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

Abstract

The invention relates to a control method of an inverter, a controller, an inverter device and energy storage equipment, and belongs to the technical field of electronic power. The inverter comprises a primary side driving circuit, a transformer, a booster circuit, a voltage detection circuit and a secondary side driving circuit, and the method comprises the following steps: controlling the booster circuit to be in a non-working state of conducting an electric signal of an input end to an output end in a startup period of the inverter; after the start-up time period of the inverter is finished, first detection voltage is determined through the voltage detection circuit, and the first detection voltage is the measured value of the voltage at the input end of the secondary side driving circuit; and when the first detection voltage is smaller than a first voltage threshold value, the boost circuit is controlled to be switched to a working state, so that the inverter is switched to a wide input voltage range working mode. The application can help to expand the allowable range of the input voltage of the inverter.

Description

Technical Field

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

[0002] An inverter is a power electronic device that converts direct current (DC) into 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, IGBTs, etc.) to switch the direction of current at high speed, and to control the on and off of the switching elements so that the output voltage presents AC characteristics. In some application scenarios, the input end of the inverter is connected to the local battery assembly and / or power generation assembly, and the output end of the inverter is connected to the power grid. At this time, the AC voltage at the output end of the inverter should be as stable as possible at the amplitude and frequency required by the power grid; however, since the DC voltage at the input end of the inverter may change over time (for example, the output voltage of the battery assembly gradually decreases with the consumption of electric energy, the output voltage of the photovoltaic power generation assembly changes with the change of light conditions, etc.), the inverter in this type of application scenario needs to have a certain degree of input voltage tolerance range, and needs to continuously adjust its own working state as the input voltage changes to meet the requirements of the connected power grid.

[0003] However, since the number of winding turns of the single-stage or multi-stage transformer in the inverter is fixed and cannot be changed during use, the allowable input voltage range is relatively limited (generally ±15% of the rated value) when the output voltage is a fixed 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 scope of the inverter. Summary of the invention

[0004] The present application provides a control method and controller of an inverter, an inverter device, and an energy storage device, which can help expand the allowable input voltage range of the inverter.

[0005] The present application provides a control method for an inverter, wherein the inverter comprises a primary drive circuit, a transformer, a boost circuit, a voltage detection circuit and a secondary drive circuit, wherein the input end of the primary drive circuit is connected to the input end of the inverter, the output end of the primary drive circuit is connected to the primary coil of the transformer, the input end of the boost circuit is connected to the secondary coil of the transformer, the output end of the boost circuit is connected to the input end of the voltage detection circuit and the input end of the secondary drive circuit respectively, and the output end of the secondary drive circuit is connected to the output end of the inverter, and the method comprises:

[0006] During the startup period of the inverter, the boost circuit is controlled to be in a non-operating state of conducting the electrical signal at the input end to the output end;

[0007] After the startup period of the inverter ends, determining a first detection voltage by the voltage detection circuit, wherein the first detection voltage is a measured value of a voltage at an input end of the secondary drive circuit;

[0008] When the first detection voltage is less than a first voltage threshold, the boost circuit is controlled to switch to a 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 detection 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 a 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, two ends of the first inductor are respectively connected to a first node and a positive terminal of the secondary coil, two ends of the first resistor are respectively connected to a gate of the first transistor and the first node, a first electrode of the first transistor is connected to the first node, a second electrode of the first transistor is connected to a positive input terminal of the secondary drive circuit, two ends of the second resistor are respectively connected to a gate of the second transistor and a negative terminal of the secondary coil, a first electrode of the second transistor is connected to a negative terminal of the secondary coil, and a second electrode of the second transistor is connected to the first node; controlling the boost circuit to be in the non-working state includes:

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

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

[0014] When the first detection voltage is less than the first voltage threshold and greater than a second voltage threshold, controlling the boost circuit to switch to the working state so that the inverter switches to the wide input voltage range working 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 a cut-off state in which the electrical connection between the input terminal and the output terminal is disconnected.

