Logic‐based space‐vector modulation for neutral‐point‐clamped multilevel inverter with DC‐link voltage balancing capability

Abstract

This study proposes a new simple and fast space-vector modulation scheme with the capability of balancing capacitor voltages in neutral-point-clamped converters. In the first step, transformations from the commonly used reference frames to the 60°-frame are discussed. Next, a new method is presented to generate an appropriate switching sequence based on the voltage of the clamp point and direction of the phase currents. The proposed method is computationally efficient and its algorithm only needs knowledge of the load current directions, leading to further simplification of the hardware. This method can easily be generalised to control diode-clamped multilevel inverters with an arbitrary number of levels. The feasibility, effectiveness, and performance of the method are investigated through simulation and experimental studies under various load conditions.