Photovoltaic energy storage inverter circuit, photovoltaic energy storage inverter and control method

Abstract

The application relates to a photovoltaic energy storage inverter circuit, a photovoltaic energy storage inverter and a control method. The photovoltaic energy storage inverter circuit is connected with a power grid and a load. The photovoltaic energy storage inverter circuit comprises a bus, a first control unit, a second control unit, an AC auxiliary power supply unit and a DC auxiliary power supply unit. The first control unit is used for controlling the DC auxiliary power supply unit to be turned on or turned off according to a power supply mode of the photovoltaic energy storage inverter circuit. The power supply mode comprises a low-power consumption mode or a normal working mode. The second control unit is used for controlling the AC auxiliary power supply unit to be turned on or turned off according to the power supply mode. The method can reduce the electric energy conversion loss of the photovoltaic energy storage inverter.

Description

Technical Field

[0001] This application relates to the field of photovoltaic energy storage technology, and in particular to a photovoltaic energy storage inverter circuit, a photovoltaic energy storage inverter, and a control method. Background Technology

[0002] A photovoltaic energy storage inverter is a device that integrates energy storage and inversion functions. It is usually connected between photovoltaic energy storage modules and the load, and is mainly used to provide a stable power supply to the load through the photovoltaic energy storage modules.

[0003] However, photovoltaic energy storage inverters suffer from high self-loss, which increases the power conversion loss of photovoltaic energy storage inverters. Summary of the Invention

[0004] Therefore, it is necessary to provide a photovoltaic energy storage inverter circuit, a photovoltaic energy storage inverter, and a control method that can reduce the power conversion loss of photovoltaic energy storage inverters, in response to the above-mentioned technical problems.

[0005] In a first aspect, this application provides a photovoltaic energy storage inverter circuit. The photovoltaic energy storage inverter circuit is connected to the power grid and a load, and includes:

[0006] busbar;

[0007] First control unit;

[0008] Second control unit;

[0009] An AC auxiliary power supply unit is provided, wherein the voltage input terminal of the AC auxiliary power supply unit is connected to the power grid, the first voltage output terminal of the AC auxiliary power supply unit is connected to the bus, and the second voltage output terminal of the AC auxiliary power supply unit is connected to the first control unit, and the control terminal of the AC auxiliary power supply unit is connected to the second control unit.

[0010] A DC auxiliary power supply unit, wherein the first voltage output terminal of the DC auxiliary power supply unit is connected to the first control unit for supplying power to the first control unit, the second voltage output terminal of the DC auxiliary power supply unit is connected to the second control unit for supplying power to the second control unit, the DC auxiliary power supply unit is connected to the bus for drawing power from the bus, and the control terminal of the DC auxiliary power supply unit is connected to the first control unit;

[0011] The first control unit is used to control the DC auxiliary power supply unit to turn on or off according to the power supply mode of the photovoltaic energy storage inverter circuit, wherein the power supply mode includes a low power consumption mode or a normal operation mode.

[0012] The second control unit is used to control the AC auxiliary power supply unit to turn on or off according to the power supply mode.

[0013] Secondly, this application also provides a photovoltaic energy storage inverter. The photovoltaic energy storage inverter includes a DC-AC conversion circuit, a DC-DC conversion circuit, and a maximum power point tracking circuit, as well as a photovoltaic energy storage inverter circuit as described in any of the first aspects above.

[0014] The DC-AC conversion circuit is connected to the bus capacitor of the photovoltaic energy storage inverter circuit, the bypass relay of the photovoltaic energy storage inverter circuit, or the inverter relay.

[0015] The DC-DC conversion circuit is connected to the photovoltaic energy storage module and the bus capacitor, respectively.

[0016] The maximum power point tracking circuit is connected to the photovoltaic energy storage module and the bus capacitor, respectively.

[0017] Thirdly, this application also provides a control method for a photovoltaic energy storage inverter based on the second aspect described above, the method comprising:

[0018] The first control unit detects whether the photovoltaic energy storage inverter is powered on.

[0019] Based on the power-on status of the photovoltaic energy storage inverter, the first control unit and the second control unit control the photovoltaic energy storage inverter to enter the corresponding power supply mode, which includes a low power consumption mode or a normal operation mode.

[0020] The first control unit periodically detects the operating status of the photovoltaic energy storage inverter and determines whether to switch the power supply mode of the photovoltaic energy storage inverter.

[0021] The aforementioned photovoltaic energy storage inverter circuit, photovoltaic energy storage inverter, and control method are described above. The photovoltaic energy storage inverter circuit is connected to the power grid and the load. The photovoltaic energy storage inverter circuit includes: a bus, a first control unit, a second control unit, an AC auxiliary power supply unit, and a DC auxiliary power supply unit. The voltage input terminal of the AC auxiliary power supply unit is connected to the power grid, and the first voltage output terminal of the AC auxiliary power supply unit is connected to the bus to supply power from the grid. The second voltage output terminal of the AC auxiliary power supply unit is connected to the first control unit to supply power to the first control unit, and the control terminal of the AC auxiliary power supply unit is connected to the second control unit. The first voltage output terminal of the DC auxiliary power supply unit is connected to the first control unit to supply power to the first control unit, and the second voltage output terminal of the DC auxiliary power supply unit is connected to the second control unit to supply power to the second control unit. The DC auxiliary power supply unit is connected to the bus to draw power from the bus, and the control terminal of the DC auxiliary power supply unit is connected to the first control unit. The first control unit is used to control the DC auxiliary power supply unit to turn on or off according to the power supply mode of the photovoltaic energy storage inverter circuit. The power supply mode includes a low power mode or a normal operating mode. The second control unit is used to control the AC auxiliary power supply unit to turn on or off according to the power supply mode. Compared with the traditional technology, this photovoltaic energy storage inverter circuit can switch the operating mode of the photovoltaic energy storage inverter circuit according to different power supply modes by controlling the DC auxiliary power supply unit to turn on or off and controlling the AC auxiliary power supply unit to turn on or off. This allows the operating mode of the photovoltaic energy storage inverter circuit to be adjusted to match the power supply mode, reducing the self-loss of the photovoltaic energy storage inverter and thus reducing the power conversion loss of the photovoltaic energy storage inverter. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a block diagram of a photovoltaic energy storage inverter circuit in one embodiment;

