Method and generator for generating reliability test waveform of insulating material for direct current system

Abstract

The invention discloses an insulating material reliability test waveform generation method for a direct current system and a generator, and the method comprises the steps: building a simulation model, obtaining valve voltage waveform data, discretizing the valve voltage waveform, obtaining a data sequence consistent with the length needed by the generation of the voltage waveform, and carrying out the discretization of the valve voltage waveform. Obtaining a direct current component of the valve voltage waveform, a ripple component of the valve voltage waveform and an amplitude of the ripple component of the valve voltage; obtaining a commutation overshoot waveform sequence based on the data sequence, and obtaining a direct current component of a commutation overshoot ripple component, a ripple component of a commutation overshoot waveform and an amplitude of the commutation overshoot ripple component based on the commutation overshoot waveform sequence; a DC voltage waveform or a ripple waveform is generated based on the DC component of the valve voltage waveform, the ripple component of the valve voltage waveform, and the amplitude of the valve voltage ripple component, the DC component of the commutation overshoot ripple component, the ripple component of the commutation overshoot waveform, and the amplitude of the commutation overshoot ripple component.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and more particularly to a method and a generator for generating a waveform for a reliability test of an insulating material for a DC system. Background Art

[0002] With the increase of renewable energy generating units, the demand for HVDC transmission corridors with smaller synchronization requirements is increasing. The converter valve is called the "heart" of the HVDC system due to its importance in the DC transmission system. Each bridge arm in the converter valve is composed of dozens or even hundreds of thyristors connected in series. In order to alleviate the voltage imbalance problem caused by the difference in thyristor parameters and reduce the overcharge voltage (i.e. commutation overshoot) borne by the two ends of the thyristor during the valve body commutation process, a damping circuit (such as Figure 1 As shown), the capacitor in the damping circuit is the damping capacitor.

[0003] However, the capacitance of these capacitors decreases with increasing charge and discharge cycles, leading to a continued focus of research both domestically and internationally. Currently, the film materials used in damping capacitors are constrained by long-term reliability issues and are still in the process of being domestically produced. The power of capacitor reliability assessment remains in the hands of foreign companies like ABB.

[0004] The working conditions of the damping capacitor determine that its dielectric material needs to withstand complex voltage waveforms with AC / DC superposition, multi-harmonic mixing, and multiple repeated pulses. Limited by the size and cost of the test equipment, the voltage waveform used in the existing reliability test can only achieve an equivalent test that takes into account some of the above factors, and cannot achieve complete equivalence of the voltage waveform under actual working conditions (such as Figure 2 and Figure 3 Because the polypropylene film material used in damping capacitors has a memory effect, meaning repeated pulse voltages reduce the material's dielectric strength, existing waveform generation methods cannot meet the requirements for material reliability verification.

[0005] At the same time, materials such as the supporting insulators and insulating epoxy resins in the converter valve will also be subjected to the same complex voltage waveforms as the damping capacitors. The waveforms currently used in the tests cannot meet the requirements of material reliability verification. Summary of the Invention

[0006] According to the present invention, a method and system for generating waveforms for a DC system insulation material reliability test and a generator are provided to solve the technical problem that the waveforms currently used in the test cannot meet the requirements of material reliability verification.

[0007] According to a first aspect of the present invention, there is provided a method for generating a waveform for a reliability test of an insulating material for a DC system, comprising:

[0008] Building a simulation model, obtaining valve voltage waveform data, discretizing the valve voltage waveform to obtain a data sequence having a length consistent with that required for generating the voltage waveform, and obtaining a DC component of the valve voltage waveform, a ripple component of the valve voltage waveform, and an amplitude of the valve voltage ripple component;

[0009] Based on the data sequence, a commutation overshoot waveform sequence is obtained, and based on the commutation overshoot waveform sequence, a DC component of the commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component are obtained;

[0010] A DC voltage waveform or a ripple waveform is generated based on the DC component of the valve voltage waveform, the ripple component of the valve voltage waveform and the amplitude of the valve voltage ripple component, the DC component of the commutation overshoot ripple component, the ripple component of the commutation overshoot waveform and the amplitude of the commutation overshoot ripple component.

