Auxiliary source architecture applied to photovoltaic system

Abstract

The invention discloses an auxiliary source framework applied to a photovoltaic system. The auxiliary source framework comprises a direct-current auxiliary source and an alternating-current auxiliary source, the direct current auxiliary source takes electricity from a direct current bus of the photovoltaic system, and the alternating current auxiliary source takes electricity from an alternating current power grid; based on the working scene of the photovoltaic system, the direct-current auxiliary source and / or the alternating-current auxiliary source independently supplies power to the functional modules of the photovoltaic system, or the direct-current auxiliary source and the alternating-current auxiliary source jointly supply redundant power to at least part of the functional modules of the photovoltaic system. The beneficial effects of the invention are that different auxiliary sources are arranged, and the power taking positions of the auxiliary sources are different, so that the power supply demands of the photovoltaic system in different working scenes can be met, and the normal work of the photovoltaic system in different working scenes can be ensured; redundant power supply of at least part of functional modules of the photovoltaic system is realized through cooperation of different auxiliary sources, and the working reliability of the photovoltaic system can be improved.

Description

Technical Field

[0001] The present application relates to the field of renewable energy power generation, and in particular to an auxiliary source architecture applied to a photovoltaic system. Background Art

[0002] When the photovoltaic system is working, it is often necessary to detect and control the circuit of the photovoltaic system accordingly. At the same time, the internal functional modules of the photovoltaic system need to communicate and interact with each other, and the photovoltaic system needs to interact with the outside world; all of these require auxiliary power supply. In the prior art, the auxiliary power supply method generally uses a separate power supply from the DC bus of the photovoltaic system to achieve power supply. This power supply method has low reliability and poor power supply performance, and it is difficult to meet the multi-scenario, multi-load and multi-function requirements of the photovoltaic system. Summary of the invention

[0003] One of the objectives of the present application is to provide an auxiliary source architecture for a photovoltaic system that can solve at least one of the defects in the above-mentioned background technology.

[0004] In order to achieve at least one of the above-mentioned purposes, the technical solution adopted in the present application is: an auxiliary source architecture applied to a photovoltaic system, including a DC auxiliary source and an AC auxiliary source; the DC auxiliary source draws power from the DC bus of the photovoltaic system, and the AC auxiliary source draws power from the AC power grid; based on the working scenario of the photovoltaic system, the DC auxiliary source and / or the AC auxiliary source separately powers the functional modules of the photovoltaic system, or the DC auxiliary source and the AC auxiliary source jointly provide redundant power supply to at least part of the functional modules of the photovoltaic system.

[0005] Preferably, the DC auxiliary source and the AC auxiliary source both output multiple supply voltages, and the supply voltages output by the DC auxiliary source and the AC auxiliary source are not exactly the same; the same supply voltage output by the DC auxiliary source and the AC auxiliary source are suitable for direct parallel connection to the functional modules of the photovoltaic system for redundant power supply; the different supply voltages output by the DC auxiliary source and the AC auxiliary source are kept consistent by means of boosting or stepping down, and then connected in parallel to the functional modules of the photovoltaic system for redundant power supply.

[0006] Preferably, for a functional module that requires the DC auxiliary source and the AC auxiliary source to perform redundant power supply through different supply voltages, the supply voltage with a lower voltage value among the supply voltages output by the DC auxiliary source and the AC auxiliary source is matched with the working voltage of the functional module, and then the supply voltage with a higher voltage value is stepped down to be consistent with the other supply voltage for redundant power supply.

[0007] Preferably, the output ports of the DC auxiliary source and the AC auxiliary source are both connected to a power parallel selection module, so that the supply voltages output by the DC auxiliary source and the AC auxiliary source are output in parallel through the power parallel selection module; the power parallel selection module uses a diode or a power rail control chip.

[0008] Preferably, the operating voltages required by different functional modules of the photovoltaic system are not completely the same; when the auxiliary source architecture supplies power to different functional modules individually or redundantly through the same supply voltage, it is suitable for reducing the voltage of the same supply voltage at least once.

[0009] Preferably, the functional modules of the photovoltaic system include an internal interaction module for information interaction within the system, and an external interaction module for human-computer interaction of the system; the supply voltage output by the DC auxiliary source includes +12V, -12V and +5V, and the supply voltage output by the AC auxiliary source includes +12V, -12V and +24V; the AC auxiliary source is suitable for directly or stepping down the internal interaction module through the output +12V and -12V voltages; the AC auxiliary source is suitable for directly or stepping down the external interaction module through the output +24V voltage; the DC The +12V and -12V voltages output by the DC auxiliary source and the AC auxiliary source are suitable for being connected in parallel to provide direct or reduced voltage redundant power supply to the internal interaction module; the +24V voltage output by the AC auxiliary source is suitable for being reduced to +5V and then connected in parallel with the +5V voltage output by the DC auxiliary source, thereby providing direct or reduced voltage redundant power supply to the external interaction module; wherein the internal interaction module includes a DC side detection circuit module, an AC side detection circuit module, an analog switch module, an internal fan module and a DSP module; the external interaction module includes an ARM module and an external fan module.

[0010] Preferably, the auxiliary source architecture is provided with a virtual ground AGND and a ground FAN_GND with reinforced insulation; the auxiliary source architecture adopts the ground AGND when powering the internal interaction module, and adopts the ground FAN_GND when powering the external interaction module.

[0011] Preferably, the functional modules of the photovoltaic system further include a PID module for suppressing the PID effect; the auxiliary source architecture is also provided with a ground PID_GND shared with the ground, and the auxiliary source architecture adopts the ground PID_GND when powering the PID module.

[0012] Preferably, the AC auxiliary source includes a first AC auxiliary source and a second AC auxiliary source; the first AC auxiliary source is suitable for powering the internal interaction module and the external interaction module individually, or for redundantly powering the internal interaction module and the external interaction module after being connected in parallel with the DC auxiliary source; the second AC auxiliary source is suitable for powering the PID module individually.