[0024] Figure 2 This is a schematic diagram of a photovoltaic energy storage inverter circuit in a low-power mode in one embodiment.

[0025] Figure 3 This is a block diagram of a photovoltaic energy storage inverter circuit in another embodiment;

[0026] Figure 4This is a schematic diagram of the photovoltaic energy storage inverter circuit in normal operating mode in one embodiment;

[0027] Figure 5 This is a block diagram of a photovoltaic energy storage inverter circuit in another embodiment;

[0028] Figure 6 This is a schematic diagram of the normal operating mode of a photovoltaic energy storage inverter circuit powered by the grid in one embodiment;

[0029] Figure 7 This is a schematic diagram of the normal operating mode of the photovoltaic energy storage inverter circuit powered by the photovoltaic energy storage module in one embodiment;

[0030] Figure 8 This is a block diagram of a photovoltaic energy storage inverter in one embodiment;

[0031] Figure 9 This is a flowchart illustrating the control method of a photovoltaic energy storage inverter in one embodiment. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0034] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0035] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0036] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0037] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0038] A photovoltaic (PV) energy storage inverter is a device that integrates energy storage and inversion functions. The PV energy storage inverter circuit in the PV energy storage inverter can convert electrical energy provided by the grid and PV energy storage components. The PV energy storage components can include PV modules, batteries, and other energy components. The PV modules can charge the batteries, supply power to the load, or feed power to the grid, while the batteries can supply power to the load or feed power to the grid.

[0039] However, at night, when the photovoltaic energy storage components cannot receive solar energy and the batteries cannot charge or discharge, the inverter circuit unit in the photovoltaic energy storage inverter needs to keep working continuously because the inverter needs to provide emergency power supply to the load. This results in no-load losses in the photovoltaic energy storage inverter, leading to greater self-loss, increased power conversion losses, and reduced economic efficiency.

[0040] Therefore, embodiments of this application provide a photovoltaic energy storage inverter circuit and a photovoltaic energy storage inverter, which can reduce the power conversion loss of the photovoltaic energy storage inverter.

[0041] like Figure 1 As shown, the photovoltaic energy storage inverter circuit of this application embodiment is connected to the power grid and the load. The photovoltaic energy storage inverter circuit includes: a bus, a first control unit, a second control unit, an AC auxiliary power supply unit, and a DC auxiliary power supply unit.

[0042] The AC (Alternating Current) auxiliary power supply unit has its voltage input terminal connected to the power grid, its first voltage output terminal connected to the busbar to supply power from the grid, its second voltage output terminal connected to the first control unit to supply power to the first control unit, and its control terminal connected to the second control unit. Similarly, the DC (Direct Current) auxiliary power supply unit has its first voltage output terminal connected to the first control unit to supply power to it, its second voltage output terminal connected to the second control unit to supply power to it, its connection to the busbar to draw power from the busbar, and its control terminal connected to the first control unit.

[0043] The first control unit is used to control the DC auxiliary power supply unit to turn on or off according to the power supply mode of the photovoltaic energy storage inverter circuit. The power supply mode includes low power mode or normal operation mode. The second control unit is used to control the AC auxiliary power supply unit to turn on or off according to the power supply mode.

[0044] The photovoltaic (PV) energy storage inverter circuit is used to convert the direct current (DC) input to the PV energy storage modules into alternating current (AC), and to store and bidirectionally flow electrical energy. The power grid can be the mains power supply system of a city or region, and the load can be various electrical devices. The busbar is the common channel connecting all components in the PV energy storage inverter circuit. When power needs to be supplied to the load, the electrical energy on the busbar is converted into AC by the inverter circuit and supplied to the load. Simultaneously, when the PV energy storage modules need charging, electrical energy flows from the busbar to the PV energy storage modules. When the load demand exceeds the output of the PV energy storage modules, the PV energy storage modules supply power to the inverter circuit through the busbar, thus distributing electrical energy among the different components.

[0045] Optionally, the first control unit is an EMS control circuit unit, i.e., an Energy Management System (EMS) unit. The EMS control circuit unit is typically a control circuit built around an ARM chip, primarily responsible for energy scheduling, human-machine interaction, and communication management. Optionally, the second control unit is a DSP control circuit unit, i.e., a Digital Signal Processor (DSP) unit. The DSP control circuit unit is typically a control circuit built around a DSP chip, primarily responsible for voltage and current sampling for the main circuit's power conversion, circuit drive control, and control of auxiliary functions related to power conversion.