[0011] Optionally, a simulation model is constructed to obtain valve voltage waveform data, the valve voltage waveform is discretized to obtain a data sequence a having a length consistent with that required for generating the voltage waveform, and a DC component Vadc of the valve voltage waveform, a ripple component Vripple of the valve voltage waveform, and an amplitude Vamp of the valve voltage ripple component are obtained, including:

[0012] A simulation model is built to obtain valve voltage waveform data. The valve voltage waveform is discretized to obtain data of sampling points within a cycle. By using interpolation methods such as equally spaced points and cubic spline interpolation, a data sequence a with the same length as required for voltage waveform generation is obtained. Its voltage amplitude is denoted as Va. The mean of Va is calculated to obtain the DC component Vadc of the valve voltage waveform. The ripple component Vripple of the valve voltage waveform is Va-Vadc, and the amplitude Vamp of the valve voltage ripple component is the maximum value of Vripple.

[0013] Optionally, obtaining a commutation overshoot waveform sequence based on the data sequence, and obtaining a DC component of the commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component based on the commutation overshoot waveform sequence, includes:

[0014] Draw a waveform diagram of data sequence a, read the data point at the commutation overshoot position, multiply the point by the commutation overshoot proportional coefficient and replace the data at the original position to obtain the commutation overshoot waveform sequence, whose voltage amplitude is recorded as Vb. Calculate the average value of Vb to obtain the DC component of the commutation overshoot waveform, namely Vbdc. Then, the ripple component of the commutation overshoot waveform, Vripple = Vb - Vbdc, and the amplitude of the commutation overshoot ripple component, Vamp, is the inverse of the minimum value of Vripple.

[0015] Optionally, generating a DC voltage waveform or a ripple waveform based on a DC component of a valve voltage waveform, a ripple component of the valve voltage waveform, and an amplitude of the valve voltage ripple component, a DC component of a commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component includes:

[0016] The DC component Vadc of the valve voltage waveform and the DC component Vbdc of the commutation overshoot waveform are sent to a DC generating module to generate a DC voltage waveform.

[0017] Optionally, generating a DC voltage waveform or a ripple waveform based on a DC component of a valve voltage waveform, a ripple component of the valve voltage waveform, and an amplitude of the valve voltage ripple component, a DC component of a commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component includes:

[0018] The ripple component Vripple of the valve voltage waveform, the ripple component Vripple of the commutation overshoot waveform, the amplitude Vamp of the valve voltage ripple component, and the amplitude Vamp of the commutation overshoot ripple component are sent to the ripple generation module to generate a ripple waveform.

[0019] According to another aspect of the present invention, a composite voltage waveform generator is also included, the generator including a DC generation module, a ripple generation module, a compensation module and a control module;

[0020] The DC generating module is a controllable DC voltage source connected to a capacitor voltage doubler rectifier circuit to generate a DC voltage waveform, and the controllable DC voltage source includes a BUCK circuit, a BOOST circuit, a forward circuit or a flyback circuit;

[0021] The ripple generation module includes a D / A converter, a power amplifier and a pulse transformer connected together, and is used to read a data sequence with a length of N and generate a voltage waveform fitted by N data points.

[0022] Optionally, the compensation module includes a controllable constant current source for compensating for a direct current in the load current, and the controllable constant current source resistor includes a current mirror.

[0023] Optionally, the control module is connected to the DC generating module and the ripple generating module respectively, and is used to calculate the DC component, the ripple component, and the amplitude of the ripple component based on the read data sequence, send the DC component to the DC generating module, and send the ripple component and the amplitude of the ripple component to the ripple generating module.

[0024] Optionally, the DC generation module, the ripple generation module and the compensation module are connected in parallel.

[0025] Optionally, the composite voltage waveform generator further includes a test platform connected to the DC generation module and the compensation module respectively.

[0026] Therefore, the test voltage waveform generated by the present invention is closer to the waveform of the actual voltage operating condition of the insulation material for the DC system, is more suitable for carrying out reliability tests of the insulation material for the DC system, and can realize the adjustment of the commutation overshoot voltage waveform based on the theoretical operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0028] Figure 1 A schematic diagram of a damping capacitor in a converter valve as described in the background art;

[0029] Figure 2 The prior art reliability test voltage waveform generation method and voltage waveform schematic diagram described in the background art;

[0030] Figure 3 A schematic diagram of a theoretical waveform of an actual voltage operating condition of a damping capacitor as described in the background technology;

[0031] Figure 4 Schematic diagram of the flow of a method for generating waveforms for a reliability test of insulation materials for a DC system according to this embodiment;

[0032] Figure 5 Schematic diagram of the principle of the complex voltage waveform generation method according to this embodiment;

[0033] Figure 6 is a schematic diagram of measured values of the voltage waveform generated according to this embodiment;

[0034] Figure 7 Schematic diagram of measured values of the commutation overshoot voltage waveform generated in this embodiment;

[0035] Figure 8 Schematic diagram of the test power supply and test platform described in this embodiment;

[0036] Figure 9 This is a schematic diagram of the control software interface described in this embodiment. DETAILED DESCRIPTION

[0037] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to provide a thorough and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments shown in the accompanying drawings is not intended to limit the present invention. In the accompanying drawings, identical elements are denoted by the same reference numerals.

