Design Study On Novel Induction Rotary Transformer With Airgap

The brushed doubly-fed induction generator has been widely used in the field of wind power generation because of its simple structure and low investment.However,the brushes and slip ring has caused many problems,such as low reliability and high costs in maintenance.As a result,researches of brushlessness doubly-fed induction machine has become a hotspot.The energy transmission of rotary transformer is not effected by the rotation speed.The primary and secondary windings,which are separated from each other,are electromagnetically coupled.The primary and secondary sides can maintain relative rotation and achieve energy transmission without physical connection.This paper proposes to take non-contact energy transferation of rotary transformers as the substitution of brushes and slip rings in order to achieve brushless operation of double-fed induction machine.It will eliminate frictional wear and the possibility of electrical sparks.Hence,the maintenance cost will be reduced,and the reliability of the system will be further improved.Considering the purpose of brushless with rotary transformer,this paper focuses on the design of rotary transformer itself.The main work and innovations are as follows:1)Research on structure and working principle of rotary transformer.This paper describes the structural characteristics and classification of the rotary transformer in detail.For the kind of axial core and adjacent winding configuration of the rotary transformer,its coupling mechanism and energy transmission characteristics are analyzed,and its magnetoresistive model,leakage inductance model and mutual inductance model are established.2)Research on design of rotary transformer.Diffenerent factors,which effect the design of rotary transformer,are explained and optimized.Based on the electromagnetic relationship and geometric relationship of the rotary transformer,finite element analysis and genetic algorithm are used to propose an optimal design method for the rotary transformer.A 1kVA rotary transformer is designed by using the proposed method.3)Research on three-dimensional finite element simulation analysis and three-dimensional model design.For the designed 1kVA rotary transformer,the finite element analysis method is used to simulate its three-dimensional model.From the perspective of installation and assembly,the three-dimensional design software was used to model and simulate the assembly of the rotary transformer.4)Prototype assembly and performance analysis.Prototype is manufactured and assembled based on the design.Performance testing and analysis are performed.The analysis results show that the designed rotary transformer can meet the design performance requirements.