[0046] In one possible implementation, in this embodiment, the photovoltaic energy storage inverter circuit may further include a bus capacitor. The first voltage output terminal of the AC auxiliary power supply unit is connected to the bus capacitor. Optionally, the AC auxiliary power supply unit is connected to the bus via the bus capacitor to charge the bus capacitor. The second voltage output terminal of the DC auxiliary power supply unit is connected to the bus capacitor. Optionally, the DC auxiliary power supply unit is connected to the bus via the bus capacitor to draw power from the bus capacitor. The bus capacitor provides dynamic energy buffering for power conversion. The bus is connected to the battery modules and photovoltaic modules in the photovoltaic energy storage components included in the photovoltaic energy storage inverter circuit via the bus capacitor to supply power to the bus.

[0047] The AC auxiliary power supply unit converts the AC power input from the power grid into high-voltage DC power suitable for the bus and low-voltage DC power suitable for the first control unit. Optionally, the AC auxiliary power supply unit includes an isolated flyback circuit. The DC auxiliary power supply unit converts the high-voltage DC power supplied from the bus into low-voltage DC power suitable for both the first and second control units. Optionally, the DC auxiliary power supply unit includes an isolated flyback circuit. Optionally, the isolated flyback circuit includes an AC input terminal, a rectifier filter, a power switch, a high-frequency transformer, and an output filter, etc.

[0048] It is understandable that the operating mode of a photovoltaic (PV) energy storage inverter circuit varies depending on its power supply mode. For example, a PV energy storage inverter circuit can be powered by the grid, or it can be powered by both the grid and / or the PV energy storage modules. Correspondingly, the power supply mode of a PV energy storage inverter circuit can include a low-power mode or a normal operating mode.

[0049] The low-power mode refers to the mode in which, during nighttime scenarios, the photovoltaic (PV) energy storage inverter circuit is powered on, but the PV modules in the PV energy storage system cannot supply power. Initially, power is supplied by the battery and the grid. When the battery cannot charge or discharge (i.e., the battery cannot supply power), power is supplied by the grid. The normal operating mode refers to the mode in which the PV energy storage inverter circuit is powered on, supplied by the grid and / or the PV energy storage system. It should be noted that, since the losses of the AC auxiliary power supply unit are less than those of the DC auxiliary power supply unit, optionally, in normal operating mode, the DC auxiliary power supply unit can be turned on and the AC auxiliary power supply unit turned off to reduce the overall losses of the PV energy storage inverter circuit. In low-power mode, the AC auxiliary power supply unit can be turned on and the DC auxiliary power supply unit turned off to reduce the no-load losses of the PV energy storage inverter circuit.

[0050] In this embodiment, the first control unit can control the DC auxiliary power supply unit to turn on or off according to the power supply mode of the photovoltaic energy storage inverter circuit, and the second control unit can control the AC auxiliary power supply unit to turn on or off according to the power supply mode, thereby switching the working mode of the photovoltaic energy storage inverter circuit.

[0051] For example, if the power supply mode is low power mode, the DC auxiliary power supply unit is controlled to be turned off and the AC auxiliary power supply unit is controlled to be turned on; if the power supply mode is normal operation mode, the DC auxiliary power supply unit is controlled to be turned on and the AC auxiliary power supply unit is controlled to be turned off.

[0052] In the aforementioned photovoltaic energy storage inverter circuit, the photovoltaic energy storage inverter circuit is connected to the power grid and the load. The photovoltaic energy storage inverter circuit includes: a bus, a first control unit, a second control unit, an AC auxiliary power supply unit, and a DC auxiliary power supply unit. The voltage input terminal of the AC auxiliary power supply unit is connected to the power grid, and the first voltage output terminal of the AC auxiliary power supply unit is connected to the bus to provide power from the power grid. The second voltage output terminal of the AC auxiliary power supply unit is connected to the first control unit to supply power to the first control unit, and the control terminal of the AC auxiliary power supply unit is connected to the second control unit. The first voltage output terminal of the DC auxiliary power supply unit is connected to the first control unit to supply power to the first control unit, and the second voltage output terminal of the DC auxiliary power supply unit is connected to the second control unit to supply power to the second control unit. The DC auxiliary power supply unit is connected to the bus to draw power from the bus, and the control terminal of the DC auxiliary power supply unit is connected to the first control unit. The first control unit is used to control the DC auxiliary power supply unit to turn on or off according to the power supply mode of the photovoltaic energy storage inverter circuit. The power supply mode includes a low power mode or a normal operating mode. The second control unit is used to control the AC auxiliary power supply unit to turn on or off according to the power supply mode. Compared with the traditional technology, this photovoltaic energy storage inverter circuit can switch the operating mode of the photovoltaic energy storage inverter circuit according to different power supply modes by controlling the DC auxiliary power supply unit to turn on or off and controlling the AC auxiliary power supply unit to turn on or off. This allows the operating mode of the photovoltaic energy storage inverter circuit to be adjusted to match the power supply mode, reducing the self-loss of the photovoltaic energy storage inverter and thus reducing the power conversion loss of the photovoltaic energy storage inverter.

[0053] In one embodiment, based on Figure 1 In the embodiment shown, when the power supply mode is low power mode: the first control unit is specifically used to control the DC auxiliary power supply unit to turn off; the second control unit is specifically used to control the AC auxiliary power supply unit to turn on.

[0054] The following is combined with Figure 2The operating logic of the photovoltaic energy storage inverter circuit is described when the power supply mode is low-power mode:

[0055] First, when the photovoltaic energy storage inverter circuit is in normal working mode, that is, when the DC auxiliary power supply unit is turned on and the AC auxiliary power supply unit is turned off, the first control unit detects whether the photovoltaic energy storage module is supplying power normally. If the voltage output by the photovoltaic energy storage module is normal, the control unit periodically detects whether the photovoltaic energy storage module is supplying power normally; if the voltage output by the photovoltaic energy storage module is abnormal, the control unit detects whether the power grid is supplying power normally.

