Inverter starting current suppression method, device, equipment and medium
By measuring the residual voltage of the inverter's filter capacitor and calculating the initial duty cycle, a PWM signal is generated to control the switching devices, thus solving the inverter's startup current overshoot problem and achieving smooth startup and cost optimization.
Patent Information
- Application Number
- CN202510225361.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2025-11-04
AI Technical Summary
Inverters may damage semiconductor devices due to current overshoot during startup. Existing technologies that increase the capacity of inductors and semiconductor devices are costly and do not conform to future development trends.
By measuring the residual voltage of the AC side filter capacitor, the initial duty cycle is calculated using a feedforward control algorithm, an initial PWM signal is generated, and the inverter switching devices are controlled to start smoothly.
It effectively avoids current overshoot, protects the inverter from damaging semiconductor devices, reduces system complexity and cost, and improves system reliability and lifespan.
Smart Images
Figure CN120896418A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of inverter technology, and in particular to a method, apparatus, device and medium for suppressing the starting current of an inverter. Background Technology
[0002] With the increasing global demand for renewable energy, new energy technologies (such as solar photovoltaic systems and wind power generation systems) have developed rapidly. String energy storage systems, as a key component of new energy systems, store electrical energy and release it when needed to ensure the stability and reliability of the power system. Currently, the DC-side voltage of string energy storage systems has gradually increased to over 1500V, and the AC-side voltage has also increased to 1000VAC.
[0003] However, in actual operation, inverters in string energy storage systems may suddenly shut down for various reasons. These reasons may include grid faults, overload protection triggering, and external environmental factors (such as extreme weather conditions). When the inverter suddenly stops working, the AC side filter capacitors remain under high voltage. If the first switching pulse when the inverter restarts is incorrect, it will cause a large current to be injected into the inverter, thereby damaging the semiconductor devices.
[0004] Therefore, how to suppress the inverter's startup current has become an urgent technical problem to be solved. Summary of the Invention
[0005] To address the aforementioned issues, this application provides a method, apparatus, device, and medium for suppressing the startup current of an inverter, which can suppress the startup current of the inverter through an algorithm.
[0006] The embodiments of this application disclose the following technical solutions:
[0007] In a first aspect, this application discloses a method for suppressing the startup current of an inverter, the method comprising:
[0008] Before the inverter starts, obtain the residual voltage on the AC side filter capacitor;
[0009] Based on the residual voltage, the initial duty cycle of the inverter is determined by a feedforward control algorithm;
[0010] Based on the initial duty cycle, an initial pulse width modulation (PWM) signal is generated;
[0011] The inverter's switching devices are controlled to start the inverter based on the initial PWM signal.
[0012] Optionally, determining the initial duty cycle of the inverter based on the residual voltage using a feedforward control algorithm includes:
[0013] Perform a three-phase to two-phase coordinate transformation on the residual voltage to obtain the coordinate-transformed residual voltage;
[0014] If the product of the residual voltage after coordinate transformation and the first vector is 0, the initial duty cycle of the inverter is determined based on the product of the residual voltage after coordinate transformation and the second vector, wherein the first vector is (sinθ, -cosθ), the second vector is (cosθ, sinθ), θ is a spatial angle, and the initial value of θ is 0°.
[0015] Optionally, the method further includes:
[0016] If the product of the residual voltage after coordinate transformation and the first vector is not zero, then after increasing θ by a preset angle, the step of determining whether the product of the residual voltage after coordinate transformation and the first vector is zero continues.
[0017] Optionally, generating an initial pulse width modulation (PWM) signal based on the initial duty cycle includes:
[0018] When the initial duty cycle is greater than the instantaneous value of the triangular wave signal, the initial PWM signal is determined to be at a high level; when the initial duty cycle is less than or equal to the instantaneous value of the triangular wave signal, the initial PWM signal is determined to be at a low level.
[0019] Optionally, the inverter adopts an active clamp three-level circuit ANPC topology.
