A Research On Reliability Of Motor Drive System Based On Electrical Vehicles

Due to energy crisis and environmental issues, traditional internal combustion engine vehicles can’t meet people’s meet,and electric vehicles (EV) are getting more attentions,which is becoming the development trend of the automotive industry.Governments and companies are increasing their R&D efforts on EV, and major automobile manufacturers have produced their own special electric vehicles, successfully opened the market.However,in the situation that EV have been accepted by the public,a variety of failure and accidents cast a shadow to the further promotion of EV.These fully expose that the safety and reliability of EV can not be guaranteed,and the reason on the one hand is that EV is an emerging industry, lack of all aspects of standards, or needing standards to be improved; the other hand, to dominate the market, car manufacturers are eager to launch their products, without enough paid attention to reliability and security and lack of adequate research.In this context,the paper does the detailed study on the reliability of the EV motor drive system.Access to some relevant information,understand the standards and requirements about the electric vehicle drive system of the state, according to the motor operating parameters given by the customers, the paper calculates some relevant parameters to meet the system, e.g. output power,output current of the system and etc.The whole system is divided into six modules,and the paper shows the choices of the programs and explains parameters matching process. According to the principle of reliability of the control system, the paper makes a detailed failure analysis:FMEA and FTA, and analyses electrical fault and fault causes maybe generated in the system. Calculate the failure rate of components for six modules,and get the failure rate of the whole system, and we can see that the designed system’s reliability meets the standards of the state,indicating that the circuit design is correct. The MOSFETs、 capacitors and the motor are thought to be the prone failure components, and the power supply module、 the inverter and its drive and protection module are the weak link of the system.Focus are need to put on improving the reliability by using high quality component, derating component、 redundancy and using integrated chip and etc.The electromagnetic compatibility of electric vehicles is the most easily overlooked safety issues.The paper analyses detaily electromagnetic compatibility for the design circuit,and points out the three elements of the electromagnetic interference in this system,and improves EMC performance of the circuit from three aspects.At the end, the paper uses Simulink to show the fast switching of the MOSFET in the circuit can cause electromagnetic interference and the effect of filtering.The results demonstrate that the design significantly improves the electromagnetic noise interference on MOSFET output according to voltage waveform and spectrum, indicating that The program of the circuit EMC design is effective.