The interest for fractional-slot permanent-magnet (PM) synchronous machines has been more and more increasing in recent years. Particularly attractive is the interior PM (IPM) machine, since it is characterized by two torque components: the PM torque and the reluctance torque. Owing to this feature, the IPM machine is able to operate under flux-weakening conditions, as required by many applications, such as automotive, machine tools, washing machines, and so on. Another feature is that the rotor position can be detected without sensor even at zero speed, by means of techniques based on high-frequency signal injection. The aim of this paper is to investigate the torque components and the sensorless position detection capability of an IPM dual three-phase machine equipped with two fractional-slot windings. These two windings are designed to be supplied by two separate converters, yielding an increase of the fault-tolerant capability of the machine. The analysis and the tests deal with the capability of the machine when it operates under healthy as well as faulty conditions, i.e., when the supply of one three-phase winding set is switched off and only one winding continues to be supplied

The paper deals with the sensorless control of salient-pole Permanent Magnet (PM) synchronous motor drives, using a high frequency injected voltage for estimating the electrical angular position of the rotor. A high frequency speed-dependent ellipse rotating voltage vector is injected to the motor. It generates a high frequency current vector in the estimated synchronous reference frame, that contains information on actual rotor position. This type of estimation technique exploits the anisotropy of the rotor and gives an estimation that is not affected by rotor speed. A recent aspect of the topic intensively investigated is the behaviour of different rotor geometries when subjected to high frequency rotor position estimations and, consequently, the design of sensorless oriented configurations. The reasons of these studies arise from the iron saturation which occurs in the rotor and that modifies and can even cancel rotor saliency and introduces a cross coupling (cross-saturation) between d- and q-axis. This paper experiments the behaviour of two of the principal sensorless oriented rotor configurations and compare the experimental results with those predicted by the finite element simulations carried out during the motor design, in order to validate prediction tools and find out new design hints

No abstract

The paper proposes a new outer-rotor configuration for an SPM starter alternator suited to be incorporated in a sensorless drive. To this aim, the rotor has a ringed-pole structure that has been already demonstrated to be adequate for zero and low speed sensorless position detection by a signal injection technique. The paper presents the machine description and modeling, the design of the sensorless drive control, predicted performance by simulations, measures on the motor, and preliminary drive performance test results.

No abstract