Flexible direct current transmission current converter harmonic wave and loss computing method based on modular multilevel converter (MMC)
A technology of flexible DC transmission and calculation method, applied in the direction of output power conversion devices, electrical components, etc., can solve the problems of difficulty in calculating converter losses, difficult to obtain analytical calculation formulas, and many power modules.
Inactive Publication Date: 2013-07-10
ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD +1
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However, the MMC converter has a complex topology, high level numbers, and many power modules, so it is difficult to obtain the analytical calculation formula for the loss of each switching device
This also brings great difficulty to the calculation of the loss of the converter
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[0020] The present invention proposes a method for calculating harmonics and losses of a flexible direct current transmission converter based on MMC, wherein the three-phase MMC converter is composed of 6 bridge arms, and each phase includes two upper and lower bridge arms, and each bridge arm is composed of N power modules are sequentially cascaded, including the following steps:
[0021] 1) Calculate the steady-state current of the MMC bridge arm, including power frequency AC, DC current and double frequency circulating current components in the bridge arm current;
[0022] 2) By calculating and reproducing the pulse waveforms of the power modules connected in series to form the six bridge arms of the MMC under different modulation modes;
[0023] 3) Calculate the current of the switching device and the voltage fluctuation of the power module capacitor according to the pulse waveform of the above power module and the bridge arm current;
[0024] 4) According to the above-me...
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The invention relates to a flexible direct current transmission current converter harmonic wave and loss computing method based on a modular multilevel converter (MMC). The method comprises the following steps: 1) computing the steady-state current of MMC bridge arms; 2) showing the impulse waveform of each power module of six sets of MMC bridge arms which are formed by connecting in series by computing again; 3) computing the current of a switch component and the voltage fluctuation of power module capacitors according to the impulse waveform and the bridge arm current; 4) computing each harmonic characteristic index of a current converter alternating-direct current port according to the impulse waveform and the voltage fluctuation of the power modules; and 5) obtaining the loss of the switch component by computing according to the impulse waveform and the current of the switch component. According to the method, each harmonic characteristic value of the MMC current converter alternating-direct current port, the loss characteristics of the switch component and the current converter and the like can be computed conveniently and quickly, and scanning computing of the harmonic and loss characteristics under a full-operation condition can be achieved easily.
Description
technical field [0001] The present invention relates to a method for calculating harmonics and losses of flexible direct current transmission converters based on MMC, in particular to a method for calculating harmonics and loss characteristics of flexible direct current transmission converter systems based on MMC topology, which belongs to flexible direct current transmission technology field. Background technique [0002] For the needs of sustainable development, the use of renewable energy such as solar energy and wind energy to generate electricity has become the development direction of the future power grid. These power generation methods have the characteristics of being far away from the main grid and fluctuating greatly over time. The flexible DC transmission system is based on the voltage source converter (VSC) and pulse width modulation (PWM) to invert the DC voltage into an AC voltage with controllable amplitude and phase, and can independently and quickly contro...
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Inventor 陈名饶宏罗雨黎小林许树楷陈俊
Owner ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD