Asymptotic MTPF control for high-speed operations in direct torque controlled IPMSM drives

This paper proposes the calculation method of the reference torque to realize high-speed operation for interior permanent magnet synchronous motor drives with direct torque control (DTC). In DTC, high-speed operation can be realized with limiting reference torque including maximum torque per flux (MTPF) control. However, the optimal MTPF control is difficult for DTC. Thus, this paper proposes the calculation method of the limiting torque considering the stable control for DTC, and uses the asymptote of MTPF locus. The proposed method is validated in simulations and experiments.