Inverter control method and controller, inverter device, and energy storage equipment

Abstract

The application relates to a control method and a controller of an inverter, an inverter device and an energy storage equipment, and belongs to the technical field of electronic power. The inverter comprises a primary side driving circuit, a transformer, a boosting circuit, a voltage detection circuit and a secondary side driving circuit. The method comprises the following steps: during a starting period of the inverter, the boosting circuit is controlled to be in an inoperative state of conducting an electrical signal at an input end to an output end; after the starting period of the inverter ends, a first detection voltage is determined through the voltage detection circuit, the first detection voltage being a measured value of a voltage at an input end of the secondary side driving circuit; and when the first detection voltage is smaller than a first voltage threshold, the boosting circuit is controlled to be switched to an operative state, so that the inverter is switched to a wide input voltage range working mode. The application can help expand the input voltage tolerance range of the inverter.

Description

Inverter control methods and controllers, inverter devices, energy storage equipment Technical Field

[0001] This application relates to the field of electronic power technology, and in particular to a control method and controller for an inverter, an inverter device, and an energy storage device. Background Technology

[0002] An inverter is a power electronic device that converts direct current (DC) to alternating current (AC) and is widely used in various power systems. The basic principle of an inverter is to use electronic switches (such as transistors and IGBTs) to rapidly switch the direction of current. By controlling the on and off of these switching elements, the output voltage exhibits AC characteristics. In some applications, the inverter's input is connected to local battery and / or power generation modules, while its output is connected to the power grid. In this case, the AC voltage at the inverter's output should be as stable as possible within the amplitude and frequency required by the power grid. However, because the DC voltage at the inverter's input may change over time (e.g., the output voltage of a battery module gradually decreases with energy consumption, or the output voltage of a photovoltaic power generation module changes with varying sunlight conditions), inverters in such applications need to have a certain allowable input voltage range and continuously adjust their operating state to meet the requirements of the connected power grid as the input voltage changes.

[0003] However, since the number of turns of the single or multi-stage transformer in the inverter is fixed and cannot be changed during use, the allowable range of the input voltage is relatively limited for cases where the output voltage is fixed (generally ±15% of the rated value). This makes the inverter unable to cope with situations where the input voltage exceeds this range (especially when the input power is low), which greatly limits the application range of the inverter. Summary of the Invention

[0004] This application provides a control method for an inverter, as well as a controller, an inverter device, and an energy storage device, which can help expand the allowable range of the inverter's input voltage.

[0005] This application provides a control method for an inverter, the inverter including a primary-side drive circuit, a transformer, a boost circuit, a voltage detection circuit, and a secondary-side drive circuit. The input terminal of the primary-side drive circuit is connected to the input terminal of the inverter, the output terminal of the primary-side drive circuit is connected to the primary winding of the transformer, the input terminal of the boost circuit is connected to the secondary winding of the transformer, the output terminal of the boost circuit is connected to the input terminals of the voltage detection circuit and the secondary-side drive circuit, and the output terminal of the secondary-side drive circuit is connected to the output terminal of the inverter. The method includes:

[0006] During the startup period of the inverter, the boost circuit is controlled to be in a non-operating state that connects the input electrical signal to the output.

[0007] After the inverter's startup period ends, a first detection voltage is determined by the voltage detection circuit. The first detection voltage is the measured value of the voltage at the input terminal of the secondary drive circuit.

[0008] When the first detected voltage is less than the first voltage threshold, the boost circuit is controlled to switch to the working state so that the inverter switches to a wide input voltage range working mode.

[0009] In some possible implementations, the method further includes:

[0010] When the first detected voltage is greater than or equal to the first voltage threshold, the boost circuit is controlled to be in the non-operating state so that the inverter switches to the normal input voltage range operating mode.

[0011] In some possible implementations, the boost circuit includes a first inductor, a first transistor, a first resistor, a second transistor, and a second resistor. The two ends of the first inductor are connected to a first node and the positive terminal of the secondary winding, respectively. The two ends of the first resistor are connected to the gate of the first transistor and the first node, respectively. The first terminal of the first transistor is connected to the first node, and the second terminal of the first transistor is connected to the positive input terminal of the secondary driving circuit. The two ends of the second resistor are connected to the gate of the second transistor and the negative terminal of the secondary winding, respectively. The first terminal of the second transistor is connected to the negative terminal of the secondary winding, and the second terminal of the second transistor is connected to the first node. Controlling the boost circuit to the non-operating state includes:

[0012] A turn-on voltage is provided to the gate of the first transistor and a turn-off voltage is provided to the gate of the second transistor, so that the first transistor operates in the linear region or saturation region and the second transistor operates in the cutoff region.

