Research Of Three Phase Switched Reluctance Motor And Drive System For Power Tools

The switched reluctance motor(SRM)is durable and can be used in high temperature and even strong vibration environments.Moreover,the control of the motor is flexible and there are many controllable parameters,so it has a wide prospect in the field of driving motor for power tools.In this paper,a three-phase SRM system is developed to realize the direct driving mode instead of the induction motor and belt speed control system,which can reduce the volume of the drill tool and improve the running efficiency,maintainability and service life.Selection of the topic has theoretical significance and practical value.The main research contents of this paper are listed as follows:Firstly,the current research situation of the SRM and its drive system for power tools are introduced.And some new structures of the SRM for power tools are introduced especially.Secondly,in order to replace the drive mode of induction motor belt speed control system,the direct drive SRM is developed based on the actual driving application of bench drill power tools.First,according to the existing bench drill drive,the rated parameters and structural size constraints of SRM motor are obtained,then the electromagnetic design of SRM is studied,and the design scheme of three-phase 6/4 pole SRM motor is obtained.Thirdly,based on the design scheme of three-phase 6/4 pole SRM motor proposed in the second part,the stepped-air-gap structure is proposed to reduce the torque ripple and the optimization design research is carried on to optimize the design.The influence of the stepped-air-gap structure parameters on the torque ripple and other performance of the motor is studied,and then the optimization design of the the stepped-air-gap structure parameters is studied by combining the response surface method(RSM)and genetic algorithm(GA)to realize the minimum torque ripple and ensure the other performances of the motor.Fourthly,the control system of SRM for bench drill drive is studied.At first,the whole structure diagram of the control system is given,and then the calculation of the parameters of each device,the selection method and the design scheme of each circuit are put forward.At last,the stepwise control mode of SRM for bench drill driving is analyzed and the control strategies of starting,running at low speed and full speed range are given.Fifthly,the direct drive 3 phase 6/4 pole SRM system for bench drilling tools is manufactured and the experimental research is carried out,including the laboratory load characteristic experiment and the actual drilling experiment.The experimental results show that the developed prototype system has good performances and can well meet the application of bench drill drilling.Finally,the full text is summarized.