Implementation of sensorless vector control for super-high speed PMSM of turbo-compressor

This paper describes the implementation of vector control schemes for a variable-speed 131 kW PMSM (permanent magnet synchronous motor) in a super-high speed application. The vector control with a synchronous reference frame current regulator has been implemented with challenging requirements such as extremely low stator inductance (28 /spl mu/H), high DC link voltage (600 V) and high excitation frequency (1.2 kHz). Because the conventional position sensor is not reliable in super-high speed applications, two different schemes have been proposed to measure the position of the rotor. As a first step, a vector control with three discrete Hall sensors is proposed. Because the discrete Hall sensors give rough position information with a resolution of /spl plusmn/30/spl deg/, a position estimation algorithm is proposed to derive a precise position. A vector control scheme without any position sensor is then proposed. The proposed sensorless algorithm is implemented by processing the output voltage of the PI current regulator, and hence the structure is simple and the estimated speed is robust to measurement noise. An experimental system has been built and the proposed control has been implemented and evaluated with and without the discrete Hall sensors. The test result, up to the speed of 60000 r/min, shows the validity of the proposed control.