Power supply device for reducing night power consumption of photovoltaic inverter

Abstract

The utility model discloses a power supply device for reducing power consumption of a photovoltaic inverter at night, the photovoltaic inverter comprises a direct current auxiliary power supply, a plurality of alternating current auxiliary power supplies, a control unit and a communication unit, and the power supply device comprises a first comparison unit, a second comparison unit and a power supply module; the direct-current auxiliary power supply stops working when the photovoltaic output voltage value is lower than the night voltage threshold value; the first comparison unit outputs a first level signal when the photovoltaic output voltage value is lower than a night voltage threshold value so as to control the plurality of alternating current auxiliary power supplies to stop working; the second comparison unit outputs a second level signal when the photovoltaic output voltage value is lower than the night voltage threshold value so as to control the power supply module to start working; and the power supply module can supply power to the control unit and the communication unit when starting to work. According to the invention, power failure of the control part and the communication part of the photovoltaic inverter can be avoided while the power consumption of the photovoltaic inverter at night is reduced, and normal work of the photovoltaic inverter at night is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic power generation, in particular to a power supply device for reducing the night power consumption of a photovoltaic inverter. BACKGROUND

[0002] The night loss of a photovoltaic inverter comes from the loss of an auxiliary power supply itself, the loss of a PV panel sampling circuit, the loss of a detection board control circuit, the loss of a relay board drive and equivalent resistance, the loss of a boost and inverter drive power supply, the loss of communication and fan drive, etc.

[0003] The patent with the application number CN201810204908.2 controls the power supply of an AC auxiliary power supply module by adding a relay at the power grid side, and disconnects the relay at night to reduce power consumption. However, when the DC side is powered off, the relay is disconnected, the control part and the communication part of the photovoltaic inverter will be completely powered off, resulting in that the photovoltaic inverter cannot work at night. UTILITARIAN CONTENT

[0004] The present application aims to provide a power supply device for reducing the night power consumption of a photovoltaic inverter, so as to reduce the night power consumption of the photovoltaic inverter and ensure that the control part and the communication part of the photovoltaic inverter are not powered off, and ensure that the photovoltaic inverter can work normally at night.

[0005] The present application provides a power supply device for reducing the night power consumption of a photovoltaic inverter, the photovoltaic inverter comprising a DC auxiliary power supply, a plurality of AC auxiliary power supplies, a control unit and a communication unit, the power supply device comprising a first comparison unit, a second comparison unit and a power module;

[0006] The DC auxiliary power supply is configured to stop working when the photovoltaic output voltage value is lower than the night voltage threshold value;

[0007] The first comparison unit is configured to output a first level signal when the photovoltaic output voltage value is lower than the night voltage threshold value, the first level signal being used to control all the plurality of AC auxiliary power supplies to stop working;

[0008] The second comparison unit is configured to output a second level signal when the photovoltaic output voltage value is lower than the night voltage threshold value, the second level signal being used to control the power module to start working; wherein the power module can supply power to the control unit and the communication unit when starting working.

[0009] In an example, the DC auxiliary power supply is further configured to start working when the photovoltaic output voltage value is higher than the daytime voltage threshold value;

[0010] The first comparison unit is configured to output a second level signal when the photovoltaic output voltage value is higher than the daytime voltage threshold, the second level signal being used to control the multiple AC auxiliary power supplies to start working all together.

[0011] The second comparison unit is configured to output a first level signal when the photovoltaic output voltage value is higher than the daytime voltage threshold, the first level signal being used to control the power supply module to stop working.

[0012] In an example, the DC auxiliary power supply has a first power voltage output end and a second power voltage output end, the first power voltage output end being used to supply power to the control unit when the DC auxiliary power supply starts working, and the second power voltage output end being used to supply power to the communication unit.

[0013] In an example, one of the multiple AC auxiliary power supplies has a third power voltage output end and / or a fourth power voltage output end.

