Maximum-Torque-Per-Ampere Control of Interior Permanent Magnet Synchronous Machine Applied for Hybrid Electric Vehicles

Permanent magnet synchronous machines are known as a good candidate for hybrid electric vehicles (HEV) due to their unique merits. According to the characteristic that d,q-axis inductances are not equal in interior permanent magnet synchronous motors (IPMSM), this paper introduces a maximum- torque-per-ampere (MTPA) control scheme, which can get a larger torque output under certain current condition. A relationship about the minimum d, q- axis currents required under certain torque output is derived by the maximum principle. In same capacity, relative to i_d=0 control, this method can significantly improve the low-speed torque and dynamic performance of the system. Moreover, the inductance saturation effect is considered, and an approximate algorithm for engineering applications is presented and applied to engineering practice. Finally, Experimental results verify the effectiveness and engineering practicability of the proposed approach.