Performance Calculation Of Brushless Hybrid Excitation Generator Based On Third Harmonic

Third harmonic excitation generator has been widely used in small and mediumsized synchronous generator because of its good phase compound excitation characteristics and simple excitation structure.However,problems such as inconvenient excitation,insufficient harmonic excitation power and brushless are still common problems of this kind of generator.Due to the existence of permanent magnet,permanent magnet motor has the advantages of rapid voltage building,high efficiency and simple structure.Therefore,this paper will study the basic structure,working mechanism,performance calculation and prototype experiment of the new generator formed by the combination of third harmonic excitation and permanent magnet excitation.A brushless hybrid excitation synchronous generator based on third harmonic excitation is proposed,On the basis of the traditional brush third harmonic hybrid excitation motor,the generator arranges the harmonic winding with the same pitch as the stator third harmonic winding on the rotor,and transfers the excitation power to the rotor side by virtue of the electromagnetic induction between the stator third harmonic winding and the rotor harmonic winding.The generation mechanism of electromotive force of stator third harmonic winding and rotor harmonic winding and the principle of brushless excitation in the third harmonic brushless synchronous generator are analyzed,and the basic structure of the third harmonic brushless hybrid excitation synchronous generator is given.Using the electromagnetic field analysis software,the finite element model of the third harmonic brushless hybrid excitation synchronous generator is established.The no-load characteristics of the stator fundamental winding and the third harmonic winding,the rotor harmonic winding and the operation characteristics of the third harmonic excitation system are calculated.A prototype of the third harmonic brushless hybrid excitation generator is developed,and its test platform is built,and its operation performance is tested.The theoretical calculation and experimental results show that the generator terminal voltage can be adjusted by changing the stator third harmonic winding current,and the results are basically consistent,which verifies the correctness of the proposed brushless excitation principle and the accuracy of the calculation method.