Research And Design Of Control System Of BLDCM For Power Tools

Brushless Direct Current Motor(BLDCM)was widely used for a variety of reasons including small size,high efficiency,long service life and simple service.However,because of the uncertainty of external environment,the brushless DC motor has the problems of inaccurate and unstable speed control in the process of speed regulation.Therefore,bettering the speed precision and stability of the control system of BLDCM for power tools with a advantageous control method is important.Based on the project of the Shanghai Electric Tool Research Institute(SETRI)," R&D of series of handheld lithium battery power tool drivers",this paper takes BLDCM for electric tools as the research object,and studies the PID parameter tuning of BLDCM control system.The main work is as follows:(1)On the Matlab/Simulink platform,a dual closed-loop control system based on traditional control BLDCM was built,and the speed control performance parameters in the simulation results were analyzed,which laid the foundation for the next step to verify the optimization algorithm simulation.(2)Combining inertia weight and Levy to optimize the bat algorithm,research a PID control method based on the optimized bat algorithm(WLBA＿PID).The step response of WLBA＿PID and genetic algorithmbased control(GA＿PID)under the same function is compared and analyzed.The result proves that WLBA＿PID has a faster response.The WLBA＿PID is applied to optimize the speed loop of the BLDCM control system.The simulation results confirm that the WLBA＿PID control method is better than GA＿PID and traditional PID in the speed overshoot and steady-state error during the speed adjustment process,which verifies that the PID control method based on the optimized bat algorithm is feasible.(3)In order to verify the feasibility of the algorithm,STSPIN32F0 controller was used as the core and the hardware and software part of the control system of BLDCM for power tools was designed.the hardware circuit includes the control given signal circuit,the drive circuit,the backEMF detection circuit and so on.the software part is written including the startup program,the position signal,the capture interrupt program,the overcurrent protection interrupt program,the overtemperature protection interrupt program,and the bat algorithm adjustment module.(4)By setting up an experimental platform,testing the experimental data and comparing it,it is verified that the use of WLBA＿PID control method can help reduce the overshoot of the BLDCM speed control system and better the system stability: Compared with traditional PID,WLBA＿PID is reduced by about 7.5% in overshoot and reduced by about 0.8% in teadystate error.