[0013] In some possible implementations, controlling the boost circuit to switch to an operating state when the first detected voltage is less than a first voltage threshold, so that the inverter switches to a wide input voltage range operating mode, includes:

[0014] When the first detected voltage is less than the first voltage threshold and greater than the second voltage threshold, the boost circuit is controlled to switch to the operating state, so that the inverter switches to the wide input voltage range operating mode; wherein the first voltage threshold is greater than the second voltage threshold; and,

[0015] When the first detection voltage is less than or equal to the second voltage threshold, the boost circuit is controlled to switch to the cut-off state, which disconnects the electrical connection between the input and output terminals.

[0016] In some possible implementations, the boost circuit includes a first inductor, a first transistor, a first resistor, a second transistor, and a second resistor. The two ends of the first inductor are connected to a first node and the positive terminal of the secondary winding, respectively. The two ends of the first resistor are connected to the gate of the first transistor and the first node, respectively. The first terminal of the first transistor is connected to the first node, and the second terminal of the first transistor is connected to the positive input terminal of the secondary driving circuit. The two ends of the second resistor are connected to the gate of the second transistor and the negative terminal of the secondary winding, respectively. The first terminal of the second transistor is connected to the negative terminal of the secondary winding, and the second terminal of the second transistor is connected to the first node. Controlling the boost circuit to switch to a cutoff state that disconnects the electrical connection between the input and output terminals includes:

[0017] A shutdown voltage is provided to the gate of the first transistor and the gate of the second transistor, respectively, so that both the first transistor and the second transistor operate in the cutoff region.

[0018] In some possible implementations, the boost circuit includes a first inductor, a first transistor, a first resistor, a second transistor, and a second resistor. The two ends of the first inductor are connected to a first node and the positive terminal of the secondary winding, respectively. The two ends of the first resistor are connected to the gate of the first transistor and the first node, respectively. The first terminal of the first transistor is connected to the first node, and the second terminal of the first transistor is connected to the positive input terminal of the secondary driving circuit. The two ends of the second resistor are connected to the gate of the second transistor and the negative terminal of the secondary winding, respectively. The first terminal of the second transistor is connected to the negative terminal of the secondary winding, and the second terminal of the second transistor is connected to the first node. Controlling the boost circuit to switch to the operating state includes:

[0019] In a manner that causes the boost circuit to boost the first voltage to obtain the second voltage, pulse width modulation signals are provided to the gates of the first transistor and the second transistor, respectively; wherein the first voltage is the voltage at the positive terminal of the secondary coil, and the second voltage is the voltage at the positive input terminal of the secondary drive circuit.

[0020] In some possible implementations, both the primary-side driving circuit and the secondary-side driving circuit are H-bridge driving circuits, and the method further includes:

[0021] Primary-side drive signals and secondary-side drive signals are provided to the primary-side drive circuit and the secondary-side drive circuit, respectively. The primary-side drive signal includes four pulse width modulation signals corresponding to four switching elements in the H-bridge of the primary-side drive circuit, and the secondary-side drive signal includes four pulse width modulation signals corresponding to four switching elements in the H-bridge of the secondary-side drive circuit.

[0022] This application also provides a controller for an inverter, the controller including a processor and a memory, the memory storing at least one executable instruction, and the processor executing the executable instruction to implement any of the inverter control methods described above.

[0023] This application also provides an inverter device, the inverter device comprising: a controller for any of the above-described inverters, and any of the above-described inverters connected to the controller.

[0024] This application also provides an energy storage device, which includes at least one set of interconnected inverter devices and battery modules, wherein the inverter devices are any of the inverter devices described above.

