Robustness evaluation of IPMSM sensorless control to magnetic saturation using un-known input observer

This paper proposes a new position sensorless control for Interior Permanent Magnet Synchronous Motor(IPMSM) drives fed by over-modulation mode PWM voltage source inverter. Over-modulation mode PWM voltage source inverter makes it possible to solve some problems such as efficiency, wide speed range operation and so on. Most position sensorless control based on inverter output voltage knowledge, however, cannot directly be utilized because voltage reference obtained by the controller is not equal to inverter output voltage. This paper proposes un-known input observer to estimate rotor position without voltage knowledge, and investigates robustness to inductance variation.