Finite element analysis of shaft eddy currents in high speed asynchronous machines

With high speed drives up to 10000 rpm, the asynchronous machine is designed with four or even two poles. Based on rated frequencies in the range of 60-75 Hz, this leads to an operation with a wide field weakening range. A high performance field oriented control is utilized to achieve an excellent torque control. Thereby, the machine model has to include effects arising from the eddy currents in the shaft. The paper presents finite element analyses of a two pole asynchronous machine with rated power of 440 kW and maximum speed of 10000 rpm. The calculations are focused on the eddy currents in the shaft and their influence on the operational behaviour of the field oriented controlled machine.