A New MTPA Control Strategy for Sensorless V/f Controlled PMSM Drives

This paper presents a new maximum torque per ampere ( MTPA) control strategy for sensorless V/f controlled PMSM drives. The proposed theoretical basis can be applied to both surface permanent magnet synchronous motor (SPMSM) and interior permanent magnet synchronous motor (IPMSM) drives to obtain high efficiency. Two closed loops are required in the proposed drive. First, by using the oscillatory active power information, a load angle compensation component is generated to adjust the load angle to stabilize the system. Second, the drive imaginary power is regulated to follow the imaginary power of MTPA performance such that the drive can operate under the minimum copper loss condition in the steady state. The imaginary power controller can generate a voltage compensation component to properly adjust the drive voltage. Hence, the demanded MTPA performance is obtained. The provided simulation results show the performance and validity of the proposed strategy. The hardware implementation of the proposed control is now undertaking and the experimental results will soon be shown in the near publication.