Improvement of predictive current control performance using on-line parameter estimation in phase controlled rectifier

In phase controlled rectifier, it´s been known that a fast response is achieved by predictive current control without any overshoot. However this current control scheme depends on mathematical relationships between the output current, the firing angle and the power source voltage. While in steady state misinformation of load parameters can cause error between reference current and feedback current. Thus in the predictive current control, an accurate parameter is necessary for attaining zero steady state error. In this paper, load parameters are estimated using least square method of on-line parameter calculation based on digitally sampled instantaneous voltage and current. The flow chart for proposed firing angle calculation algorithm is obtained for the fastest current control performance in transient state. The performance of proposed algorithm is verified through simulations and experiments.