[0038] Unless otherwise specified, the terms used herein (including technical terms) have the meanings commonly understood by those skilled in the art. In addition, it is understood that terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0039] According to a first aspect of the present invention, a method 400 for generating a waveform for a DC system insulation material reliability test is provided. Figure 4 As shown, the method 400 includes:

[0040] S401: Build a simulation model, obtain valve voltage waveform data, discretize the valve voltage waveform, obtain a data sequence of the same length as required for voltage waveform generation, and obtain a DC component of the valve voltage waveform, a ripple component of the valve voltage waveform, and an amplitude of the valve voltage ripple component;

[0041] S402: Obtaining a commutation overshoot waveform sequence based on the data sequence, and obtaining a DC component of the commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component based on the commutation overshoot waveform sequence;

[0042] S403: Generate a DC voltage waveform or a ripple waveform based on the DC component of the valve voltage waveform, the ripple component of the valve voltage waveform and the amplitude of the valve voltage ripple component, the DC component of the commutation overshoot ripple component, the ripple component of the commutation overshoot waveform and the amplitude of the commutation overshoot ripple component.

[0043] Optionally, a simulation model is constructed to obtain valve voltage waveform data, the valve voltage waveform is discretized to obtain a data sequence a having a length consistent with that required for generating the voltage waveform, and a DC component Vadc of the valve voltage waveform, a ripple component Vripple of the valve voltage waveform, and an amplitude Vamp of the valve voltage ripple component are obtained, including:

[0044] A simulation model is built to obtain valve voltage waveform data. The valve voltage waveform is discretized to obtain data of sampling points within a cycle. By using interpolation methods such as equally spaced points and cubic spline interpolation, a data sequence a with the same length as required for voltage waveform generation is obtained. Its voltage amplitude is denoted as Va. The mean of Va is calculated to obtain the DC component Vadc of the valve voltage waveform. The ripple component Vripple of the valve voltage waveform is Va-Vadc, and the amplitude Vamp of the valve voltage ripple component is the maximum value of Vripple.

[0045] Optionally, obtaining a commutation overshoot waveform sequence based on the data sequence, and obtaining a DC component of the commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component based on the commutation overshoot waveform sequence, includes:

[0046] Draw a waveform diagram of data sequence a, read the data point at the commutation overshoot position, multiply the point by the commutation overshoot proportional coefficient and replace the data at the original position to obtain the commutation overshoot waveform sequence, whose voltage amplitude is recorded as Vb. Calculate the average value of Vb to obtain the DC component of the commutation overshoot waveform, namely Vbdc. Then, the ripple component of the commutation overshoot waveform, Vripple = Vb - Vbdc, and the amplitude of the commutation overshoot ripple component, Vamp, is the inverse of the minimum value of Vripple.

[0047] Optionally, generating a DC voltage waveform or a ripple waveform based on a DC component of a valve voltage waveform, a ripple component of the valve voltage waveform, and an amplitude of the valve voltage ripple component, a DC component of a commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component includes:

[0048] The DC component Vadc of the valve voltage waveform and the DC component Vbdc of the commutation overshoot waveform are sent to a DC generating module to generate a DC voltage waveform.

[0049] Optionally, generating a DC voltage waveform or a ripple waveform based on a DC component of a valve voltage waveform, a ripple component of the valve voltage waveform, and an amplitude of the valve voltage ripple component, a DC component of a commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component includes:

[0050] The ripple component Vripple of the valve voltage waveform, the ripple component Vripple of the commutation overshoot waveform, the amplitude Vamp of the valve voltage ripple component, and the amplitude Vamp of the commutation overshoot ripple component are sent to the ripple generation module to generate a ripple waveform.

[0051] According to another aspect of the present invention, a composite voltage waveform generator is also included, the generator including a DC generation module, a ripple generation module, a compensation module and a control module;

[0052] The DC generating module is a controllable DC voltage source connected to a capacitor voltage doubler rectifier circuit to generate a DC voltage waveform, and the controllable DC voltage source includes a BUCK circuit, a BOOST circuit, a forward circuit or a flyback circuit;

[0053] The ripple generation module includes a D / A converter, a power amplifier and a pulse transformer connected together, and is used to read a data sequence with a length of N and generate a voltage waveform fitted by N data points.

