Performance Analysis of a Direct Current Motor Speed Control using Single-Phase H-Bridge Thyristor Rectifier

Abstract

Direct Current (D.C.) motor is an important drive configuration for many applications that is required in automation movements. Thyristors are used to regulate the supply voltage in order to control the speed of the direct current motor. Thyristors have problem of overheating during installation hence, the need for a better cooling means via heat sink which reduces the heat level of the semiconductor for proper performance and good efficiency of the system. The aim of this research is to analyze the performance of a direct current motor speed using Thyristor. Armature Voltage Control method is applied in which voltage supply to the armature winding of the direct current motor is regulated in order to vary the speed of the DC motor. The circuit is modelled in MATLAB/Simulink. Mathematical model is used to model a separately excited D.C. motor of capacity of 5HP (3.78kW), with a rated voltage of 240V and rated speed of 1750RPM. The speed of the DC drive is controlled by regulating the armature voltage. Armature voltage is regulated using different 1-ϕ AC/DC converters. Some of the Thyristor-based circuits that are utilized for controlling the speed of a DC motor are the half converter, semi converter, full converter, and dual converter. Results obtained are presented on tables and corresponding graphs which are used for proper analysis of the system. This is accomplished through the use of power semiconductor unit. Finally, the study carried out shows that a Thyristor can be used in controlling the speed of a direct current (D.C.) motor.