Method, device and inverter system for secondary ripple suppression of an inverter system

Abstract

The embodiment of the application discloses a kind of secondary ripple suppression method, equipment and inverter system of inverter system, method includes obtaining the output power of inverter output end;Based on output power, the control signal of active damping circuit is determined using power pulsation control loop;Based on control signal, the on-off of first switch tube and second switch tube is controlled, and the suppression of secondary wave ripple of inverter output is realized.The embodiment of the application utilizes auxiliary active damping circuit to realize the suppression of the output ripple of inverter, solves the technical problems that the device volume is larger, the cost is higher and the response speed is poorer in prior art depends on output capacitor filter to suppress ripple, realizes the wave suppression capability of power supply is improved without significantly increasing output filter capacitor, and neither need to increase the device volume, nor reduce the equipment cost, improve the dynamic response speed technical effect, effectively improve the voltage stabilizing precision of transformer system.

Description

Technical Field

[0001] The present invention relates to the field of inverter control technology, and in particular to a method, apparatus and inverter system for suppressing secondary ripple in an inverter system. Background Technology

[0002] In modern switching power supply design, output voltage ripple is one of the key indicators affecting system performance and reliability. As electronic devices evolve towards higher precision, miniaturization, and higher power density, traditional methods relying on output capacitor filters to suppress ripple are increasingly facing challenges such as increased size, higher cost, and limited dynamic response. Therefore, a new method is needed to suppress output ripple. Summary of the Invention

[0003] This invention provides a method, device, and inverter system for suppressing secondary ripple in an inverter system, which solves the technical problems of large equipment size, high cost, and poor response speed in the prior art that relies on output capacitor filters to suppress ripple.

[0004] This invention provides a method for suppressing secondary ripple in an inverter system, used to suppress the secondary ripple output of a three-level asymmetrical half-bridge inverter system. The inverter system includes a three-level asymmetrical half-bridge inverter, an active damping circuit, and a transformer. The active damping circuit is connected to the secondary winding of the transformer. The active damping circuit includes a first switch and a second switch connected in series with the secondary winding of the transformer. The method includes: Obtain the output power at the output terminal of the inverter; Based on the output power, the control signal of the active damping circuit is determined using a power pulsation control loop; The control signal controls the switching on and off of the first and second switching transistors to suppress the secondary ripple of the inverter output.

[0005] Furthermore, based on the output power, the control signal for the active damping circuit determined using the power ripple control loop includes: The output power and power reference value are input to the power pulsation control loop to obtain the target value of the damping current of the active damping circuit; Based on the target value of the damping current and the current sampling value of the active damping circuit, the control signal of the active damping circuit is obtained using a current control loop.

[0006] Furthermore, obtaining the output power at the inverter output terminal includes: The output voltage and output current of the inverter output terminal are sampled at a set frequency within a set time period. The average output voltage of the inverter is determined based on the sampled output voltages, and the average output current of the inverter is determined based on the sampled output currents. The output power is determined using the average value of the output voltage and the average value of the output current.

[0007] Furthermore, based on the target value of the damping current and the current sampling value of the active damping circuit, the control signal for the active damping circuit obtained using the current control loop includes: Based on the target value of the damping current and the current sampling value of the active damping circuit, closed-loop control calculation is performed using the current control loop to obtain the duty cycle of the control signals of the first switch and the second switch. The control signal is generated using the duty cycle of the control signal.

[0008] This invention also provides an inverter system, which includes a three-level asymmetrical half-bridge inverter, an active damping circuit, and a transformer. The input terminal of the inverter is electrically connected to the target power grid, and the output terminal of the inverter is electrically connected to the primary winding of the transformer. The active damping circuit is connected to one secondary winding of the transformer; the other secondary winding of the transformer is connected to the load. The active damping circuit includes a first switch and a second switch connected in series with the secondary winding of the transformer.

[0009] Furthermore, the active damping circuit also includes two freewheeling diodes, an active damping inductor, and an active damping capacitor; The two freewheeling diodes are connected in parallel across the first switching transistor and the second switching transistor, respectively. The active damping inductor and the active damping capacitor are connected in series and then in parallel across the two ends of the second switching transistor.

[0010] Furthermore, the inverter system also includes a control unit equipped with a power ripple control loop and a current control loop; The control unit is electrically connected to the active damping circuit.

