The losses in the synchronous machine during converter-fed operation will be detailed in order to minimize losses during operation with a switched power supply. Ideally a new rotor concept will be studied that joins and compromises between the advantages of the DFIG generator during variable speed operation and the synchronous generator at directly connected synchronized grid operation.
By using current controlled magnetization equipment on the rotor, one can achieve better PSS -action from the field winding and also better torque control and response from the SM. The intention is to develop a common action plan for the frequency converter and the rotor magnetization to optimize performance during startup and pumping, but also during synchronized generation. This will be tested with our industry partner.