Implementation of Improved Control Strategy of DC-AC Converter using Delta-Sigma Modulator

Abstract

This Chapter presents a comparative study between two current control techniques, namely, conventional Delta Modulator and novel Delta-Sigma Modulator. The use of Delta modulator in variable speed drives poses a problem of noise while converting analog signal in to digital form; to optimize Pulse Width Modulated (PWM) inverter waveforms on-line without any optimization process. But in the Delta-Sigma Modulator the noise varies. It can be successfully applied to over-sampling digital-to-analog and analog-to-digital data converters, switch mode power supplies and inverters It is easy to implement, smooth inverter operation and provides low harmonics at the inverter output. The comparative study between the above said current controllers has been verified by the MATLAB computer simulation in terms of the high frequency power spectra, average switching frequency, rms current error and total harmonic distortion of load current waveforms. The obtained theoretical results are validated with experimental platform based on TMS320F2812 digital signal processor for effectiveness of the study.