[0056] Secondly, when the grid output voltage is abnormal, the photovoltaic energy storage inverter circuit is determined to enter the shutdown mode; when the grid output voltage is normal, the second control unit sends an activation signal to the AC auxiliary power supply unit to control the AC auxiliary power supply unit to turn on. Then, when the grid provides power, the AC auxiliary power supply unit provides bus voltage to the photovoltaic energy storage inverter circuit and power to the first control unit.

[0057] Finally, in order to reduce the losses of the photovoltaic energy storage inverter circuit, the first control unit sends a shutdown signal to the DC auxiliary power supply unit to control the DC auxiliary power supply unit to shut down.

[0058] As one possible implementation method, such as Figure 3 As shown, the photovoltaic energy storage inverter circuit also includes a bypass relay, which is connected to the first control unit, the power grid, and the load respectively; the first control unit is used to turn on the circuit under its control to provide the power from the power grid to the load.

[0059] A bypass relay is a device that provides bypass protection for a circuit, primarily used to maintain the mains power load in the absence of a power source. In the event of a power grid failure or instability leading to abnormal power supply, the bypass relay automatically switches to a backup power source. When the mains power supply is normal, the bypass relay can provide the mains voltage to the load.

[0060] In this embodiment, when the first control unit is specifically used to control the DC auxiliary power supply unit to turn off and the second control unit is specifically used to control the AC auxiliary power supply unit to turn on, the first control unit can also send a working signal to the bypass relay to control the bypass relay to work. Then the grid voltage can be transmitted to the bypass relay, and the bypass relay can provide voltage to the load after converting the grid voltage. At this time, the photovoltaic energy storage inverter circuit is in bypass output mode.

[0061] In this embodiment, when the power supply mode is low power mode, the first control unit can control the DC auxiliary power supply unit to turn off, and the second control unit can control the AC auxiliary power supply unit to turn on. This allows the first control unit to control the bypass relay to connect the power supply circuit between the grid and the load, so that the power grid can provide power to the load through the bypass relay. This avoids the grid voltage passing through other circuits in the photovoltaic energy storage inverter circuit, reducing the no-load loss of the photovoltaic energy storage inverter circuit.

[0062] In one embodiment, based on the above embodiment, when the power supply mode is the normal operating mode: the first control unit is specifically used to control the DC auxiliary power supply unit to turn on; the second control unit is specifically used to control the AC auxiliary power supply unit to turn off.

[0063] Understandably, when the power supply mode is normal operation mode, the photovoltaic energy storage inverter circuit may be powered by the grid or by the photovoltaic energy storage components. The first control unit can also periodically detect whether the grid is supplying power normally, and then switch the photovoltaic energy storage inverter circuit from low power mode to normal operation mode based on the detection results.

[0064] The following is combined with Figure 4 The operating logic of the photovoltaic energy storage inverter circuit is described under the normal power supply mode:

[0065] In the first scenario, if the power grid supply is normal, the first control circuit can detect whether the photovoltaic energy storage module is powered normally. Optionally, if the photovoltaic energy storage module is powered abnormally, the first control unit periodically checks whether the power grid supply is normal. If the photovoltaic energy storage module is powered normally, the first control unit controls the DC auxiliary power supply to turn on. Then, the DC auxiliary power supply supplies power to the first control unit and the second control unit respectively. The photovoltaic energy storage module supplies power to the bus through the main circuit, and then supplies power to the load through the bus. The second control unit controls the AC auxiliary power supply to turn off, and the photovoltaic energy storage inverter circuit enters the normal working mode.

[0066] In the second scenario, if the power grid supply is abnormal, the first control circuit controls the DC auxiliary power supply to turn on. Then, the DC auxiliary power supply supplies power to the first control unit and the second control unit respectively. The photovoltaic energy storage module supplies power to the bus through the main circuit, and then supplies power to the load through the bus. The second control unit controls the AC auxiliary power supply to turn off, and the photovoltaic energy storage inverter circuit enters the normal operation mode.

[0067] As one possible implementation method, such as Figure 5As shown, the photovoltaic energy storage inverter circuit also includes an inverter relay. The inverter relay is connected to the first control unit, the second control unit, and the load, respectively. The inverter relay is used to conduct under the control of the first control unit and the second control unit to provide the load with the electrical energy from the photovoltaic energy storage module and / or the electrical energy from the grid.

[0068] The inverter relay is used to convert direct current (DC) to alternating current (AC). When the photovoltaic energy storage inverter circuit is in normal mode, the second control unit controls the AC auxiliary power supply unit to shut down, and the first control unit controls the DC auxiliary power supply unit to turn on. Then, the first and second control units can control the inverter relay to connect the power supply circuit between the photovoltaic energy storage module and the load, thereby providing the load with the electrical energy from the photovoltaic energy storage module and / or the grid.

[0069] The following describes the working logic of the first and second control units controlling the inverter relay to conduct: First, the activated AC auxiliary power supply can provide bus voltage to the photovoltaic energy storage inverter circuit and power to the first control unit. First, the first control unit sends an activation signal to the DC auxiliary power supply unit to control it to turn on. Then, the DC auxiliary power supply unit can supply power to both the first and second control units. The voltage provided by the DC auxiliary power supply unit to the first control unit is greater than the voltage provided to the second control unit. Then, when the bus voltage reaches a preset value, the first control unit sends an activation signal to the inverter relay to conduct it. Afterward, the second control unit sends a deactivation signal to the AC auxiliary power supply to control it to turn off, thereby establishing the power supply circuit between the photovoltaic energy storage module and the load, so as to provide the load with the electrical energy from the photovoltaic energy storage module and / or the power from the grid.

