On-line improved inverter waveform by variable step delta modulation

Abstract

This paper presents a new technique using delta modulation for inverter operation. Delta modulation (DM) schemes have the ability to optimize pulse width modulated (PWM) inverter waveforms online. The tuned and the multi-integrator DM are the two schemes proposed for PWM waveform synthesis so far. The methods were found useful for variable speed PWM inverter-fed AC drives. However it was observed that during tuning and filtering process, fundamental output voltage of the inverters reduced. With an aim to overcome this effect, a new technique called the variable step rectangular wave delta modulation (RWDM) is proposed. The method has the capability to maintain a near constant fundamental voltage of the output waveform of the inverters. Both analytical and experimental verifications are carried out for tuned and variable step RWDM Author(s) Chowdhury, A.H. Dept. of Electr. & Comput. Eng., Texas Univ., Austin, TX, USA Mansoor, A. ; Choudhury, M.A. ; Rahman, M.A.