[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, two ends of the first inductor are respectively connected to a first node and a positive terminal of the secondary coil, two ends of the first resistor are respectively connected to a gate of the first transistor and the first node, a first electrode of the first transistor is connected to the first node, a second electrode of the first transistor is connected to a positive input terminal of the secondary drive circuit, two ends of the second resistor are respectively connected to a gate of the second transistor and a negative terminal of the secondary coil, a first electrode of the second transistor is connected to the negative terminal of the secondary coil, and a second electrode of the second transistor is connected to the first node; controlling the boost circuit to switch to a cut-off state in which the electrical connection between the input terminal and the output terminal is disconnected includes:

[0017] A turn-off 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 a cut-off 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, two ends of the first inductor are respectively connected to a first node and a positive terminal of the secondary coil, two ends of the first resistor are respectively connected to a gate of the first transistor and the first node, a first electrode of the first transistor is connected to the first node, a second electrode of the first transistor is connected to a positive input terminal of the secondary drive circuit, two ends of the second resistor are respectively connected to a gate of the second transistor and a negative terminal of the secondary coil, a first electrode of the second transistor is connected to a negative terminal of the secondary coil, and a second electrode of the second transistor is connected to the first node; controlling the boost circuit to switch to a working state includes:

[0019] A pulse width modulation signal is provided to the gate of the first transistor and the gate of the second transistor respectively in such a manner that the boost circuit performs a boost conversion on the first voltage to obtain a 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 drive circuit.

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

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

[0022] The present application also provides a controller for an inverter, the controller comprising a processor and a memory, the memory storing at least one executable instruction, and the processor being used to execute the executable instruction to implement any one of the above inverter control methods.

[0023] The present application also provides an inverter device, which includes: a controller of any one of the above inverters, and any one of the above inverters connected to the controller.

[0024] The present application also provides an energy storage device, which includes at least one group of interconnected inverter devices and battery components, and the inverter device is any one of the above-mentioned inverter devices.

[0025] In the embodiment of the present application, for an inverter in which both the primary and secondary sides of the transformer are provided with drive circuits, a boost circuit and a voltage detection circuit are added between the secondary coil of the transformer and the secondary drive circuit, so that the inverter can operate in a wide input voltage range operating mode - the voltage detection circuit can obtain a first detection voltage at the input end of the secondary drive circuit after the inverter startup period ends, and by controlling the boost circuit to switch to the working state when the first detection voltage is low (lower than the first voltage threshold), the voltage across the secondary coil can be increased by a certain amplitude on the original basis, so that the inverter can normally output the required output voltage when the input voltage is less than the original lower limit value; in this way, the embodiment of the present application can help expand the allowable input voltage range of the inverter, help improve the performance of the inverter and related products and expand their scope of application.

[0026] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0029] Figure 2It is a schematic diagram of the steps of an inverter control method provided by an embodiment of the present application;

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

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

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

[0033] Figure 6 It is a structural block diagram of an energy storage device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0035] The terms used in the embodiments of the present disclosure are only used to explain the embodiments of the present disclosure, and are not intended to limit the present disclosure. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one" or "one" do not indicate a quantitative limit, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing in front of "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Similar words such as "connect" or "connected" 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 the present application. Figure 1The inverter includes a primary drive circuit 11, a transformer T0, a boost circuit 12, a voltage detection circuit 13 and a secondary drive circuit 14. The input end of the primary drive circuit 11 is connected to the input end of the inverter (having a positive pole A1 and a negative pole A0), the output end of the primary drive circuit 11 is connected to the primary coil of the transformer T0, the input end of the boost circuit 12 is connected to the secondary coil of the transformer T0, the output end of the boost circuit 12 is respectively connected to the input end of the voltage detection circuit 13 and the secondary drive circuit 14, and the output end of the secondary drive circuit 14 is connected to the output end of the inverter (having a positive pole B1 and a negative pole B0).