[0020] Secondly, this application discloses an inverter startup current suppression device, the device comprising: a voltage acquisition module, a duty cycle determination module, a signal generation module, and an inverter startup module;
[0021] The voltage acquisition module is used to acquire the residual voltage on the AC side filter capacitor before the inverter starts.
[0022] The duty cycle determination module is used to determine the initial duty cycle of the inverter based on the residual voltage using a feedforward control algorithm.
[0023] The signal generation module is used to generate an initial pulse width modulation (PWM) signal based on the initial duty cycle.
[0024] The inverter startup module is used to control the switching devices of the inverter to start the inverter according to the initial PWM signal.
[0025] Optionally, the duty cycle determination module includes: a first determination submodule and a second determination submodule;
[0026] The first determining submodule is used to perform a three-phase to two-phase coordinate transformation on the residual voltage to obtain the residual voltage after coordinate transformation;
[0027] The second determining submodule is used to determine the initial duty cycle of the inverter based on the product of the residual voltage after coordinate transformation and the first vector if the product of the residual voltage after coordinate transformation and the first vector is 0, wherein the first vector is (sinθ, -cosθ), the second vector is (cosθ, sinθ), θ is a spatial angle, and the initial value of θ is 0°.
[0028] Optionally, the duty cycle determination module further includes a third determination submodule;
[0029] The third determining submodule is used to, if the product of the residual voltage after coordinate transformation and the first vector is not 0, increase θ by a preset angle and then continue to execute the step of determining whether the product of the residual voltage after coordinate transformation and the first vector is 0.
[0030] Optionally, the signal generation module is specifically used to: determine that the initial PWM signal is high level when the initial duty cycle is greater than the instantaneous value of the triangular wave signal; and determine that the initial PWM signal is low level when the initial duty cycle is less than or equal to the instantaneous value of the triangular wave signal.
[0031] Optionally, the inverter adopts an active clamp three-level circuit ANPC topology.
[0032] Thirdly, this application discloses an inverter startup current suppression device, the device comprising: a memory and a processor;
[0033] The memory is used to store programs;
[0034] The processor is configured to execute the program to implement the various steps of the inverter startup current suppression method as described in the first aspect.
[0035] Fourthly, this application discloses a computer-readable medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the inverter startup current suppression method as described in the first aspect.
[0036] Compared with the prior art, this application has the following beneficial effects:
[0037] This application provides a method, apparatus, device, and medium for suppressing the startup current of an inverter. The method includes: acquiring the residual voltage on the AC side filter capacitor before the inverter starts; determining the initial duty cycle of the inverter based on the residual voltage using a feedforward control algorithm; generating an initial PWM signal based on the initial duty cycle; and controlling the switching devices of the inverter to start the inverter based on the initial PWM signal. Therefore, the inverter startup current suppression method provided in this application, by measuring the residual voltage and calculating a suitable initial duty cycle based on the residual voltage value, can effectively avoid current overshoot during inverter startup, prevent damage to the semiconductor devices in the inverter due to excessive current, and ensure that the inverter can smoothly transition to normal operating conditions during startup. Attached Figure Description
[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0039] Figure 1A A flowchart illustrating an inverter startup current suppression method provided in this application embodiment;
[0040] Figure 1B A control diagram of an inverter voltage loop is provided for an embodiment of this application;
[0041] Figure 2 A topology diagram of an ANPC three-level circuit provided in an embodiment of this application;
[0042] Figure 3 A flowchart illustrating a method for determining the initial duty cycle as provided in an embodiment of this application;
[0043] Figure 4 A schematic diagram of an inverter start-up current suppression device provided in an embodiment of this application;
[0044] Figure 5 This is a schematic diagram of a computer-readable medium provided in an embodiment of this application. Detailed Implementation
[0045] As mentioned earlier, inverters in string energy storage systems may suddenly shut down for various reasons. When the inverter suddenly stops working, the AC side filter capacitors remain under high voltage. If the first switching pulse when the inverter restarts is incorrect, it will cause a large current to flow into the inverter, thereby damaging the semiconductor devices.
