DC-Signal Injection for Stator-Resistance Estimation in Symmetrical Six-Phase Induction Motors Under Open-Phase Fault

Multiphase machines are often chosen due to their enhanced fault tolerance. Six-phase ones especially convenient because they may be fed by off-the-shelf three-phase converters. In particular, those with symmetrical windings offer superior postfault capabilities. On the other hand, estimation of stator resistance is important for purposes such as thermal monitoring and preserving control performance. Resistance dc-signal injection provides low sensitivity parameter deviations compared techniques. It has previously been shown that dc signal can added in non-torque-producing ($x$-$y$) plane a six-phase machine avoid torque disturbances typically arise machines. However, extending this method case an open-phase (OPF) not straightforward, associated current restrictions. This paper addresses induction motor OPF. that, contrast healthy operation, should carefully performed so minimum copper loss, peak phase zero-sequence braking achieved. A solution attains optimum performance all these aspects simultaneously proposed. Adapted controller also presented. Experimental results confirm theory.