Masaki Hano

Position sensorless control method at zero speed region for permanent magnet synchronous motors based on block commutation drive

A new position sensor-less method has been developed for permanent magnet synchronous motor (PMSM) drives in zero speed regions. This method utilizes the induced voltage caused by magnetic saturation (IVMS) of PMSM. The rotor position can be detected by IVMS. Furthermore, we introduce a bi-polar pulse modulation to the zero-speed region. By this modulation, both the normal and reversal direction IVMS can be detected and the bi-direction drive achieved. The principle of the proposed method and the experimental results are discussed in this paper.

All-speed-range drive for surface permanent magnet synchronous motors by combined use of two position sensorless methods

A new position sensorless method is proposed for surface permanent magnet synchronous motors in all speed regions. In this method, two sensorless methods are switched in accordance with the rotating speed. In low speed regions, an Induced Voltage caused by a Magnetic Saturation (IVMS) based method is used. This method is switched to a back EMF based sinusoidal current method at a medium or high speed. Some control blocks are commonly used for both methods. Therefore, the methods can be switched smoothly and rapidly. The basic idea and the experimental results are described.