[0013] Preferably, the working scenes of the photovoltaic system are divided into daytime working scenes and nighttime working scenes according to the light intensity; in the daytime working scene, the DC auxiliary source and the first AC auxiliary source are turned on to supply power, and the second AC auxiliary source is turned off; in the nighttime working scene, the DC auxiliary source is turned off, and the first AC auxiliary source and the second AC auxiliary source are turned on to supply power; wherein, the opening and closing of the second AC auxiliary source is controlled by the signal of the DC auxiliary source.

[0014] Compared with the prior art, the beneficial effects of this application are:

[0015] (1) By setting different auxiliary sources and taking power from different locations, the power supply requirements of the photovoltaic system in different working scenarios can be met, thereby ensuring the normal operation of the photovoltaic system in different working scenarios.

[0016] (2) The working reliability of the photovoltaic system can be improved by realizing redundant power supply to at least some functional modules of the photovoltaic system through the coordinated cooperation between different auxiliary sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a schematic diagram of the structure of an existing photovoltaic system.

[0018] Figure 2 for Figure 1 Schematic diagram of the control circuit structure of the photovoltaic system shown.

[0019] Figure 3 This is a schematic diagram of the overall structure of this application.

[0020] Figure 4 This is a schematic diagram of the specific structure of the DC side detection circuit of the photovoltaic system for powering the present application.

[0021] Figure 5 This is a schematic diagram of the specific structure of powering the AC side detection circuit of the photovoltaic system in this application.

[0022] Figure 6 This is a schematic diagram of the specific structure of the application for supplying power to the internal fan module of the photovoltaic system.

[0023] Figure 7 This is a schematic diagram of the specific structure of the DSP module of the photovoltaic system for powering the present application.

[0024] Figure 8 This is a schematic diagram of the specific structure of the ARM module of the photovoltaic system for powering the power supply in this application.

[0025] Fig. 9 This is a schematic diagram of the specific structure of powering the external fan module of the photovoltaic system in this application.

[0026] Fig.10 This is a schematic diagram of the working logic of this application under daytime and night scene switching.

[0027] Fig.11 This is a schematic diagram of the level status of each auxiliary source when this application is started during the day.

[0028] Fig.12 This is a schematic diagram of the level status of each auxiliary source when switching at night in this application. DETAILED DESCRIPTION

[0029] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0030] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present application.

[0031] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0032] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] The terms "including" and "having" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0035] In order to better understand the technical solution of the present application, the structure of the existing photovoltaic system and the corresponding control circuit may be briefly described below.

[0036] like Figure 1 As shown in FIG. 1 , a schematic diagram of the structure of an existing photovoltaic system is shown. The photovoltaic system mainly includes n PV units, n DC / DC units and DC / AC units. Each PV unit can be connected in parallel with the input side of the DC / AC unit through the corresponding DC / DC unit, and the output end of the DC / AC unit can be connected to the AC grid through a grid-connected relay.

[0037] It should be known that during the operation of the photovoltaic system, due to the high potential difference between the cells of the PV unit and other parts of the assembly, the PID effect, i.e., potential induced decay, may be induced; therefore, a PID module is generally required to be set up for the photovoltaic system to suppress the PID effect. The specific structure and setting position of the PID module are well-known technologies to those skilled in the art, so they will not be elaborated in detail here.

[0038] Based on the above photovoltaic system, when it is connected to the grid, the control circuit of the photovoltaic system is as follows: Figure 2 As shown. The control circuit includes DSP module, ARM module, drive circuit module, protection circuit module, DC side detection circuit module and AC side detection circuit module. Among them, the drive circuit module is mainly used to drive the DC / DC unit, DC / AC unit and the internal fan module used for heat dissipation in the system. The DC side detection circuit module mainly detects the current, voltage and temperature of the DC side functional unit of the photovoltaic system; the AC side detection circuit module mainly detects the current, voltage and temperature of the AC side functional unit of the photovoltaic system. The protection circuit module is mainly used for circuit protection when the functional unit of the photovoltaic system is abnormal. The DSP module monitors the status of the DC side and AC side of the photovoltaic system in real time through the DC side / AC side detection circuit module and the protection circuit module, and outputs the drive signal for corresponding control, including DC / DC drive, DC / AC drive, internal fan drive, etc. The ARM module is mainly used for human-computer interaction between the photovoltaic system and the outside world, such as communicating with the DSP module, obtaining the photovoltaic system status information and transmitting it on the display; the photovoltaic system can be upgraded according to needs; and the start and stop of the external fan module can also be controlled.

[0039] The normal operation of the control circuit of the photovoltaic system often requires an auxiliary source for power supply. Based on the above photovoltaic system, the auxiliary source often has the following requirements:

[0040] (1) Redundant power supply requirements: The DSP module needs to monitor the status of the DC side and AC power grid of the photovoltaic system in real time. Therefore, the power supply of the DSP module and the DC side / AC detection circuit module needs to maintain an uninterrupted working state. Therefore, it is necessary to design redundant power supply for the DSP module and related circuit modules. Similarly, ARM and its peripheral circuits also need redundant power supply design.

[0041] (2) Load distribution requirements: Considering that the power of the external fan module and the internal fan module is relatively large, in order to reduce the size of the auxiliary power transformer, the external fan module and the internal fan module need to be powered by different auxiliary sources; in order to balance the power load, the loads of several power supplies need to be kept as balanced as possible.

[0042] (3) Ground management requirements: Different grounds need to be set for external and internal use. This is because the system needs to interact with the outside world, so it is required to strengthen insulation treatment to ensure the safety of the system. In addition, in the external ground, the system is equipped with a PID module to suppress the PID effect. This module needs to use a separate ground.

[0043] (4) Meeting the requirements for startup in different scenarios: PV systems have different working scenarios, such as day, night, and failure, and these scenarios all require the system auxiliary source to operate normally.

[0044] Based on the above power supply requirements, one of the preferred embodiments of the present application is as follows: Figure 3 As shown, an auxiliary source architecture for a photovoltaic system is provided, including a DC auxiliary source and an AC auxiliary source. The DC auxiliary source draws power from the DC bus of the photovoltaic system, and the AC auxiliary source draws power from the AC power grid. Based on the working scenario of the photovoltaic system, the DC auxiliary source and / or the AC auxiliary source can independently power the functional modules of the photovoltaic system, or the DC auxiliary source and the AC auxiliary source can jointly provide redundant power supply to at least some functional modules of the photovoltaic system.

