Finite Element Analysis And Research Of Brushless Doubly Fed Machine With Radial Laminated Reluctance Rotor

ABSTRACT:With wind power generation as a kind of renewable energy has been extensive concerned all over the world, People pay more and more attention on special generator, which is suitable for wind power generation systems. The brushles doubly fed machine (BDFM) is a new type AC machine, it has lots of advantages such as brushless, simplicity and reliability. Besides, it has the characters both asynchronous machine and synchronous machine. The BDFM can be easily to realize variable speed constant frequency constant voltage generation by controlling excition frenquency and voltage. So the BDFM can be applied in harsh environment like wind power generation, etc. In the frequency-variable speed-adjustable system, the BDFM needs a much smaller power electronic converter, compared to a conventional AC induction machine, and reduce the cost of the system. Therefore, the BDFM has good prospect of popularizing, and research of the BDFM has important theoretical significance and practical value.In this paper, first, present the stator and rotor structures of the BDFM. Then take salient reluctance rotor BDFM as an example, the operation principle of the BDFM is clearly elucidated, and the modulation of the reluctance rotor to stator winding field is revealed. Second, presents a BDFM with radial laminated reluctance rotor(RLR-rotor) as research object, the finite element method (FEM) is used to analyze transient field of this novel machine. The flux linkage, air gap magnetic density, voltage of no-load operation and the torque capability, voltage of power winding of load operation are calculated and analyzed. The influence of radial laminated reluctance rotor pole-number to the performance parameter of no-load and load opration are discussed. BDFM's performances with different rotor structures are comparatived studied. All these sesults provide theoretical foundation for the optimization design and practical application.The winding function theory is used to calculate the inductance of the BDFM with radial laminated reluctance rotor, and compare to the inductance value computed by FEM. Introduces the experimental measurement method of inductance. Briefly explain several operation model of the BDFM, and then, Experiment researches on a 1.5 KW RLR-rotor BDFM have been made. The resistance and inductance parameters are tested on it. Verify the constraint relations between motor's speed and excition frequency. The investigation on asynchronous operation, synchronous operation, supersynchronous operation and subsynchronous operation are conducted in experiment. The experimental results are compared to simulation results by FEM. Experimental results demonstrate the validity of the finite element model. It show that the machine can be made and realize in engineering application. All the researches are proposed as a basis for further investigation of the BDFM and its system.