[0025] In this embodiment, for an inverter with drive circuits on both the primary and secondary sides of the transformer, a boost circuit and a voltage detection circuit are added between the secondary coil of the transformer and the secondary drive circuit. This allows the inverter to operate in a wide input voltage range mode. The voltage detection circuit obtains a first detected voltage at the input terminal of the secondary drive circuit after the inverter's startup period ends. By controlling the boost circuit to switch to operating mode when the first detected voltage is low (below a first voltage threshold), the voltage across the secondary coil can be increased by a certain margin. This allows the inverter to output the required output voltage even when the input voltage is below the original lower limit. Thus, this embodiment helps expand the allowable input voltage range of the inverter, improving the performance of the inverter and related products and expanding their applicability.

[0026] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0028] Figure 1 is a partial circuit structure diagram of an inverter provided in an embodiment of this application;

[0029] Figure 2 is a flowchart illustrating the steps of an inverter control method provided in an embodiment of this application.

[0030] Figure 3 is a schematic diagram of the circuit structure of a boost circuit in an inverter provided in an embodiment of this application;

[0031] Figure 4 is a structural block diagram of an inverter controller provided in an embodiment of this application;

[0032] Figure 5 is a structural block diagram of an inverter device provided in an embodiment of this application;

[0033] Figure 6 is a structural block diagram of an energy storage device provided in an embodiment of this application. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0035] The terminology used in the embodiments section of this disclosure is for illustrative purposes only and is not intended to limit the disclosure. Unless otherwise defined, the technical or scientific terms used herein should be understood in their ordinary sense by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” and similar words used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “a” or “one,” and similar words do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising,” “including,” or “containing,” and similar words mean that the elements or objects preceding “comprising,” encompass the elements or objects listed following “comprising,” and their equivalents, and do not exclude other elements or objects. The terms “connected,” “linked,” or “connected,” and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0036] Figure 1 is a structural block diagram of an inverter provided in an embodiment of this application. Referring to Figure 1, the inverter includes a primary-side drive circuit 11, a transformer T0, a boost circuit 12, a voltage detection circuit 13, and a secondary-side drive circuit 14. The input terminal of the primary-side drive circuit 11 is connected to the input terminal of the inverter (having a positive terminal A1 and a negative terminal A0), and the output terminal of the primary-side drive circuit 11 is connected to the primary winding of the transformer T0. The input terminal of the boost circuit 12 is connected to the secondary winding of the transformer T0, and the output terminal of the boost circuit 12 is connected to the input terminals of the voltage detection circuit 13 and the secondary-side drive circuit 14, respectively. The output terminal of the secondary-side drive circuit 14 is connected to the output terminal of the inverter (having a positive terminal B1 and a negative terminal B0).

[0037] Figure 2 is a schematic flowchart of an inverter control method provided in an embodiment of this application. Referring to Figure 2, the method is applied to an inverter (the circuit structure in Figure 1 is an example of an inverter, and the method can be executed, for example, by a controller connected to the inverter, which is connected to one or more of the primary drive circuit 11, transformer T0, boost circuit 12, voltage detection circuit 13, and secondary drive circuit 14), and includes the following steps.

[0038] In step 201, during the inverter's startup period, the control boost circuit is in a non-operating state, which connects the input electrical signal to the output.

[0039] In step 202, after the inverter's startup period ends, a first detection voltage is determined by a voltage detection circuit. The first detection voltage is the measured value of the voltage at the input terminal of the secondary drive circuit.

[0040] In step 203, when the first detected voltage is less than the first voltage threshold, the boost circuit is controlled to switch to the working state so that the inverter switches to a wide input voltage range working mode.

[0041] In this embodiment, for an inverter where both the primary and secondary sides of transformer T0 have drive circuits, a boost circuit 12 and a voltage detection circuit 13 are added between the secondary coil of transformer T0 and the secondary drive circuit. This allows the inverter to operate in a wide input voltage range mode. The voltage detection circuit 13 obtains the first detected voltage at the input terminal of the secondary drive circuit 14 after the inverter's startup period ends. By controlling the boost circuit 12 to switch to operating mode when the first detected voltage is low (below a first voltage threshold), the voltage across the secondary coil can be increased by a certain margin. This allows the inverter to output the required output voltage even when the input voltage is below the original lower limit. Thus, this embodiment helps expand the allowable input voltage range of the inverter, improving the performance of the inverter and related products and expanding their applicability.