[0046] Currently, increasing the capacity of inductors and semiconductor devices is commonly used to suppress inverter startup current. However, this method is costly and does not align with the future trend of string energy storage systems using discrete components to reduce costs. Therefore, how to suppress inverter startup current through algorithms has become a pressing technical problem to be solved.
[0047] In view of this, embodiments of this application provide a method, apparatus, device, and medium for suppressing inverter startup current. This method, by measuring the residual voltage and calculating a suitable initial duty cycle based on the residual voltage value, can effectively avoid current overshoot during inverter startup, preventing damage to semiconductor devices in the inverter due to excessive current, and ensuring a smooth transition to normal operating conditions during startup. Furthermore, this method employs a software algorithm for startup current suppression, eliminating the need for additional hardware investment, thereby reducing the complexity and cost of string energy storage systems. In addition, by reducing current overshoot, the method provided in this application can extend the lifespan of the inverter and improve the overall reliability of the string energy storage system.
[0048] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.
[0049] See Figure 1A This figure is a flowchart of a startup current suppression method for an inverter provided in an embodiment of this application. See also... Figure 1B This figure is a control diagram of an inverter voltage loop provided in an embodiment of this application. The method includes:
[0050] S101: Obtain the residual voltage on the AC side filter capacitor before the inverter starts.
[0051] In the inverter startup current suppression method provided in this application embodiment, the inverter adopts an active neutral point clamped (ANPC) topology. This topology achieves more efficient voltage conversion and current control by adding additional switching devices and capacitors, and is particularly suitable for high-voltage, high-power applications.
[0052] See Figure 2 The figure is a topology diagram of an ANPC three-level circuit provided in an embodiment of this application. Figure 2In the diagram, Q1A-Q6A are the IGBT switches for phase A, Q1B-Q6B are the IGBT switches for phase B, and Q1C-Q6C are the IGBT switches for phase C. C1 and C2 are DC bus voltage support capacitors used to stabilize the DC side voltage. C6, C7, and C8 are AC side filter capacitors used to filter out harmonic components on the AC side and ensure the quality of the output voltage. LA, LB, and LC are AC side filter inductors that work together with the filter capacitors to form a low-pass filter, further reducing high-frequency noise in the output voltage. Sdc is a DC side switch used to control the connection or disconnection of the DC power supply. SA, SB, and SC are AC side switches used to control the connection between the inverter and the grid. BAT1 is the battery.
[0053] Before starting the inverter, the residual voltage on the AC-side filter capacitors (C6, C7, C8) needs to be measured. Specifically, firstly, high-precision voltage sensors are installed on the AC-side filter capacitors. These voltage sensors should have sufficient bandwidth and accuracy to accurately capture any residual voltage values that may exist. The presence of residual voltage can adversely affect the inverter startup process, such as causing excessive startup current or damaging the equipment. Therefore, accurate measurement of residual voltage is crucial for ensuring the safe operation of the equipment. Subsequently, the voltage values across each AC-side filter capacitor are recorded using the voltage sensors. Since the voltage on the AC-side filter capacitors may not have fully discharged due to shutdown or fault, the measured voltage value is the residual voltage. It should be noted that in practical applications, three-phase imbalance is quite common due to the complexity of the power grid and the diversity of equipment. Therefore, to ensure the accuracy and reliability of the measurement results, each AC-side filter capacitor (C6, C7, C8) must be measured individually to obtain the true residual voltage value of each capacitor.
[0054] S102: Determine the initial duty cycle of the inverter based on the residual voltage using a feedforward control algorithm.
[0055] Accurate calculation of the initial duty cycle is crucial for ensuring a smooth start-up of the inverter, effectively preventing damage to the inverter due to startup current overshoot, and ensuring the stability and reliability of the string energy storage system.
