ABSTRACT

Dynamic modelling of a DC-DC chopper for improved performance is carried out. Modern power electronic systems require high quality, small, lightweight, reliable and efficient power supplies. High frequency (HF) electronic power processors are used in the direct current to direct current (DC-DC) power conversions for functions such as: conversion of DC input voltage to DC output voltage; regulation of the DC output voltage against load and line variations; reduction of voltage ripple on the DC output voltage below the required level; provision of isolation between the input source and the load; and protection of the supplied system and the input source from electromagnetic interference. Two controller types of Class A DC-DC choppers have been presented using two basic element (thyristor and Metal oxide silicon field effect transistor or metal oxide semiconductor field effect transistor (MOSFET) with difference converter configurations – half, semi, full, and dual arrangements- with a view to ascertaining ones with better performance. These configurations were studied and results obtained from implemented model in Simulink MATLAB. Model for DC drive used in the proposed system in form of Laplace transformation equations which was equally implemented in MATLAB/Simulink was presented. Brief comparisons between thyristor-based and MOSFET-based controllers showed thyristor converters consistently showed higher revolutions per minute (2230) and speed, but lesser efficiency in terms of speed control. However, MOSFET-based controllers showed greater efficiency in speed control but lower revolution per minute (1520), implying better speed control between actual and reference speed.