[0014] When the one of the multiple AC auxiliary power supplies starts working, the third power voltage output end or the fourth power voltage output end is used to supply power to the control unit together with the first power voltage output end; or,

[0015] When the one of the multiple AC auxiliary power supplies starts working, the third power voltage output end or the fourth power voltage output end is used to supply power to the communication unit together with the second power voltage output end; or,

[0016] When the one of the multiple AC auxiliary power supplies starts working, the third power voltage output end is used to supply power to the control unit together with the first power voltage output end, and the fourth power voltage output end is used to supply power to the communication unit together with the second power voltage output end.

[0017] In an example, the power supply device further comprises a wake-up unit connected to the control unit, the wake-up unit being configured to control at least one of the multiple AC auxiliary power supplies to start working when a wake-up signal is received.

[0018] In an example, the power supply device further comprises multiple first switch tubes, each of the multiple AC auxiliary power supplies being connected to a power grid through any one of the multiple first switch tubes; the first level signal being able to control the multiple first switch tubes to be all turned off.

[0019] In an example, the power supply device further comprises a second switch tube, the power supply module being connected to the power grid through the second switch tube; the second level signal being able to control the second switch tube to be turned on.

[0020] In an example, the input end of the DC auxiliary power supply is connected with the photovoltaic module, the first input end of the first comparison unit and the second input end of the second comparison unit are both connected with the output end of the DC auxiliary power supply, and the second input end of the first comparison unit and the first input end of the second comparison unit are configured according to the night voltage threshold.

[0021] In an example, the power supply module has a fifth power voltage output end and a sixth power voltage output end, when the power supply module starts to work, the fifth power voltage output end supplies power to the control unit, and the sixth power voltage output end supplies power to the communication unit.

[0022] In an example, the power supply device further comprises a first voltage reduction circuit and / or a second voltage reduction circuit, the first voltage reduction circuit is arranged between the fifth power voltage output end and the control unit, and the second voltage reduction circuit is arranged between the sixth power voltage output end and the communication unit.

[0023] The power supply device for reducing night power consumption of a photovoltaic inverter provided in the application can reduce the night power consumption of the photovoltaic inverter while ensuring that the control part and the communication part of the photovoltaic inverter do not power off, and ensures that the photovoltaic inverter can work normally at night. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic diagram of a photovoltaic inverter system provided by an embodiment of the application;

[0025] Figure 2 is a schematic diagram of a photovoltaic inverter system and a power supply device provided by an embodiment of the application;

[0026] Figure 3 is a schematic diagram of a first comparison unit provided by an embodiment of the application;

[0027] Figure 4 is a schematic diagram of a second comparison unit provided by an embodiment of the application;

[0028] Figure 5 is a schematic diagram of a photovoltaic inverter system and another power supply device provided by an embodiment of the application;

[0029] Figure 6 is a schematic diagram of a photovoltaic inverter system and still another power supply device provided by an embodiment of the application;

[0030] Figure 7 is a schematic diagram of a photovoltaic inverter system and yet another power supply device provided by an embodiment of the application.

[0031] The implementation, functional features and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer and more apparent, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, and not to limit the present application.

[0033] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] As shown in Figure 1 The photovoltaic inverter system includes a photovoltaic assembly, a boost circuit (indicated by BOOST in the figure), and a photovoltaic inverter, which includes a DC auxiliary power supply (indicated by DC auxiliary in the figure), a rectification filter circuit, a voltage dividing circuit, a plurality of AC auxiliary power supplies (indicated by AC1 auxiliary to ACn auxiliary in the figure), a driving unit, a sampling unit, a first buck circuit (indicated by BUCK1 in the figure), a second buck circuit (indicated by BUCK2 in the figure), a control unit, and a communication unit.

[0035] The output voltage of the photovoltaic assembly, i.e., the photovoltaic output voltage, is boosted by the boost circuit to supply power to the DC auxiliary power supply, which has a first power voltage output terminal and a second power voltage output terminal. The first power voltage output terminal outputs a first DC voltage, for example, a 12V DC voltage, through a diode. The first DC voltage can directly supply power to the driving unit and the sampling unit. The first DC voltage can also be stepped down by the first buck circuit, for example, to 5V, to supply power to the control unit. The second power voltage output terminal outputs a second DC voltage, for example, a 15V DC voltage, through a diode. The second DC voltage can directly supply power to a load such as a PLC. The second DC voltage can also be stepped down by the second buck circuit, for example, to 10V, to supply power to the communication unit.

