Position Estimation of Permanent Magnet Synchronous Motor Using Un-known Input Observer

This paper proposes a new position estimation method for Interior Permanent Magnet Synchronous Motor(IPMSM) drives fed by over- modulation mode PWM voltage source inverter. It is being attractive to expand drive region of IPMSM to high speed range for application to electric vehicles, electrical household appliance and so on. Although over-modulation mode PWM voltage source inverter makes it possible to solve above problems, position sensorless drive based on sta- tor voltage knowledge cannot directly be utilized because voltage reference is not equal to inverter output voltage. In this paper, un-known input observer is proposed to estimate rotor position without stator voltage knowledge.