Research On Reliability Test Of Permanent Magnet Synchronous Motor And Driver

The permanent magnet synchronous motor(PMSM)is widely applied to industrial products such as computerized numerical control machine tools,electric vehicles and automatic production equipment,because it has a higher efficiency,lower rotational inertia and faster dynamic response,The PMSM must be controlled by a matching servo driver(SM),and thus it could working well.The PMSM and SM form a servo drive system(SDS).At present,the reliability of SDY made in china is far from the reliability of SDY made by other developed countries.In china,the high-end CNC equipment applied to the SDS is dominated by a small number of companies,such as FANUC,DMG,SIEMENS Inc.To improve the reliability level of the PMSM and SM made in china,and enhance the market competitiveness of China’s computerized numerical control equipment system,the reliability test of PMSM and SM is studied in this thesis.The reliability test could be used to assess the current level of reliability and exposure the potential shortcomings of the design weaknesses.These provide a technical support to improve product design.The main contents and conclusions are list as follows:In chapter 1,the background and significance of this thesis are briefly described.The overview of the PMSM and related driving technologies are summarized.The fault detection methods used for inverter failure,drive circuit fault and stator current amplitude fluctuation are reviewed.The reliability test technology applied to PMSM and SM is summarized,and it is determined that the constant stress accelerated test can be applied to the PMSM and SM.Lastly,The main contents of this paper are given.In chapter 2,by analyzing the composition and working principle of the PMSM and SM,and synthetic using the theoretical analysis and simulation test,the causes of faults such as stator inter-turn short circuit,open circuit fault,stator current amplitude fluctuation and stator current waveform distortion are determined.The high temperature and large current load are the main stress factors casing failure.These provide the technical support for designing and carrying out reliability test of PMSM and SM.In chapter 3,to solve the problems of low accuracy and low efficiency in the fault detection methods applied for PMSM and SM,the vector angle and vector magnitude of the negative sequence component vector are redefined and negative sums are synthesized according to the principle of negative sequence component calculation.Then,a new method is proposed to detect the amplitude fluctuation and waveform distortion of the stator current by using the negative sequence length and the vector angle of the current,which could provide a technical method for the real-time detection of the fault time of the permanent magnet synchronous motor and the driver in the reliability test.The validity of the method is verified by a experimental.In chapter 4,based on the rated design parameters of PMSM and SM,the reliability test device of PMSM and SM is designed.The reliability test is carried out and based on the reliability test method of fault detection proposed in this paper.The current amplitude of the stator current is analyzed,and the fault time is obtained.Then,the life of the PMSM and SM is determined to obey the Weibull distribution by using the graph analysis method and the goodness of fit test.The reliable life is obtained by using the maximum likelihood estimation,and thus the reliability of the PMSM and SM is evaluated.In chapter 5,the research contents of this thesis is summarized and the further study works is presented.