New nonlinear control of three-phase NPC boost rectifier operating under severe disturbances

This paper proposes a new nonlinear control of three-phase three-level neutral point clamped (NPC) boost rectifier operating under severe disturbances. The nonlinear control strategy is employed to take into account the essential nonlinearities of the system and it totally differ from the common approach of linearizing the nonlinear system around a nominal operating point. In order to apply this technique, a nonlinear state-space mathematical model of the rectifier is developed. An input/output feedback linearization is then designed and the linearizing control law is derived. The resulting model is linearized and decoupled. Afterwards, the stabilizing controllers are designed based on linear techniques to control power factor, output and neutral point voltages. This control uses a 3kHz pulse width modulator (PWM). Simulation results are performed using Simulink/Matlab and PSB tool. The controllers’ performance has been evaluated under diverse parameter variations and input and output disturbances. A low output voltage ripples and line-current THD and also a small overshoot and a fast settling time are obtained.