Comparative study of model predictive control and direct power control for PWM rectifiers with active power ripple minimization

Direct power control (DPC) and model predictive control (MPC) are two well known methods to achieve direct control of active power and reactive power in PWM rectifiers. They both select a voltage vector, according to a switching table or by minimizing a cost function, and then apply it in the next control period. The use of only one voltage vector during one control period leads to high power ripples and variable switching frequency, especially in DPC. Recently duty cycle control was proposed in DPC to achieve steady state performance improvement. This paper proposes an improved MPC with duty cycle control and compared it to prior DPC with duty cycle control in terms of power ripple reduction, dynamic response and robustness against external load disturbance. The duration of the selected vector is determined by minimizing the active power ripple during one control period. Simulation and experimental results are presented to confirm the theoretical study.