A New Hybrid Control Strategy in Flux-Weakening Region for High Performance Traction IPMSM

This paper investigates a novel hybrid flux weakening (FW) control scheme for interior permanent magnet synchronous motor (IPMSM) drives operating in a wide DC-link voltage range. Due to possible fluctuations in the motor parameters or considering dc-link voltage variation, the available voltage margin can be really too small and therefore the dynamic performance is degraded. One of the main objectives of the proposed FW regulator is to maintain the modulation index within a certain range, in order to exploit most of the battery voltage and minimize the losses and total harmonic distortion (THD) of the power converter. To control the motor in the FW region the proposed method exploits a hybrid control strategy based on a feed-back voltage controller feeding a virtual DC voltage variation into a DC-voltage, torque, and speed dependent look-up table (LUT) which sets the optimal current references also considering variable motor inductances.