Sensorløs kontrol af permanent magnet motorer / Sensorless control of permanent magnet electric machines

This PhD project is a part of the Danfoss Professor Programme. Permanent magnet motors exhibit high efficiency and great power density and are very good alternatives to induction motors. Permanent magnet brushless DC motors (With trapezoidal back EMF) and permanent magnet synchronous motors (With sinusoidal back EMF) are the main two types of permanent magnet motors. This PhD project deals with control of Interior type Permanent Magnet Synchronous Motors (IPMSMs) without using a shaft mounted position sensor. Since high dynamic performances are not essential for the drives for some applications, considerable attention will be paid to the open loop speed control strategies. These open loop speed control strategies should incorporate solutions for the open loop instability of IPMSMs in high speeds. Vector control using estimated rotor position is another sensorless control solution for IPMSMs. This technique will also be studied in this project. The performance of the open loop control strategy and the sensorless vector control strategy will be compared. To verify the results of this project, tests are carried out on a laboratory test system. (P. D. Chandana Perera, Frede Blaabjerg, John K. Pedersen; Paul Thøgersen, Danfoss Drives A/S)