Photovoltaic inverter, auxiliary power supply device thereof and main control module awakening method

Abstract

The invention discloses a photovoltaic inverter, an auxiliary power supply device thereof and a main control module awakening method. The auxiliary power supply device of the photovoltaic inverter comprises a flyback power supply module which is provided with an input end used for being connected with a power grid, a first output end and a second output end, and the flyback power supply module comprises a flyback isolation transformer, the flyback isolation transformer comprises a first output winding connected to the first output end and a second output winding connected to the second output end; the load module is provided with an enable signal access end used for receiving a first enable signal, and the load module is connected to the first output end; the main control power supply enabling module is connected to the second output end, and the main control power supply enabling module is further provided with a power supply output end used for being connected with a main control module of the photovoltaic inverter so as to supply power to the main control module after the photovoltaic inverter is in a standby mode and enables the load module.

Description

Technical Field

[0001] The invention relates to an auxiliary power supply device of a photovoltaic inverter and a method for waking up a main control module, in particular to a photovoltaic inverter with low standby power consumption at night and supporting waking up of a main control module and an auxiliary power supply device thereof. Background Art

[0002] Photovoltaic inverters usually generate electricity during the day and enter standby mode at night. When a traditional inverter enters standby mode, both the monitoring system and the main control system are continuously powered, resulting in large standby losses. Generally speaking, the inverter monitoring system needs to maintain communication with the external monitoring system and usually does not lose power. The main control system only needs to be powered when functions such as nighttime program upgrades are enabled. Therefore, the monitoring system can transmit a power enable signal to the main control system, so that the main control system is powered when it needs to work and enters a dormant state when it does not need to work, effectively reducing standby losses.

[0003] The monitoring system involves external communication lines and other parts that can be touched by humans, while the main control system is generally not isolated from the main circuit. Therefore, according to safety regulations, the communication between the monitoring system and the main control system must meet reinforced insulation or double insulation. At present, reinforced insulation design is more common. In high-voltage systems, the safety distance requirements are higher, but there are few isolation devices that meet the requirements on the market and the cost is high.

[0004] The above information disclosed in the Background section is only for enhancement of understanding of the background of the present application and therefore it may contain information that does not constitute the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0005] The present invention provides a photovoltaic inverter and an auxiliary power supply device thereof, which can reduce the standby loss of the photovoltaic inverter while making the circuit simple and low in cost. The present invention also provides a method for waking up a main control module of a photovoltaic inverter.

[0006] In order to achieve the above object, a technical solution adopted by the present invention is as follows:

[0007] An auxiliary power supply device for a photovoltaic inverter, comprising:

[0008] A flyback power supply module, comprising an input terminal for connecting to a power grid, and a first output terminal and a second output terminal, wherein the flyback power supply module comprises a flyback isolation transformer, and the flyback isolation transformer comprises a first output winding connected to the first output terminal and a second output winding connected to the second output terminal;

[0009] A load module having an enable signal access terminal for receiving a first enable signal, wherein the load module is connected to the first output terminal;

[0010] A main power enabling module is connected to the second output terminal, and the main power enabling module also has a power supply output terminal for connecting to the main control module of the photovoltaic inverter, so as to supply power to the main control module after the photovoltaic inverter is in standby mode and the load module is enabled.

[0011] In some preferred embodiments, the first output terminal is configured to be connected to a monitoring module of the photovoltaic inverter, and the enable signal access terminal is configured to be connected to the monitoring module.

[0012] In some preferred embodiments, the flyback power supply module is configured to adjust the output voltage of the second output winding according to the winding ratio and the load cross regulation rate after the load module is connected to the first output winding.

[0013] In some preferred embodiments, the flyback power supply module further includes a rectifier circuit, which is connected between the input terminal and the input winding of the flyback isolation transformer to supply the power taken from the power grid to the input winding. The flyback isolation transformer is an isolation transformer inherent in the photovoltaic inverter itself.

[0014] In some preferred embodiments, the load module includes a cooling fan or a heating resistor of the photovoltaic inverter. The load module uses the inherent resistive devices (fan, resistor, etc.) of the photovoltaic inverter itself as a resistive load.

