Compensation of control delay and discrete control error in predictive direct power control for three-level PWM rectifier

Abstract

In three-level pulse width modulation (PWM) rectifier, the performances of the conventional predictive direct power control (PDPC) method are seriously degraded by the one-control-period delay and the discrete error of control variables. This paper investigates the problem by evaluating the influences of the control delay and the discrete control error on the performances of the system, and proposes a novel three-level PDPC method with compensation of control delay and discrete control error. An instantaneous power predictor is designed to compensate the control delay. Optimized prediction and control equations are deduced considering the variations of grid voltages during one control period in order to improve the control precision. Simulation and experimental results prove that the proposed three-level PDPC strategy achieves excellent steady-state and dynamic performances.