Accurate Detection of Initial Rotor Position in a Multi-Pole Synchronous Machine

This paper presents a method for initial rotor position estimation of PMSM drive. The method is suitable for salient pole motors, and is accurate even for inductance with non-sinusoidal profile. The main idea of the method is to apply six voltage pulses to the motor and measure the current´s response according to the rotor position. This response is then pretabulated in dependence of electrical angle and stored. Before start up of the drive, the detection algorithm only needs to apply the same six voltage vectors, measure the current´s response and find its closest match within the stored pre-tabulated responses. The proposed approach is computationally simple and very accurate, as it is shown in experimental results.