Hybrid sensorless control of IPMSM for direct drive applications

This paper presents a new hybrid sensorless control of interior permanent magnet synchronous machines (IPMSM) for direct drive applications. The control combines both high frequency injection and back EMF based method, and realizes position, speed, and torque control in the entire speed range. Owing to the reliability and the space-saving feature, the sensorless control is applied to direct drive applications with great expectations. As successful applications, an injection molding machine and a compressor are introduced in this paper. In each application, the optimally designed IPMSM for the sensorless control is employed. The design concepts of the application specific machine considering the control performance are also introduced. Experimental results show the effectiveness to the required specification of the control modes.