Rotor position estimating method for e.g. three phase linear permanent magnet synchronous motor, involves determining component of signal varying with position of rotor of machine, and determining position of rotor from component

摘要

The method involves injecting a high frequency signal (Us) in a winding of a permanent magnet synchronous machine that is not provided with ferromagnetic materials, by using a high frequency signal generator. An induced signal i.e. voltage (Ui), is determined at a neutral point (N) of the machine. A component i.e. amplitude, of the signal varying with position of a rotor of the machine based on anisotropic properties of a permanent magnet of the machine is determined from the induced signal. The position of the rotor is determined from the signal component. An independent claim is also included for a device for estimating position of a rotor in a permanent magnet synchronous machine, comprising a high frequency signal generator.