Sensorless control of the axial flux permanent magnet synchronous motor at standstill and at low speed

Abstract

The paper presents a simple sensorless method, which can be used at standstill. Therefore method can be used to determine initial poles position of the axial flux permanent magnet motor. Moreover presented method can yield rotor position at low speed. An appropriate speed range for the method is limited. The paper shows the way of extend that speed range. Identification of rotor position is provided by current responses which are result of the single test voltage step. This paper deals with theory of the method confirmed by laboratory results on experimental set with 40 kVA / 16 poles / 3000 rpm axial flux permanent magnet motor.

Sensorless position identification of permanent magnet motor by zero voltage vector

“…This method can be used to detect only an initial rotor position. Combining the PIPCRM method with zero voltage vector method, the speed range has been extended [6].…”

Permanent magnet disk generator with coreless windings

“…The biggest drawback is a need of use stronger magnets to obtain the same power like in conventional iron-core machine which is the reason of higher reluctance of magnetic circuit. Besides some sensorless control methods cannot be applied in this topology (Wiśniewski and Koczara, 2009). For analytical discussion, magnetic circuit of this machine can be simplified to four magnets -two on first rotor disk and other two on the second disk.…”