Comments on “A Performance Investigation of a Four-Switch Three-Phase Inverter-Fed IM Drives at Low Speeds Using Fuzzy Logic and PI Controllers”

A recent paper by M. Zaky & M. Metwaly (doi: 10.1109/TPEL.2016.2583660) proposed a fuzzy logic controller (FLC) to mitigate the negative effects of motor parameter variation influence on indirect rotor field oriented control (IRFOC) without proposing a tuning method. However, neither rotor nor magnetizing inductances were investigated. Instead, the variation in stator resistance and load inertia—which have less effect on the orientation algorithm—is demonstrated. This correspondence introduces a typical system model with similar simulation platform and parameters. With identical tests, two errors to the original paper have been found. First, the reported speed which is in rev/min should be in rad/s. Second, the motor speed response to increasing inertia is opposite. The obtained results from the evaluation model confirm the claimed issues which conflict with the interpretations of the commented paper results.