This paper presents an implementation and experimental investigation of sensorless speed control schemes for a variable-speed permanent magnet synchronous motor (PMSM) in super-high speed (>50000 rpm) applications. A very wide speed range (500-100000 rpm) and extremely low stator impedance of the motor demand very special requirements to the associated power converter and control algorithms. Position sensorless control is necessary because it is difficult to measure the rotor position by reliable position sensors. A testing system for super-high speed PMSM operation has been built and the feasibility of open-loop control modes has been examined. A closed-loop sensorless vector control scheme has been developed in which a self-tuning rotor position observer and an adaptive flux-weakening scheme are included. Experimental results of both open- and closed-loop schemes operating up to 60000 rpm are presented.