Title: A predictive algorithm for minimising dead-time distortions in sine-wave VSI with L-C output filter

Authors: Suvarun Dalapati

Addresses: Department of Electrical Engineering, Bengal Engineering and Science University, Shibpur, P.O. Botanic Garden, Howrah 711103, West Bengal, India

Abstract: In many applications, single-phase sine-wave inverters are operated with low-pass filters at the output to deliver a low-distortion sinusoidal voltage to the load. In such cases, it is essential that the output be as close to a sinusoid as possible. However, conventional bridge-type inverters, which must be operated with some dead time, suffer from dead-time distortion problems. This effect distorts the output voltage-waveform from its sinusoidal nature to one having significant amounts of low-frequency harmonics. In such cases, dead-time distortion is minimised by employing some suitable algorithm. This paper presents one such algorithm, predictive in nature, for minimising dead-time distortion in the output voltage of a sinusoidal Voltage Source Inverter (VSI) with L-C filter at the output. The algorithm operates by sensing only the load-current. Performance of this algorithm is verified for a single-phase full-bridge inverter, first by simulations and then via experiments, employing Digital Signal Processors (DSP) based inverter. It achieves THD values lesser than 3% for a wide range of load magnitudes and power-factors.

Keywords: sine-wave VSI; voltage source inverters; dead-time distortion; THD; total harmonic distortion; predictive algorithm; DSP based control; sine-triangle modulation; digital signal processing; simulation.

DOI: 10.1504/IJPELEC.2013.058672

International Journal of Power Electronics, 2013 Vol.5 No.5/6, pp.392 - 429

Accepted: 26 Nov 2013
Published online: 14 Jan 2014 *

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