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

[0038] In step 201, during the startup period of the inverter, the boost circuit is controlled to be in a non-operating state of conducting an electrical signal at an input end to an output end.

[0039] In step 202, after the start-up period of the inverter ends, a first detection voltage is determined by a voltage detection circuit, where the first detection voltage is a measured value of a voltage at an input terminal of a secondary drive circuit.

[0040] In step 203, when the first detection 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 the wide input voltage range working mode.

[0041] In the embodiment of the present application, for an inverter in which both the primary and secondary sides of the transformer T0 are provided with drive circuits, a boost circuit 12 and a voltage detection circuit 13 are added between the secondary coil of the transformer T0 and the secondary drive circuit, so that the inverter can operate in a wide input voltage range operating mode - the voltage detection circuit 14 can obtain the first detection voltage at the input end of the secondary drive circuit 14 after the inverter startup period ends, and by controlling the boost circuit 12 to switch to the working state when the first detection voltage is low (lower than the first voltage threshold), the voltage across the secondary coil can be increased by a certain amplitude on the original basis, so that the inverter can normally output the required output voltage when the input voltage is less than the original lower limit. In this way, the embodiment of the present application can help expand the allowable input voltage range of the inverter, help improve the performance of the inverter and related products and expand their scope of application.

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

[0043] In one example, the power-on start-up period of the inverter includes the following process: the controller of the inverter controls the boost circuit 12 to operate in a non-operating state of conducting the electrical signal of the input end to the output end, and based on the sinusoidal pulse width modulation (SPWM) algorithm, attempts to invert the DC voltage between the positive electrode A1 of the input end and the negative electrode A0 of the input end into an AC voltage between the positive electrode B1 of the output end and the negative electrode B0 of the output end that meets the output demand; with the iteration of the algorithm cycle, the working state of the inverter tends to be stable when the input voltage remains unchanged, and the power-on start-up period ends when the specified condition is met, and the voltage detection circuit 13 collects the above-mentioned first detection voltage to provide 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 electrode B1 of the output end and the negative electrode B0 of the output end within a predetermined time period is less than the fluctuation threshold. In this way, after the power-on startup period ends, the controller determines the first detection voltage through the voltage detection circuit 13 in the above step 202, 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 the above step 203, so that the inverter switches to the wide input voltage range working mode.

[0044] In one example, an inverter switched to a wide input voltage range operating mode operates as follows: the inverter controller generates pulse width modulation (PWM) signals corresponding to the boost circuit 12, the primary drive circuit 11, and the secondary drive circuit 14, respectively, based on circuit measurement parameters (for example, including at least one of the input voltage value, the input current value, the output voltage amplitude, the output voltage phase, and the output current value), so as to control the primary drive circuit 11 and the secondary drive circuit 14 based on the SPWM algorithm and the boost conversion, so that the bus voltage of the secondary coil of the transformer T0 is boosted and converted to AC voltage. At this time, since the boost circuit 12 performs a boost conversion on the bus voltage of the secondary coil on the original basis, when the output voltage amplitude and / or frequency output requirements between the output positive electrode B1 and the output negative electrode B0 remain unchanged (for example, the amplitude is fixed to 220V and the frequency is 50Hz), the minimum allowable value of the DC voltage between the input positive electrode A1 and the input negative electrode A0 can be smaller than when the boost circuit 12 is not in operation (as an example, the input voltage allowable range can be expanded from ±15% of the rated value to ±40% of the rated value). That is, the input voltage allowable range of the inverter is expanded.

