Reliability Research Of Sensorless PMSM System

The modern industrial development process is becoming faster and faster, the useof the motor is becoming more and more, users’ requirement is becoming higher andhigher, the problem of motor in the running process is also becoming more and more.Based on the concept of reliability, analyse the common failures of the motor, themotor reliability analysis and research is very necessary. PMSM is a motor which isdeveloping rapidly and frequently used in recent years. When motor is running inopen loop state, speed controlling performance and stability is poor, the motorefficiency is low, can even appear out-of-step phenomenon, therefore accurate rotorposition and speed information is very important. These information are usuallymeasured by mechanical sensor (photoelectric encoder, hall sensors, rotatingtransformer, etc.) directly or indirectly. But, joining the mechanical sensor can bring alot of limitations, So in recent years, the sensorless permanent magnet synchronousmotor vector control strategy is an important research direction.The paper is mainly about the studying for the reliability of the system start ofsensorless permanent magnet synchronous motor. This paper first introduces theresearch background and significance, as well as the application field of permanentmagnet synchronous motor; secondly, working principle、structure and mathematicalmodel of permanent magnet synchronous motor are introduced, including thecoordinate transformation of three phase stationary、 two-phase static coordinatesystem and rotating coordinate system, the basic equations of motor and vector fieldoriented control; then introduced the specific method of sensorless control ofpermanent magnet synchronous motor, the establishment of the counter electromotiveforce equation, set up the PMSM simulation model under the Matlab/Simulinkenvironment, research the control system through the simulation; finally analyzed thestart process of sensorless permanent magnet synchronous motor, the possible reasonsfor the motor out-of-step and harm, and starting from the reliability, expounded the common motor faults, harm and its protection.At the end of this article, put forward the deficiency of this topic research andthe job prospects in the future.