[0045] It should be known that, from the above content, the working scenarios of the photovoltaic system mainly include daytime, nighttime and faults. If the photovoltaic system works in the daytime scenario, that is, the PV unit receives strong light, so that the photovoltaic system supplies power to the AC power grid or load, at this time, both the DC auxiliary source and the AC auxiliary source can be powered normally; in order to ensure the working safety of the photovoltaic system, the DC auxiliary source and the AC auxiliary source can be coordinated to provide redundant power supply to some of the more important functional modules in the photovoltaic system, thereby effectively improving the working reliability of the photovoltaic system. If the photovoltaic system works in the night scene, that is, the PV unit cannot receive light, at this time the DC auxiliary source cannot be powered, and only the AC auxiliary source can be powered from the AC power grid. Therefore, in this scenario, only the AC auxiliary source can be used to power the functional modules of the photovoltaic system. If a photovoltaic system fails, the corresponding auxiliary source is powered according to the location of the fault, that is, if the fault occurs on the DC side of the photovoltaic system, the photovoltaic system is powered by the AC auxiliary source; if the fault occurs on the AC side of the photovoltaic system, the photovoltaic system is powered by the DC auxiliary source. Therefore, the present application can meet the power supply requirements of the photovoltaic system in different working scenarios by setting different auxiliary sources and different power supply locations of each auxiliary source, thereby ensuring the normal operation of the photovoltaic system in different working scenarios.

[0046] In this embodiment, Figure 3 As shown, both the DC auxiliary source and the AC auxiliary source output multiple supply voltages, and the supply voltages output by the DC auxiliary source and the AC auxiliary source are not exactly the same. The same supply voltage output by the DC auxiliary source and the AC auxiliary source can be directly connected in parallel to the functional modules of the photovoltaic system for redundant power supply; the different supply voltages output by the DC auxiliary source and the AC auxiliary source are kept consistent by stepping up or down, and then connected in parallel to the functional modules of the photovoltaic system for redundant power supply.

[0047] It should be known that for redundant power supply of functional modules, it is necessary to ensure that the supply voltages output by the DC auxiliary source and the AC auxiliary source are consistent. However, the photovoltaic system includes many types of functional modules, and the working voltages required by different functional modules are not exactly the same; if the number of supply voltages output by the DC auxiliary source and the AC auxiliary source completely corresponds to the type of functional module, then the DC auxiliary source and the AC auxiliary source will have to design more output interfaces, which will greatly increase the design difficulty of the DC auxiliary source and the AC auxiliary source. Therefore, in this embodiment, the DC auxiliary source and the AC auxiliary source can be provided with supply voltage interfaces that are not exactly the same. For functional modules that do not meet the requirements of direct redundant power supply by the DC auxiliary source and the AC auxiliary source, at least one of the supply voltages output by the DC auxiliary source and the AC auxiliary source can be boosted or reduced, so that the DC auxiliary source and the AC auxiliary source finally output a consistent supply voltage to provide redundant power supply to the corresponding functional modules. For ease of understanding, the boost or reduction scenarios of the supply voltage will be described in detail below through specific examples.

[0048] Specifically, for the step-down scenario, the operating voltage of the functional module that needs redundant power supply can be set to 5V. If the supply voltage output by the DC auxiliary source that powers the functional module is 5V, and the supply voltage output by the AC auxiliary source that powers the functional module is 12V. Then, in order to ensure that the functional module can work reliably, the supply voltage output by the AC auxiliary source needs to be stepped down to 5V and connected in parallel with the 5V supply voltage output by the DC auxiliary source to provide redundant power supply to the functional module. Of course, if the operating voltage of the functional module is 3.3V, then the supply voltages output by the DC auxiliary source and the AC auxiliary source need to be stepped down to 3.3V and connected in parallel to achieve redundant power supply to the functional module.

[0049] For the boost scenario, the working voltage of the functional module that needs redundant power supply can be set to 12V. If the supply voltage output by the DC auxiliary source that powers the functional module is 5V, and the supply voltage output by the AC auxiliary source that powers the functional module is 12V. Then, in order to ensure that the functional module can work reliably, the supply voltage output by the DC auxiliary source needs to be boosted to 12V and connected in parallel with the 12V supply voltage output by the AC auxiliary source to provide redundant power supply to the functional module. Of course, if the working voltage of the functional module is 24V, then the supply voltage output by the DC auxiliary source and the AC auxiliary source need to be boosted to 24V and connected in parallel to achieve redundant power supply to the functional module.

[0050] It is understandable that if the supply voltages output by the DC auxiliary source and the AC auxiliary source are boosted or bucked at the same time, the circuit structure complexity of the auxiliary source architecture of the present application will increase. Therefore, in the present embodiment, for the functional modules that require the DC auxiliary source and the AC auxiliary source to perform redundant power supply through different supply voltages, when designing the supply voltages output by the DC auxiliary source and the AC auxiliary source, the supply voltage with a lower voltage value is matched with the working voltage of the functional module, and then the supply voltage with a higher voltage value is bucked to be consistent with the other supply voltage for redundant power supply to the functional module, thereby effectively reducing the complexity of the auxiliary source architecture. Of course, the supply voltage with a higher voltage value among the supply voltages output by the DC auxiliary source and the AC auxiliary source can also be matched with the working voltage of the functional module, and the supply voltage with a lower voltage value can be boosted to be consistent with the supply voltage with a higher voltage value for redundant power supply. For the supply voltages output by the DC auxiliary source and the AC auxiliary source, whether the supply voltage with a high voltage value is stepped down or the supply voltage with a low voltage value is stepped up can be selected according to the actual needs of technical personnel in this field; in order to facilitate the description of subsequent contents, in this embodiment, it is preferred to adopt the method of stepping down the supply voltage with a high voltage value.

