Influence of Rotor Cage on the Performance of a Synchronous Reluctance Generator

Abstract

The influence of rotor cage on the performance of an autonomous self-excited reluctance generator supplying loads of different power factors is presented. It is seen that for the same excitation capacitance, terminal load connection, and speed, the self-excited reluctance generator with a cage exhibits a better ability to preserve the voltage waveshape following a sudden addition or removal of load than does a cageless self-excited reluctance generator. This is because during the transient disturbance, the rotor cage supports some DC current in the d-axis, making it act as a field winding. The solution of steady-state model equations formulated directly from the dynamic model are solved using the MATLAB® (The MathWorks, Natick, Massachusetts, USA) optimization technique ‘fsolve.’ The cageless self-excited reluctance generator is only capable of yielding less than half the rated power, while the self-excited reluctance generator with a cage is able to produce more than two-thirds of the rated power. This is due to the inability of the cageless machine to excite at capacitance values high enough to circulate the rated current in the machine windings.

Keywords:

• synchronous reluctance generator
• load characteristics
• self-excitation