Direct flux control of interior permanent magnet synchronous motor drives for wide-speed operation

This paper describes a novel speed and torque control strategy based on direct flux control (DFC) for interior permanent magnet synchronous motors (IPMSM). The principle of this method of flux and torque control lies in controlling the stator flux vector trajectory. The stator flux vector calculator achieves dynamic control of stator flux providing a fast build up of torque. The torque regulator limits the torque reference and prevent the current exceeding the limitation. Important features of the proposed scheme are no current controllers, constant switching frequency and less dependance on machine parameters. The experimental results verify the effectiveness of the proposed scheme. It operates well not only in the constant torque range but also in the flux-weakening range. The dynamic response in step speed and torque command for proposed strategy is faster than conventional current control scheme used in IPMSM drives.