A composite voltage waveform generator

Abstract

This invention discloses a composite voltage waveform generator, comprising a DC generation module, a ripple generation module, a compensation module, and a control module. The DC generation module is a controllable DC voltage source connected to a capacitor voltage doubler rectifier circuit to generate a DC voltage waveform. 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, used to read a data sequence of length N and generate a voltage waveform fitted from N data points. The test voltage waveform generated by this invention is closer to the actual voltage condition waveform of insulating materials used in DC systems, making it more suitable for reliability testing of insulating materials used in DC systems. Furthermore, it allows for adjustment of the commutation overshoot voltage waveform based on theoretical operating conditions.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and more specifically, to a composite voltage waveform generator. Background Technology

[0002] With the increase in new energy generator units, the demand for high-voltage direct current (HVDC) transmission corridors with lower synchronization requirements is growing. The converter valve, due to its importance in the DC transmission system, is called the "heart" of the HVDC system. Each arm of the converter valve consists of dozens or even hundreds of thyristors connected in series. To alleviate the voltage imbalance caused by differences in thyristor parameters and to reduce the overcharge voltage across the thyristors during commutation (i.e., commutation overshoot), a damping circuit (such as...) is often connected in parallel across the thyristors. Figure 1 As shown in the figure, the capacitor in the damping circuit is the damping capacitor.

[0003] However, the capacitance of this type of capacitor decreases with increasing charge-discharge cycles, making its lifespan assessment a hot research topic both domestically and internationally. Currently, the production of thin-film materials for damping capacitors is still in the process of localization due to limitations in long-term reliability and other issues, and the authority to assess capacitor reliability remains largely in the hands of foreign companies such as ABB.

[0004] The operating conditions of damping capacitors dictate that their dielectric materials must withstand complex voltage waveforms involving superimposed AC and DC currents, mixed harmonics, and multiple repetitive pulses. Limited by the size and cost of testing equipment, existing reliability tests can only achieve equivalent tests considering some of these factors, and cannot achieve complete equivalence of the actual operating voltage waveform (e.g., ...). Figure 2 and Figure 3 (As shown). Since the polypropylene film material used in the damping capacitor is a material with a memory effect, that is, the insulation strength of the material will decrease when subjected to repeated pulse voltages, the existing waveform generation method cannot meet the requirements for material reliability verification.

[0005] Meanwhile, the insulators that provide support and the epoxy resin that provides insulation 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 for material reliability verification. Summary of the Invention

[0006] According to the present invention, a composite voltage waveform generator is provided to solve the technical problem that the waveforms currently used in experiments cannot meet the requirements for material reliability verification.

[0007] According to the present invention, a composite voltage waveform generator is provided, the generator comprising a DC generation module, a ripple generation module, a compensation module, and a control module;

[0008] The DC generation module is a controllable DC voltage source connected to a capacitor voltage multiplier rectifier circuit to generate a DC voltage waveform. The controllable DC voltage source includes a BUCK circuit, a BOOST circuit, a forward circuit, or a flyback circuit.

[0009] The ripple generation module includes a D / A converter, a power amplifier, and a pulse transformer connected together, used to read a data sequence of length N and generate a voltage waveform fitted by N data points.

[0010] Optionally, the compensation module includes a controllable constant current source for compensating for the DC current in the load current, and the controllable constant current source resistor includes a current mirror.

[0011] Optionally, the control module is connected to the DC generation module and the ripple generation module respectively, and is used to calculate the DC component, ripple component and amplitude of ripple component based on the read data sequence, send the DC component to the DC generation module, and send the ripple component and amplitude of ripple component to the ripple generation module.

[0012] Optionally, the DC generation module, the ripple generation module, and the compensation module are connected in parallel.

[0013] Optionally, the composite voltage waveform generator also includes a test platform, which is connected to the DC generation module and the compensation module, respectively.

[0014] Therefore, the test voltage waveform generated by this invention is closer to the waveform of the actual voltage condition of the insulating material for DC system, making it more suitable for conducting reliability tests on the insulating material for DC system, and the commutation overshoot voltage waveform can be adjusted based on the theoretical operating conditions. Attached Figure Description

[0015] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0016] Figure 1 A schematic diagram of the damping capacitor in the converter valve described in the background art;

[0017] Figure 2 The existing reliability test voltage waveform generation method and voltage waveform diagram described in the background art are as follows;

[0018] Figure 3 This is a schematic diagram of the theoretical waveform of the actual voltage condition of the damping capacitor described in the background technology.

[0019] Figure 4 This is a schematic diagram of a composite voltage waveform generator according to this embodiment;

[0020] Figure 5 This is a schematic diagram of the control software interface described in this embodiment. Detailed Implementation

[0021] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0022] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0023] According to the present invention, a composite voltage waveform generator is provided, the generator comprising a DC generation module, a ripple generation module, a compensation module, and a control module;

[0024] The DC generation module is a controllable DC voltage source connected to a capacitor voltage multiplier rectifier circuit to generate a DC voltage waveform. The controllable DC voltage source includes a BUCK circuit, a BOOST circuit, a forward circuit, or a flyback circuit.