[0054] Optionally, the compensation module includes a controllable constant current source for compensating for a direct current in the load current, and the controllable constant current source resistor includes a current mirror.

[0055] Optionally, the control module is connected to the DC generating module and the ripple generating module respectively, and is used to calculate the DC component, the ripple component, and the amplitude of the ripple component based on the read data sequence, send the DC component to the DC generating module, and send the ripple component and the amplitude of the ripple component to the ripple generating module.

[0056] Optionally, the DC generation module, the ripple generation module and the compensation module are connected in parallel.

[0057] Optionally, the composite voltage waveform generator further includes a test platform connected to the DC generation module and the compensation module respectively.

[0058] Specifically, valve voltage waveform data can be obtained through theoretical calculations using an existence function, simulation model construction, and actual operating condition testing. After obtaining the waveform data, the waveform must be discretized to obtain data from sampling points within a cycle. Using interpolation techniques such as equally spaced points and cubic spline interpolation, a data sequence a of the same length as required to generate the voltage waveform is obtained, with its voltage amplitude denoted as Va. By taking the mean of Va, the DC component of the valve voltage waveform, Vadc, is obtained. The ripple component of the valve voltage waveform, Vripple, is then calculated as Va - Vadc, with the ripple component amplitude, Vamp, being the maximum value of Vripple.

[0059] After obtaining data sequence a, plot its waveform. Read the data point at the commutation overshoot location, multiply it by the commutation overshoot proportional coefficient (customizable based on experimental needs), and replace the data at the original location to obtain the commutation overshoot waveform, sequence b. Its voltage amplitude is Vb. Calculate the mean value of Vb to obtain the DC component of the valve voltage waveform, Vbdc. The ripple component of the valve voltage waveform, Vripple, is then calculated as Vb - Vbdc. The ripple component's amplitude, Vamp, is the inverse of Vripple's minimum value.

[0060] The realization of voltage waveform consists of 4 parts: DC generation module, ripple generation module, compensation module and control module, as shown in the attached figure. Figure 5 shown.

[0061] The DC generating module may be composed of a controllable DC voltage source including but not limited to a buck circuit, a boost circuit, a forward circuit, or a flyback circuit. The module receives the expected DC voltage amplitude through a communication port and generates a corresponding amplitude.

[0062] The ripple generating module may be composed of a ripple generator including but not limited to a signal generator and an operational amplifier, and may generate a voltage waveform fitted by N data points by reading a data sequence of length N.

[0063] The compensation module may be composed of a controllable constant current source including but not limited to a current mirror, and compensates for the bias magnetism that may be generated in the transformer by the DC component in the load current by measuring the DC current in the loop.

[0064] The control module calculates Vdc, Vripple and Vamp by reading the data sequence, and sends the corresponding instructions to the DC generation module and the ripple module to realize the voltage waveform.

[0065] The DC system insulation material reliability test waveform generated by this method is shown in the attached figure. Figure 6 As shown, compared with the test voltage waveform generated by this patent (see Figure 6 ) and existing waveform generation methods (Appendix Figure 2 ) It can be seen that the test voltage waveform generated by this patent is closer to the waveform of the actual voltage working condition of the insulation material used in the DC system (Appendix Figure 3 ), which is more suitable for carrying out reliability tests of insulation materials used in DC systems, and can adjust the commutation overshoot voltage waveform based on theoretical working conditions (Appendix Figure 7 ).

[0066] The actual picture of the equipment is attached Figure 8 As shown, the host computer control program is written in C# and installed in the industrial computer to realize the theoretical calculation of voltage waveform or the input of simulation data. The control software interface is shown in the attached Figure 9 shown.

[0067] Therefore, the test voltage waveform generated by the present invention is closer to the waveform of the actual voltage operating condition of the insulation material for the DC system, is more suitable for carrying out reliability tests of the insulation material for the DC system, and can realize the adjustment of the commutation overshoot voltage waveform based on the theoretical operating conditions.