[0051] In this embodiment, it can be seen from the above content that the working voltages required by different functional modules of the photovoltaic system are not completely the same, and the number of functional modules of the photovoltaic system is large. However, the number of output interfaces of the auxiliary source is limited. In this embodiment, Figure 3 As shown, when the auxiliary source architecture uses the same supply voltage to supply power to different functional modules individually or redundantly, the same supply voltage can be stepped down at least once. Specifically, the supply voltage output by the auxiliary source architecture can supply power to functional modules whose operating voltage is equal to or lower than the output supply voltage, and for functional modules whose operating voltage is lower than the output supply voltage, power can be supplied by stepping down the supply voltage.

[0052] It should be noted that in order to reduce the design difficulty of the auxiliary source architecture, multiple functional modules powered by the same supply voltage can be arranged and connected in order from high to low according to the working voltage, so that the supply voltage is sequentially stepped down at least once to achieve power supply. It should be known that there are many specific circuit structures that can achieve step-down of the supply voltage, among which the most common step-down circuit is the Buck circuit, etc. Therefore, in this embodiment, the Buck circuit is preferably used for stepping down the supply voltage.

[0053] In this embodiment, the functional modules of the photovoltaic system include an internal interaction module for information interaction within the system and an external interaction module for human-computer interaction. Figure 3As shown, the supply voltages of the DC auxiliary source and the AC auxiliary source can be specifically designed based on the operating voltages of the functional modules of the traditional photovoltaic system. In one specific example, the supply voltages output by the DC auxiliary source are +12V, -12V and +5V, and the supply voltages output by the AC auxiliary source are +12V, -12V and +24V.

[0054] According to the working scenario of the photovoltaic system, the AC auxiliary source can directly or step down the power supply to the internal interactive module through the output +12V and -12V voltages; the AC auxiliary source can directly or step down the power supply to the external interactive module through the output +24V voltage. The +12V and -12V voltages output by the DC auxiliary source and the AC auxiliary source can be connected in parallel to provide direct or step down redundant power supply to the internal interactive module; the +24V voltage output by the AC auxiliary source can be stepped down to +5V and then connected in parallel with the +5V voltage output by the DC auxiliary source, thereby providing direct or step down redundant power supply to the external interactive module.

[0055] It can be understood that the internal interaction module and the external interaction module are distinguished according to the communication scenarios of the functional modules; specifically, the internal interaction module mainly includes a DC / DC side drive module, a DC / AC side drive module, a DC side detection circuit module, an AC side detection circuit module, an analog switch module, an internal fan module and a DSP module, etc.; the external interaction module mainly includes an ARM module and an external fan module, etc.

[0056] It should be noted that the maximum load of the photovoltaic system is the fan module, and the load power of other functional modules is relatively small, so the fan module needs to be focused on in the load distribution of the auxiliary source. Specifically, since the power of the internal fan module and the external fan module is relatively large, if the load is unevenly distributed, the auxiliary source will be too hot during operation, thereby reducing the reliability of the photovoltaic system for a long time. In addition, while meeting the high power requirements of the internal fan module and the external fan module, it is necessary to reduce the size of the auxiliary source transformer as much as possible. Therefore, in this embodiment, the external fan module and the internal fan module need to be powered by different auxiliary sources. At the same time, the DSP module needs to continuously monitor the busbar of the photovoltaic system and the status of the AC power grid, and needs to communicate the upgrade of the photovoltaic system at night, so the DSP module is powered by the +12V_VCC output by the auxiliary source uninterruptedly. More specifically, for a few extreme scenarios, such as AC power grid power failure and PV unit fire, the redundant power supply of the auxiliary source architecture of the present application can greatly improve the system reliability and ensure that the system can still be powered normally when a sudden failure occurs. The ARM module needs to communicate with the DSP module in real time to display the current status of the system and upgrade the system when necessary; therefore, a redundant power supply design is adopted for the ARM module to ensure uninterrupted power supply to the system control chip and prevent sudden power failure.

[0057] In this embodiment, Figure 3 As shown, in order to ensure the stability of the redundant power supply of the DC auxiliary source and the AC auxiliary source, the power supply parallel selection module can be connected to the output ports of the DC auxiliary source and the AC auxiliary source, so that the supply voltages output by the DC auxiliary source and the AC auxiliary source are output in parallel through the power supply parallel selection module. Specifically, the +12V supply voltage output interfaces of the DC auxiliary source and the AC auxiliary source are respectively connected to the power supply parallel selection modules P1 and P2, and the +12V supply voltage is output in parallel through the power supply parallel selection modules P1 and P2. The +5V supply voltage output interface of the DC auxiliary source is connected to the power supply parallel selection module P3, and the +24V supply voltage output interface of the AC auxiliary source is connected to the power supply parallel selection module P4 after the voltage is reduced to +5V, and the +5V supply voltage is output in parallel through the power supply parallel selection modules P3 and P4.

[0058] Those skilled in the art should know that the redundant power supply of the DC auxiliary source and the AC auxiliary source can be regarded as the parallel power supply of the two power supplies. The parallel power supply of the two power supplies may have the following problems: if the voltage difference between the two power supplies is large, it will cause the current to flow from the low voltage power supply to the high voltage power supply, thereby making the power supply unable to work normally. The outputs of the two power supplies are not completely equal, which may cause circuit instability, etc. Therefore, in order to ensure the working safety of the DC auxiliary source and the AC auxiliary source when performing redundant power supply in this embodiment, a power supply parallel selection module can be connected to the output interface of the DC auxiliary source and the AC auxiliary source to guide the supply voltage output by the auxiliary source.

[0059] It should be known that there are many specific structures of the power parallel selection module that can realize the above functions. Common power parallel selection modules use diodes or power rail control chips. In the case where the power parallel selection module uses diodes, the diodes connected to the DC auxiliary source and AC auxiliary source output interfaces are turned on in opposite directions, and when the output power supply of the DC auxiliary source and the AC auxiliary source is inconsistent, the auxiliary source can be protected by the cutoff of the diode. In the case where the power parallel selection module uses a power rail control chip, the power rail control chip can guide the flow of the supply voltage through the power rail on the circuit board.