[0011] Furthermore, the inverter includes: The rectifier bridge unit, filter capacitor, and three-level inverter bridge arm; The three-level inverter bridge arm includes four switches connected in series, and one freewheeling diode is connected in parallel for each switch. The rectifier bridge unit is connected to the three-level inverter bridge arm, and the filter capacitor is connected in parallel across the second and third switching transistors in the three-level inverter bridge arm; The third and fourth switching transistors in the three-level inverter bridge arm are connected to the primary winding of the transformer through a filter unit.

[0012] This invention also provides a secondary ripple suppression device for an inverter system, the device comprising: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the secondary ripple suppression method for the inverter system described in any of the above embodiments.

[0013] This invention also provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the secondary ripple suppression method for the inverter system described in any of the above embodiments.

[0014] This invention discloses a method, device, and inverter system for suppressing secondary ripple in an inverter system. The method includes acquiring the output power at the inverter output terminal; determining the control signal of an active damping circuit based on the output power using a power ripple control loop; and controlling the switching on and off of a first and second switching transistor based on the control signal to suppress the secondary ripple at the inverter output. This invention utilizes an auxiliary active damping circuit to suppress the inverter output ripple, solving the technical problems of existing technologies that rely on output capacitor filters for ripple suppression, such as large equipment size, high cost, and poor response speed. It achieves improved ripple suppression capability of the power supply without significantly increasing the output filter capacitor, reducing equipment size, lowering equipment cost, and improving dynamic response speed, effectively improving the voltage regulation accuracy of the transformer system. Attached Figure Description

[0015] Figure 1 This is a structural diagram of an inverter system provided in an embodiment of the present invention; Figure 2 This is a structural diagram of the control unit provided in an embodiment of the present invention; Figure 3 This is a flowchart of the secondary ripple suppression method for an inverter system provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a secondary ripple suppression device for an inverter system provided in an embodiment of the present invention. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0017] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this invention are used to distinguish different objects, not to limit a specific order. The various embodiments of this invention described below can be performed individually or in combination with each other; the embodiments of this invention do not impose specific limitations in this regard.

[0018] Figure 1 This is a structural diagram of an inverter system provided in an embodiment of the present invention. Figure 1 As shown, the inverter system includes a three-level asymmetric half-bridge (AHB) inverter 10, an active damping circuit 20, and a transformer 30. The input terminal of the inverter 10 is electrically connected to the target power grid, and the output terminal of the inverter 10 is electrically connected to the primary winding of the transformer 30. The active damping circuit 20 is connected to one secondary winding of the transformer 30. The other secondary winding of the transformer 30 is connected to the load Ro. The active damping circuit 20 includes a first switch T5 and a second switch T6 connected in series with the secondary winding of the transformer 30.

[0019] like Figure 1 As shown, the active damping circuit 20 also includes two freewheeling diodes D. T5 and D T6 Active damping inductor Ls, active damping capacitor Cs; two freewheeling diodes D T5 and D T6 The active damping inductor Ls and the active damping capacitor Cs are connected in parallel across the first switch T5 and the second switch T6, respectively; the active damping inductor Ls and the active damping capacitor Cs are connected in series and then in parallel across the second switch T6.

[0020] Figure 2 This is a structural diagram of the control unit provided in an embodiment of the present invention.

[0021] Optionally, such as Figure 2 As shown, the inverter system also includes a control unit 40 equipped with a power pulsation control loop 41 and a current control loop 42; the control unit 40 is electrically connected to the active damping circuit 20.

[0022] The power ripple control loop 41 utilizes a PIR (Proportional-Integral-Resonant) controller to determine the target value of the damping current of the active damping circuit. This is achieved by subtracting the output power ΔP from the output of the inverter 10 from the power reference value ΔP*, and inputting this subtraction to the PIR controller of the power ripple control loop 41. This yields the target value of the damping current for the active damping circuit. Wherein, the power reference value △P* is the set value within the allowable power fluctuation range of the switching power supply; and then the damping current target value is... and the current sampling value I of the active damping circuit Ls The difference is calculated and sent to the current control loop 42. The control signal of the active damping circuit 20 is obtained by the PIR controller in the current control loop 42.