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

[0046] In one example, the inverter switched to the normal input voltage range working mode operates in the following manner: the controller of the inverter generates pulse width modulation (PWM) signals corresponding to the primary drive circuit 11 and the secondary drive circuit 14 respectively based on the circuit measurement parameters (for example, including at least one of the input voltage value, the input current value, the output voltage amplitude, the output voltage phase, and the output current value), so as to make the primary drive circuit 11 and the secondary drive circuit 14 perform DC-AC voltage conversion based on the SPWM algorithm when the bus voltage of the secondary coil of the transformer T0 is not stepped up. At this time, since the bus voltage of the secondary coil is not stepped up by the boost circuit 12, the controller can perform the inverter control of the inverter based on a simpler control process (there is no need to generate a pulse width modulation signal corresponding to the boost circuit 12, and there is no need to consider its influence in the algorithm design). When the above-mentioned first voltage threshold is configured to an appropriate numerical 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 numerical ranges, and situations such as "the output voltage of the inverter fluctuates too much before and after the working mode is switched" or "the inverter does not switch to the wide input voltage range working mode in time" will rarely occur. In practical applications, for example, an appropriate voltage value can be selected as the above-mentioned first voltage threshold according to the above-mentioned standards by experimental measurement.

[0047] In some possible implementations, the above step 203 includes the following steps not shown in the drawings: when the first detection voltage is less than the first voltage threshold and greater than the second voltage threshold, controlling the boost circuit to switch to the working state so that the inverter switches to the wide input voltage range working mode; and when the first detection voltage is less than or equal to the second voltage threshold, controlling the boost circuit to switch to the cut-off state that disconnects the electrical connection between the input terminal and the output terminal. The first voltage threshold is greater than the second voltage threshold.

[0048] In one example, the situation where the first detection voltage is less than the first voltage threshold is divided by the controller into two situations: greater than the second voltage threshold and less than or equal to the second voltage threshold, and the controller controls the inverter to switch to the wide input voltage range working mode only in the former situation, and controls the inverter to switch to the off-grid state in the latter situation (that is, the boost circuit 12 in the cut-off state cuts off the current in the secondary coil, so that the output end of the inverter has no power output). In this way, the controller can actively control the inverter to switch to the off-grid state when it is determined that the voltage value of the input voltage is too small and it is impossible to enable the inverter to output the required output voltage through the boost conversion of the boost circuit 12, thereby avoiding adverse effects on the equipment connected to the output end of the inverter (such as power grid equipment). It should be understood that when the above-mentioned second voltage threshold is configured as an appropriate value, the inverter can switch to the off-grid state in time when the input voltage is too low; in practical applications, for example, an appropriate voltage value can be selected according to the above-mentioned standard by experimental measurement as the above-mentioned second voltage threshold. In one example, the first voltage threshold is set to the difference between a reference voltage and a preset threshold, wherein 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, and the preset threshold is a fixed value (such as 0.1V, 0.2V, 0.3V, 0.5V, 1V, 2V, 5V, 10V, etc.) set in advance through experience or experimental measurement, and the second voltage threshold is set to 0.5 to 0.7 times the reference voltage (for example, 0.55, 0.6, 0.65 times, etc.).

[0049] Figure 3 is a schematic diagram of a circuit structure of a boost circuit in an inverter provided in an embodiment of the present application. Figure 3 , Figure 3 The boost circuit shown includes a first inductor L1, a first transistor Q1, a first resistor R1, a second transistor Q2 and a second resistor R2. Among them, the two ends of the first inductor L1 are respectively connected to the first node P1 and the input end IN of the boost circuit (connected to the positive end of the secondary coil), the two ends of the first resistor R1 are respectively connected to the gate of the first transistor Q1 and the first node P1, the first electrode of the first transistor Q1 is connected to the first node P1, the second electrode of the first transistor Q1 is connected to the output end OUT of the boost circuit (connected to the positive input end of the secondary drive circuit 14), the two ends of the second resistor R2 are respectively connected to the gate of the second transistor Q2 and the negative end B0 of the secondary coil (that is, the AC common end GND of the inverter), the first electrode of the second transistor Q2 is connected to the negative end B0 of the secondary coil, and the second electrode of the second transistor Q2 is connected to the first node P1. Figure 3 In the description, the first electrode of the transistor is the source and the second electrode is the drain. Figure 3The boost circuit shown further includes two capacitors C1 and C2 (used to filter out high-frequency noise) connected in parallel between the output terminal OUT of the boost circuit and the negative terminal B0 of the secondary coil.

