A Novel Accurate Filterless Initial Rotor Position Estimation Algorithm for Salient Pole Permanent Magnet Synchronous Machines

The initial rotor position is essential information required to determine the angular position of the magnetic flux in a permanent magnet synchronous machine (PMSM). Accurate control of PMSMs relies on precise knowledge of the rotor flux position. In this paper, a novel estimation method is proposed to detect the initial rotor position of a PMSM at standstill. By applying two types of suitable DC voltage pulses to the stator windings, both the magnetic pole position and magnetic polarity are detected. The proposed algorithm consists of three steps: initial magnetic pole position determination, magnetic polarity determination, and offset angle calculation. This method is robust, easy to implement, and free from filters and their tuning complexities. The functionality of the proposed position estimation algorithm is verified through various simulations using the MATLAB/Simulink platform. The simulation results demonstrate the accurate estimation of the initial rotor position under different operating conditions, making it highly suitable for auto-phasing in variable frequency drives (VFDs).