Indirect controller application on cascaded H-bridge rectifier

This paper investigates the feasibility of indirect controller for a cascaded H-bridge rectifier. Using this method, the converter can connect directly to the medium voltage levels and eliminates the necessity to current sensors. In order to have a good approximation to the real current and to improve the converter performance, the dynamics of output capacitors are entered to the PWM procedure. In this study, the controller is designed to maintain voltage balance among different H-bridge cells, even if the attached loads to the dc links are different. The controller should also program the input current to be sinusoidal and in-phase with the input voltage. The performance of the controller is verified by different simulations on a 7-level cascaded H-bridge rectifier, in Matlab/Simulink environment.