[0042] It should be noted that in the inverter shown in Figure 1, each of the primary-side drive circuit 11 and the secondary-side drive circuit 14 can include: a single switching element connected in series with the primary / secondary coil, two switching elements (one connected in series with the primary / secondary coil and the other connected in parallel with the primary / secondary coil), a half-bridge circuit, or a full-bridge circuit (H-bridge circuit), etc. In one example, the inverter controller is connected to the control terminal of each switching element in the primary-side drive circuit 11 and the secondary-side drive circuit 14 respectively, so as to realize the inverter conversion function by controlling the on and off of the switching elements based on an appropriate control algorithm (such as a sinusoidal pulse width modulation algorithm). In one example, the control method of the above-mentioned inverter also includes the following steps not shown in the figures: providing primary-side drive signals and secondary-side drive signals to the primary-side drive circuit and the secondary-side drive circuit respectively, wherein the primary-side drive signal includes four pulse width modulation signals corresponding to the four switching elements in the H-bridge of the primary-side drive circuit, and the secondary-side drive signal includes four pulse width modulation (PWM) signals corresponding to the four switching elements in the H-bridge of the secondary-side drive circuit.

[0043] In one example, the inverter's startup period includes the following process: The inverter's controller controls the boost circuit 12 to operate in a non-operating state, which connects the input electrical signal to the output, and attempts to invert the DC voltage between the positive input terminal A1 and the negative input terminal A0 into an AC voltage between the positive output terminal B1 and the negative output terminal B0 to meet the output requirements based on a sinusoidal pulse width modulation (SPWM) algorithm. As the algorithm cycle iterates, the inverter's operating state tends to stabilize under constant input voltage, and the startup period ends when a specified condition is met. The voltage detection circuit 13 then collects the first detected voltage and provides it to the controller. The specified condition may be, for example, that the maximum change in the amplitude and / or frequency of the output voltage between the positive output terminal B1 and the negative output terminal B0 within a predetermined time period is less than a fluctuation threshold. Thus, after the power-on startup period ends, the controller determines the first detection voltage through the voltage detection circuit 13 in step 202 above, and controls the boost circuit 12 to switch to the working state when the first detection voltage is less than the first voltage threshold in step 203 above, so that the inverter switches to the wide input voltage range working mode.

[0044] In one example, the inverter switching to a wide input voltage range operating mode operates as follows: the inverter's controller generates pulse width modulation (PWM) signals corresponding to the boost circuit 12, primary-side drive circuit 11, and secondary-side drive circuit 14 based on circuit measurement parameters (e.g., at least one of input voltage value, input current value, output voltage amplitude, output voltage phase, and output current value), respectively. Based on the SPWM algorithm and boost conversion control, the primary-side drive circuit 11 and secondary-side drive circuit 14 perform DC-AC voltage conversion when the bus voltage of the secondary winding of transformer T0 is boosted. At this time, since the boost circuit 12 has boosted the bus voltage of the secondary coil, the minimum allowable value of the DC voltage between the positive output terminal B1 and the negative output terminal B0 can be smaller than when the boost circuit 12 is not operating (for example, the allowable input voltage range can be expanded from ±15% of the rated value to ±40% of the rated value). That is, the allowable input voltage range of the inverter is expanded.

[0045] In some possible implementations, the control method for the inverter described above also includes the following steps not shown in the figures: when the first detected voltage is greater than or equal to a first voltage threshold, the boost circuit is controlled to be in a non-operating state so that the inverter switches to a normal input voltage range operating mode (here, the normal input voltage range is relative to a wide input voltage range).

[0046] In one example, the inverter switching to normal input voltage range operating mode operates as follows: The inverter controller generates pulse width modulation (PWM) signals corresponding to the primary-side drive circuit 11 and the secondary-side drive circuit 14 based on circuit measurement parameters (e.g., at least one of input voltage value, input current value, output voltage amplitude, output voltage phase, and output current value). Based on the SPWM algorithm, this enables the primary-side drive circuit 11 and the secondary-side drive circuit 14 to perform DC-AC voltage conversion without boosting the bus voltage of the secondary winding of transformer T0. Since the bus voltage of the secondary winding is not boosted by the boost circuit 12, the controller can perform inverter control based on a simpler control process (no need to generate PWM signals corresponding to the boost circuit 12, and its influence is not considered in the algorithm design). When the first voltage threshold is configured to an appropriate value, the inverter can flexibly switch between the normal input voltage range operating mode and the wide input voltage range operating mode to adapt to different scenarios where the input voltage is in different ranges. It will also reduce the occurrence of situations such as "excessive fluctuation of output voltage before and after switching operating modes" or "inverter not switching to the wide input voltage range operating mode in time". In practical applications, an appropriate voltage value can be selected as the first voltage threshold according to the above standard by means of experimental determination, for example.

