Parameter Extraction Method of Converter Three-port Electromagnetic Interference Model

Abstract

The invention discloses a converter three-port electromagnetic interference model parameter extraction method, and the method comprises the following steps: (1) designing a port test scheme accordingto a power converter three-port electromagnetic interference model topology, selecting an element value of an external test circuit, and measuring a plurality of groups of different port voltage and current time domain data; (2) performing time-frequency conversion on the port voltage and current time domain data by using a method of combining apFFT with time-shifting phase difference compensationto obtain port voltage and current frequency domain amplitude and phase with higher precision; (3) performing fitting by utilizing simulation software to obtain the frequency spectrum amplitudes of the equivalent current source and the equivalent internal resistance in the three-port model, and verifying the model precision through an experiment. Compared with an existing converter electromagnetic interference equivalent internal resistance extraction method, the method has the advantages that the test process is convenient, the precision of the model is hardly influenced by an external testcircuit, a high-precision port EMI model is obtained through an optimized data processing method, and an important theoretical support is provided for subsequent EMI filter design.

Description

technical field [0001] The invention belongs to the technical field of converter port modeling, and in particular relates to a method for extracting parameters of a converter three-port electromagnetic interference model. Background technique [0002] With the development of power electronics technology, converters using pulse width modulation are widely used in the field of new energy; as the switching frequency of power switching devices continues to increase, the electromagnetic interference (EMI) caused by high-speed switching is also increasing. More and more serious, high-frequency EMI will not only affect the normal operation of the system itself, shorten the service life, but also bring high-order harmonic interference to the power grid, thus affecting the safe and stable operation of the entire power grid system. [0003] At present, the electromagnetic interference in the converter system is mainly suppressed by adding a filter device. The design of the filter need...

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Problems solved by technology

In the case of few signal frequency points, the spectrum analysis results obtained by the above method have certain accuracy, but when the signal contains multiple frequency components, the inter-spectrum interference is serious, and the error of spectrum correction is greatly increased, so the above method does not Not suitable for correction of dense spectrum

[0007] In order to solve the above problems, the document "Huang Xiangdong, Wang Zhaohua, Luo Peng, et al. All-phase FFT dense spectrum identification and correction [J]. Electronic Journal, 2011 (01): 174-17" proposed a dense spectrum based on all-phase FFT Spectrum identification and correction algorithm, all-phase FFT has a good performance in suppressing spectrum leakage, and the phase of the obtained spectrum is the initial phase, but the author's simulation and application of this method only involve a few simple frequency points, and did not discuss Performance of spectral correction over a wide frequency band

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