A New Topology of Low Speed Doubly Salient Brushless DC Generator for Wind Power Generation

The unit machine of the traditional doubly salient electro-magnetic generator (DSEG) has a 6/4-pole structure, so it must have a large number of stator poles when used as a low speed wind turbine generator. The matching relationship between the stator pole number and the rotor pole number of a multi-poles-rotor DSEG is deduced, and a new 3N/4N-pole DSEG is proposed. The magnetostatic field distribution, excitation inductance characteristic, as well as output characteristic of the DSEG is investigated by 2-D and 3-D finite element analysis. Comparisons between the two different structures are presented in terms of power density, voltage ripple and efficiency. A low speed 24/32-pole prototype machine is developed, and the experimental results are given to verify the validity of the simulation analysis and the reasonable structure of 3N/4N-pole DSEG.