Fuzzy logic based control system for cascaded H-bridge converter

In this paper a simple and effective control system for a Cascaded H-Bridge (CHB) converter is proposed. The proposed control system utilizes the square of the capacitor voltages as the control variable for the voltage control loops. Therefore, the individual capacitor voltage control loop and the cluster voltage control loop are completely decoupled without adding any complexity to the system. A fuzzy logic control system is proposed to regulate the individual capacitor voltages of the cells while a proportional-integral controller is used for the cluster voltage control loop. The operation of the proposed control system is verified using simulations and experiments on a single-phase 7-level CHB converter based STATCOM.