[0056] See Figure 3 This figure is a flowchart illustrating a method for determining the initial duty cycle according to an embodiment of this application. First, the three-phase AC voltage signal (u) of the AC-side filter capacitor is... a u b u c The three-phase to two-phase DC flow rate is converted through a 3S / 2R coordinate transformation (transformation from a three-phase to a two-phase stationary coordinate system). α u βThis transformation process simplifies the complex three-phase voltage signal into a more easily processed two-phase DC signal, thereby obtaining the residual voltage (u) after coordinate transformation. α u β Subsequently, the residual voltage (u) after coordinate transformation is determined. α u β The product of the spatial angle θ and the first vector (sinθ, -cosθ) is checked to see if it is 0 or close to 0. If the product is 0 or close to 0, it indicates that the current angle θ has been aligned with the direction of the residual voltage, which means that the residual voltage has minimal impact on the system at this angle. The initial value of the spatial angle θ is set to 0°, that is, starting from zero degrees, an attempt is made to find a suitable θ value.
[0057] If (i.e., the product of the residual voltage after coordinate transformation and the first vector is 0 or close to 0), then according to the residual voltage after coordinate transformation (u) α u β The initial duty cycle of the inverter is determined by the product of the first vector and the second vector (cosθ, sinθ). If not (i.e., the product of the residual voltage after coordinate transformation and the first vector is not 0 and is not close to 0), then the preset angle is gradually increased by θ (e.g., 0.2° each time), and the step of judging whether the product of the residual voltage after coordinate transformation and the first vector is 0 is continued until a value of θ that makes the dot product close to 0 is found. This gradual adjustment process continuously approaches the optimal angle θ through iteration, thereby ensuring that the finally determined initial duty cycle can effectively suppress the start-up current overshoot and achieve a smooth start-up of the inverter.
[0058] S103: Generate the initial pulse width modulation (PWM) signal based on the initial duty cycle.
[0059] Pulse Width Modulation (PWM) is a technique that adjusts the output voltage or current by changing the width of a pulse signal. Specifically, a PWM signal consists of a series of periodic pulses, and the duration of the high-level signal of each pulse (i.e., the duty cycle) determines the effective output voltage. A higher duty cycle results in a higher effective output voltage; a lower duty cycle results in a lower effective output voltage.
[0060] In the inverter startup current suppression method provided in this application embodiment, in order to achieve smooth startup of the inverter, an initial PWM signal needs to be generated based on the previously calculated initial duty cycle. The key to generating the initial PWM signal lies in selecting a suitable carrier signal, and the triangular wave signal is a commonly used carrier signal. The waveform of the triangular wave signal is a linearly rising and falling triangular shape, with good linearity and symmetry, which can effectively reduce harmonic distortion and thus improve the quality of the PWM signal. The specific rules for generating the initial PWM signal are as follows: the initial duty cycle is compared with the triangular wave signal in real time. When the initial duty cycle is greater than the instantaneous value of the triangular wave signal, a high-level PWM signal is generated (usually represented by "1"); when the initial duty cycle is less than or equal to the instantaneous value of the triangular wave signal, a low-level PWM signal is generated (usually represented by "0"). In this way, the initial duty cycle is accurately converted into a series of periodic PWM pulse signals.
[0061] S104: Control the switching devices of the inverter to start the inverter based on the initial PWM signal.
[0062] After generating the initial PWM signal, it can be used to control the switching devices (such as IGBTs) in the inverter, thereby achieving a smooth start-up of the inverter. IGBTs, as high-performance power semiconductor devices, have advantages such as fast switching speed and low on-state voltage drop, and are widely used in the main circuit of inverters. Through the control of the initial PWM signal, the IGBT can turn on when the level is high, converting the DC bus voltage to AC voltage output; and turn off when the level is low, cutting off the current path. This precise switching control ensures that the inverter outputs a stable voltage waveform during startup, avoiding damage to the equipment due to current overshoot or voltage surges.
[0063] It's important to note that to ensure stable inverter operation and synchronization with the grid, phase-locked loop (PLL) technology is typically employed. A PLL is an automatic phase correction device that detects the phase difference between the inverter's output voltage and the grid voltage in real time, and adjusts the inverter's output frequency through feedback control to maintain consistency with the grid frequency. This synchronization mechanism is particularly crucial for grid-connected inverters because it ensures that the inverter's output power quality meets grid standards, while preventing power fluctuations or equipment damage caused by frequency differences.
