Sensorless observation of a very-high-speed permanent magnet synchronous machine

For optimally efficient control of a high-speed PM machine, continuous accurate information of the rotor position is necessary. At very high speeds, however, measurement of the rotor angle is difficult and/or expensive. This paper uses a solution of a sensorless observer based on a linear quadratic estimator combined with a phase locked loop. The sensorless observer is thoroughly analyzed and implemented for the use in a vector controller of high-speed permanent magnet synchronous machine for a micro-CHP application. The analysis contains robustness and stability analysis. The influence of delays in the control loop is accounted for in the observer. Measurements performed on a test setup show very good performance of the observer in tracking rotor speed and position. The sensorless vector controller show better output performance than the same controller relying on a Hall-sensor signal.