[0023] Optionally, such as Figure 1 As shown, the inverter 10 includes: Rectifier bridge unit 11, filter capacitor C fly And a three-level inverter bridge arm 12; the three-level inverter bridge arm 12 includes four series-connected switching transistors T1, T2, T3, and T4, and one freewheeling diode is connected in parallel for each switching transistor. Figure 1 The corresponding numbers are D and D respectively. T1 D T3 D T4 D T5 ); rectifier bridge unit 11 is connected to three-level inverter bridge arm 12, and filter capacitor C fly The second and third switching transistors in the three-level inverter bridge arm 12 are connected in parallel across the two ends of the second and third switching transistors; the third and fourth switching transistors in the three-level inverter bridge arm 12 are connected to the primary winding of the transformer 30 through the filter unit 50.

[0024] The filter unit 50 includes a capacitor Cr and an inductor Lr, and the primary winding of the transformer 30 is also connected in parallel with an excitation inductor Lm. Optionally, such as Figure 1 As shown, the secondary winding of transformer 30 is connected to the load Ro through a rectifier diode D, and a filter capacitor Co is connected in parallel across the load Ro. The rectifier diode D uses its unidirectional conductivity to rectify the AC output from the secondary winding into unidirectional pulsating DC; the filter capacitor Co is used to smooth the output voltage, reduce voltage ripple, and make the output voltage Vo more stable; the load Ro is used to convert the rectified and filtered DC energy into other forms of energy.

[0025] Figure 3 This is a flowchart of a secondary ripple suppression method for an inverter system provided in an embodiment of the present invention. This secondary ripple suppression method for an inverter system is used to suppress secondary ripple in inverter systems. Figure 1The secondary ripple of the inverter system output of the three-level asymmetric half-bridge shown is suppressed.

[0026] Ripple is the periodic fluctuation component superimposed on the DC component of the output power / current. Secondary ripple refers to the power fluctuation component with a frequency twice the fundamental frequency of the power grid (usually 100Hz / 120Hz, corresponding to a 50Hz / 60Hz power grid). During inverter or AC-DC conversion, the output power will naturally generate a pulsating component twice the power frequency, which is secondary ripple. If this ripple is too large, it will cause voltage fluctuations in the subsequent circuits, affecting the stability of the load.

[0027] Active damping is a technique that introduces a virtual damping effect into the system through control algorithms rather than additional physical passive components to suppress oscillations or ripples. Traditional passive damping requires additional passive components such as resistors and capacitors to absorb ripples / suppress oscillations, but this introduces additional power losses, reduces system efficiency, and increases device size. Active damping uses voltage / current feedback and control algorithms to achieve the equivalent effect of a damping branch without requiring additional physical components. It can suppress ripples and resonances without introducing additional losses, making it suitable for power conversion scenarios with high efficiency requirements.

[0028] like Figure 3 As shown, the secondary ripple suppression method for this inverter system specifically includes the following steps: S101, obtain the output power of the inverter output terminal.

[0029] Specifically, the core formula for calculating inverter output power is P=U×I, where P represents output power in watts (W), U represents output voltage in volts (V), and I represents output current in amperes (A). Therefore, the output power of the inverter can be obtained simply by measuring the output voltage and output current at the inverter's output terminals.

[0030] Optionally, S101 specifically includes: sampling the output voltage and output current of the inverter output terminal at a set frequency within a set time period; determining the average value of the inverter output voltage based on the sampled output voltages, and determining the average value of the inverter output current based on the sampled output currents; and determining the output power using the average value of the output voltage and the average value of the output current.

[0031] Specifically, to ensure measurement accuracy, the output voltage and output current of the inverter 10 are sampled at a set time and a set frequency, and the average value of the output voltage and the average value of the output current of the inverter 10 are calculated respectively. The output power of the inverter 10 is obtained by multiplying the average value of the output voltage by the average value of the output current.

[0032] S102, based on the output power, uses a power pulsation control loop to determine the control signal for the active damping circuit.

[0033] Specifically, after obtaining the output power of the inverter 10, it is sent to the power pulsation control loop 41 of the control unit 40, and the target value of the damping current of the active damping circuit 20 is calculated using the PIR controller. Therefore, based on the target value of the damping current and the current sampling value I of the active damping circuit Ls The control signal for the active damping circuit 20 is obtained by using the PIR controller in the current control loop 42.