[0070] In one possible implementation, the second control unit is specifically used to detect whether the bus voltage is greater than a preset voltage threshold, and if the bus voltage is greater than the preset voltage threshold, to control the AC auxiliary power supply unit to shut down.

[0071] In this embodiment, when the power supply mode is the normal operating mode, the first control unit can control the DC auxiliary power supply unit to turn on, and the second control unit can control the AC auxiliary power supply unit to turn off. This allows the first control unit to control the inverter relay to connect the power supply circuit between the photovoltaic energy storage component and the load, or between the grid and the load. In this way, power can be supplied through an auxiliary power supply unit in the mode where power is supplied to the photovoltaic energy storage inverter circuit through the grid or the photovoltaic energy storage component, thereby reducing the loss of the photovoltaic energy storage inverter circuit.

[0072] It is understandable that before the photovoltaic energy storage module and / or the power supply circuit between the grid and the load are connected, the first control unit can detect whether the photovoltaic energy storage inverter circuit is in the power-on state, and then control the AC auxiliary power supply unit and the DC auxiliary power supply unit according to different states.

[0073] The first approach describes the operating logic of the photovoltaic energy storage inverter circuit when it is in the powered-on state, supplied by the photovoltaic energy storage components and / or the grid:

[0074] In one embodiment, the first control unit is further configured to detect whether the photovoltaic energy storage inverter circuit is in the power-on state, and when the photovoltaic energy storage inverter circuit is in the power-on state, control the DC auxiliary power supply unit to be turned on, and control the inverter relay to conduct the power supply circuit between the photovoltaic energy storage component and / or the power grid and the load.

[0075] Understandably, the AC auxiliary power supply unit and the DC auxiliary power supply unit can be turned on by default before the photovoltaic energy storage inverter circuit enters normal operating mode. Optionally, when the grid is powered on, the AC auxiliary power supply unit supplies power to the first control unit and provides bus voltage to the photovoltaic energy storage inverter circuit, and the first control unit can detect whether the photovoltaic energy storage inverter circuit is in the powered-on state; when the photovoltaic energy storage module is powered on, the DC auxiliary power supply unit supplies power to the first control unit and the second control unit, and the first control unit can detect whether the photovoltaic energy storage inverter circuit is in the powered-on state.

[0076] As an optional implementation, the first control unit can determine whether the photovoltaic energy storage inverter circuit is in the powered-on state based on the received instruction. Optionally, if the instruction is a power-on instruction, it can be determined that the photovoltaic energy storage inverter circuit is in the powered-on state; if the instruction is not a power-on instruction, it can be determined that the photovoltaic energy storage inverter circuit is in the powered-off state.

[0077] In this embodiment, when the photovoltaic energy storage inverter circuit is in the powered-on state, the first control unit sends an activation signal to the DC auxiliary power supply unit to control the DC auxiliary power supply unit to turn on, and sends an activation signal to the inverter relay to control the inverter relay to conduct the power supply circuit between the photovoltaic energy storage module and / or the power grid and the load.

[0078] The second approach describes the operating logic of the photovoltaic energy storage inverter circuit when it is not powered on, and it is supplied by the photovoltaic energy storage components and / or the grid:

[0079] The first type: When the grid is supplying power, the first control unit is also specifically used to control the DC auxiliary power supply unit to shut down and control the bypass relay to connect the power supply circuit between the grid and the load when the photovoltaic energy storage inverter circuit is not turned on.

[0080] Understandably, when the first control unit controls the DC auxiliary power supply unit to be turned off, even if the bus voltage can provide voltage to the DC auxiliary power supply unit, the DC auxiliary power supply unit will not be turned on. At this time, the first control unit can send a working signal to the bypass relay to control the bypass relay to be turned on, thereby connecting the power supply circuit between the power grid and the load.

[0081] In this case, only the AC auxiliary power supply unit, the first control unit, and the drive circuit of the bypass relay work in the photovoltaic energy storage inverter circuit, thereby reducing the power consumption of the photovoltaic energy storage inverter circuit in the off state.

[0082] The second type: When the photovoltaic energy storage module is powered, the first control unit is also specifically used to detect whether the power grid is in normal working condition when the photovoltaic energy storage inverter circuit is not turned on, and when the power grid is in normal working condition, control the DC auxiliary power supply unit to turn off and control the bypass relay to turn on the power supply circuit between the photovoltaic energy storage module and the load.

[0083] As one possible implementation, when the photovoltaic energy storage module is powered, if the photovoltaic energy storage inverter circuit is in a non-powered state and the power grid is in an abnormal operating state, the photovoltaic energy storage inverter circuit can be controlled to enter a standby mode, and the first control unit can periodically detect whether the photovoltaic energy storage inverter circuit is in a powered-on state.

[0084] Therefore, the first control unit also needs to detect whether the power grid is in normal working condition. When the power grid is in normal working condition, the AC auxiliary power supply unit supplies power to the first control unit and provides bus voltage to the photovoltaic energy storage inverter circuit. The first control unit can control the DC auxiliary power supply unit to shut down. At the same time, the first control unit can control the bypass relay to turn on, thereby connecting the power supply circuit between the photovoltaic energy storage module and the load.

