Simple Overmodulation Scheme for Improved Dynamic Performance of IPMSM

In the automotive application, the traction motor is controlled under the voltage-limiting condition due to limited battery voltage. In this paper, it is shown that by simply changing the overmodulation scheme of PWM, the dynamic performance of IPMSM can be improved conspicuously. The current regulator, exploiting cross-coupling nature of dq-axes voltages of IPMSM to secure a voltage margin at q-axis for the rapid regulation of q-axis current, can be easily implemented by the scheme only limiting pole voltages to DC link voltage with 60° DPWM with −30° phase shift clamping. The effectiveness of the proposed method is confirmed by simulation and experimental results.