Speed control of series motors by means of thyristor bridges

The behavior of a single-phase gate controlled thyristor bridge supplying a R-L network is digitally simulated. The results are compared with an experiment on the same system to verify the correctness of the digital model. A series motor is digitally simulated together with the digital model of the thyristor bridge. Speed control of the series motor is achieved by controlling the gate signals to the thyristors for delay angles from 60 degrees to 12 degrees for varying load torque. Torque and speed feedback are used to maintain constant speed of the motor for a full load torque step input. The steady state error is less than 0.2% of the no load speed