Multi-frequency uniformization carrier slope random distribution pulse width modulation method

Abstract

The invention discloses a multi-frequency equalization carrier slope random distribution pulse width modulation method to increase the equivalent bandwidth of symmetrically distributed harmonics centered on multiple carrier frequencies to realize the increase of the uniform distribution of the harmonics in a frequency domain. The method comprises steps of (1) selecting a required random carrier sequence and a modulated wave and comparing the two to generate a switching device driving signal for pulse width modulation; (2) determining a multiple n of an equivalent carrier frequency f of the random carrier sequence and selecting a main circuit topology; and (3) inputting the switching device driving signal generated in the step (1) to the main circuit topology in the step (2) and performingmulti-frequency equalization carrier slope random distribution pulse width modulation. The method of the invention can greatly improve the frequency domain distribution bandwidth of the harmonics without changing the mean and variance of the random carrier sequence, and realize the more uniform distribution of a plurality of harmonic peaks near the carrier and the multiplier thereof in a wider frequency domain.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and specifically refers to a multi-frequency multiplier uniform carrier slope random distribution pulse width modulation method. Background technique [0002] In power electronics technology, pulse width modulation technology with fixed switching frequency has been widely used, but its output harmonics have a large number of peaks near the switching frequency and its multiplier, and these harmonics are the main cause of noise and mechanical vibration. [0003] Researchers often achieve the purpose of suppressing electromagnetic interference, vibration and noise reduction by adding filters and vibration and noise reduction equipment. The disadvantages of these methods are obvious, such as the high cost of the active filter, the complexity of harmonic detection and compensation; the slow dynamic response of the passive filter, and the poor filtering effect on the fast changing process; th...

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Problems solved by technology

[0007] The purpose of the present invention is to solve the problem that the output harmonic of the random pulse width modulation technology has a prominent maximum single harmonic spectrum amplitude and dense distribution of harmonic spectral lines near the low multiple carrier frequency, and proposes a multiple Frequency equalization carrier slope random distribution pulse width modulation method; this method combines the principle of "equivalent carrier frequency doubling" in carrier phase shift pulse width modulation and carrier slope random distribution pulse width modulation technology, which can be used without changing the random carrier Under the premise of sequence mean and variance, the frequency domain distribution bandwidth of harmonics is greatly improved, and multiple harmonic peaks near the carrier and its multiplier are evenly distributed in a wider frequency domain

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