Rotary Transformer Core Loss And Magnetic Field Research Based On Energy Transfer

With the rapid growth of the economy,countries attach more importance to wind energy.The doubly-fed induction generator is widely used in the field of wind power generation for its simple structure and low cost,.The traditional doubly-fed induction motor has a brush slip ring structure,which improves the maintenance cost of the motor and reduces the reliability of the motor operation.Therefore,the none-brushing of the doubly-fed induction motor has become a research hotspot,and the rotary transformer is used instead of the brush slip ring structure,which is the focus of research.In this paper provided a rotary transformer to replace the brush and slip ring structure of the doubly-fed induction motor.For a rotary transformer proposed by Shandong University for energy transmission in the low-frequency field,the magnetic fvield,core loss and temperature field are studied..Taking the influencing factors into account,the core magnetic field and loss of the new type of resolver are accurately analyzed,which would be usedin the structure optimize and the efficiency impoving,to promote the rotary transformer application.In this paper,the core loss of rotary transformer based on energy transfer is systematically analyzed and studied.The main work and innovation are as follows:1)Selection of calculation method for the iron loss of the resolver.In this paper,the common methods for calculating iron loss are analyzed in detail,and the equivalent magnetic circuit method and finite element method are the most common.Aiming at the equivalent magnetic circuit method,this paper takes the iron core structure size of the resolver into consideration,and proposes the equivalent magnetic circuit model of the resolver and the variable magnetoresistance model considering the saturation phenomenon of ferromagnetic material,and analyzes the advantages and disadvantages of the method.Compared with the finite element method,the finite element method is chosen as the main research method for studying iron loss.2)Suitable for the calculation model of the core loss of the resolver.This paper analyzes the shortcomings of several common core loss models in the calculation of iron loss for rotary transformers.The actual core structure of the resolver is taken into account in the calculation model of iron loss,and the effects of harmonics and saturation of core materials are considered.Three variable coefficient discrete segmentation models suitable for calculating the core loss of a resolver are proposed.3)Finite element analysis of the resolver.The two-dimensional and three-dimensional finite element methods are used to analyze the core magnetic field of the resolver.According to the actual working conditions of the resolver,a finite element model considering the eddy current loss of the iron core is proposed.The analysis results are combined with the three variable coefficient discrete segmentation models proposed in this paper to calculate the iron loss and at the same time innovate.The electromagnetic field is coupled with the temperature field,and the temperature change of the resolver core caused by the core loss is analyzed and calculated.4)No-load test of rotary transformer.The no-load experiment is carried out by using the prototype of the rotary transformer,and the quantitative analysis is carried out according to the experimental results and the calculated values.The correctness and rationality of the three-term discrete segmented model of variable coefficients and the finite element model of rotary transformer considering eddy current are verified.