Research On The Back-EMF Of Permanent Magnet Synchronous Traction Motor During Coasting With High Speed

Permanent magnet synchronous motors (PMSMs) have been widely used in industrial manufacture and civil products with the merits such as little volume, light weight, high efficiency and power factor and high reliability, etc. For the existing of permanent magnet material, the back EMF can be generated during coasting. In order to apply PMSM to railway vehicle traction system, the problem of high back EMF must be solved.In this work, based on the influence of back-EMF on parameters of PMSM, the selection of back-EMF on different many applications is analyzed, and verified by different instances. According to the analysis above, When PMSM is applied to high speed railway vehicle traction system, the high back EMF problem may occer, and will cause uncontrolled generation during coasting. After some research on the forming mechanism and operation of uncontrolled generation, two methods to solve the uncontrolled generation problem have been analyzed on in terms of theory.Finally, the simulation and experimental results are presented in order to demonstrate the effectiveness of the proposed techniques to the high back-EMF problem during coasting.