[0047] In some possible implementations, step 203 above includes the following steps (not shown in the figures): when the first detected voltage is less than a first voltage threshold and greater than a second voltage threshold, controlling the boost circuit to switch to an operating state to switch the inverter to a wide input voltage range operating mode; and when the first detected voltage is less than or equal to the second voltage threshold, controlling the boost circuit to switch to a cutoff state that disconnects the electrical connection between the input and output terminals. The first voltage threshold is greater than the second voltage threshold.

[0048] In one example, the controller distinguishes between two scenarios: the first detected voltage being less than a first voltage threshold, and the second voltage threshold being greater than or equal to. The controller only controls the inverter to switch to a wide input voltage range operating mode in the former case, while in the latter case, it controls the inverter to switch to an off-grid state (i.e., the boost circuit 12, in its off state, cuts off the current in the secondary coil, resulting in no power output from the inverter's output). Thus, the controller can proactively control the inverter to switch to an off-grid state when it determines that the input voltage is too low to allow the boost circuit 12 to output a voltage that meets the requirements, thereby avoiding adverse effects on the equipment connected to the inverter's output (such as grid equipment). It should be understood that when the second voltage threshold is configured to an appropriate value, the inverter can switch to an off-grid state promptly when the input voltage is too low. In practical applications, an appropriate voltage value can be selected as the second voltage threshold according to the above criteria, for example, through experimental determination. In one example, the first voltage threshold is set as the difference between a reference voltage and a preset threshold. The reference voltage is the voltage value at the positive input terminal of the secondary drive circuit 14 when the inverter stably outputs an AC signal that meets the requirements under ideal conditions. The preset threshold is a fixed value (e.g., 0.1V, 0.2V, 0.3V, 0.5V, 1V, 2V, 5V, 10V, etc.) that is set in advance through experience or experimental determination. Meanwhile, the second voltage threshold is set as 0.5 to 0.7 times the reference voltage (e.g., 0.55, 0.6, 0.65 times, etc.).

[0049] Figure 3 is a schematic diagram of the circuit structure of a boost circuit in an inverter according to an embodiment of this application. Referring to Figure 3, the boost circuit shown in Figure 3 includes a first inductor L1, a first transistor Q1, a first resistor R1, a second transistor Q2, and a second resistor R2. The two ends of the first inductor L1 are connected to the first node P1 and the input terminal IN of the boost circuit (connected to the positive terminal of the secondary winding). The two ends of the first resistor R1 are connected to the gate of the first transistor Q1 and the first node P1. The first terminal of the first transistor Q1 is connected to the first node P1, and the second terminal of the first transistor Q1 is connected to the output terminal OUT of the boost circuit (connected to the positive input terminal of the secondary drive circuit 14). The two ends of the second resistor R2 are connected to the gate of the second transistor Q2 and the negative terminal B0 of the secondary winding (i.e., the AC common terminal GND of the inverter). The first terminal of the second transistor Q2 is connected to the negative terminal B0 of the secondary winding, and the second terminal of the second transistor Q2 is connected to the first node P1. In Figure 3, the first terminal of the transistor is the source, and the second terminal is the drain, as an example. In addition, the boost circuit shown in Figure 3 also includes two capacitors C1 and C2 connected in parallel between the output terminal OUT of the boost circuit and the negative terminal B0 of the secondary coil (for filtering out high-frequency noise).

[0050] Based on the above circuit structure, the control boost circuit 12 in the above method is in a non-operating state, including: providing an enable voltage to the gate of the first transistor Q1 and a disable voltage to the gate of the second transistor Q2, so that the first transistor Q1 operates in the linear region or saturation region and the second transistor Q2 operates in the cutoff region. The control boost circuit 12 in the above method is switched to a cutoff state, disconnecting the electrical connection between the input and output terminals, including: providing disable voltages to the gates of the first transistor Q1 and the second transistor Q2, respectively, so that both the first transistor Q1 and the second transistor Q2 operate in the cutoff region. The control boost circuit 12 in the above method is switched to an operating state, including: providing pulse width modulation signals to the gates of the first transistor Q1 and the second transistor Q2, respectively, in a manner that causes the boost circuit 12 to boost the first voltage to obtain a second voltage; wherein the first voltage is the voltage at the input terminal IN of the boost circuit, and the second voltage is the voltage at the output terminal OUT of the boost circuit.

