Optimum digital control of PWM rectifiers

The paper presents an optimum digital control technique suitable for three-phase PWM rectifiers with a capacitive filter in the DC link. The proposed technique is based on a predictive current control loop, which does not need line voltage sensing and results in minimum RMS current absorption and unity power factor in any operating condition. Moreover, a smooth transition from sinusoidal to square-wave operation is provided and calculation delays are compensated. The control algorithm has been implemented on a INTEL 80C196KC microcontroller and tested on a 2.5 kVA prototype. Some experimental results are reported together with a description of the implemented algorithms. >