[0036] The control unit is used to control the standby, debugging, driving, grid connection, and generation of wake-up signals of the photovoltaic inverter, and the like. The communication unit is used to read various parameter values, states, faults, and the like reported by the system.

[0037] The AC power grid supplies power to the plurality of AC auxiliary power supplies through the rectification filter circuit and the voltage dividing circuit. The voltage dividing circuit includes voltage dividing resistors R1 and R2.

[0038] One of the plurality of AC auxiliary power supplies (shown as AC1 in the figure) has a third power supply voltage output and a fourth power supply voltage output. The third power supply voltage output can output a first DC voltage, for example 12V DC voltage, through a diode, and supply power together with the first power supply voltage output. The fourth power supply voltage output can output a second DC voltage, for example 15V DC voltage, through a diode, and supply power together with the second power supply voltage output.

[0039] The other AC auxiliary power supplies (shown as AC2-ACn in the figure) of the plurality of AC auxiliary power supplies can supply power to the fan and other loads.

[0040] As shown in the figure, the power supply device includes a first comparison unit, a plurality of first switch tubes (shown as Q1-Qn in the figure), a second comparison unit, a second switch tube (shown as Qm in the figure), a power module, and a wake-up unit. Figure 2

[0041] Each of the plurality of AC auxiliary power supplies is connected to the power grid through any one of the plurality of first switch tubes. Specifically, AC1 is connected to the power grid through first switch tube Q1, AC2 is connected to the power grid through first switch tube Q2, AC3 is connected to the power grid through first switch tube Q3, and ACn is connected to the power grid through first switch tube Qn.

[0042] The input of the first comparison unit is connected to the first power supply voltage output, for example, the input of the first comparison unit is connected between the first power supply voltage output and the diode, and the output of the first comparison unit is connected to the control terminal of all first switch tubes through a diode. In the example in the figure, all first switch tubes are triodes, the base of the triode is the control terminal, the emitter of the triode is connected to the AC auxiliary power supply, and the collector of the triode is connected to the voltage dividing circuit.

[0043] The input of the power module is connected to the AC power grid through the second switch tube, the power module has a fifth power supply voltage output and a sixth power supply voltage output, the fifth power supply voltage output can supply power to the control unit through a diode, and the sixth power supply voltage output can supply power to the communication unit through a diode.

[0044] The input of the second comparison unit is connected to the first power supply voltage output, for example, the input of the second comparison unit is connected after the diode, and the output of the second comparison unit is connected to the control terminal of the second switch tube. In the example in the figure, the second switch tube is a triode, the base of the triode is the control terminal, the emitter of the triode is connected to the power module, and the collector of the triode is connected to the AC power grid.​

[0045] The input terminal of the wake-up unit is connected to the control unit, and the output terminal of the wake-up unit is connected to the control terminal of all the first switching transistors via diodes.

[0046] like Figure 3 As shown, in one example, the first comparison unit includes comparator U1, which can be an LM2903 comparator. The non-inverting input terminal of comparator U1 (the first input terminal of the first comparison unit) is connected to the first power supply voltage output terminal via resistor R4, that is, connected to the first power supply voltage output terminal and... Figure 2 Between the diodes, one end of capacitor C2 is connected to resistor R4, and the other end of capacitor C2 is grounded. The inverting input of comparator U1 (the second input of the first comparison unit) is configured according to the nighttime or daytime voltage threshold. Specifically, the 15V power supply voltage can be divided by voltage divider resistors R1 and R2 and then output to the inverting input of comparator U1 through resistor R3. Filter capacitor C1 is connected in parallel across voltage divider resistor R2, one end of capacitor C3 is connected to the inverting input of comparator U1, and the other end of capacitor C3 is grounded. The positive power supply of comparator U1 is connected to a 5V power supply, and the negative power supply of comparator U1 is grounded. The output of comparator U1 is pulled up by resistor R5 and connected to a 3.3V power supply. The output of comparator U1 also outputs a level signal after passing through diode D1 and resistor R6. One end of capacitor C4 and one end of resistor R7 are connected after resistor R6, and the other ends of capacitor C4 and resistor R7 are grounded. Diode D2 constitutes the wake-up unit. The anode of diode D2 is connected to the control unit to receive the wake-up signal; the cathode of diode D2 is connected between diode D1 and resistor R6. Wake-up signals include SVG commands, PID commands, and grid-connected operation commands, etc.

