Design of a sinusoidal current source using a sliding-mode-controlled asymmetrical full-bridge multilevel converter

An analysis and design of an asymmetrical full-bridge multilevel converter in sliding-mode operation for inverter applications in small power systems are presented. A five-level sinusoidal current source inverter is proposed with the lowest number of controllable devices and the simplest control electronics. The current source nature of the inverter is achieved by means of a sliding-mode control loop forcing the inverter output current to track a sinusoidal reference. The theoretical predictions have been verified by experiments in a 1 kW prototype in both stand-alone and grid connection operations.