Model Predictive Based Direct Power Control Method Using Switching State Preference for Independent Phase Loss Decrease of Three-Phase Pulsewidth Modulation (PWM) Rectifiers
Minh Hoang Nguyen, Sangshin Kwak, Seungdeog Choi
Abstract
Nowadays, active rectifiers are increasingly used, particularly in grid-connected applications. The high efficiency and reliability of active rectifiers become crucial for increasing the system performance. Due to the lack of model predictive control methods considering the different aging levels among phase legs of rectifiers, this paper thus introduces a direct power control-based model predictive control for independent loss reduction in each phase of the active rectifier. Different from conventional techniques, the target of proposed model predictive direct power control scheme is lowering switching loss in the leg having highest aging level of active rectifier, resulting in increasing its corresponding lifetime and lifetime of entire rectifier. As opposed to the model predictive control method based on incorporating additional terms regarding switching loss in the cost function, a switching state preselection strategy is proposed in this study to determine clamping region and corresponding preselected switching state for the leg having highest aging level of active rectifier. The use of the proposed method lowers thermal stress in the leg having highest aging level and increases lifetime of active rectifier. Simulation and experimental results for the proposed technique are presented and compared with conventional model predictive direct power control method to validate the accuracy and feasibility of the proposed method.