Adaptive control of DC link voltage of PWM VSC rectifier under unbalanced voltage source and uncertain parameters

This paper proposes an adaptive variable-structure control scheme for a three-phase PWM converter under unbalanced conditions. The controller regulates the DC output of PWM converter in presence of unknown disturbance and uncertainty in model parameters of the converter. Using differential geometric tools, the system is transformed to a normal form. Then an adaptive control scheme is designed to regulate the output of the transformed system. The stability of the proposed controller is proved using the Lyapunov theory. Simulation results illustrate the effectiveness of the proposed method.