Dependence of Zero-Sequence Voltage Measurements on Static Eccentricity of PMSMs

The impact of the static eccentricity fault on electrical machines has been extensively explored in the literature. Various contributions have provided valuable models, such as the modified winding function approach (MWFA), which effectively characterizes the inductance behavior of an eccentric permanent magnet synchronous machine (PMSM). Recently, a comprehensive solution for the MWFA formula has been published, presenting an analytical expression for the machine's phase inductances and their harmonic components. Building on this achievement, the presented study investigates how static eccentricity influences the measurements obtained from a sensorless technique reliant on zero-sequence voltage, such as direct flux control (DFC). DFC offers highly consistent and precise inductance-dependent measurements, rendering it a viable option for designing fault detection techniques. In this study, a mathematical model is formulated to analytically describe DFC measurements for an eccentric machine in order to investigate its viability for eccentricity detection. Subsequently, experimental results are provided and analyzed.