-off control of the control chip 200, thereby reducing power loss and improving the working efficiency of the entire photovoltaic inverter auxiliary power supply.

[0038] Specifically, the first switching unit 310 and the second switching unit 320 can be N-channel MOS transistors, which have a gate (control terminal), a drain (voltage input) and a source (voltage output).

[0039] Optional, such as Figure 1 As shown, this embodiment of the application also includes a first voltage divider unit 400 and a second voltage divider unit 500. The first end of the first voltage divider unit 400 is electrically connected to the voltage input terminal 100, and the second end of the first voltage divider unit 400 is electrically connected to the control terminal of the first switching unit 310. The first voltage divider unit 400 is used to provide a high level to the first switching unit 310 to control the first switching unit 310 to conduct.

[0040] Optionally, the second voltage divider unit 500 includes a third voltage divider resistor R3, a fourth voltage divider resistor R4, and a first capacitor C1. The first end of the third voltage divider is electrically connected to the control chip 200, the second end of the third voltage divider resistor R3 is electrically connected to the control terminal of the second switching unit 320, the first end of the fourth voltage divider resistor R4 is electrically connected between the third voltage divider resistor R3 and the control terminal of the second switching unit 320, the other end of the fourth voltage divider resistor R4 is grounded, and the first capacitor C1 is connected in parallel with the fourth voltage divider resistor R4.

[0041] In this embodiment, by setting a first voltage divider unit 400 and a second voltage divider unit 500, a stable voltage input is provided for the first switching unit 310 and the control chip 200, ensuring the stability and reliability of the circuit. Specifically, the first voltage divider unit 400, through the cooperation of a first voltage divider resistor R1, a second voltage divider resistor R2, and a Zener diode ZD1, provides a stable high level to the first switching unit 310, thereby ensuring the normal conduction of the first switching unit 310. Meanwhile, the second voltage divider unit 500, through the cooperation of a third voltage divider resistor R3, a fourth voltage divider, and a first capacitor C1, performs voltage division and filtering on the control signal of the control chip 200, improving the stability and accuracy of the control signal.

[0042] Optional, such as Figure 2 As shown, a diode D1 is also electrically connected between the second voltage divider resistor R2 and the first switching unit 310. The anode of the diode D1 is electrically connected to the second end of the second voltage divider resistor R2, and the cathode is electrically connected to the control terminal of the second switching unit 320.

[0043] Optional, such as Figure 2 As shown, this embodiment of the application further includes a first current-limiting resistor R5 and a second current-limiting resistor R6, which are connected in series. The first end of the first current-limiting resistor R5 is electrically connected to the voltage input terminal 100, and the second end of the first current-limiting resistor R5 is electrically connected to the first end of the second current-limiting resistor R6. The second end of the second current-limiting resistor R6 is electrically connected to the drain of the first switching unit 310. A diode D1 is also electrically connected between the second voltage divider resistor R2 and the first switching unit 310. The anode of the diode D1 is electrically connected to the second end of the second voltage divider resistor R2, and the cathode is electrically connected to the control terminal of the second switching unit 320.

[0044] At the same time, such as Figure 2 As shown, this embodiment of the application further improves the reliability and stability of the circuit by setting components such as diode D1, first current-limiting resistor R5, second current-limiting resistor R6, and charging / discharging unit 600. The diode D1 prevents backflow from damaging the circuit; the first current-limiting resistor R5 and the second current-limiting resistor R6 limit the current magnitude, preventing excessive current at the voltage input terminal 100 from damaging the first switching unit 310.

[0045] The charging and discharging unit 600 provides power and discharge to the power pins of the control chip 200, ensuring its normal operation. The charging and discharging unit 600 includes a first charging capacitor C2 and a second charging capacitor C3 connected in parallel. One end of the first charging capacitor C2 is electrically connected to the source of the second switching unit 320, and the other end is grounded. One end of the second charging capacitor C3 is electrically connected to the source of the second switching unit 320, and the other end is grounded.

[0046] In this embodiment of the application, in order to further improve the reliability and stability of the circuit, in some possible embodiments, protective elements such as overcurrent protectors and overvoltage protectors can be added. A voltage input terminal 100 and the first switching unit 310 can be set to prevent damage to circuit components when abnormal conditions such as overcurrent or overvoltage occur. Heat dissipation treatment can also be carried out on the circuit, such as adding heat sinks and fans, to improve the heat dissipation performance of the circuit and prevent the circuit from malfunctioning due to overheating.

[0047] The second aspect of this application discloses a starting device for an auxiliary power supply of a photovoltaic inverter (not shown in the figure), comprising a starting circuit and a circuit board for the auxiliary power supply of the photovoltaic inverter as described above, wherein the starting circuit for the auxiliary power supply of the photovoltaic inverter is etched onto the circuit board. By providing a starting device for the auxiliary power supply of the photovoltaic inverter, it is possible to prevent the auxiliary power supply from being shut down after it has been started, thereby reducing standby power consumption and improving efficiency under no-load and power load conditions.