[0085] In this case, only the AC auxiliary power supply unit, the first control unit, and the drive circuit of the bypass relay work in the photovoltaic energy storage inverter circuit, thereby reducing the power consumption of the photovoltaic energy storage inverter circuit in the off state.

[0086] The following is combined with Figure 6 The working logic of the photovoltaic energy storage inverter circuit in normal operating mode when powered by the grid is described:

[0087] First, the AC auxiliary power supply unit supplies power to the first control unit and provides bus voltage to the photovoltaic energy storage inverter circuit.

[0088] Secondly, the first control unit detects whether the photovoltaic energy storage inverter circuit is in the powered-on state.

[0089] Again: ① When the photovoltaic energy storage inverter circuit is in the off state, the first control unit controls the DC auxiliary power supply unit to shut down and conducts the power supply circuit between the grid and the load through the bypass relay. The photovoltaic energy storage inverter circuit enters the bypass standby mode. At the same time, the first control unit periodically checks whether it is in the on state.

[0090] ② When the photovoltaic energy storage inverter circuit is in the power-on state, the first control unit controls the DC auxiliary power supply unit to turn on and conducts the power supply circuit between the grid and the load through the inverter relay. The inverter DCAC unit works to boost the voltage. When the bus voltage is greater than the preset voltage threshold, the second control unit controls the AC auxiliary power supply unit to turn off, so that the photovoltaic energy storage inverter circuit enters the normal operation mode.

[0091] The following is combined with Figure 7 The working logic of the photovoltaic energy storage inverter circuit in its normal operating mode, where it is powered by the photovoltaic energy storage module, is described as follows:

[0092] First, the DC auxiliary power supply unit supplies power to the first control unit and the second control unit, respectively.

[0093] Secondly, the first control unit detects whether the photovoltaic energy storage inverter circuit is in the powered-on state.

[0094] Furthermore, ① when the photovoltaic energy storage inverter circuit is in a non-powered state, the first control unit detects whether the power grid is supplying power normally. If the power grid supply is abnormal, it enters standby mode, and the first control unit periodically checks whether it is in the power-on state; if the power grid supply is normal, the AC auxiliary power supply supplies power to the first control unit and provides bus voltage to the photovoltaic energy storage inverter circuit. The first control unit controls the DC auxiliary power supply unit to shut down and controls the bypass relay to connect the power supply circuit between the power grid and the load. The photovoltaic energy storage inverter circuit enters bypass standby mode, and the first control unit periodically checks whether it is in the power-on state.

[0095] ② When the photovoltaic energy storage inverter circuit is in the power-on state, the first control unit controls the DC auxiliary power supply unit to turn on and conducts the power supply circuit between the photovoltaic energy storage component and the load through the inverter relay. The inverter MPTT or inverter DCDC unit works to boost the voltage. When the bus voltage is greater than the preset voltage threshold, the second control unit controls the AC auxiliary power supply unit to turn off, so that the photovoltaic energy storage inverter circuit enters the normal operation mode.

[0096] In one embodiment, such as Figure 8As shown, this embodiment also provides a photovoltaic energy storage inverter, which includes a DC-AC conversion unit, a DC-DC conversion unit, and a maximum power point tracking unit, as well as a photovoltaic energy storage inverter circuit as described above. The DC-AC conversion unit is connected to the bus capacitor of the photovoltaic energy storage inverter circuit, the bypass relay of the photovoltaic energy storage inverter circuit, or the inverter relay. The DC-DC conversion unit is connected to the photovoltaic energy storage module and the bus capacitor. The maximum power point tracking unit is connected to the photovoltaic energy storage module and the bus capacitor.

[0097] Specifically, such as Figure 8 As shown, the DC-DC conversion unit is connected to the battery module in the photovoltaic energy storage module, and the maximum power point tracking unit is linked to the photovoltaic module in the photovoltaic energy storage module.

[0098] Among them, the Direct Current to Alternating Current (DCAC) unit converts direct current (DC) to alternating current (AC). The Direct Current to Direct Current (DCDC) unit is an electronic device or circuit module that converts DC power to another type of DC power. The Maximum Power Point Tracking (MPPT) unit is a component in photovoltaic energy storage systems used to improve the power generation efficiency of solar cells.

[0099] In this embodiment, the photovoltaic energy storage inverter can convert the electrical energy provided by the grid or photovoltaic energy storage components into electrical energy that is adapted to the load through each unit, thereby improving the reliability and efficiency of power supply to the load.

[0100] In one embodiment, this embodiment also provides a control method based on the above-mentioned photovoltaic energy storage inverter, such as... Figure 9 As shown, the method includes:

[0101] Step 901: The first control unit detects whether the photovoltaic energy storage inverter is in the powered-on state.

[0102] Step 902: Based on the power-on status of the photovoltaic energy storage inverter, the first control unit and the second control unit control the photovoltaic energy storage inverter to enter the corresponding power supply mode, which includes low power consumption mode or normal operation mode.

[0103] Step 903: The first control unit periodically detects the operating status of the photovoltaic energy storage inverter and determines whether to switch the power supply mode of the photovoltaic energy storage inverter.

[0104] In this embodiment, when the grid and / or photovoltaic energy storage components are powered, the AC auxiliary power supply operates and can provide voltage to the first control unit. The first control unit can detect whether the photovoltaic energy storage inverter is in the powered-on state. Then, whether the photovoltaic energy storage inverter is in the powered-on state or not, the first control unit and the second control unit control the photovoltaic energy storage inverter to enter the corresponding power supply mode. Next, the first control unit can periodically detect the operating status of the photovoltaic energy storage inverter and determine whether the grid and / or photovoltaic energy storage components are supplying power normally based on the operating status. Then, it can determine whether to switch the power supply mode of the photovoltaic energy storage inverter based on whether the grid and / or photovoltaic energy storage components are supplying power normally.