[0015] In some preferred embodiments, the master power enabling module includes:

[0016] A power supply circuit connected between the second output terminal and the power supply output terminal;

[0017] A voltage sampling circuit, used for sampling the voltage output by the second output terminal;

[0018] A control circuit is used to output a second enable signal to the power supply circuit when the sampling value of the voltage sampling circuit is greater than a first threshold, and to turn off the second enable signal when the sampling value is less than a second threshold.

[0019] In some preferred embodiments, the power supply circuit includes a Buck circuit, a Boost circuit or a Buck-Boost circuit, and the control circuit is electrically connected to a control end of a switch tube of the power supply circuit.

[0020] In some preferred embodiments, one end of the voltage sampling circuit is connected to the second output end, and the other end is grounded or connected to the earth at the same potential. The voltage sampling circuit includes a first resistor and a second resistor connected in series, and the middle point of the first resistor and the second resistor is connected to the input end of the comparison circuit, and the output end of the comparison circuit is connected to the control circuit.

[0021] In some preferred embodiments, the voltage sampling circuit includes a resistor voltage divider sampling circuit or an operational amplifier sampling circuit, a comparison circuit is connected between the voltage sampling circuit and the control circuit, the comparison circuit includes a comparator or an operational amplifier, and the first threshold value and the second threshold value are the same or different.

[0022] Another technical solution adopted by the present invention is as follows:

[0023] A photovoltaic inverter comprises a monitoring module and a main control module. The photovoltaic inverter also comprises the auxiliary power supply circuit. The monitoring module is connected to the first output end of the auxiliary power supply circuit. The main control module is connected to the main power enabling module so that when the photovoltaic inverter is in standby mode and the load module is enabled, the main power enabling module supplies power to the main control module.

[0024] Furthermore, the monitoring module is connected to a first output terminal of the auxiliary power supply circuit to be powered by the auxiliary power supply circuit.

[0025] Furthermore, the monitoring module is electrically connected to the load module, specifically to an enable signal access terminal of the load module (for example, a load driving circuit connected to the load module), thereby sending a first enable signal to the load module through the monitoring module, and waking up the main control module through the cooperation of the flyback power supply circuit and the main control power supply enable module.

[0026] Another technical solution adopted by the present invention is as follows:

[0027] A method for waking up a main control module of a photovoltaic inverter, wherein the photovoltaic inverter adopts the auxiliary power supply device or is the photovoltaic inverter. When the photovoltaic inverter is in standby mode, a first enable signal is sent to the load module to enable the load module, the flyback power supply module adjusts the output voltage of the second output winding according to the winding ratio and the load cross regulation rate, and the main control power supply enabling module supplies power to the main control module to wake up the main control module.

[0028] Furthermore, a first enabling signal is sent to the load module through the monitoring module.

[0029] The above solution adopted by the present invention has the following advantages:

[0030] The auxiliary power supply circuit of the present invention or the photovoltaic inverter using the auxiliary power supply circuit can reduce nighttime standby losses compared to traditional inverter auxiliary power supplies; at the same time, the auxiliary power supply circuit is relatively simple and can utilize the existing load and isolation transformer of the inverter, transmit an enable signal through the load, and transmit the signal through the cross-regulation rate characteristic of the output winding of the flyback isolation transformer, thereby eliminating optocoupler devices and related circuits and effectively reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The figure shows a connection structure of an auxiliary power supply circuit, a power grid, a monitoring module and a main control module according to an embodiment of the present invention.

[0033] Figure 2 The figure is a circuit diagram of an auxiliary power supply circuit of a photovoltaic inverter according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] The following embodiments provide a photovoltaic inverter and an auxiliary power supply device used therein, which can support the selection of waking up a main control module as needed in a nighttime standby mode, thereby reducing standby power consumption.

