Voltage balancing method for a seven-level stacked multicell converter using reduced switching transitions

This paper proposes a voltage balancing method for a seven-level stacked multicell converter (SMC) based on phase disposition pulse-width modulation (PD-PWM) using reduced switching transitions. This method is called optimal-transition voltage balancing method. The selection of the optimal transition sequence is performed by minimizing a cost function and the transitions that would result in more switchings of the converter semiconductor devices are avoided. The simulation results show a significant reduction of the average switching frequency as compared to the use of the optimal-state voltage balancing method, while maintaining the balance of the FC voltages. Moreover, the proposed PD-PWM voltage balancing method is robust to unbalanced linear loads, non-linear loads and transients.