Investigation of harmonic distortion in line and load currents of the sinusoidal pulse-width modulated single-phase AC chopper

This paper presents the single-phase sinusoidal pulse width modulated ac chopper topology with power MOSFET embedded four-quadrant switch (4QSW) realizations and examines from the power quality viewpoint the potential for its use in ac power control. The examination is conducted for resistive and inductive loads by theoretical estimate of the current harmonic content at the ac utility and load. Sinusoidal pulse-width modulation (SPWM) in the ac chopper provides output voltage with symmetrical half cycles that comprise symmetrical pulses with widths and magnitudes proportional to the amplitude of the sinusoidal reference signal. It has two control parameters; the amplitude modulation index (m) and the frequency modulation ratio (p). MATLAB simulation data and results prove that manipulation of m and p alters the harmonic profile of the line and load currents substantially and, therefore, can be used for harmonic mitigation and selective elimination. Thus, cost-effective and compact current harmonic filters can be designed using the SPWM technique.