[0047] like Figure 4 As shown, in one example, the second comparison unit includes comparator U2, which can be an LM2903 comparator. The inverting input of comparator U2 is connected to the output of the first power supply voltage via resistor R11, i.e., connected to... Figure 2The one end of the capacitor C7 is connected with the resistor R11, and the other end of the capacitor C7 is grounded. The same direction input end of the comparator U2 is configured according to the night voltage threshold or the daytime voltage threshold, specifically, the 15V power supply voltage can be output to the same direction input end of the comparator U2 through the resistors R8 and R9 and the resistor R10. The filter capacitor C5 is connected in parallel with the resistors R9, one end of the capacitor C6 is connected with the opposite direction input end of the comparator U1, and the other end of the capacitor C6 is grounded. The positive power supply end of the comparator U2 is connected with the 5V power supply, and the negative power supply end of the comparator U2 is grounded. The output end of the comparator U2 is connected with the 3.3V power supply through the pull-up resistor R12, and the output end of the comparator U2 is also output to the level signal through the diode D3 and the resistor R13. One end of the capacitor C8 and one end of the resistor R14 are connected after the resistor R13, and the other end of the capacitor C8 and the other end of the resistor R14 are grounded.

[0048] During the daytime, the output voltage of the photovoltaic module gradually increases, and after the DC auxiliary power supply normally works, the voltage output by the first power supply voltage output end of the DC auxiliary power supply is greater than the voltage of the opposite direction input end of the comparator U1, the comparator U1 outputs a high level, at this time, the diode D1 is turned on, and Q1, Q2…Qn can be controlled to be turned on, and the AC auxiliary power supply is normally started. At this time, the DC auxiliary power supply and the AC1 auxiliary power supply are connected in parallel to supply power. On the contrary, the comparator U2 outputs a low level, the diode D3 is cut off, and Qm is cut off, at this time, the power supply module does not work, and the driving unit, the sampling unit, the control unit and the communication unit are powered by the DC auxiliary power supply and the AC1 auxiliary power supply. In addition, during the daytime, when the light is weak, the AC auxiliary power supply works, and the DC auxiliary power supply stops working, which can avoid frequent starting and stopping of the DC auxiliary power supply.

[0049] During the nighttime, the output voltage of the photovoltaic module gradually decreases, and the voltage output by the first power supply voltage output end of the DC auxiliary power supply is less than the voltage of the opposite direction input end of the comparator U1, the comparator U1 outputs a low level, at this time, the diode D1 is turned off, and Q1, Q2…Qn are cut off, at this time, the AC auxiliary power supply and the DC auxiliary power supply are all turned off. On the contrary, the comparator U2 outputs a high level, the diode D3 is turned on, and Qm is turned on, at this time, the power supply module starts to work, and the control unit and the communication unit are powered. In this way, during the nighttime, since the DC auxiliary power supply and the AC auxiliary power supply are all turned off, the nighttime power consumption is mainly the loss of the power supply module, the control unit and the communication unit. The control part and the communication part of the system have electricity during the daytime and the nighttime, which increases the flexibility of the system, and the AC auxiliary power supply can work at any time through the wake-up signal.