[0050] Based on the above circuit structure, the control boost circuit 12 in the above method is in a non-working state, including: providing a turn-on voltage to the gate of the first transistor Q1 and providing a turn-off voltage to the gate of the second transistor Q2, so that the first transistor Q1 works in a linear region or a saturation region and the second transistor Q2 works in a cut-off region. The control boost circuit 12 in the above method switches to a cut-off state that disconnects the electrical connection between the input terminal and the output terminal, including: providing a turn-off voltage to the gate of the first transistor Q1 and the gate of the second transistor Q2, respectively, so that the first transistor Q1 and the second transistor Q2 both work in the cut-off region. The control boost circuit 12 in the above method switches to a working state, including: providing a pulse width modulation signal to the gate of the first transistor Q1 and the gate of the second transistor Q2, respectively, in a manner that the boost circuit 12 performs a step-up conversion on 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] It can be seen that the boost circuit of the embodiment of the present application can refer to the AC-AC BUCK-BOOST circuit (AC-AC buck-boost circuit) under the control of a single-chip microcomputer to achieve switching between the above-mentioned different states; in some implementations, the above-mentioned first transistor Q1 and / or second transistor Q2 can be replaced by a circuit structure composed of two or more transistors to achieve a more complex control process according to application requirements.

[0052] Figure 4 is a structural block diagram of a controller of an inverter provided in an embodiment of the present application. Figure 4 The controller of the inverter 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 above inverter control methods. As an example, the processor 21 can be, for example, 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] The embodiment of the present application also provides a computer-readable storage medium, which is a non-volatile storage medium, and the storage medium stores executable instructions of a processor, and the executable instructions are configured to enable the processor to implement any of the above inverter control methods when executed by the processor. Taking the above memory 22 as an example, the computer-readable storage medium of the embodiment of the present application can be used to implement the output control of the inverter reactive power without the aid of an output current sensor.

[0054] Figure 5 is a structural block diagram of an inverter device provided in an embodiment of the present application. 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 may be a combination of any of the above-mentioned inverters and controllers, and the details of the optional implementation methods are not repeated here.

[0055] Figure 6 is a structural block diagram of an energy storage device provided in an embodiment of the present application. The energy storage device includes at least one controller of any one of the above inverters. Figure 6 In one example, the energy storage device includes at least one group of battery assemblies 31 and inverter devices 32 (including a controller and an inverter connected to the controller) connected to each other, so that the inverter device 32 can convert the direct current output by the battery assembly 31 into alternating current and output it to the power grid or power-consuming equipment. In some implementations, the energy storage device also includes a photovoltaic assembly (not shown in the drawings) connected to the battery assembly 31 and the inverter device 32, respectively, so that the electric energy generated by the photovoltaic assembly can charge the battery assembly 31 or be output to the power grid or power-consuming equipment through the inverter device 32. As described above, the embodiments of the present application can help expand the allowable input voltage range of the inverter, help improve the performance of the inverter and related products and expand their scope of application.

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

Claims

1. A control method for an inverter, characterized in that: The inverter comprises a primary drive circuit, a transformer, a boost circuit, a voltage detection circuit and a secondary drive circuit, wherein an input end of the primary drive circuit is connected to an input end of the inverter, an output end of the primary drive circuit is connected to a primary coil of the transformer, an input end of the boost circuit is connected to a secondary coil of the transformer, an output end of the boost circuit is respectively connected to input ends of the voltage detection circuit and the secondary drive circuit, and an output end of the secondary drive circuit is connected to an output end of the inverter, and the method comprises: During the startup period of the inverter, the boost circuit is controlled to be in a non-operating state of conducting the electrical signal at the input end to the output end; After the startup period of the inverter ends, determining a first detection voltage by the voltage detection circuit, wherein the first detection voltage is a measured value of a voltage at an input end of the secondary drive circuit; When the first detection voltage is less than a first voltage threshold, the boost circuit is controlled to switch to a working state, so that the inverter switches to a wide input voltage range working mode.