[0105] For example, if the photovoltaic energy storage inverter is in normal operating mode and the photovoltaic energy storage module is not powered, the normal operating mode can be switched to low power mode; or, if the photovoltaic energy storage inverter is in low power mode and the photovoltaic energy storage module is powered normally, the low power mode can be switched to normal operating mode.

[0106] In this embodiment, firstly, the first control unit detects whether the photovoltaic energy storage inverter is in the power-on state. Then, based on the power-on state of the photovoltaic energy storage inverter, the first control unit and the second control unit control the photovoltaic energy storage inverter to enter the corresponding power supply mode, which includes a low-power mode or a normal operating mode. Subsequently, the first control unit periodically detects the operating state of the photovoltaic energy storage inverter and determines whether to switch the power supply mode of the photovoltaic energy storage inverter, so as to flexibly adjust the power supply mode of the photovoltaic energy storage inverter, thereby reducing the self-loss of the photovoltaic energy storage inverter circuit, thereby reducing the power conversion loss of the photovoltaic energy storage inverter and improving economic efficiency.

[0107] The following sections describe in detail the process by which photovoltaic energy storage inverters switch operating modes according to different power supply modes:

[0108] In one possible implementation, the photovoltaic energy storage component in the photovoltaic energy storage inverter includes a photovoltaic component and an energy storage component, and the above method further includes:

[0109] When the power supply mode is normal operation mode, the first control unit detects whether the power grid and photovoltaic modules are in normal power supply state, and detects whether the photovoltaic energy storage module is in charging and discharging state.

[0110] If the power grid is in a normal power supply state, the photovoltaic modules are in an abnormal power supply state, and the energy storage modules are not in a charging or discharging state, the first control unit controls the DC auxiliary power supply unit to shut down and controls the bypass relay to turn on, and the second control unit controls the AC auxiliary power supply unit to turn on, so that the photovoltaic energy storage inverter enters a low power consumption mode.

[0111] In another possible implementation, the above method further includes:

[0112] When the power supply mode is low power mode, the first control unit detects whether the power grid input is in a normal power supply state;

[0113] If the power grid is in a normal power supply state, the system detects whether the photovoltaic modules are in a normal power supply state. If the photovoltaic modules are in a normal power supply state, the first control unit controls the DC auxiliary power supply unit to turn on, and the second control unit controls the AC auxiliary power supply unit to turn off, so that the photovoltaic energy storage inverter enters the normal working mode.

[0114] If the power grid is in an abnormal power supply state, the system detects whether the energy storage component is in a charging or discharging state. If the energy storage component is in the charging or discharging state, the first control unit controls the DC auxiliary power supply unit to turn on, and the second control unit controls the AC auxiliary power supply unit to turn off, so that the photovoltaic energy storage inverter enters the normal operating mode.

[0115] In this embodiment, by detecting whether the photovoltaic module and energy storage module included in the photovoltaic energy storage module are in a normal power supply state under different power supply modes, and detecting whether the power grid is in a normal power supply state, the DC auxiliary power supply unit can be turned on or off by the first control unit, the AC auxiliary power supply unit can be turned on or off by the second control unit, and the bypass relay can be turned on by the first control unit. In this way, the self-loss of the photovoltaic energy storage inverter can be reduced under different power supply modes, thereby reducing the power conversion loss of the photovoltaic energy storage inverter.

[0116] In the description of this specification, references to terms such as "possible embodiments" or "possible implementations" refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0117] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0118] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A photovoltaic energy storage inverter circuit, characterized in that, The photovoltaic energy storage inverter circuit is connected to the power grid and the load, and the photovoltaic energy storage inverter circuit includes: busbar; First control unit; Second control unit; An AC auxiliary power supply unit is provided, wherein the voltage input terminal of the AC auxiliary power supply unit is connected to the power grid, the first voltage output terminal of the AC auxiliary power supply unit is connected to the bus, and the second voltage output terminal of the AC auxiliary power supply unit is connected to the first control unit, and the control terminal of the AC auxiliary power supply unit is connected to the second control unit. A DC auxiliary power supply unit, wherein the first voltage output terminal of the DC auxiliary power supply unit is connected to the first control unit for supplying power to the first control unit, the second voltage output terminal of the DC auxiliary power supply unit is connected to the second control unit for supplying power to the second control unit, the DC auxiliary power supply unit is connected to the bus for drawing power from the bus, and the control terminal of the DC auxiliary power supply unit is connected to the first control unit; The first control unit is used to control the DC auxiliary power supply unit to turn on or off according to the power supply mode of the photovoltaic energy storage inverter circuit, wherein the power supply mode includes a low power consumption mode or a normal operation mode. The second control unit is used to control the AC auxiliary power supply unit to turn on or off according to the power supply mode.

2. The photovoltaic energy storage inverter circuit according to claim 1, characterized in that, When the power supply mode is the low-power mode: The first control unit is specifically used to control the DC auxiliary power supply unit to shut down; The second control unit is specifically used to control the AC auxiliary power supply unit to turn on.

3. The photovoltaic energy storage inverter circuit according to claim 2, characterized in that, The photovoltaic energy storage inverter circuit also includes: A bypass relay is connected to the first control unit, the power grid, and the load, respectively. The bypass relay is activated under the control of the first control unit to supply electrical energy from the power grid to the load.