[0050] When the wake-up signal is high, diode D2 conducts, controlling Q1, Q2...Qn to conduct, allowing the AC auxiliary power supply to start normally. When the wake-up signal is low, diode D2 is off, Q1, Q2...Qn are off, and the AC auxiliary power supply stops working. As needed, the wake-up signal can control the start or stop of any single AC auxiliary power supply, or at least one of multiple AC auxiliary power supplies. This increases the system's intelligence.

[0051] Based on the above, in one example, the DC auxiliary power supply is configured to stop working when the photovoltaic output voltage value is lower than the nighttime voltage threshold; the first comparison unit is configured to output a first level signal when the photovoltaic output voltage value is lower than the nighttime voltage threshold, the first level signal being used to control all of the plurality of AC auxiliary power supplies to stop working; the second comparison unit is configured to output a second level signal when the photovoltaic output voltage value is lower than the nighttime voltage threshold, the second level signal being used to control the power module to start working.

[0052] For example, if the voltage output from the first power supply voltage output terminal of the aforementioned DC auxiliary power supply is less than the voltage at the inverting input terminal of comparator U1, it can be considered that the photovoltaic output voltage value is lower than the nighttime voltage threshold. At this time, both the AC auxiliary power supply and the DC auxiliary power supply are turned off, i.e., they stop working; while the power module starts working, supplying power to the control unit and the communication unit.

[0053] In one example, the DC auxiliary power supply is further configured to start operating when the photovoltaic output voltage value is higher than the daytime voltage threshold; the first comparison unit is configured to output a second level signal when the photovoltaic output voltage value is higher than the daytime voltage threshold, the second level signal being used to control all of the plurality of AC auxiliary power supplies to start operating; the second comparison unit is configured to output a first level signal when the photovoltaic output voltage value is higher than the daytime voltage threshold, the first level signal being used to control the power module to stop operating.

[0054] For example, if the voltage output from the first power supply voltage output terminal of the aforementioned DC auxiliary power supply is greater than the voltage at the inverting input terminal of comparator U1, it can be considered that the photovoltaic output voltage value is higher than the daytime voltage threshold. At this time, the power module does not work, and the DC auxiliary power supply and AC1 auxiliary power supply provide power to the drive unit, sampling unit, control unit, and communication unit.

[0055] Figure 5 This is a schematic diagram of a photovoltaic inverter system and another power supply device provided in an embodiment of this application.

[0056] and Figure 2 The examples are different, in Figure 5 In the example, the AC1 auxiliary power source only supplies power to loads such as fans, and does not supply power together with the DC auxiliary power source.

[0057] With Figure 2 Different from the example, in the example of Figure 5 the output voltage of the fifth power voltage output terminal of the power module supplies power to the control unit after passing through the first voltage reduction circuit, and the output voltage of the sixth power voltage output terminal of the power module supplies power to the communication unit after passing through the second voltage reduction circuit.

[0058] Figure 6 is a schematic diagram of a photovoltaic inverter system and a power supply device provided by an embodiment of the present application.

[0059] With Figure 2 Different from the example, in the example of Figure 6 the AC1 auxiliary source only supplies power together after the third power voltage output terminal and the first power voltage output terminal are converged.

[0060] With Figure 2 Different from the example, in the example of Figure 6 the output voltage of the sixth power voltage output terminal of the power module supplies power to the communication unit after passing through the second voltage reduction circuit.

[0061] Figure 7 is a schematic diagram of a photovoltaic inverter system and a power supply device provided by an embodiment of the present application.

[0062] With Figure 2 Different from the example, in the example of Figure 7 the AC1 auxiliary source only supplies power together after the fourth power voltage output terminal and the second power voltage output terminal are converged.

[0063] With Figure 2 Different from the example, in the example of Figure 7 the output voltage of the fifth power voltage output terminal of the power module supplies power to the control unit after passing through the first voltage reduction circuit.

[0064] The preferred embodiments of the present application are described above with reference to the accompanying drawings, and are not intended to limit the scope of the present application. Any modification, equivalent replacement and improvement made by those skilled in the art without departing from the scope and spirit of the present application shall fall within the scope of the present application.