[0060] It should be noted that when a diode is used for parallel redundant power supply, no additional auxiliary circuit is required, which makes the circuit structure simple and can effectively save costs; but when the power of the auxiliary source is high, the loss of the diode is large, which makes the diode heat up more seriously and requires the installation of a heat sink. When a power rail control chip is used for parallel redundant power supply, the conduction loss can be effectively reduced, and the current can also be prevented from flowing back to the external chip. It has the ability to detect the output of the auxiliary source, such as overvoltage or undervoltage detection, and can also be hot-swapped. Some power rail control chips can even realize the current sharing design between different auxiliary sources. Therefore, the use of a power rail control chip can greatly improve the reliability of the auxiliary source architecture, but it requires additional circuit design, which increases the design difficulty and cost of the auxiliary source architecture. Therefore, in actual use, technicians in this field can select a suitable redundant power supply solution based on factors such as the auxiliary source output power, system thermal analysis, and cost. In order to facilitate the description of the subsequent content, the power parallel selection module will be described using a diode as an example in the subsequent content.

[0061] In this embodiment, Figure 3 As shown, the auxiliary source architecture is provided with a virtual ground AGND and a ground FAN_GND with enhanced insulation. In order to improve the insulation capability of the photovoltaic system during human-machine interaction with the outside of the system and ensure the safety of the photovoltaic system, the auxiliary source architecture uses the ground AGND when supplying power to the internal interaction module, and the auxiliary source architecture uses the ground FAN_GND when supplying power to the external interaction module.

[0062] It should be known that the management of the ground by the above-mentioned auxiliary source architecture is based on the situation that the photovoltaic system does not suppress the PID effect; if the photovoltaic system suppresses the PID effect, that is, the photovoltaic system is equipped with a PID module, then in order to ensure the working safety of the photovoltaic system, the auxiliary source architecture is also provided with a ground PID_GND shared with the ground, and the auxiliary source architecture uses the ground PID_GND when powering the PID module.

[0063] In this embodiment, Figure 3 As shown, based on the setting of the PID module in the photovoltaic system, the PID module needs to be powered separately. Then the AC auxiliary source can be divided into a first AC auxiliary source and a second AC auxiliary source; wherein the first AC auxiliary source can power the internal interaction module and the external interaction module separately, or after being connected in parallel with the DC auxiliary source, provide redundant power supply to the internal interaction module and the external interaction module. The second AC auxiliary source is used to power the PID module separately. Specifically, the supply voltages output by the first AC auxiliary source are +12V, -12V and +24V; the supply voltages output by the second AC auxiliary source according to the working requirements of the PID module are +600V, +12V and -12V.

[0064] In this embodiment, Figure 3 and Fig.10 As shown, based on the photovoltaic system provided with a PID module, the PID repair function of the photovoltaic system is only used at night or under insufficient light conditions; the working scene of the auxiliary source architecture can be divided into daytime working scenes and nighttime working scenes according to the light intensity. In order to meet the normal power supply demand for the photovoltaic system, the standby power consumption of the photovoltaic system at night or other low light conditions can be reduced as much as possible. In the daytime working scene, due to sufficient light, the auxiliary source architecture can turn on the DC auxiliary source and the first AC auxiliary source to realize redundant power supply to the photovoltaic system, and the second AC auxiliary source is turned off at this time. In the night working scene, due to insufficient light, the PV unit cannot work normally, and then the DC side of the photovoltaic system has basically no voltage. At this time, the DC auxiliary source can be turned off, and the first AC auxiliary source is turned on to power the functional module of the photovoltaic system separately through the AC power grid, and the second AC auxiliary source is turned on to power the PID module through the AC power grid to realize the PID repair of the photovoltaic system. Among them, the opening and closing of the second AC auxiliary source is controlled by the signal of the DC auxiliary source.

[0065] For ease of understanding, the specific switching process of the two working scenarios will be described in detail below.

[0066] 1. The auxiliary source switching process in the working scenario from night to day.

[0067] like Figure 3 and Fig.11 As shown, the output voltage of the PV unit of the photovoltaic system gradually increases with the increase of light, and at this time, the bus voltage of the photovoltaic system is equal to the output voltage of the PV unit. When the bus voltage rises to the starting voltage of the photovoltaic system, the DC auxiliary source starts to work and can output a supply voltage of +12V_TG. At the same time, the DC auxiliary source can also output a control voltage of +12V_PIDc tr to the second AC auxiliary source, control the gate drive chip power supply relay of the second AC auxiliary source to be attracted, so that the second AC auxiliary source stops working due to the power supply disconnection of the gate drive chip, and at this time, the second AC auxiliary source stops outputting a supply voltage of +12V_PID to the PID module. In this process, the +12V_VCC required for the power supply of the internal interactive module of the photovoltaic system is converted from the single power supply of the first AC auxiliary source to the common redundant power supply of the DC auxiliary source and the first AC auxiliary source.

[0068] 2. Auxiliary source switching process in day-to-night working scenarios.

[0069] like Figure 3 and Fig.12As shown in the figure, the output voltage of the PV unit of the photovoltaic system gradually decreases as the light weakens, but at this time the MPPT circuit of the photovoltaic system can still keep the bus voltage stable. When the output voltage of the PV unit drops to the point where the MPPT circuit cannot stabilize the bus voltage, the bus capacitor continues to provide energy, and the DC auxiliary source can continue to work until the bus capacitor voltage drops to the starting voltage after a period of time, and the DC auxiliary source is turned off to stop the output of the +12V_TG supply voltage. At the same time, the +12V_PIDctr control voltage of the DC auxiliary source also stops outputting, and the gate drive chip power supply relay of the second AC auxiliary source is disconnected, so that the second AC auxiliary source is started due to the power supply of the gate drive chip. At this time, the second AC auxiliary source can output the +12V_PID supply voltage to the PID module. In this process, the +12V_VCC required for the power supply of the internal interactive module of the photovoltaic system will be converted from the common redundant power supply of the DC auxiliary source and the first AC auxiliary source to be powered only by the first AC auxiliary source.

