2017 Volume 6 Issue 6 Pages 370-380
The simple and robust construction of reluctance machines and the fact that they need an unsophisticated control have reignited interest in these machines. The constructional modifications and new configurations such as brushless doubly fed reluctance machines (BDFRM) show superior performance compared to their traditional counterparts, especially in variable speed applications such as pumps and wind generators. The design of BDFRM is different from other machines, as there are unusual pole combinations of stator and rotor besides the absence of a winding on the rotor. The operation and performance of the machine greatly depends on the mutual interaction between the stator windings. This interaction is modulated by the rotor with increased saliency. This paper examines a few critical issues in the design of BDFRM. Design optimization is performed using the gradient method from non-linear programming for 6-4-2 pole and 8-6-4 pole configurations of BDFRM. The performance of these optimized machines is examined through finite element analysis employing MAXWELL 16 software and then compared with 2kW prototypes constructed for laboratory use. A comparative analysis of the two configurations are presented and experimental results show that the BDFRM with the 8-6-4 ducted rotor is superior to BDFRM with the 6-4-2 reluctance and ducted rotor configurations.