[0051] As can be seen, the boost circuit in this embodiment can refer to the AC-AC BUCK-BOOST circuit (AC-AC buck-boost circuit) under the control of a microcontroller to realize the switching between the above-mentioned different states; in some implementations, the first transistor Q1 and / or the second transistor Q2 can be replaced by a circuit structure composed of two or more transistors to realize a more complex control process according to application requirements.

[0052] Figure 4 is a structural block diagram of an inverter controller provided in an embodiment of this application. Referring to Figure 4, the inverter controller includes a processor 21 and a memory 22 for storing executable instructions of the processor 21; wherein, the processor 21 is used to execute the executable instructions to implement any of the inverter control methods described above. As an example, the processor 21 may be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components.

[0053] This application embodiment also provides a computer-readable storage medium, which is a non-volatile storage medium storing executable instructions for a processor. These executable instructions are configured to cause the processor to implement any of the aforementioned inverter control methods when executed by the processor. Taking the aforementioned memory 22 as an example, the computer-readable storage medium of this application embodiment can be used to achieve reactive power output control of the inverter without relying on an output current sensor.

[0054] Figure 5 is a structural block diagram of an inverter device provided in an embodiment of this application. Referring to Figure 5, the inverter device includes: a controller 200, and an inverter 100 connected to the controller 200. The inverter 100 and the controller 200 can be any combination of the inverter and controller described above; details of their optional implementations will not be elaborated here.

[0055] Figure 6 is a structural block diagram of an energy storage device provided in an embodiment of this application. The energy storage device includes a controller for at least one of the inverters described above. Referring to Figure 6, in one example, the energy storage device includes at least one set of battery modules 31 and inverter devices 32 (including a controller and an inverter connected to the controller) connected to each other, such that the inverter devices 32 can convert the direct current output from the battery modules 31 into alternating current for output to the grid or electrical appliances. In some implementations, the energy storage device also includes photovoltaic modules (not shown in the figures) connected to the battery modules 31 and the inverter devices 32 respectively, such that the electrical energy generated by the photovoltaic modules can charge the battery modules 31 or be output to the grid or electrical appliances through the inverter devices 32. As described above, the embodiments of this application can help expand the input voltage tolerance range of inverters, which helps improve the performance of inverters and related products and expand their applicability.

[0056] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A control method for an inverter, characterized in that, The inverter includes a primary-side drive circuit, a transformer, a boost circuit, a voltage detection circuit, and a secondary-side drive circuit. The input terminal of the primary-side drive circuit is connected to the input terminal of the inverter, and the output terminal of the primary-side drive circuit is connected to the primary winding of the transformer. The input terminal of the boost circuit is connected to the secondary winding of the transformer, and the output terminal of the boost circuit is connected to the input terminals of both the voltage detection circuit and the secondary-side drive circuit. The output terminal of the secondary-side drive circuit is connected to the output terminal of the inverter. The voltage detection circuit is used to obtain a first detection voltage, which is a measured value of the voltage at the input terminal of the secondary-side drive circuit. The method includes: during the inverter's startup period, controlling the boost circuit to be in a non-operating state where the electrical signal at the input terminal is turned on to the output terminal; after the inverter's startup period ends, determining the first detection voltage through the voltage detection circuit; and when the first detection voltage is less than a first voltage threshold, controlling the boost circuit to switch to an operating state so that the inverter switches to a wide input voltage range operating mode.

2. The method according to claim 1, characterized in that, The method further includes: when the first detection voltage is greater than or equal to the first voltage threshold, controlling the boost circuit to be in the non-operating state, so that the inverter switches to the normal input voltage range operating mode.

