Modeling and deterministic robust control of a three-phase four-switch PWM voltage-source rectifier based on direct power control

摘要

This paper proposes a mathematical model of the three-phase four-switch pulse width modulated (PWM) voltage-source recti??er (VSR) based on direct power control (DPC). The derived model has the advantages of specific physical meaning, more versatile and precise, and most nonlinear control strategies of six-switch VSR could be utilized for four-switch VSR. By analyzing the proposed model, the dynamic of voltage difference between the two capacitors is considered a second-order dynamic. A compensation algorithm is applied to arrange its transition process to balance the voltage of the two capacitors. The filter inductors may be uncertain and the grid angular frequency changes slowly. That would lead to undesired high-order dynamic which generates more harmonics and affects the stability of the system. Deterministic robust control (DRC) is introduced to provide affordable performance under the dynamic of uncertain nonlinearities or above-mentioned parameters uncertainty. Test result shows the deterministic robust control based on proposed model is of excellent performance and robustness.