Hybrid position observer of IPMSM with online rotor flux identification

A hybrid rotor position observer with online rotor flux identification was proposed for interior permanent magnet synchronous motor (IPMSM) sensorless drive system. To achieve wide-speed-range operation, rotor position was estimated using pulsating high frequency injection (HFI) at low-speed-range and model reference adaptive system (MRAS) based method at high-speed-range. The hybrid position observer requires accurate motor electric parameters, but the rotor flux is inconvenient to measure. To settle this problem, the rotor flux was identified based on the simplified stator voltage equation in low speed region, and the identification result was used for position estimation at high-speed-range. At last, the two rotor position estimation algorithms were combined with the rotor flux identification method, constituting a hybrid rotor position observer used for wide-speed-range operation. Experiments were conducted with low-cost DSP, experimental results show the validity and practicability of the constructed hybrid rotor position observer.