Feng Yaojing

Research of interior permanent magnet brushless DC motor for electric vehicles

Permanent magnet brushless motors for electric vehicles are presently given an increasing attention. With this trend, this paper deals with an interior permanent magnet (IPM) brushless DC motor (BLDCM), which is supposed to apply in a two-seater pure electric car. Firstly, the performance indicators of the motor were determined according to the power requirements of the car at different driving speed, and a 10kW IPM-BLDCM was designed preliminarily. Then, choosing air gap length, permanent magnet thickness and the number of stator winding turns as variables, parametric analysis was made to research the influence of structural parameters on system efficiency and the torque-current ratio. After an optimization design, a prototype was fabricated and tested. The test results show that the optimized prototype can meet the need of the driving system both in constant torque region and constant power region.

Characteristic analysis of the cryogenic permanent magnet synchronous motor for the submerged LNG pump

This paper introduces a submerged LNG (liquefied natural gas) pump cryogenic permanent magnet synchronous motor (PMSM). A 22kW/6000rpm prototype is designed for low temperature operation at −161°C. The influence of temperature on magnetic and electric parameters of materials is analyzed, and a coupled simulation model of electromagnetic-fluid-thermal-stress field is established. On this basis, the motor characteristics such as the loss, back EMF and torque are obtained. The accuracy of the simulation model is verified by the prototype test at −196°C liquid nitrogen. Simulation and test results show that the performance of the cryogenic PMSM is better than that of the traditional motor.

Research on optimal design of permanent magnet synchronous motors based on field-circuit coupled method

This paper deals with the optimal design of permanent magnet synchronous motors (PMSMs). Firstly, the general rules and principles of motor optimization are summarized, and a field-circuit coupled optimal design method is presented based on combined selection of variable parameters, objective functions and constraint conditions. Then, choosing multiple structural dimensions as variables, parametric analysis is made to research the influence of structural design parameters on performance of the PMSM. On this basis, an optimal design for a two-pole line-start PMSM is made, which can successfully reduce the dosage of permanent magnet and improve the performance-price ratio.

An attempt to improve the braking capacities of eddy current retarder with double-rotor excitation structure

Vehicle retarders receive more and more attention along with its use growing. This paper introduces a new type of eddy current retarder with double-rotor excitation and liquid-cooled stator structure. It can be considered to consist of two retarder units combined in the radial direction. Four different double-rotor eddy current retarders were proposed, including a double electric excitation rotor, a double permanent magnet (PM) rotor and two kinds of PM and electric hybrid excitation rotor structures. Each retarder has its own advantages, and might replace some of existing products, with its improved braking capacities and better cooling performance. FE based analysis of the four retarders were carried out respectively, and their properties and operating effects were compared.