[0034] S103 controls the on / off state of the first and second switching transistors based on the control signal to suppress the secondary ripple of the inverter output.

[0035] Specifically, the power change control of the active damping circuit 20 is achieved by controlling the on and off of the first and second switching transistors using control signals. This controls the magnetic flux in the secondary winding connected to the active damping circuit 20. By controlling the rate of change of magnetic flux in the secondary winding, the magnetic flux changes of the primary winding and the other secondary winding of the transformer 30 are balanced and compensated, ultimately suppressing the secondary ripple of the three-level AHB output.

[0036] Based on the above technical solutions, S102 specifically includes: The output power ΔP and the power reference value ΔP* are input to the power pulsation control loop 41 to obtain the target value of the damping current of the active damping circuit 20. Based on the target value of damping current and the current sampling value I of the active damping circuit 20 Ls The control signal for the active damping circuit 20 is obtained using the current control loop 42.

[0037] Specifically, after obtaining the output power ΔP at the output terminal of inverter 10, the output power ΔP is subtracted from the power reference value ΔP*, and the difference is sent to the power pulsation control loop 41 of control unit 40. The target value of damping current of active damping circuit 20 is calculated using PIR controller. This will further reduce the target value of the damping current. and the current sampling value I of the active damping circuit Ls The difference is calculated and sent to the current control loop 42. The control signal of the active damping circuit 20 is obtained by the PIR controller in the current control loop 42.

[0038] Optionally, based on the target value of the damping current and the current sampling value I of the active damping circuit 20 LsThe control signals for the active damping circuit 20 obtained using the current control loop 42 include: Based on the target value of damping current and the current sampling value I of the active damping circuit 20 Ls Using the current control loop 42 for closed-loop control calculations, the first switching transistor D is obtained. T5 Second switch D T6 The duty cycle of the control signal; the control signal is generated using the duty cycle of the control signal.

[0039] This invention utilizes an auxiliary active damping circuit to suppress the output ripple of the inverter, solving the technical problems of large equipment size, high cost, and poor response speed in the prior art that relies on output capacitor filters to suppress ripple. It achieves the technical effect of improving the power supply's ripple suppression capability without significantly increasing the output filter capacitor, reducing equipment cost, and improving dynamic response speed without increasing equipment size, thus effectively improving the voltage regulation accuracy of the transformer system.

[0040] Figure 4 This is a schematic diagram of a secondary ripple suppression device for an inverter system provided in an embodiment of the present invention. This secondary ripple suppression device for an inverter system is intended to represent various forms of digital computers, such as laptops, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. The secondary ripple suppression device for an inverter system can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0041] like Figure 4 As shown, the secondary ripple suppression device 100 of the inverter system includes at least one processor 101 and a memory, such as a read-only memory (ROM) 102 and a random access memory (RAM) 103, communicatively connected to the at least one processor 101. The memory stores computer programs executable by the at least one processor. The processor 101 can perform various appropriate actions and processes based on the computer program stored in the ROM 102 or loaded into the RAM 103 from storage unit 108. The RAM 13 can also store various programs and data required for the operation of the secondary ripple suppression device 100 of the inverter system. The processor 101, ROM 102, and RAM 13 are interconnected via a bus 104. An input / output (I / O) interface 105 is also connected to the bus 104.

[0042] Multiple components in the secondary ripple suppression device 100 of the inverter system are connected to the I / O interface 105, including: an input unit 106, such as a keyboard, mouse, etc.; an output unit 107, such as various types of displays, speakers, etc.; a storage unit 108, such as a disk, optical disk, etc.; and a communication unit 109, such as a network card, modem, wireless transceiver, etc. The communication unit 109 allows the secondary ripple suppression device 100 of the inverter system to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0043] Processor 101 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 101 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. Processor 101 performs the various methods and processes described above, such as a secondary ripple suppression method for an inverter system.

[0044] In some embodiments, the secondary ripple suppression method for the inverter system can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 108. In some embodiments, part or all of the computer program can be loaded and / or installed on the secondary ripple suppression device 100 of the inverter system via ROM 102 and / or communication unit 109. When the computer program is loaded into RAM 103 and executed by processor 101, one or more steps of the cell testing method described above can be performed. Alternatively, in other embodiments, processor 101 can be configured to perform the secondary ripple suppression method for the inverter system by any other suitable means (e.g., by means of firmware).