[0070] For ease of understanding, the specific power supply process of the internal interaction module, the external interaction module and the PID module in different working scenarios will be described in detail below. Among them, the specific structure and working principle of the internal interaction module, the external interaction module and the PID module are well-known technologies for those skilled in the art, so they will not be elaborated in detail here.

[0071] (1) Power supply for DC / DC side drive module and DC / AC side drive module.

[0072] like Figure 3 As shown, the DC / DC side driver module is used to drive the DC / DC unit of the photovoltaic system, and the power interface of the DC / DC side driver module can be connected to the +12V supply voltage interface of the DC auxiliary source. Therefore, in the daytime working scenario, the +12V supply voltage output by the DC auxiliary source is +12V_TG to realize the power supply to the DC / DC side driver module; in the night working scenario, insufficient light causes the PV unit to fail to work normally, then the DC / DC unit can also stop working at this time, so the power supply to the DC / DC side driver module can be stopped when the DC auxiliary source is turned off.

[0073] The DC / AC side drive module is used to drive the DC / AC unit of the photovoltaic system. Since the DC / AC unit may work in SVG mode at night, it is necessary to connect the power interface of the DC / AC side drive module to the +12V supply voltage interface of the first AC auxiliary source. In this way, whether in the daytime or nighttime working scenario, the +12V supply voltage output by the first AC auxiliary source is +12V_TG_AC to realize the power supply of the DC / AC side drive module.

[0074] (2) Power supply for analog switch module.

[0075] like Figure 4 As shown, the analog switch module is mainly used to disconnect the PV unit, so the analog switch module includes analog switches corresponding to the number of PV units. The working voltage of the analog switch is 5V. In the daytime working scenario, the +12V supply voltage output by the DC auxiliary source and the first AC auxiliary source can output +5V_VCC voltage to power each analog switch after being stepped down by the Buck circuit; in the night working scenario, the DC auxiliary source stops supplying power, and the +12V supply voltage output by the first AC auxiliary source can output +5V_VCC voltage to power each analog switch after being stepped down by the Buck circuit.

[0076] It should be noted that since the first AC auxiliary source draws power from the AC grid, in order to ensure that the first AC auxiliary source can output a stable supply voltage, a voltage stabilizing unit needs to be provided at the output interface of the first AC auxiliary source. A common voltage stabilizing unit uses a low dropout regulator LDO.

[0077] (3) Power supply for the DC side detection circuit module.

[0078] like Figure 3 and Figure 4 As shown, the DC side detection circuit module mainly includes a DC side detection module, a DC side protection module and a reference voltage module. Specifically, the DC side detection module includes a PV voltage detection circuit, a PV current sampling circuit, a PV current sensor, an MPPT current sampling circuit, an MPPT current sensor, a DC temperature detection circuit, a bus voltage detection circuit and a bus insulation impedance detection circuit. The DC side protection module includes a DC lightning protection fault detection circuit, a 12V undervoltage detection circuit, a bus overvoltage protection circuit and an MPPT overcurrent protection circuit. The reference voltage module includes a 1.65V reference voltage circuit and a 0.51V reference voltage circuit.

[0079] Among them, the number of PV voltage detection circuit, MPPT current sampling circuit, MPPT current sensor, PV current sampling circuit, PV current sensor and DC temperature detection circuit corresponds to the number of PV units, and is n. The operating voltage of PV voltage detection circuit, MPPT current sampling circuit, bus voltage detection circuit, DC lightning protection fault detection circuit, PV current sampling circuit, 1.65V reference voltage circuit, 0.51V reference voltage circuit and bus insulation impedance detection circuit is 12V. The operating voltage of MPPT current sensor, PV current sensor, DC temperature detection circuit, 12V undervoltage detection circuit, bus overvoltage protection circuit and MPPT overcurrent protection circuit is 5V.

[0080] In the daytime working scenario, the DC auxiliary source and the first AC auxiliary source each output a set of ±12V supply voltages, which can form a dual-power ±12V power supply unit after passing through their respective power supply parallel selection modules. The dual-power ±12V power supply unit can output ±12V_VCC voltage to power the above-mentioned corresponding circuits. For circuits and sensors with a working voltage of 5V, the +12V supply voltage output by the DC auxiliary source and the first AC auxiliary source can output +5V_VCC voltage for power supply after being stepped down by the Buck circuit. In the night working scenario, the DC auxiliary source will stop supplying power, and the first AC auxiliary source will supply power to the DC side detection circuit module alone. The specific power supply process is basically the same as the above process, except that the redundant power supply is changed to a separate power supply.

[0081] (4) Power supply for the detection circuit module on the AC side.

[0082] like Figure 3 and Figure 5 As shown, the AC side detection circuit module mainly includes an AC side detection module, an AC side protection module and a reference voltage module. Specifically, the AC side detection module includes an AC current sampling circuit, an external power grid voltage detection circuit, an internal power grid voltage detection circuit and an AC temperature detection circuit. The AC side protection module includes an AC overcurrent protection circuit, an AC lightning protection fault detection circuit and an AC leakage current detection circuit. The reference voltage module includes an AC DC component detection circuit.

[0083] Generally speaking, the photovoltaic system is a three-level topology structure, so the number of AC temperature detection circuits, AC current sampling circuits, external grid voltage detection circuits, and internal grid voltage detection circuits are all three. The working voltage of the AC temperature detection circuit and the AC overcurrent protection circuit is 5V, the working voltage of the AC current sampling circuit is 5V and 12V according to its topology structure, and the working voltage of the AC leakage current detection circuit, AC DC component detection circuit, AC lightning protection fault detection circuit, external grid voltage detection circuit, and internal grid voltage detection circuit are all 12V.

[0084] In the daytime working scenario, the DC auxiliary source and the first AC auxiliary source each output a set of ±12V supply voltages, which can form a dual-power ±12V power supply unit after passing through their respective power supply parallel selection modules. The dual-power ±12V power supply unit can output ±12V_VCC voltage to power the above-mentioned corresponding circuits. For the circuit with a working voltage of 5V, the +12V supply voltage output by the DC auxiliary source and the first AC auxiliary source can output +5V_VCC voltage for power supply after being stepped down by the Buck circuit. In the night working scenario, the DC auxiliary source will stop supplying power, and the first AC auxiliary source will supply power to the AC side detection circuit module alone. The specific power supply process is basically the same as the above process, except that the redundant power supply is changed to a separate power supply.

