engleski

Flying Start and Continuous Operation of a Permanent Magnet Wind Generator Based on Discontinuous Currents, Discrete Second-Order Sliding-Mode Observer and Phase-Locked Loop

In wind energy conversion systems of type 4, the critical operating point in permanent magnet generators (PMGs) is the moment of switching-on the generator-side converter (GSC). The induced back-electromotive force acting on PMG terminals can cause inrush currents if the synchronization between PMG and GSC is not carried out well. The main condition for achieving a satisfying synchronization process is to know the rotor angle, the rotating speed, and the induced back-EMF before the GSC is switched on. This synchronization process together with the switching-on of the GSC is called the flying start of a PMG. In this paper, a novel sensorless PMG flying start method is proposed in order to ensure good synchronization. The flying start method is based on an extended flux PMG model in a rotating reference frame with a discrete second-order sliding-mode observer and a phase- locked loop controller during the discontinuous operating mode. This is based on discontinuous currents which are induced because of the PMG rotation caused by wind energy. The proposed method ensures the operation of PMGs in the continuous operating mode as well. The effectiveness of the proposed method is verified on saturable models of low- and high- power surface and interior permanent magnet generators through simulations in Simulink and PLECS.

Permanent magnet generators (PMGs) ; wind power generation ; sensorless drives ; sliding mode observer ; phase locked loop

nije evidentirano