1. Riga Technical University,Dep. Electrical Machine and Devices,Riga,Latvia
2. Electromechatronic Systems Research Centre, University of Beira Interior,Covilhã,Portugal
3. Tallinn University of Technology,Dep. Electrical Power Engineering and Mechatronics,Tallinn,Estonia
4. Aalto University,Dept. of Electrical Engineering and Automation,Espoo,Finland