Research And Implementation Of Motor Intelligent Protector

As a kind of power device,the electric motor is widely used in industrial production and daily life.The safe and stable operation of the electric motor directly affects the production efficiency of the enterprise and people’s daily life.In the event of failure,the effective protection of the motor can reduce the huge economic losses,so the research of motor protector is of great significance.Firstly,the shortcomings of the traditional overload protection model in the protector is analyzed in this thesis,and fourth-order thermal circuit model equivalent to the internal structure of the motor as the motor overload protection model is proposed.At the same time,genetic algorithm is used to identify the parameters in the thermal circuit model.The thermal circuit model of the motor was simulated and verified under various working conditions in SIMULINK.The results show that the fourth-order thermal circuit model of the motor can better reflect the dynamic temperature rise of the motor.By discretizing the fourth-order thermal circuit model,the discretized temperature rising recurrence formula is obtained,which can be used in the protector to realize the real-time calculation of the dynamic temperature rise of the motor.Finally,STM32F105VCT6 is used as the control core,and ATT7022 EU is used as the signal conditioning circuit to complete the hardware and software design of the protector.Peripheral circuits using a modular design method are built around the controller,including power circuit modules,signal acquisition and conditioning modules,key circuit modules,display modules,alarm modules,switch input,output modules and communication interface modules,etc.The software part adopts C language to design the initialization subroutine,including the man-machine interaction procedure,the communication procedure,the protection procedure and the real-time clock procedure.Based on the above design,the functions of motor protection,control,parameter real-time display,and one master control multiple slaves are realized.