[0036] Reference Figure 1 As shown, a photovoltaic inverter includes a monitoring module 110, a main control module 120 and an auxiliary power supply device 100. Figure 1 In the figure, the main circuit of the photovoltaic inverter is not shown. The monitoring module 110 is a device for maintaining communication with an external monitoring system, including sensors, communication devices, etc., which is usually not powered off; that is, the monitoring module 110 is not powered off even when the photovoltaic inverter is in standby mode. The main control module 120 includes the control circuit of the photovoltaic inverter, etc., and in the standby state, it only needs to be powered on when enabling functions such as nighttime upgrade programs. The auxiliary power supply device 100 is used to supply power to the monitoring module 110 and the main control module 120, especially to supply power to the monitoring module 110 and the main control module 120 in standby mode.

[0037] Combination Figure 2 As shown, the auxiliary power supply device 100 includes a flyback power supply module 101, a load module 102 and a main control power supply enabling module 103. The flyback power supply module 101 has an input terminal IN1 for connecting to the power grid 200, and a first output terminal OUT1 and a second output terminal OUT2. In this embodiment, the input terminal IN1 is specifically connected to the power grid 200 and draws power from the power grid 200. The flyback power supply module 101 includes a flyback isolation transformer 1, which is an isolation transformer inherent in the flyback power supply of the photovoltaic inverter.

[0038] The flyback isolation transformer 1 includes an input winding 11, a first output winding 12 and a second output winding 13. The input winding 11 is a primary winding connected to the input terminal IN1. The first output winding 12 is connected to the first output terminal OUT1, and the second output terminal OUT2 is connected to the second output terminal OUT2. The first output winding 12 and the second output winding 13 are both secondary windings for supplying power to the load. The flyback power supply module 101 also includes a rectifier circuit, which is connected between the input terminal and the input winding 11 of the flyback isolation transformer 1 to supply power from the power grid 200 to the input winding 11. The rectifier circuit and the flyback isolation transformer 1 constitute a power circuit unit of the flyback power supply module 101. The flyback power supply module 101 is configured to adjust the output voltage of the second output winding 13 according to the winding ratio and the load cross adjustment rate after the load module 102 is connected to the first output winding 12.

[0039] The load module 102 has an enable signal access terminal IN2 for receiving a first enable signal. Specifically in this embodiment, the enable signal access terminal is used to connect the monitoring module 110 of the photovoltaic inverter to receive the first enable signal IN2 from the monitoring module 110, and the load module 102 is connected to the first output terminal OUT1. The first output winding 12 continuously supplies power to the monitoring module 110 through the first output terminal OUT1; when the load module 102 receives the first enable signal from the monitoring module 110, the load module 102 works, and at this time, the flyback power supply module 101 adjusts the output voltage of the second output winding 13 accordingly. The load module 102 uses the resistive devices (fans, resistors, etc.) inherent in the photovoltaic inverter itself as a resistive load. Specifically in this embodiment, the load module 102 includes a cooling fan M of the photovoltaic inverter. In some other embodiments, the load module 102 includes a heating resistor of the photovoltaic inverter.

[0040] The load module 102 also includes a load driving circuit 6, such as a fan driving circuit. The enable signal access terminal IN2 is connected to the load driving circuit 6. When the first enable signal from the monitoring module 110 is received, the load driving circuit 6 drives the load to run. Specifically in this embodiment, when the monitoring module 110 sends the first enable signal, the load driving circuit 6 drives the fan M to run; when there is no enable signal, the fan M stops. The load driving circuit 6 includes a switch, which can be a relay or a semiconductor switch tube, such as an IGBT, a MOSFET, a transistor, a thyristor, etc., to switch the load.

[0041] The main control power enabling module 103 is connected to the second output terminal OUT2 and has a power supply output terminal OUT3. The power supply output terminal OUT3 is used to connect to the main control module 120 of the photovoltaic inverter, so that the main control power enabling module 103 supplies power to the main control module 120 after the photovoltaic inverter is in the standby mode and the load module 102 is enabled (the load module 102 receives the first enabling signal).

[0042] The master power enabling module 103 includes a power circuit 5, a voltage sampling circuit 2 and a control circuit 4. The power circuit 5 is connected between the second output terminal OUT2 and the power supply output terminal OUT3. The voltage sampling circuit 2 is used to sample the voltage output by the second output terminal OUT2. The control circuit 4 is used to output a second enabling signal to the power circuit 5 when the sampling value of the voltage sampling circuit 2 is greater than the first threshold value, and turn off the second enabling signal when the sampling value is less than the second threshold value.

