Design of a doubly-fed reluctance machine for wind energy generation

This paper presents the design of a 30 kW doubly-fed reluctance machine (DFRM) used for wind energy generation. Wind represents a variable-speed intermittent source of energy in nature and can be utilized using doubly-fed induction machines (DFIMs). The use of reluctance rotors can further improve energy efficiency and the reliability by eradicating the mechanical brushes and slip rings. This paper focuses on the machine design with a view to matching site-specific features with the loss distribution within the machine. The wind profile at the installation site is investigated so as to derive parameterized wind speeds, particularly, the annual cubic mean speed. By coordinating the loss components, it is possible to change the point of maximum efficiency of the machine to be near the actual nominal load corresponding to this wind speed. In a long term, a maximized overall energy production can be achieved for the generator. The DFRM is modeled in finite element (FE) and loss balancing is conducted for the rated condition. The total energy production is used as a key criterion to refine the machine design considering various stator winding arrangements and reluctance rotor topologies.