[0064] In summary, this application provides a method for suppressing inverter startup current. This method, by measuring the residual voltage and calculating a suitable initial duty cycle based on the residual voltage value, effectively avoids current overshoot during inverter startup, preventing damage to semiconductor devices in the inverter due to excessive current and ensuring a smooth transition to normal operation during startup. Furthermore, this method employs a software algorithm for startup current suppression, eliminating the need for additional hardware investment and reducing the complexity and cost of string energy storage systems. In addition, by reducing current overshoot, the method provided in this application can extend the inverter's lifespan and improve the overall reliability of the string energy storage system.
[0065] See Figure 4 The figure is a schematic diagram of an inverter start-up current suppression device provided in an embodiment of this application. The inverter start-up current suppression device 400 includes: a voltage acquisition module 401, a duty cycle determination module 402, a signal generation module 403, and an inverter start-up module 404.
[0066] The voltage acquisition module 401 is used to acquire the residual voltage on the AC side filter capacitor before the inverter starts; the duty cycle determination module 402 is used to determine the initial duty cycle of the inverter based on the residual voltage through a feedforward control algorithm; the signal generation module 403 is used to generate an initial pulse width modulation (PWM) signal based on the initial duty cycle; and the inverter start-up module 404 is used to control the switching devices of the inverter to start the inverter based on the initial PWM signal.
[0067] In some specific implementations, the duty cycle determination module 402 includes: a first determination submodule and a second determination submodule; the first determination submodule is used to perform a three-phase to two-phase coordinate transformation on the residual voltage to obtain the residual voltage after coordinate transformation; the second determination submodule is used to determine the initial duty cycle of the inverter based on the product of the residual voltage after coordinate transformation and the first vector if the product of the residual voltage after coordinate transformation and the first vector is 0, wherein the first vector is (sinθ, -cosθ), the second vector is (cosθ, sinθ), θ is a spatial angle, and the initial value of θ is 0°.
[0068] In some specific implementations, the duty cycle determination module 402 also includes a third determination submodule; the third determination submodule is used to increase θ by 0.2° and continue to execute the step of determining whether the product of the residual voltage after coordinate transformation and the first vector is 0 if the product of the residual voltage after coordinate transformation and the first vector is not 0.
[0069] In some specific implementations, the signal generation module 403 is specifically used to: determine that the initial PWM signal is high level when the initial duty cycle is greater than the instantaneous value of the triangular wave signal; and determine that the initial PWM signal is low level when the initial duty cycle is less than or equal to the instantaneous value of the triangular wave signal.
[0070] In some specific implementations, the inverter adopts an active clamp three-level circuit ANPC topology.
[0071] In summary, this application provides an inverter startup current suppression device. This device, by measuring the residual voltage and calculating a suitable initial duty cycle based on the residual voltage value, effectively avoids current overshoot during inverter startup, preventing damage to semiconductor devices in the inverter due to excessive current and ensuring a smooth transition to normal operation during startup. Furthermore, this device employs a software algorithm for startup current suppression, eliminating the need for additional hardware investment and reducing the complexity and cost of string energy storage systems. In addition, by reducing current overshoot, the device provided in this application can extend the inverter's lifespan and improve the overall reliability of the string energy storage system.
[0072] This application also provides a corresponding inverter start-up current suppression device and a computer-readable medium for implementing the inverter start-up current suppression method provided in this application.
[0073] The inverter's startup current suppression device includes a memory and a processor. The memory stores instructions or code, and the processor executes the instructions or code to enable the device to perform an inverter startup current suppression method according to any embodiment of this application.
[0074] See Figure 5 This figure is a schematic diagram of a computer-readable medium provided in an embodiment of this application. The computer-readable medium 500 stores a computer program 511, which, when executed by a processor, implements the steps of the inverter startup current suppression method of Figure 1.