[0025] The ripple generation module includes a D / A converter, a power amplifier, and a pulse transformer connected together, used to read a data sequence of length N and generate a voltage waveform fitted by N data points.

[0026] Optionally, the compensation module includes a controllable constant current source for compensating for the DC current in the load current, and the controllable constant current source resistor includes a current mirror.

[0027] Optionally, the control module is connected to the DC generation module and the ripple generation module respectively, and is used to calculate the DC component, ripple component and amplitude of ripple component based on the read data sequence, send the DC component to the DC generation module, and send the ripple component and amplitude of ripple component to the ripple generation module.

[0028] Optionally, the DC generation module, the ripple generation module, and the compensation module are connected in parallel.

[0029] Optionally, the composite voltage waveform generator also includes a test platform, which is connected to the DC generation module and the compensation module, respectively.

[0030] Specifically, the valve voltage waveform data can be obtained through methods such as constructing an existence function theory calculation, building a simulation model for simulation calculation, and actual working condition testing. After obtaining the waveform data, the waveform needs to be discretized to obtain the data of sampling points within one period. Through interpolation methods such as equally spaced points and cubic spline interpolation, a data sequence 'a' with the same length as the voltage waveform is obtained, and its voltage amplitude is denoted as Va. The mean of Va is calculated to obtain the DC component of the valve voltage waveform, Vadc. Then, the ripple component of the valve voltage waveform, Vripple = Va - Vadc, and the amplitude of the ripple component, Vamp, is the maximum value of Vripple.

[0031] After obtaining data sequence 'a', plot its waveform. Read the data point at the commutation overshoot position, multiply this point by the commutation overshoot ratio coefficient (customizable according to experimental needs), and replace the data at the original position to obtain the commutation overshoot waveform, i.e., sequence 'b', whose voltage amplitude is denoted as Vb. Calculate the mean of Vb to obtain the DC component of the valve voltage waveform, i.e., Vbdc. Then, the ripple component of the valve voltage waveform, Vripple = Vb - Vbdc, and the amplitude of the ripple component, Vamp, is the negative of the minimum value of Vripple.

[0032] The voltage waveform implementation consists of four parts: a DC generation module, a ripple generation module, a compensation module, and a control module, as shown in the attached diagram. Figure 4 As shown.

[0033] The DC generation module can consist of a controllable DC voltage source based on principles including, but not limited to, BUCK, BOOST, forward, or flyback circuits. It receives the expected DC voltage amplitude through a communication port and generates the corresponding amplitude.

[0034] The ripple generation module may consist of, but is not limited to, a ripple generator based on the principles of a signal generator and an operational amplifier. It can generate a voltage waveform fitted from N data points by reading a data sequence of length N.

[0035] The compensation module may consist of a controllable constant current source, including but not limited to a current mirror, which compensates for the bias magnetism that may be generated in the transformer by measuring the DC current in the circuit.

[0036] The control module reads the data sequence, calculates Vdc, Vripple, and Vamp, and sends the corresponding instructions to the DC generator module and the ripple module, thereby realizing the voltage waveform.

[0037] Based on the reliability test waveform of the insulation material for DC systems generated by this method, compare the test voltage waveform generated by this patent with that of existing waveform generation methods (see appendix). Figure 2As can be seen, the test voltage waveform generated by this patent is closer to the waveform of the actual voltage condition of the insulating material used in the DC system (see appendix). Figure 3 It is more suitable for conducting reliability tests on insulation materials used in DC systems, and can adjust the commutation overshoot voltage waveform based on theoretical operating conditions.

[0038] A host computer control program was written in C# and installed on an industrial computer to input theoretical calculations or simulation data of voltage waveforms. The control software interface is shown in the attached image. Figure 5 As shown.

[0039] Therefore, the test voltage waveform generated by this invention is closer to the waveform of the actual voltage condition of the insulating material for DC system, making it more suitable for conducting reliability tests on the insulating material for DC system, and the commutation overshoot voltage waveform can be adjusted based on the theoretical operating conditions.

[0040] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take 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.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0041] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0042] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The function specified in one or more boxes.

[0043] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0044] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0045] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A composite voltage waveform generator, characterized by, The generator includes a DC generation module, a ripple generation module, a compensation module, and a control module; The DC generation module is a controllable DC voltage source connected to a capacitor voltage multiplier rectifier circuit to generate a DC voltage waveform. 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, used to read a data sequence of length N and generate a voltage waveform fitted by N data points.

2. The composite voltage waveform generator according to claim 1, characterized in that, The compensation module includes a controllable constant current source resistor for compensating the DC current in the load current, and the controllable constant current source resistor includes a current mirror.

3. The composite voltage waveform generator according to claim 2, characterized in that, The control module is connected to the DC generation module and the ripple generation module respectively. It is used to calculate the DC component, ripple component and amplitude of ripple component based on the read data sequence, send the DC component to the DC generation module, and send the ripple component and amplitude of ripple component to the ripple generation module.

4. The composite voltage waveform generator according to claim 1, characterized in that, The DC generation module, ripple generation module, and compensation module are connected in parallel.

5. The composite voltage waveform generator according to claim 1, 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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