Visualization and Quantitative Evaluation of Eddy Current Loss in Bar-Wound Type Permanent Magnet Synchronous Motor for Mild-Hybrid Vehicles

This paper describes the conductor eddy current loss that occurs in a permanent magnet type synchronous motor with a distributed winding stator using a rectangular copper wire designed for mild hybrid system applications for small vehicles.Compared with the conventional round wire inserter method,the space factor can be improved and the coil-end length can be shortened by applying a so-called hairpin windings using a pre-formed into hairpin shape of bar conductor,and as a result,DC current resistance of the armature winding can be reduced.However,since the conductor cross-sectional area tends to increases,the conductor eddy current loss generated by the space harmonics linkage becomes too large to ignore.In order to study the reduction of the conductor eddy current loss,it is important to visualize the spatial leakage flux distribution which causes loss and finely analyze how the magnetic path is formed.Therefore,analysis of the conductor eddy current loss distribution generated in the bar-wound conductor is performed using the CAE model that faithfully reproduces the coil-end shape of the actual machine.Furthermore,it was qualitatively clarified what ratio of conductor eddy current loss at various driving points.Finally,the results of preliminary study on reduction of conductor eddy current loss are reported.

Design and optimization of an airflow-vibration sieving device for the effective cleaning of cyperus esculentus L.harvesting mixture

The threshing mixture of Cyperus esculentus(Tiger nut)planted in sandy areas is complex during harvesting,and there are problems of high impurity rate and high cleaning loss rate of the seeds.In this paper,the threshing mixture of Cyperus esculentus is taken as the research object,and the suspension speed of each component is measured to design an“airflow+vibration”sieving device.Use the vector polygon method to explore the law of motion of the vibrating sieve,establish the force model of the seeds on the sieve surface,and analyze the conditions for the seeds to penetrate the sieve.According to the principle of seeds penetrating the sieve and long stalks not penetrating the sieve,the geometric model of sieve blades opening degree adjustment mechanism is constructed.Study of the conditions under which long stalks can be thrown out of the machine.The experiment bench of the cleaning device was built,and the evaluation indexes were the rate of seed impurity and the rate of cleaning loss of the device,and the crank speed,sieve blades opening degree and fan speed were used as the experiment factors to study the influence law of each influencing factor on the evaluation index through single-factor experiment.Using response surface methodology to find the optimal combination of working parameters of the cleaning device.To verify the device’s application on the combine harvester to improve the effectiveness of the cleaning operation of the Cyperus esculentus combine harvester.