Repetitive control-based phase voltage modulation amendment for FOC-based five-phase PMSMs under single-phase open fault

Abstract

This article investigates the most elementary phase voltage modulation (PVM) for a more generic five-phase permanent magnet synchronous motor drive under a single-phase open fault. Most works on this topic are intended for some specific motor types, and in most cases, it assumes the inverter can still be treated as a linear switching-mode power amplifier. This article figures out that due to an oscillating neutral, the phase voltage is unable to be linearly modulated, which is to say the simplest sinusoidal pulsewidth modulation is problematic to fit a newly developed well-decoupled model under single-phase open fault. To this end, a nonlinear transform incorporating the faulty phase voltage is theoretically proposed, which alleviates the influence of oscillating neutral on PVM, and several approaches to cancel the need for phase voltage sensors are comparatively investigated. Accordingly, the PVM with repetitive control and back electromotive force compensation is put forward to fix the “faulty inverter” in practice. Plausible PVM approaches are tested experimentally, and the superiority of the proposed PVM is confirmed by experimental results.