3. The method according to claim 2, characterized in that, The boost circuit includes a first inductor, a first transistor, a first resistor, a second transistor, and a second resistor. The two ends of the first inductor are respectively connected to a first node and the positive terminal of the secondary coil. The two ends of the first resistor are respectively connected to the gate of the first transistor and the first node. The first terminal of the first transistor is connected to the first node. The second terminal of the first transistor is connected to the positive input terminal of the secondary driving circuit. The two ends of the second resistor are respectively connected to the gate of the second transistor and the negative terminal of the secondary coil. The first terminal of the second transistor is connected to the negative terminal of the secondary coil. The second terminal of the second transistor is connected to the first node. Controlling the boost circuit to be in the non-operating state includes: providing an enable voltage to the gate of the first transistor and a disable voltage to the gate of the second transistor, so that the first transistor operates in the linear region or saturation region and the second transistor operates in the cutoff region.

4. The method according to claim 1, characterized in that, The step of controlling the boost circuit to switch to the operating state when the first detected voltage is less than the first voltage threshold, so that the inverter switches to the wide input voltage range operating mode, includes: controlling the boost circuit to switch to the operating state when the first detected voltage is less than the first voltage threshold and greater than the second voltage threshold, so that the inverter switches to the wide input voltage range operating mode; wherein the first voltage threshold is greater than the second voltage threshold; and controlling the boost circuit to switch to the cutoff state when the first detected voltage is less than or equal to the second voltage threshold, disconnecting the electrical connection between the input terminal and the output terminal.

5. The method according to claim 4, characterized in that, The boost circuit includes a first inductor, a first transistor, a first resistor, a second transistor, and a second resistor. The two ends of the first inductor are respectively connected to a first node and the positive terminal of the secondary coil. The two ends of the first resistor are respectively connected to the gate of the first transistor and the first node. The first terminal of the first transistor is connected to the first node. The second terminal of the first transistor is connected to the positive input terminal of the secondary driving circuit. The two ends of the second resistor are respectively connected to the gate of the second transistor and the negative terminal of the secondary coil. The first terminal of the second transistor is connected to the negative terminal of the secondary coil. The second terminal of the second transistor is connected to the first node. The step of controlling the boost circuit to switch to a cutoff state that disconnects the electrical connection between the input and output terminals includes: providing a shutdown voltage to the gate of the first transistor and the gate of the second transistor, respectively, so that both the first transistor and the second transistor operate in the cutoff region.

6. The method according to any one of claims 1 to 5, characterized in that, The boost circuit includes a first inductor, a first transistor, a first resistor, a second transistor, and a second resistor. The two ends of the first inductor are respectively connected to a first node and the positive terminal of the secondary coil. The two ends of the first resistor are respectively connected to the gate of the first transistor and the first node. The first terminal of the first transistor is connected to the first node. The second terminal of the first transistor is connected to the positive input terminal of the secondary driving circuit. The two ends of the second resistor are respectively connected to the gate of the second transistor and the negative terminal of the secondary coil. The first terminal of the second transistor is connected to the negative terminal of the secondary coil. The second terminal of the second transistor is connected to the first node. The method of controlling the boost circuit to switch to the working state includes: providing pulse width modulation signals to the gates of the first transistor and the second transistor respectively, in a manner that causes the boost circuit to boost the first voltage to obtain the second voltage; wherein the first voltage is the voltage at the positive terminal of the secondary coil, and the second voltage is the voltage at the positive input terminal of the secondary driving circuit.

7. The method according to any one of claims 1 to 5, characterized in that, Both the primary-side driving circuit and the secondary-side driving circuit are H-bridge driving circuits. The method further includes: providing a primary-side driving signal and a secondary-side driving signal to the primary-side driving circuit and the secondary-side driving circuit, respectively. The primary-side driving signal includes four pulse width modulation signals corresponding to four switching elements in the H-bridge of the primary-side driving circuit, and the secondary-side driving signal includes four pulse width modulation signals corresponding to four switching elements in the H-bridge of the secondary-side driving circuit.

8. A controller for an inverter, characterized in that, The controller includes a processor and a memory, the memory storing at least one executable instruction, and the processor being configured to implement the method as described in any one of claims 1 to 7 when executing the executable instruction.

9. An inverter device, characterized in that, The inverter device includes: a controller as described in claim 8, and an inverter connected to the controller, wherein the inverter is the inverter to which the method of any one of claims 1 to 7 is applied.

10. An energy storage device, characterized in that, The energy storage device includes at least one set of interconnected inverter devices and battery modules, wherein the inverter device is the inverter device as described in claim 9.

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