A digital predictive current controller for single-phase PWM rectifier

The nonlinear nature of utility rectifiers using power semiconductor injects undesirable current harmonics into the utility supply. This harmonic pollution of the utility supply can cause interference with the operation of other electrical equipment connected to the same utility grid. PWM rectifiers combined with suitable current control techniques are considered as a modern approach for providing rectifiers with low harmonic pollution.; This thesis presents a digital-based fixed switching frequency current control scheme for single-phase PWM rectifiers using a novel slope detective controller. This scheme achieves a symmetrical zero-centered current error by predicting the desired switching times based upon the current error slopes in previous PWM switching cycles. It works independently from circuit parameters variations and has a stable transient response. Simulated characteristics of the proposed scheme are provided and comparisons of the performances with other existing schemes are given to validate the effectiveness of the proposed control scheme.