Position Sensorless Control of Interior Permanent Magnet Synchronous Motors Using Unknown Input Observer for High-Speed Drives

This paper proposes a new position sensorless control for interior permanent-magnet synchronous motor (IPMSM) drives fed by overmodulation mode pulsewidth modulation (PWM) voltage source inverter. It is attractive to expand the speed range of the IPMSM for application to electric vehicles, electrical household appliances, and so on. An overmodulation mode PWM voltage-source inverter makes it possible to solve problems such as efficiency, wide speed range operation, and so on. Most position sensorless controls based on inverter output voltage knowledge, however, cannot directly be utilized because the voltage reference obtained by the controller is not equal to the inverter output voltage. This paper proposes unknown input observer to estimate rotor position without voltage knowledge, and investigates robustness to inductance variation.