Dynamic overmodulation in the synchronous reference frame for IPMSMs

Overmodulation is frequently required during the transient interval at high speed operations of interior permanent magnet synchronous motors (IPMSMs). In this work, an overmodulation method is developed in the synchronous reference frame with a provision of assigning different priorities to d and q-axes currents. During the current boosting in motoring, the d-axis current is increased by priority to minimize the overmodulation period. However in the regeneration process, the q-axis current is decreased by priority during a load reduction. Simulation and experimental results show that the proposed method, compared with the existing minimum-phase error method, in shortening the overmodulation period.