ON ANALYSIS OF BRAKING OF CONVERTER FED DC MOTOR DRIVES

Abstract

Electric motor drives require reliable and accurate braking to decelerate and stop the load. Thus Braking is an important area in today's world, when majority of traction work is done by electric motors. With high volume of d.c.motors involved in traction purposes it becomes more important to have proper braking of D.C. Motor Drives. Converter fed DC Motor Drives are most commonly used .Dynamic Braking and Regenerative Braking are the primary modes of Braking. However, Dynamic Braking is not considered to be efficient. The proposed analysis with variable dynamic braking resistor block utilizes the maximum braking torque capability of the drive, keeping braking current constant and thus braking time is reduced considerably. For Regenerative Braking, a chopper controlled braking is used. The analysis proposes that there are upper and lower limits of duty ratio of chopper between which energy recovery is possible else not and efficiency of energy recovery depends on the duty ratio of the chopper