2. The method according to claim 1, characterized in that The method further comprises: When the first detection 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 a 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, two ends of the first inductor are respectively connected to a first node and a positive terminal of the secondary coil, two ends of the first resistor are respectively connected to a gate of the first transistor and the first node, a first electrode of the first transistor is connected to the first node, a second electrode of the first transistor is connected to a positive input terminal of the secondary drive circuit, two ends of the second resistor are respectively connected to a gate of the second transistor and a negative terminal of the secondary coil, a first electrode of the second transistor is connected to a negative terminal of the secondary coil, and a second electrode of the second transistor is connected to the first node; The step of controlling the boost circuit to be in the non-operating state comprises: An on voltage is provided to the gate of the first transistor and an off voltage is provided to the gate of the second transistor, so that the first transistor operates in a linear region or a saturation region and the second transistor operates in a cut-off region.

4. The method according to claim 1, characterized in that: When the first detection voltage is less than a first voltage threshold, controlling the boost circuit to switch to a working state so that the inverter switches to a wide input voltage range working mode includes: When the first detection voltage is less than the first voltage threshold and greater than a second voltage threshold, controlling the boost circuit to switch to the working state so that the inverter switches to the wide input voltage range working mode; wherein the first voltage threshold is greater than the second voltage threshold; and, When the first detection voltage is less than or equal to the second voltage threshold, the boost circuit is controlled to switch to a cut-off state in which the electrical connection between the input terminal and the output terminal is disconnected.

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, two ends of the first inductor are respectively connected to a first node and a positive terminal of the secondary coil, two ends of the first resistor are respectively connected to a gate of the first transistor and the first node, a first electrode of the first transistor is connected to the first node, a second electrode of the first transistor is connected to a positive input terminal of the secondary drive circuit, two ends of the second resistor are respectively connected to a gate of the second transistor and a negative terminal of the secondary coil, a first electrode of the second transistor is connected to a negative terminal of the secondary coil, and a second electrode of the second transistor is connected to the first node; The step of controlling the boost circuit to switch to a cut-off state where the electrical connection between the input terminal and the output terminal is disconnected comprises: A turn-off voltage is provided to the gate of the first transistor and the gate of the second transistor respectively, so that the first transistor and the second transistor both operate in a cut-off 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, two ends of the first inductor are respectively connected to a first node and a positive terminal of the secondary coil, two ends of the first resistor are respectively connected to a gate of the first transistor and the first node, a first electrode of the first transistor is connected to the first node, a second electrode of the first transistor is connected to a positive input terminal of the secondary drive circuit, two ends of the second resistor are respectively connected to a gate of the second transistor and a negative terminal of the secondary coil, a first electrode of the second transistor is connected to a negative terminal of the secondary coil, and a second electrode of the second transistor is connected to the first node; The step of controlling the boost circuit to switch to a working state comprises: A pulse width modulation signal is provided to the gate of the first transistor and the gate of the second transistor respectively in such a manner that the boost circuit performs a boost conversion on the first voltage to obtain a 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 drive circuit.

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

8. A controller for an inverter, characterized in that: The controller includes a processor and a memory, wherein at least one executable instruction is stored in the memory, and the processor is configured to implement the method according to any one of claims 1 to 7 when executing the executable instruction.

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

10. An energy storage device, characterized in that: The energy storage device comprises at least one group of interconnected inverter devices and battery components, and the inverter device is the inverter device according to claim 9.

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