[0048] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0049] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A start-up circuit for a photovoltaic inverter auxiliary power supply, characterized in that, include: The voltage input terminal (100) is electrically connected to an external circuit, and the voltage input terminal (100) is used to receive the start-up voltage input from the outside; The control chip (200) is electrically connected to the voltage input terminal (100) and the external auxiliary power supply. The control chip (200) is used to receive the start-up voltage of the voltage input terminal (100) to control the external auxiliary power supply to start. The switching module (300) includes a first switching unit (310) and a second switching unit (320). The first switching unit (310) is electrically connected between the voltage input terminal (100) and the control chip (200). The first switching unit (310) is used to control the conduction or disconnection between the voltage input terminal (100) and the control chip (200). The second switch unit (320) is electrically connected to the control chip (200) and the first switch unit (310) respectively. The second switch unit (320) is used to turn off the first switch unit (310) according to the control signal output by the control chip (200) so that the control chip (200) stops working.

2. The start-up circuit for a photovoltaic inverter auxiliary power supply of claim 1, wherein, The control terminal of the second switching unit (320) is electrically connected to the control terminal of the control chip (200). The voltage input terminal (100) of the second switching unit (320) is electrically connected to the control terminal of the first switching unit (310). When the control chip (200) sends a control signal, the second switching unit (320) is turned on and pulls down the high level of the first switching unit (310) to turn off the first switching unit (310), so that the voltage input terminal (100) is disconnected from the control chip (200) and the control chip (200) stops working.

3. The starting circuit of the photovoltaic inverter auxiliary power supply as described in claim 1, characterized in that, It also includes a first voltage divider unit (400) and a second voltage divider unit (500). The first end of the first voltage divider unit (400) is electrically connected to the voltage input terminal (100), and the second end of the first voltage divider unit (400) is electrically connected to the control terminal of the first switching unit (310). The first voltage divider unit (400) is used to provide a high level to the first switching unit (310) to control the first switching unit (310) to be turned on.

4. The starting circuit of the photovoltaic inverter auxiliary power supply as described in claim 3, characterized in that, The first voltage divider unit (400) includes a first voltage divider resistor (R1), a second voltage divider resistor (R2), and a Zener diode (ZD1). The first voltage divider resistor (R1) and the second voltage divider resistor (R2) are connected in series. The first end of the first voltage divider resistor (R1) is electrically connected to the voltage input terminal (100). The second end of the first voltage divider resistor (R1) is electrically connected to the first end of the second voltage divider resistor (R2). The second end of the second voltage divider resistor (R2) is electrically connected to one end of the first switching unit (310) and the Zener diode (ZD1). The other end of the Zener diode (ZD1) is grounded.

5. The starting circuit of the photovoltaic inverter auxiliary power supply as described in claim 3, characterized in that, The second voltage divider unit (500) includes a third voltage divider resistor (R3), a fourth voltage divider resistor (R4), and a first capacitor (C1). The first end of the third voltage divider is electrically connected to the control chip (200), the second end of the third voltage divider resistor (R3) is electrically connected to the control terminal of the second switching unit (320), the first end of the fourth voltage divider resistor (R4) is electrically connected between the third voltage divider resistor (R3) and the control terminal of the second switching unit (320), the other end of the fourth voltage divider resistor (R4) is grounded, and the first capacitor (C1) is connected in parallel with the fourth voltage divider resistor (R4).

6. The starting circuit of the photovoltaic inverter auxiliary power supply as described in claim 4, characterized in that, A diode (D1) is also electrically connected between the second voltage divider resistor (R2) and the first switching unit (310). The anode of the diode (D1) is electrically connected to the second end of the second voltage divider resistor (R2), and the cathode is electrically connected to the control terminal of the second switching unit (320).

7. The starting circuit of the photovoltaic inverter auxiliary power supply as described in claim 1, characterized in that, It also includes a first current-limiting resistor (R5) and a second current-limiting resistor (R6), which are connected in series. The first end of the first current-limiting resistor (R5) is electrically connected to the voltage input terminal (100), the second end of the first current-limiting resistor (R5) is electrically connected to the first end of the second current-limiting resistor (R6), and the second end of the second current-limiting resistor (R6) is electrically connected to the drain of the first switching unit (310).

8. The starting circuit of the photovoltaic inverter auxiliary power supply as described in claim 1, characterized in that, It also includes a charging and discharging unit (600), one end of which is electrically connected to the source of the first switching unit (310), and the other end is grounded. The charging and discharging unit (600) is used to charge the voltage delivered by the first switching unit (310) and to supply power to the power pin of the control chip (200).

9. The starting circuit of the photovoltaic inverter auxiliary power supply as described in claim 8, characterized in that, The charging and discharging unit (600) includes a first charging capacitor (C2) and a second charging capacitor (C3) connected in parallel. One end of the first charging capacitor (C2) is electrically connected to the source of the second switching unit (320), and the other end is grounded. One end of the second charging capacitor (C3) is electrically connected to the source of the second switching unit (320), and the other end is grounded.

10. A starting device for an auxiliary power supply of a photovoltaic inverter, characterized in that, Includes the startup circuit of the photovoltaic inverter auxiliary power supply as described in any one of claims 1-9; The starting circuit of the photovoltaic inverter auxiliary power supply is etched onto the circuit board.

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