Passivity‐based control of multilevel cascade inverters: High‐performance with reduced switching frequency

Abstract

SUMMARYThis paper approaches the control problem of (buck-type) single-phase multilevel cascade inverters. The main pursued objective is the generation of an output voltage waveform with very low harmonic distortion under reduced switching frequency operation. For developing the proposed controller a pulsewidth modulation-based design is first considered, in order to obtain a continuous time control law, to later on, using quantization arguments, modify it to achieve the reduced switching frequency. Owing to its proved capacity for generating high-performance circuit responses, in the high-frequency step design a passivity-based approach is followed while for the low-frequency one a hysteresis-type scheme is introduced. The usefulness of the scheme is validated via numerical simulations comparing the proposed scheme with a classical PWM-based design.

A novel voltage balance method for cascaded H-bridge rectifier

“…So, it needs no special PI for DC-link voltage balance. In [7], the inherent stability problem of such topology is concerned and passivity-based controller is introduced. Though oscillatory state can be avoided, more calculation is needed, the control method becomes complex greatly.…”