Analysis of temperature field for a surface-mounted and interior permanent magnet synchronous motor adopting magnetic-thermal coupling method

Aiming at obtaining high power density of surface-mounted and interior permanent magnet synchronous motor(SIPMSM),it is important to accurately calculate the temperature field distribution of SIPMSM,and a magnetic-thermal coupling method is proposed.The magnetic-thermal coupling mechanism is analyzed.The thermal network model and finite element model are built by this method,respectively.The effects of power frequency on iron losses and temperature fields are analyzed by the magnetic-thermal coupling finite element model under the condition of rated load,and the relationship between the load and temperature field is researched under the condition of the synchronous speed.In addition,the equivalent thermal network model is used to verify the magnetic-thermal coupling method.Then the temperatures of various nodes are obtained.The results show that there are advantages in both computational efficiency and accuracy for the proposed coupling method,which can be applied to other permanent magnet motors with complex structures.

Experimental Study on the Disease-preventing Model of Culturing Chinese Sucker( Myxocyprinus asiatius) in River Crab( Eriocheir sinensis) Pond

From 2015 to 2016,the hepatopancreatic lesion syndrome had a higher mortality rate,which caused great economic losses to farmers. In order to study the high-efficiency disease-preventing crab pond intercropping mode,an experiment was successfully conducted to intercrop Chinese sucker( Myxocyprinus asiaticus) in a crab pond in 2017. We optimized the traditional stocking mode,and mainly cultured river crabs when intercropping Chinese suckers. Meanwhile,the cultivation environment was strengthened,and the test pond was not affected by disease throughout the year. The results showed that the production benefits were river crab 115 620 yuan/hm^2,Chinese sucker 44 280 yuan/hm^2,and silver carp and bighead carp 5 418 yuan/hm^2,with a total output of 165 318 yuan/hm`2,and the output-input ratio was 1∶ 1. 72. The Chinese sucker-intercropping river crab culture mode promoted the improvement of pond culture environment,effectively controlled the occurrence of hepatopancreatic lesion syndrome,and significantly improved the economic benefits of crab pond culture.

Study on Resource Conservation of Chinese Sucker( Myxocyprinus asiaticus)

Chinese sucker( Myxocyprinus asiatius) is a national secondary protection animal in China,as well as unique economic fish in China having extremely important scientific research value and edible value. With the aggravation of water pollution and the massive construction of water conservancy and hydropower projects,the natural spawning ground of Chinese sucker has been seriously damaged. The current number of wild resources has decreased sharply,and the decreasing trend is continuing. This paper summarized the current resource status and monitoring and assessment methods of Chinese suckers,and put forward the research prospect,so as to provide theoretical reference and technical support for resource protection and development and utilization of Chinese sucker in China.

Study on Nutritional Requirement of Chinese Sucker(Myxocyprinus asiaticus)

Chinese sucker( Myxocyprinus asiatius) is a kind of unique fish in China,as well as a kind of national secondary protection animal.With the artificial propagation and fingerling rearing technology getting mature,adult fish culture is becoming more and more mature.This paper summarized the research results of the nutritional needs of Chinese sucker in recent years,and put forward the development direction,so as to provide reference for the development of Chinese sucker culture industry.

Multi-Objective Optimization of Surface-Mounted and Interior Permanent Magnet Synchronous Motor Based on Taguchi Method and Response Surface Method

The surface-mounted and interior permanent magnet synchronous motor(SIPMSM)has the characteristics of multiple variables,strong coupling and nonlinearity.In order to improve the performance of SIPMSM,this paper presents a multi-objective optimal design process using Taguchi and response surface methodology(RSM).The peak value of cogging torque(PVCT),ratio value of average torque and permanent magnet weight(RTW),torque ripple and back-EMF total harmonics distortion(ETHD)are selected as optimization goals.The experiment matrix is established by Taguchi method,and analyzed the tendency and proportion of the effect of the optimization parameters on SIPMSM performance.The rules of choosing multi-objective optimization parameters are obtained.The least-squares method is used to establish the optimal objective function,and RSM is used to obtain the resolutions of the optimization objective function.Comparing the initial performance with optimized performance verifies the effectiveness of the proposed method.

The Characteristics Analysis and Cogging Torque Optimization of a Surface-Interior Permanent Magnet Synchronous Motor

This paper proposes optimal stator skewed slot analytical method for cogging torque reduction in surface-interior permanent magnet synchronous motor(SIPMSM)and analyzes the characteristics of SIPMSM.The series-parallel equivalent magnetic circuit models(EMCMs)of SIPMSM is built based on the characteristics of magnetic circuits,which is used to design the basic electromagnetic parameters of SIPMSM.Analytical expressions of cogging torque are derived from applying analytical techniques.Stator skewed slot for cogging torque minimum is adopted,and the stator skewed slot pitch is confirmed based on the analytical expressions of the resultant cogging torque.The cogging torque,torque ripple,back electromotive force(back-EMF),power-angle characteristics,efficiency and power factor of SIPMSM are analyzed by establishing 3-dimensional finite element model(3-D-FED)of SIPMSM with stator skewed slot and straight slot.It is shown that the comprehensive performance of optimized SIPMSM is improved as confirmed by finite element analysis and analytical calculation results.