Non-linear control and stabilization of PWM current source rectifiers in the regeneration mode

PWM current source rectifiers are the preferred alternative to phase-controlled rectifiers when power factor and harmonic distortion are of concern. However, these rectifiers exhibit nonlinear characteristics and may become unstable under regenerative conditions, such as are encountered in current source inverter-based AC drives operating in the braking mode. This paper offers a solution to the design of stable and operating point independent controllers. It uses input-output linearization based on a nonlinear state variable feedback approach. Furthermore, an instantaneous power feedforward term is used to stabilize the control system. The theoretical analysis and controller design are presented. Results demonstrate the superior performance of the proposed technique over standard linear controllers.