[0085] (5) Power supply for internal fan module.

[0086] like Figure 3 and Figure 6 As shown, the internal fan module includes an internal fan and an internal fan status detection circuit. The internal fan is used to dissipate heat on the DC side of the photovoltaic system, and the internal fan status detection circuit is used to detect the working status of the internal fan. The working voltage of the internal fan is 12V, and the working voltage of the internal fan status detection circuit is 5V and 12V according to the topology structure.

[0087] In the daytime working scenario, the +12V supply voltage output by the DC auxiliary source can directly power the internal fan and the internal fan status detection circuit. At the same time, the +12V supply voltage output by the DC auxiliary source and the first AC auxiliary source can output +5V_VCC voltage to power the internal fan status detection circuit after being stepped down by the Buck circuit. In the night working scenario, the DC side of the photovoltaic system stops working due to insufficient light, so the internal fan can stop working at night when the DC auxiliary source is turned off.

[0088] (6) Power supply for DSP module.

[0089] like Figure 3 and Figure 7 As shown, the DSP module includes a hardware anti-through and forced dead zone circuit, a hardware protection blocking interface, a master / slave DSP, and a string acquisition board DSP. The number of hardware anti-through and forced dead zone circuits and hardware protection blocking interfaces is the same as the number of PV units, which is n; and the operating voltage of the hardware anti-through and forced dead zone circuits and hardware protection blocking interfaces is 5V. The I / O interface operating voltage of the master / slave DSP is 3.3V, the CPU operating voltage is 1.2V, the I / O interface operating voltage of the string acquisition board DSP is 3.3V, and the CPU operating voltage is 1.8V.

[0090] In the daytime working scenario, the +12V supply voltage output by the DC auxiliary source and the first AC auxiliary source can output a +5V_VCC voltage after being stepped down by the Buck circuit. Since the function of the DSP module is mainly used for communication, in order to suppress high-frequency noise and spike interference on the signal line and power line, the supply voltage output by the DC auxiliary source and the first AC auxiliary source needs to be suppressed by a suppression unit, and a common suppression unit is a magnetic bead. Then the stepped-down +5V_VCC voltage can output a +5V_VDD voltage after the magnetic bead to power the hardware anti-through and forced dead zone circuits and the hardware protection blocking interface. The low-voltage dropout regulator LDO not only has a voltage stabilization function, but also has a voltage reduction function. The +5V_VCC stepped down by the Buck circuit can be stepped down to +3.3V after passing through the low-voltage dropout regulator LDO, and then output a +3.3V_VDD voltage through the magnetic bead to power the master / slave DSP and the I / O interface of the string acquisition board DSP respectively. At the same time, the +3.3V voltage stepped down by the low-dropout regulator LDO can be further stepped down by the Buck circuit to +1.8V and +1.2V, and then output +1.8V_VDD and +1.2V_VDD respectively after passing through the magnetic beads, so as to respectively power the master / slave DSP and the CPU of the string acquisition board DSP. In the night working scenario, the DC auxiliary source will stop supplying power, and the first AC auxiliary source will supply power to the DSP module alone. The specific power supply process is basically the same as the above process, except that the redundant power supply is changed to a separate power supply.

[0091] (7) Power supply for ARM module.

[0092] like Figure 3 and Figure 8 As shown, the ARM module includes an ARM, a display and an ARM peripheral circuit. The operating voltage of the ARM peripheral circuit and the display is 5V, and the operating voltage of the ARM is 3.3V.

[0093] In the daytime working scenario, the +24V supply voltage output by the first AC auxiliary source is connected in parallel with the +5V supply voltage output by the DC auxiliary source after passing through the Buck circuit to power the ARM module and the display. Then, the +5V voltage stepped down by the Buck circuit can be stepped down and stabilized by the low voltage dropout regulator LDO to output a +3.3V voltage to power the ARM. In the field working scenario, the DC auxiliary source will stop supplying power, and the first AC auxiliary source will supply power to the ARM module alone. The specific power supply process is basically the same as the above process, except that the redundant power supply is changed to a separate power supply.

[0094] (8) Power supply for external fan module.

[0095] like Figure 3 and Fig. 9As shown, the external fan module includes an external fan and an external fan status detection circuit. The working voltage of the external fan is 24V, and the working voltage of the external fan status detection circuit is 12V; there may be multiple external fans, and the number of interfaces for the first AC auxiliary source to output +24V supply voltage matches the number of external fans; for example Fig. 9 As shown, the number of external fans is two, and the number of interfaces for the first AC auxiliary source to output +24V supply voltage is also two, and the two external fans are directly powered respectively. For the external fan status detection circuit, one of the +24V supply voltages output by the first AC auxiliary source can be stepped down to +12V through the Buck circuit to power the external fan status detection circuit. Since the external fan module is only powered by the first AC auxiliary source, the external fan module is in working state regardless of whether it is working in the daytime or at night.

[0096] (9) Power supply for PID module.

[0097] like Figure 3 As shown in the figure, since the PID repair function of the photovoltaic system is only used at night or when there is insufficient light, a relay is set at the power supply of the gate drive chip of the second AC auxiliary source, and the relay uses a normally closed contact connection chip. The relay can be closed or opened by the 12V control voltage output by the DC auxiliary source as a control signal; the PID module has an operating voltage of 600V and 12V according to the topology.

[0098] In the daytime working scenario, the DC auxiliary source starts working and can output +12V_PIDctr voltage to the second AC auxiliary source as the control voltage. At this time, the relay at the gate drive chip of the second AC auxiliary source is energized, so that the second AC auxiliary source stops working due to the power supply disconnection of the gate drive chip. In the night working scenario, the DC auxiliary source stops outputting the +12V_PIDctr control voltage due to being turned off. At this time, the relay at the gate drive chip of the second AC auxiliary source will be disconnected, so that the second AC auxiliary source can work normally to output +600V and ±12V_PID supply voltages to the PID module.