[0075] It should be noted that, in the context of this application, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.
[0076] It should be noted that the machine-readable medium described above in this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wires, optical fibers, RF (radio frequency), etc., or any suitable combination thereof.
[0077] The aforementioned computer-readable medium may be included in the aforementioned electronic device; or it may exist independently and not assembled into the electronic device.
[0078] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.
[0079] While several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this application. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.
[0080] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.
Claims
1. A method for suppressing the starting current of an inverter, characterized in that, The method includes: Before the inverter starts, obtain the residual voltage on the AC side filter capacitor; Based on the residual voltage, the initial duty cycle of the inverter is determined by a feedforward control algorithm; Based on the initial duty cycle, an initial pulse width modulation (PWM) signal is generated; The inverter's switching devices are controlled to start the inverter based on the initial PWM signal.
2. The method according to claim 1, characterized in that, The step of determining the initial duty cycle of the inverter based on the residual voltage using a feedforward control algorithm includes: Perform a three-phase to two-phase coordinate transformation on the residual voltage to obtain the coordinate-transformed residual voltage; If the product of the residual voltage after coordinate transformation and the first vector is 0, the initial duty cycle of the inverter is determined based on the product of the residual voltage after coordinate transformation and the second vector, wherein the first vector is (sinθ, -cosθ), the second vector is (cosθ, sinθ), θ is a spatial angle, and the initial value of θ is 0°.
3. The method according to claim 2, characterized in that, The method further includes: If the product of the residual voltage after coordinate transformation and the first vector is not zero, then after increasing θ by a preset angle, the step of determining whether the product of the residual voltage after coordinate transformation and the first vector is zero continues.
4. The method according to claim 1, characterized in that, The step of generating an initial pulse width modulation (PWM) signal based on the initial duty cycle includes: When the initial duty cycle is greater than the instantaneous value of the triangular wave signal, the initial PWM signal is determined to be at a high level; when the initial duty cycle is less than or equal to the instantaneous value of the triangular wave signal, the initial PWM signal is determined to be at a low level.
5. The method according to claim 1, characterized in that, The inverter adopts an active clamp three-level circuit ANPC topology.
6. A startup current suppression device for an inverter, characterized in that, The device includes: a voltage acquisition module, a duty cycle determination module, a signal generation module, and an inverter start-up module; The voltage acquisition module is used to acquire the residual voltage on the AC side filter capacitor before the inverter starts. The duty cycle determination module is used to determine the initial duty cycle of the inverter based on the residual voltage using a feedforward control algorithm. The signal generation module is used to generate an initial pulse width modulation (PWM) signal based on the initial duty cycle. The inverter startup module is used to control the switching devices of the inverter to start the inverter according to the initial PWM signal.
7. The apparatus according to claim 6, characterized in that, The duty cycle determination module includes: a first determination submodule and a second determination submodule; The first determining submodule is used to perform a three-phase to two-phase coordinate transformation on the residual voltage to obtain the residual voltage after coordinate transformation; The second determining submodule is used to determine the initial duty cycle of the inverter based on the product of the residual voltage after coordinate transformation and the first vector if the product of the residual voltage after coordinate transformation and the first vector is 0, wherein the first vector is (sinθ, -cosθ), the second vector is (cosθ, sinθ), θ is a spatial angle, and the initial value of θ is 0°.
8. The apparatus according to claim 7, characterized in that, The duty cycle determination module also includes a third determination sub-module; The third determining submodule is used to, if the product of the residual voltage after coordinate transformation and the first vector is not 0, increase θ by a preset angle and then continue to execute the step of determining whether the product of the residual voltage after coordinate transformation and the first vector is 0.
9. A starting current suppression device for an inverter, characterized in that, The device includes: a memory and a processor; The memory is used to store programs; The processor is configured to execute the program to implement the various steps of the inverter start-up current suppression method as described in any one of claims 1 to 5.
10. A computer-readable medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements each step of the inverter startup current suppression method as described in any one of claims 1 to 5.