Experimental Setup for the Evaluation of the Duty Cycle Influence over the Distorting Regime

Abstract

This paper deals with specific aspects related to the PWM supplying of a load that consists of a uncontrolled rectifier, filtering elements (a coil and capacitor), a chopper with MOSFET and a DC motor. An original experimental setup was conceived. It allows the study of the influence exercised by a simple PWM technique's operational parameter (namely the duty cycle) along with the LC filter over the harmonic distortions of the waveforms acquired from the load terminals. Various operational contexts were addressed. The MATLAB/Simulink package was employed in order to design, simulate and implement the algorithm used in the control side. An interface relying on ControlDesk was conceived. Afterward, the algorithm was implemented in a real time setup by using the dSPACE controller board. An analysis of certain power quality indices (power factor, THD and distorting power factor) was made and conclusions were drawn.