[0099] In this embodiment, the working modes of the photovoltaic system include grid-connected and off-grid. The grid-connected and off-grid connection of the photovoltaic system and the AC power grid can be controlled by a grid-connected relay, and the working voltage of the grid-connected relay is generally +7V. Figure 3As shown in the figure, according to the working mode of the grid-connected relay, a +7V supply voltage output interface can be designed on the DC auxiliary source to power the grid-connected relay. In the daytime working scenario, the DC auxiliary source can output a +7V supply voltage to the grid-connected relay to ensure that the grid-connected relay can stably attract to achieve the grid connection of the photovoltaic system; in the night working scenario, the photovoltaic system needs to be disconnected from the grid, and the DC auxiliary source can stop supplying power to the grid-connected relay to disconnect the grid-connected relay.

[0100] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. An auxiliary source architecture applied to a photovoltaic system, characterized in that: include: A DC auxiliary source; the DC auxiliary source draws power from a DC bus of a photovoltaic system; and AC auxiliary source; the AC auxiliary source draws power from the AC power grid; Based on the working scenario of the photovoltaic system, the DC auxiliary source and / or the AC auxiliary source independently supplies power to the functional modules of the photovoltaic system, or the DC auxiliary source and the AC auxiliary source jointly provide redundant power to at least some functional modules of the photovoltaic system.

2. The auxiliary source architecture applied to a photovoltaic system according to claim 1, characterized in that: The DC auxiliary source and the AC auxiliary source both output multiple supply voltages, and the supply voltages output by the DC auxiliary source and the AC auxiliary source are not completely the same; The same supply voltage output by the DC auxiliary source and the AC auxiliary source is suitable for being directly connected in parallel to a functional module of a photovoltaic system for redundant power supply; The different supply voltages output by the DC auxiliary source and the AC auxiliary source are kept consistent by means of voltage step-up or voltage step-down, and then connected in parallel to the functional modules of the photovoltaic system for redundant power supply.

3. The auxiliary source architecture applied to a photovoltaic system according to claim 2, characterized in that: For functional modules that require the DC auxiliary source and the AC auxiliary source to perform redundant power supply via different supply voltages; The supply voltage with a lower voltage value among the supply voltages output by the DC auxiliary source and the AC auxiliary source is matched with the working voltage of the functional module, and then the supply voltage with a higher voltage value is stepped down to be consistent with the other supply voltage for redundant power supply.

4. The auxiliary source architecture applied to a photovoltaic system according to claim 2, characterized in that: The output ports of the DC auxiliary source and the AC auxiliary source are both connected to a power parallel selection module; The supply voltages output by the DC auxiliary source and the AC auxiliary source are output in parallel through the power parallel selection module; the power parallel selection module uses a diode or a power rail control chip.

5. The auxiliary source architecture applied to a photovoltaic system according to any one of claims 2 to 4, characterized in that: The working voltages required by different functional modules of the photovoltaic system are not exactly the same; when the auxiliary source architecture supplies power to different functional modules individually or redundantly through the same supply voltage, it is suitable for reducing the voltage of the same supply voltage at least once.

6. The auxiliary source architecture applied to a photovoltaic system according to claim 5, characterized in that: The functional modules of the photovoltaic system include an internal interaction module for information interaction within the system and an external interaction module for human-computer interaction; The supply voltage output by the DC auxiliary source includes +12V, -12V and +5V, and the supply voltage output by the AC auxiliary source includes +12V, -12V and +24V; The AC auxiliary source is suitable for directly or stepping down the voltage to supply power to the internal interaction module through the output +12V and -12V voltages; The AC auxiliary source is suitable for directly or stepping down the voltage supply to the external interaction module through the output +24V voltage; The +12V and -12V voltages output by the DC auxiliary source and the AC auxiliary source are suitable for being connected in parallel to provide direct or reduced voltage redundant power supply to the internal interaction module; The +24V voltage output by the AC auxiliary source is suitable for being stepped down to +5V and then connected in parallel with the +5V voltage output by the DC auxiliary source, thereby providing direct or stepped-down redundant power supply to the external interaction module; The internal interaction module includes a DC side detection circuit module, an AC side detection circuit module, an analog switch module, an internal fan module and a DSP module; the external interaction module includes an ARM module and an external fan module.

7. The auxiliary source architecture applied to a photovoltaic system according to claim 6, characterized in that: The auxiliary source architecture is provided with a virtual ground AGND and a reinforced insulation ground FAN_GND; The auxiliary source architecture uses the ground AGND when supplying power to the internal interaction module, and the auxiliary source architecture uses the ground FAN_GND when supplying power to the external interaction module.

8. The auxiliary source architecture applied to a photovoltaic system according to claim 7, characterized in that: The functional modules of the photovoltaic system also include a PID module for suppressing the PID effect; The auxiliary source architecture is also provided with a ground PID_GND shared with the ground, and the auxiliary source architecture adopts the ground PID_GND when supplying power to the PID module.

9. The auxiliary source architecture applied to a photovoltaic system according to claim 8, characterized in that: The AC auxiliary source includes a first AC auxiliary source and a second AC auxiliary source; The first AC auxiliary source is suitable for independently supplying power to the internal interaction module and the external interaction module, or for redundantly supplying power to the internal interaction module and the external interaction module after being connected in parallel with the DC auxiliary source; The second AC auxiliary source is suitable for independently powering the PID module.

10. The auxiliary source architecture applied to a photovoltaic system according to claim 9, characterized in that: The working scenes of the photovoltaic system are divided into daytime working scenes and nighttime working scenes according to the light intensity; In the daytime working scenario, the DC auxiliary source and the first AC auxiliary source are turned on to supply power, and the second AC auxiliary source is turned off; In the night working scenario, the DC auxiliary source is turned off, and the first AC auxiliary source and the second AC auxiliary source are turned on to supply power; Wherein, the on and off of the second AC auxiliary source is controlled by the signal of the DC auxiliary source.

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