Identification of D–q inductances and initial rotor position in high-speed motors for fuel-cell air compressors in consideration of voltage distortions

Abstract

Position sensors are challenging for high-speed motors because of mechanical issues, such as vibration and heat. When the motor’s initial position is unknown, startup failures or temporary reverse rotation can occur. Reverse rotation may cause minor damage to an air-foil bearing, reducing its durability. An initial position estimation algorithm for high-speed motor drives is needed to address this issue. Furthermore, implementing current controllers and sensorless control algorithms requires knowledge of the motor’s electrical parameters. This study presents a method to estimate dq-axis inductances and the motor’s initial position. The inductances are determined in consideration of the voltage distortion caused by the inverter nonlinearity. Moreover, because the inductances can be estimated at low voltage levels, the risk of rotor movement during the estimation process is minimized. Simulation and experimentation on a 120 krpm high-speed motor for fuel-cell systems confirm the effectiveness of the proposed method.