[0045] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0046] Computer programs used to implement the secondary ripple suppression method for the inverter system of this invention can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The computer programs can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0047] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. 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 thereof.

[0048] To provide user interaction, the systems and techniques described herein can be implemented on a secondary ripple suppression device of the inverter system, which includes: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the secondary ripple suppression device of the inverter system. Other types of devices can also be used to provide user interaction; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0049] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0050] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0051] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and no limitation is imposed herein.

[0052] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for suppressing secondary ripple in an inverter system, characterized in that, This method is used to suppress secondary ripple in the output of a three-level asymmetrical half-bridge inverter system, wherein the inverter system includes a three-level asymmetrical half-bridge inverter, an active damping circuit, and a transformer, the active damping circuit being connected to the secondary winding of the transformer; the active damping circuit includes a first switch and a second switch connected in series with the secondary winding of the transformer, and the method includes: Obtain the output power at the output terminal of the inverter; Based on the output power, the control signal of the active damping circuit is determined using a power pulsation control loop; The control signal controls the switching on and off of the first and second switching transistors to suppress the secondary ripple of the inverter output.

2. The method for suppressing secondary ripple in an inverter system according to claim 1, characterized in that, Based on the output power, the control signal for the active damping circuit determined using the power ripple control loop includes: The output power and power reference value are input to the power pulsation control loop to obtain the target value of the damping current of the active damping circuit; Based on the target value of the damping current and the current sampling value of the active damping circuit, the control signal of the active damping circuit is obtained using a current control loop.

3. The method for suppressing secondary ripple in an inverter system according to claim 1, characterized in that, Obtaining the output power at the inverter output terminal includes: The output voltage and output current of the inverter output terminal are sampled at a set frequency within a set time period. The average output voltage of the inverter is determined based on the sampled output voltages, and the average output current of the inverter is determined based on the sampled output currents. The output power is determined using the average value of the output voltage and the average value of the output current.

4. The method for suppressing secondary ripple in an inverter system according to claim 2, characterized in that, Based on the target value of the damping current and the current sampling value of the active damping circuit, the control signal of the active damping circuit obtained by the current control loop includes: Based on the target value of the damping current and the current sampling value of the active damping circuit, closed-loop control calculation is performed using the current control loop to obtain the duty cycle of the control signals of the first switch and the second switch. The control signal is generated using the duty cycle of the control signal.

5. An inverter system, characterized in that, The inverter system includes a three-level asymmetric half-bridge inverter, an active damping circuit, and a transformer. The input terminal of the inverter is electrically connected to the target power grid, and the output terminal of the inverter is electrically connected to the primary winding of the transformer. The active damping circuit is connected to one secondary winding of the transformer; the other secondary winding of the transformer is connected to the load. The active damping circuit includes a first switch and a second switch connected in series with the secondary winding of the transformer.

6. The inverter system according to claim 5, characterized in that, The active damping circuit also includes two freewheeling diodes, an active damping inductor, and an active damping capacitor; The two freewheeling diodes are connected in parallel across the first switching transistor and the second switching transistor, respectively. The active damping inductor and the active damping capacitor are connected in series and then in parallel across the two ends of the second switching transistor.

7. The inverter system according to claim 5, characterized in that, The inverter system also includes a control unit equipped with a power ripple control loop and a current control loop; The control unit is electrically connected to the active damping circuit.

8. The inverter system according to claim 5, characterized in that, The inverter includes: The rectifier bridge unit, filter capacitor, and three-level inverter bridge arm; The three-level inverter bridge arm includes four switches connected in series, and one freewheeling diode is connected in parallel for each switch. The rectifier bridge unit is connected to the three-level inverter bridge arm, and the filter capacitor is connected in parallel across the second and third switching transistors in the three-level inverter bridge arm; The third and fourth switching transistors in the three-level inverter bridge arm are connected to the primary winding of the transformer through a filter unit.

9. A secondary ripple suppression device for an inverter system, characterized in that, The device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the secondary ripple suppression method for the inverter system according to any one of claims 1-4.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the secondary ripple suppression method for the inverter system according to any one of claims 1-4.

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