[0043] The power circuit 5 includes a Buck circuit, a Boost circuit or a Buck-Boost circuit, and the power circuit 5 includes a switch tube, which may be an IGBT, a MOSFET, a transistor, a thyristor, etc. The control circuit 4 outputs a second enable signal through its enable pin, and the enable pin is electrically connected to the control end of the switch tube of the power circuit 5. In this embodiment, the power circuit 5 is specifically a Buck circuit.

[0044] The voltage sampling circuit 2 includes a resistor voltage-dividing sampling circuit or an operational amplifier sampling circuit. A comparison circuit 3 is connected between the voltage sampling circuit 2 and the control circuit 4. The comparison circuit 3 includes a comparator or an operational amplifier. The first threshold value and the second threshold value are the same or different. The first threshold value and the second threshold value of the comparison circuit 3 are not necessarily the same. When they are different, a hysteresis comparison function can be realized.

[0045] Specifically in this embodiment, one end of the voltage sampling circuit 2 is connected to the second output terminal OUT2, and the other end is grounded or connected to the ground at the same potential. The voltage sampling circuit 2 includes a first resistor R1 and a second resistor R2 connected in series. The middle point of the first resistor R1 and the second resistor R2 is connected to the input end of the comparison circuit 3, and the output end of the comparison circuit 3 is connected to the enable pin EN of the control circuit 4.

[0046] The principles of the above photovoltaic inverter and its auxiliary power supply circuit are as follows:

[0047] When the load module 102 is enabled through the monitoring module 110, the main power enabling module 103 works and the main control module 120 is activated. When the load module 102 is not enabled, the main power enabling module 103 is turned off and the main control module 120 is dormant. In this embodiment, instead of using an optocoupler device, the signal is transmitted through the cross-regulation rate characteristic of the output winding of the flyback transformer, which can effectively reduce the cost; the information transmission is realized by using the cross-regulation rate characteristic of the isolated flyback transformer as the principle, which can reduce the standby loss of the photovoltaic inverter.

[0048] Specifically, after the load module 102 is enabled, the voltage of the first output winding 12 reaches a given voltage (connected to the load module 102), and the flyback power supply module 101 controls the voltage of the second output winding 13 to change according to the winding ratio and the load cross-regulation rate. At this time, since the voltage sampling circuit 2 is connected to the second output segment, the voltage is divided by the series resistors R1 and R2, and the R2 voltage is connected to the voltage threshold judgment circuit in the power supply circuit 5, and compared with the given threshold by the comparator, the output is connected to the enable pin EN of the control circuit 4. When the voltage of the second output is higher than the first threshold, the second enable signal is output, and the power supply circuit 5 works; when it is lower than the second threshold, the second enable signal is turned off, and the power supply circuit 5 stops working.

[0049] This embodiment also provides a method for waking up the main control module 120 of a photovoltaic inverter. When the photovoltaic inverter is in standby mode, a first enable signal is sent to the load module 102 to enable the load module 102. The flyback power supply module 101 adjusts the output voltage of the second output winding 13 according to the winding ratio and the load cross-regulation rate. The main control power supply enable module 103 supplies power to the main control module 120 to wake up the main control module 120. Further, the first enable signal is sent to the load module 102 through the monitoring module 110.

[0050] Compared with the auxiliary power supply of the traditional inverter, this embodiment can reduce the nighttime standby loss of the photovoltaic inverter; at the same time, the additional circuit is simple, using the existing load and isolation transformer of the photovoltaic inverter to transmit signals, eliminating the optocoupler device and related circuits, and effectively reducing costs.

[0051] As shown in this specification and claims, the terms "comprises" and "include" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list, and the method or device may also include other steps or elements. The term "and / or" as used herein includes any combination of one or more of the relevant listed items.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. If a definition used herein conflicts or is inconsistent with a definition in other public documents, the definition used herein shall prevail.

