Design and implementation of four quadrant DC drive using chopper

The speed of separately excited DC motor can be controlled from 0 to rated speed using chopper. The chopper firing circuit receives signal from controller and the chopper responds by providing variable voltage to the armature of the motor for achieving desired speed. There are two control loops, one for controlling current and another for speed. The controller used is Proportional-Integral type which ceases the delay and provides fast control. In this way, the Modelling of separately excited DC motor is done. After obtaining the complete model of the system, it is simulated using MATLAB (Simulink) in open loop. The simulation of DC motor drive is done and analysed under various speeds and load torque conditions. The above simulated model will be implemented as applicable to hybrid Electric Vehicles (HEV´s) in open loop working in all the four quadrants of operation as per voltage verses current plot. The IGBT´s are triggered by pulse width modulation (PWM) technique. Recent HEV´s employ a complex control system which involves the vehicle to work on electric motor till the speed is appreciable to switch over the control of the vehicle to the IC engine, where the vehicle is driven by the IC engine. The speed limits depend on the efficiency of the IC engines in the initial gears i.e. first and second gear. Therefore in the above context, the four quadrant operation is designed to operate at speeds from 0 to 700rpm (0 to 100kmph).