A Two Stage AC-DC Converter for Speed Control of a DC Motor

In this paper a AC-DC converter has been proposed for the application of speed control of a DC motor. The converter comprises two stages. The first stage is the diode bridge rectifier and the second stage is DC-DC buck converter. The two stages are coupled by a dc-link capacitor which also eliminate the ripple present in the output of the rectifier. For DC-DC buck converter, a feedback control system, based on PWM technique, has been designed which regulates its output to control the speed of dc motor. The prototype model has been designed and results obtained with it have a closed resemblance with the simulation results which has been done in LTspice software. The results of the simulation and prototype demonstrate that the output voltage of DC-DC converter and hence the speed of the dc motor can be controlled by controlling the duty cycle of DC-DC converter. The results also demonstrate the faster dynamic response of the converters.