[0068] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0069] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0070] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0071] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0072] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0073] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for generating waveforms for a DC system insulation material reliability test, characterized in that: include: Building a simulation model, obtaining valve voltage waveform data, discretizing the valve voltage waveform to obtain a data sequence having a length consistent with that required for generating the voltage waveform, and obtaining a DC component of the valve voltage waveform, a ripple component of the valve voltage waveform, and an amplitude of the valve voltage ripple component; Based on the data sequence, a commutation overshoot waveform sequence is obtained, and based on the commutation overshoot waveform sequence, a DC component of the commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component are obtained; A DC voltage waveform or a ripple waveform is generated based on the DC component of the valve voltage waveform, the ripple component of the valve voltage waveform and the amplitude of the valve voltage ripple component, the DC component of the commutation overshoot ripple component, the ripple component of the commutation overshoot waveform and the amplitude of the commutation overshoot ripple component.

2. The method according to claim 1, characterized in that Build a simulation model, obtain valve voltage waveform data, discretize the valve voltage waveform, obtain a data sequence a with a length consistent with that required for voltage waveform generation, obtain the DC component Vadc of the valve voltage waveform, the ripple component Vripple of the valve voltage waveform, and the amplitude Vamp of the valve voltage ripple component, including: A simulation model is built to obtain valve voltage waveform data. The valve voltage waveform is discretized to obtain data of sampling points within a cycle. By using interpolation methods such as equally spaced points and cubic spline interpolation, a data sequence a with the same length as required for voltage waveform generation is obtained. Its voltage amplitude is denoted as Va. The mean of Va is calculated to obtain the DC component Vadc of the valve voltage waveform. The ripple component Vripple of the valve voltage waveform is Va-Vadc, and the amplitude Vamp of the valve voltage ripple component is the maximum value of Vripple.

3. The method according to claim 2, characterized in that Based on the data sequence, a commutation overshoot waveform sequence is obtained, and based on the commutation overshoot waveform sequence, a DC component of the commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component are obtained, including: Draw a waveform diagram of data sequence a, read the data point at the commutation overshoot position, multiply the point by the commutation overshoot proportional coefficient and replace the data at the original position to obtain the commutation overshoot waveform sequence, whose voltage amplitude is recorded as Vb. Calculate the average value of Vb to obtain the DC component of the commutation overshoot waveform, namely Vbdc. Then, the ripple component of the commutation overshoot waveform, Vripple = Vb - Vbdc, and the amplitude of the commutation overshoot ripple component, Vamp, is the inverse of the minimum value of Vripple.

4. The method according to claim 3, characterized in that Generating a DC voltage waveform or a ripple waveform based on a DC component of a valve voltage waveform, a ripple component of the valve voltage waveform, and an amplitude of the valve voltage ripple component, a DC component of a commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component, including: The DC component Vadc of the valve voltage waveform and the DC component Vbdc of the commutation overshoot waveform are sent to a DC generating module to generate a DC voltage waveform.

5. The method according to claim 4, characterized in that Generating a DC voltage waveform or a ripple waveform based on a DC component of a valve voltage waveform, a ripple component of the valve voltage waveform, and an amplitude of the valve voltage ripple component, a DC component of a commutation overshoot ripple component, a ripple component of the commutation overshoot waveform, and an amplitude of the commutation overshoot ripple component, including: The ripple component Vripple of the valve voltage waveform, the ripple component Vripple of the commutation overshoot waveform, the amplitude Vamp of the valve voltage ripple component, and the amplitude Vamp of the commutation overshoot ripple component are sent to the ripple generation module to generate a ripple waveform.

6. A composite voltage waveform generator, characterized in that: The generator includes a DC generation module, a ripple generation module, a compensation module and a control module; The DC generating module is a controllable DC voltage source connected to a capacitor voltage doubler rectifier circuit to generate a DC voltage waveform, and the controllable DC voltage source includes a BUCK circuit, a BOOST circuit, a forward circuit or a flyback circuit; The ripple generation module includes a D / A converter, a power amplifier and a pulse transformer connected together, and is used to read a data sequence with a length of N and generate a voltage waveform fitted by N data points.

7. The composite voltage waveform generator according to claim 6, characterized in that: The compensation module includes a controllable constant current source for compensating for the direct current in the load current, and the controllable constant current source resistor includes a current mirror.

8. The composite voltage waveform generator according to claim 7, characterized in that: The control module is connected to the DC generation module and the ripple generation module respectively, and is used to calculate the DC component, the ripple component, and the amplitude of the ripple component based on the read data sequence, send the DC component to the DC generation module, and send the ripple component and the amplitude of the ripple component to the ripple generation module.

9. The composite voltage waveform generator according to claim 6, characterized in that: The DC generation module, the ripple generation module and the compensation module are connected in parallel.

10. The composite voltage waveform generator according to claim 6, characterized in that: The composite voltage waveform generator also includes a test platform, which is connected to the DC generation module and the compensation module respectively.

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