4. The photovoltaic energy storage inverter circuit according to claim 1, characterized in that, When the power supply mode is the normal operating mode: The first control unit is specifically used to control the DC auxiliary power supply unit to turn on; The second control unit is specifically used to control the AC auxiliary power supply unit to shut down.

5. The photovoltaic energy storage inverter circuit according to claim 4, characterized in that, The photovoltaic energy storage inverter circuit also includes: An inverter relay is connected to the first control unit, the second control unit, and the load, respectively. The inverter relay is used to turn on under the control of the first control unit and the second control unit to provide the load with electrical energy from the photovoltaic energy storage module and / or the power grid.

6. The photovoltaic energy storage inverter circuit according to claim 4, characterized in that, The second control unit is specifically used to detect whether the bus voltage of the bus is greater than a preset voltage threshold, and when the bus voltage is greater than the preset voltage threshold, control the AC auxiliary power supply unit to shut down.

7. The photovoltaic energy storage inverter circuit according to claim 5, characterized in that, The first control unit is also used to detect whether the photovoltaic energy storage inverter circuit is in the power-on state. When the photovoltaic energy storage inverter circuit is in the power-on state, it controls the DC auxiliary power supply unit to turn on and controls the inverter relay to connect the power supply circuit between the photovoltaic energy storage component and / or the power grid and the load.

8. The photovoltaic energy storage inverter circuit according to claim 7, characterized in that, The first control unit is also configured to control the DC auxiliary power supply unit to shut down and control the bypass relay to connect the power supply circuit between the power grid and the load when the photovoltaic energy storage inverter circuit is in a non-power-on state.

9. The photovoltaic energy storage inverter circuit according to claim 8, characterized in that, The first control unit is also configured to detect whether the power grid is in normal working condition when the photovoltaic energy storage inverter circuit is in a non-power-on state, and when the power grid is in normal working condition, control the DC auxiliary power supply unit to turn off and control the bypass relay to connect the power supply circuit between the power grid and the load.

10. The photovoltaic energy storage inverter circuit according to claim 1, characterized in that, The photovoltaic energy storage inverter circuit also includes: Bus capacitor, the bus capacitor being connected to the bus; The first voltage output terminal of the AC auxiliary power supply unit is connected to the bus via the bus capacitor, and is used to charge the bus capacitor. The second voltage output terminal of the DC auxiliary power supply unit is connected to the bus via the bus capacitor, and is used to draw power from the bus capacitor; The busbar is connected to the battery module and photovoltaic module in the photovoltaic energy storage component of the photovoltaic energy storage inverter circuit through the busbar capacitor, and is used to supply power to the busbar.

11. A photovoltaic energy storage inverter, characterized in that, The photovoltaic energy storage inverter includes a DC-AC conversion unit, a DC-DC conversion unit, and a maximum power point tracking unit, as well as the photovoltaic energy storage inverter circuit as described in any one of claims 1-9. The DC-AC conversion unit is connected to the bus capacitor of the photovoltaic energy storage inverter circuit, the bypass relay of the photovoltaic energy storage inverter circuit, or the inverter relay. The DC-DC conversion unit is connected to the photovoltaic energy storage module and the bus capacitor, respectively. The maximum power point tracking unit is connected to the photovoltaic energy storage module and the bus capacitor, respectively.

12. A control method for a photovoltaic energy storage inverter based on claim 11, characterized in that, The method includes: The first control unit detects whether the photovoltaic energy storage inverter is powered on. Based on the power-on status of the photovoltaic energy storage inverter, the first control unit and the second control unit control the photovoltaic energy storage inverter to enter the corresponding power supply mode, which includes a low power consumption mode or a normal operation mode. The first control unit periodically detects the operating status of the photovoltaic energy storage inverter and determines whether to switch the power supply mode of the photovoltaic energy storage inverter.

13. The method according to claim 12, characterized in that, The photovoltaic energy storage component in the photovoltaic energy storage inverter includes a photovoltaic component and an energy storage component, and the method further includes: When the power supply mode is the normal working mode, the first control unit detects whether the power grid and the photovoltaic module are in a normal power supply state, and detects whether the photovoltaic energy storage module is in a charging and discharging state. If the power grid is in the normal power supply state, the photovoltaic module is in the abnormal power supply state, and the energy storage module is not in the charging and discharging state, then the first control unit controls the DC auxiliary power supply unit to shut down and controls the bypass relay to turn on, and the second control unit controls the AC auxiliary power supply unit to turn on, so that the photovoltaic energy storage inverter enters the low power consumption mode.

14. The method according to claim 12, characterized in that, The photovoltaic energy storage component in the photovoltaic energy storage inverter includes a photovoltaic component and an energy storage component, and the method further includes: When the power supply mode is low power mode, the first control unit detects whether the power grid input is in a normal power supply state; If the power grid is in the normal power supply state, then detect whether the photovoltaic module is in the normal power supply state; When the photovoltaic module is in the normal power supply state, the first control unit controls the DC auxiliary power supply unit to turn on, and the second control unit controls the AC auxiliary power supply unit to turn off, so that the photovoltaic energy storage inverter enters the normal operation mode.

15. The method according to claim 14, characterized in that, The method further includes: If the power grid is in an abnormal power supply state, then detect whether the energy storage component is in a charging or discharging state; When the energy storage component is in the charging and discharging state, the first control unit controls the DC auxiliary power supply unit to turn on, and the second control unit controls the AC auxiliary power supply unit to turn off, so that the photovoltaic energy storage inverter enters the normal operation mode.

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