An Inter-Turn Short-Circuits Fault Detection Strategy Considering Inverter Nonlinearity and Current Measurement Errors for Sensorless Control of SPMSM

Aiming at the misdiagnosis problem of the interturn short-circuit (ITSC) fault detection method caused by the inverter nonlinearity and the current measurement errors, a d-axis residual voltage-based fault diagnostic strategy is proposed for sensorless control of the surface permanent magnet synchronous motor (SPMSM). The model of the three-phase wye-connected SPMSM with ITSC fault is established, and the expression of the d-axis residual voltage caused by the ITSC fault, the inverter nonlinearity, the current measurement errors and the motor parameter errors is derived. The proposed fault diagnostic strategy can eliminate the current relative gain coefficient error and locate the ITSC fault by using the eighth and second harmonics of the estimated d-axis residual voltage, respectively. The experimental results verify the effectiveness of the proposed fault diagnostic strategy.

I. Introduction

Sensorless control is a major area of interest within the field of the permanent magnet synchronous motor (PMSM) control [1]. The interturn short-circuit (ITSC) fault not only increases the current and temperature of the short-circuit coil, accelerates the damage of the winding insulation, but also increases the position estimation error, affects the performance and the reliability of the PMSM sensorless control. Therefore, it is important to perform the early fault diagnosis to minimize the risk of catastrophic faults [16].