A closed-loop I/f sensorless control based on current vector orientation for permanent magnet synchronous motors

To overcome the drawbacks of conventional I/f scalar control method, the limits of the current amplitude and torque angle have been investigated. In this paper, the closed-loop I/f sensorless control strategy based on direct current vector oriented is proposed. The key of this strategy is to integrate the torque angle loop using instantaneous power estimation into the I/f scalar strategy. Thus, the proposed strategy possesses the merits of high current utilization, enhanced reliability, low loss and simple structure. Moreover, it can be applied to both of salient and nonsalient PMSMs. Finally, experiment results are given to verify the validity.