[0053] As shown in this specification and claims, the terms "comprises" and "include" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list, and the method or device may also include other steps or elements. The term "and / or" as used herein includes any combination of one or more of the relevant listed items.

[0054] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0055] A person skilled in the art may understand that all or part of the steps in the above-mentioned embodiment method may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0056] In addition, each functional unit in the embodiment may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0057] The above embodiment is only for illustrating the technical concept and features of the present invention, and is a preferred embodiment. Its purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An auxiliary power supply device for a photovoltaic inverter, characterized in that: include: A flyback power supply module, comprising an input terminal for connecting to a power grid, and a first output terminal and a second output terminal, wherein the flyback power supply module comprises a flyback isolation transformer, and the flyback isolation transformer comprises a first output winding connected to the first output terminal and a second output winding connected to the second output terminal; A load module having an enable signal access terminal for receiving a first enable signal, wherein the load module is connected to the first output terminal; A main power enabling module is connected to the second output terminal, and the main power enabling module also has a power supply output terminal for connecting to the main control module of the photovoltaic inverter, so as to supply power to the main control module after the photovoltaic inverter is in standby mode and the load module is enabled.

2. The auxiliary power supply device according to claim 1, characterized in that: The flyback power supply module is configured to adjust the output voltage of the second output winding according to the winding ratio and the load cross regulation rate after the load module is connected to the first output winding; the first output end is configured to be connected to the monitoring module of the photovoltaic inverter, and the enable signal access end is configured to be connected to the monitoring module.

3. The auxiliary power supply device according to claim 1, characterized in that: The flyback power supply module further includes a rectifier circuit, which is connected between the input end and the input winding of the flyback isolation transformer to supply power taken from the power grid to the input winding.

4. The auxiliary power supply device according to claim 1, characterized in that: The load module includes a cooling fan or a heating resistor of the photovoltaic inverter.

5. The auxiliary power supply device according to claim 1, characterized in that: The main control power enabling module includes: A power supply circuit connected between the second output terminal and the power supply output terminal; A voltage sampling circuit, used for sampling the voltage output by the second output terminal; A control circuit is used to output a second enable signal to the power supply circuit when the sampling value of the voltage sampling circuit is greater than a first threshold, and to turn off the second enable signal when the sampling value is less than a second threshold.

6. The auxiliary power supply device according to claim 5, characterized in that: The power supply circuit includes a Buck circuit, a Boost circuit or a Buck-Boost circuit, and the control circuit is electrically connected to a control end of a switch tube of the power supply circuit.

7. The auxiliary power supply device according to claim 5, characterized in that: One end of the voltage sampling circuit is connected to the second output end, and the other end is grounded or at the same potential as the earth. The voltage sampling circuit includes a first resistor and a second resistor connected in series. The middle point of the first resistor and the second resistor is connected to the input end of the comparison circuit, and the output end of the comparison circuit is connected to the control circuit.

8. The auxiliary power supply device according to claim 5, characterized in that: The voltage sampling circuit includes a resistor voltage divider sampling circuit or an operational amplifier sampling circuit. A comparison circuit is connected between the voltage sampling circuit and the control circuit. The comparison circuit includes a comparator or an operational amplifier. The first threshold value and the second threshold value are the same or different.

9. A photovoltaic inverter, comprising a monitoring module and a main control module, characterized in that: The photovoltaic inverter also includes an auxiliary power supply circuit as described in any one of claims 1 to 8, the monitoring module is connected to the first output end of the auxiliary power supply circuit, and the main control module is connected to the main power enabling module, so that when the photovoltaic inverter is in standby mode and the load module is enabled, the main power enabling module supplies power to the main control module.

10. A method for waking up a main control module of a photovoltaic inverter, characterized in that: The photovoltaic inverter adopts the auxiliary power supply device as described in any one of claims 1 to 8 or is the photovoltaic inverter as described in claim 9. When the photovoltaic inverter is in standby mode, a first enable signal is sent to the load module to enable the load module, the flyback power supply module adjusts the output voltage of the second output winding according to the winding ratio and the load cross regulation rate, and the main control power supply enable module supplies power to the main control module to wake up the main control module.

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