Claims

1. A power supply device for reducing the nighttime power consumption of a photovoltaic inverter, characterized in that, The photovoltaic inverter includes a DC auxiliary power supply, multiple AC auxiliary power supplies, a control unit, and a communication unit. The power supply device includes a first comparison unit, a second comparison unit, and a power module. The DC auxiliary power supply is configured to stop working when the photovoltaic output voltage value is lower than the nighttime voltage threshold. The first comparison unit is configured to output a first level signal when the photovoltaic output voltage value is lower than the nighttime voltage threshold. The first level signal is used to control all of the plurality of AC auxiliary power supplies to stop working. The second comparison unit is configured to output a second level signal when the photovoltaic output voltage value is lower than the nighttime voltage threshold. The second level signal is used to control the power module to start working. When the power module starts working, it can supply power to the control unit and the communication unit.

2. The power supply device according to claim 1, characterized in that, The DC auxiliary power supply is also configured to start working when the photovoltaic output voltage value is higher than the daytime voltage threshold. The first comparison unit is configured to output a second level signal when the photovoltaic output voltage value is higher than the daytime voltage threshold. The second level signal is used to control all of the plurality of AC auxiliary power supplies to start working. The second comparison unit is configured to output a first level signal when the photovoltaic output voltage value is higher than the daytime voltage threshold. The first level signal is used to control the power module to stop working.

3. The power supply device according to claim 2, characterized in that, The DC auxiliary power supply has a first power voltage output terminal and a second power voltage output terminal. When the DC auxiliary power supply starts working, the first power voltage output terminal supplies power to the control unit, and the second power voltage output terminal supplies power to the communication unit.

4. The power supply device according to claim 3, characterized in that, One of the plurality of AC auxiliary power supplies has a third power voltage output terminal and / or a fourth power voltage output terminal; When one of the AC auxiliary power supplies is started, the third power supply voltage output terminal or the fourth power supply voltage output terminal together with the first power supply voltage output terminal supply power to the control unit; or, When one of the AC auxiliary power supplies is activated, the third or fourth power supply voltage output terminal, together with the second power supply voltage output terminal, supplies power to the communication unit; or... When one of the AC auxiliary power supplies is activated, the third power supply voltage output terminal, together with the first power supply voltage output terminal, supplies power to the control unit, and the fourth power supply voltage output terminal, together with the second power supply voltage output terminal, supplies power to the communication unit.

5. The power supply device according to claim 1, characterized in that, The power supply device further includes a wake-up unit connected to the control unit, which is configured to control at least one of the plurality of AC auxiliary power supplies to start working when a wake-up signal is received.

6. The power supply device according to claim 1, characterized in that, The power supply device also includes a plurality of first switching transistors, each of the plurality of AC auxiliary power supplies being connected to the power grid through any one of the plurality of first switching transistors; the first level signal can control all of the plurality of first switching transistors to disconnect.

7. The power supply device according to claim 1, characterized in that, The power supply device also includes a second switching transistor, and the power module is connected to the power grid through the second switching transistor; the second level signal can control the second switching transistor to conduct.

8. The power supply device according to claim 1, characterized in that, The input terminal of the DC auxiliary power supply is connected to the photovoltaic module. The first input terminal of the first comparison unit and the second input terminal of the second comparison unit are both connected to the output terminal of the DC auxiliary power supply. The second input terminal of the first comparison unit and the first input terminal of the second comparison unit are configured according to the nighttime voltage threshold.

9. The power supply device according to claim 1, characterized in that, The power module has a fifth power voltage output terminal and a sixth power voltage output terminal. When the power module starts working, the fifth power voltage output terminal supplies power to the control unit, and the sixth power voltage output terminal supplies power to the communication unit.

10. The power supply device according to claim 9, characterized in that, The power supply device further includes a first step-down circuit and / or a second step-down circuit. The first step-down circuit is disposed between the fifth power supply voltage output terminal and the control unit, and the second step-down circuit is disposed between the sixth power supply voltage output terminal and the communication unit.

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