Study on Mathematical Model and Lyapunov-Based Control for Three-Level NPC Voltage-Source Rectifier

In this paper, the mathematical model of three-level neutral-point-clamped (NPC) voltage source rectifier (VSR) using switching functions is founded firstly, and its operating principle is analyzed. Then a new nonlinear control law based on Lyapunov's stability theory for the PWM rectifier is presented. With this control law, the converter can be stabilized globally for handling large-signal disturbances, and exhibit good transient response. Also, by designing PI controller of DC-link voltage and adding feedforward control of load current, the steady state error of the converter resulting from parameter uncertain can be eliminated effectively. Computer simulations of the system confirm the validity of the mathematical model and the effectiveness of the proposed control strategy