Analytic modelling and realisation for sigma-delta-modulated power amplifier

作者:Hsieh G C*; Chen H L
来源:IET Power Electronics, 2009, 2(5): 496-507.
DOI:10.1049/iet-pel.2008.0077

摘要

A sigma-delta-modulated (SDM) power amplifier implemented by a simple cycle-by-cycle integral control is presented. The SDM pulse train for simulating the input signal is polarity-dependent. There is a leading negative bit pulse followed by a positive pulse for the train pulse formation converted from a positive input amplitude, or, a leading negative pulse followed by a positive bit pulse formed from the negative one. Analytic modelling to describe the signal conversion and system analysis is conducted thoroughly The proposed conversion strategy provides group-mode harmonics randomly scattered over the spectrum with low amplitudes for reducing the EMI problem. An experimental demonstration to verify the performance of a 1 kVA SDM AC power amplifier is conducted. The resulted efficiency is up to 90% and the total harmonic distortion less than 2% before the EMI filtering.

  • 出版日期2009-9