An Improved Virtual Signal Injection Control of MTPA for an IPMSM

An improved virtual signal injection based-maximum torque per ampere (MTPA) control method for interior permanent magnet synchronous motor (IPMSM) is proposed in this paper. A small square wave is mathematically injected into the current angle to help to obtain the MTPA indicator (the gradient of torque with respect to the current angle). Compared with the existing virtual signal injection based-MTPA control method, the proposed one updates MTPA indicator in each control period, which simplifies the implementation and enhances the dynamic and steady-state performance. The effectiveness of the proposed method was verified by simulation and hardware-in-the-loop test.