Control Design Strategy for Flying Capacitor Multilevel Converters Based on Petri Nets

Multilevel power converters belong to a class of hybrid systems, where continuous and discrete variables coexist, representing a challenge for their control design. Flying capacitor multilevel converters require controlling the flying capacitor voltages and the output current. In this regard, several works have studied this problem. However, the discrete nature of the converter has not been directly included in the control design. In this paper, a hybrid representation of the converter is considered, and using Petri net (PN) methodology, a control scheme is proposed to regulate the flying capacitor voltages and the output current. An analysis of stability, using Lyapunov method, is presented, and sufficient stability conditions are obtained. From these conditions, the commutation rules are defined and used to define the transition rules for the PNs. Experimental results validate the performance of the proposed scheme.