Input-output linearization and generalized PI control of a single-phase active multilevel rectifier

A two stages robust Generalized PI feedback controller for a single-phase active multilevel rectifier is proposed. The controller is based on the system modeled in the d-q synchronous reference frame. Based on input-output linearization theory a current controller that decouples the d-q components and compensates unknown perturbations is obtained. Performing a transformation of the system, stability of zero dynamics is verified. Due to the fact that the internal dynamics contains variables of interest; an external control loop by means of a Generalized PI controller connected in cascade with the current loop in the d-axis is designed to regulate its behavior and compensate an unknown load demand. This control scheme achieves fast regulation of the DC voltage without steady state errors, high power factor, low harmonic content and robustness in face of unknown perturbations. The presented control scheme is tested by simulations on a switched model.