Study on three-level PWM rectifier based on space vector pulse-width-modulation

The neutral-point-clamped three-level PWM rectifier topology is studied in this paper,and the decoupled state-space equations in synchronous rotating reference frame(d-q frame) are derived.The hierarchical controller structure is adopted,namely,the inner current-loop is responsible for reference current tracking and the outer voltage-loop is responsible for load regulation.The design methodologies for proportional-integral(PI) controllers are presented,for the inner current-loop and outer voltage-loop,respectively.The proposed three-level PWM rectifier based on space vector pulse-width-modulation(SVPWM) strategy is simulated using MATLAB/SIMULINK.Simulation results demonstrate that the proposed three-level PWM rectifier provides excellent performance both in steady-state and dynamic load variations.Besides,pure sinusoidal waveforms can be achieved in grid currents with a unity power factor.