Research On Optimal Control Strategy Of 400kW Mine Permanent Magnet Direct Drive All-in-one Machine

Chinese coal output is the first in the world,it is the important energy backing of Chinese industrial development.The advent of mine permanent magnet direct drive all-in-one represents the upgrading of coal machine types.Due to the particularity of the structure and control requirements of mine permanent magnet direct drive all-in-one,it has become a new problem to match a control system with high adaptability.As mine motor needs to deal with complex working conditions under mine,frequent switching of working conditions will lead to fluctuations of various parameters of the motor,which will have certain impact on the motor.Besides,direct drive motor is not protected by decelerating equipment,and the torque and current values of the motor are large,so the motor will bear great impact.Therefore,the corresponding control strategy should have better dynamic adjustment ability to reduce this kind of impact for the motor.In this thesis,a fuzzy PI control strategy based on improved extended Kalman filter is proposed for a mine permanent magnet direct drive integrated machine with 400 k W power and 80r/min speed.The main research contents are summarized from the following four aspects:Firstly,the integrated design idea of frequency converter and motor is introduced.The finite element model of permanent magnet direct drive all-in-one machine is established according to the fixed rotor structure.Through finite element analysis,the electromagnetic field distribution diagram of the motor,no-load back potential curve and various load parameter curves of the motor are obtained.On this basis,the mathematical model of permanent magnet direct drive integrated machine is established,and the motor vector control system is built around it.Secondly,the prediction principle and algorithm structure of the extended Kalman filter are introduced.The extended Kalman filter model is added on the basis of the vector control model,and the control effect of the extended Kalman filter is tested by simulating different working conditions in mine.The simulation results show that the extended Kalman filter can realize the basic control purpose under different working conditions,but the problems of low observation accuracy and insufficient dynamic adjustment ability of the extended Kalman filter are put forward.In order to improve the observation accuracy of the extended Kalman filter under different working conditions,the whale algorithm is used to optimize the noise matrix of the extended Kalman filter.The simulation results show that the observation accuracy of the extended Kalman filter control system based on the improved whale algorithm has been improved obviously,and the control strategy can realize accurate feedback of motor information under any mining conditions.Finally,in order to improve the dynamic adjustment ability of the control strategy after switching conditions,the designed fuzzy PI controller replaces the PI speed ring of the original control system,and realizes the combination of extended Kalman filter and fuzzy PI controller.The simulation results show that the optimization strategy can suppress the parameter fluctuation caused by switching conditions,and reduce the impact on the mine permanent magnet direct drive all-in-one machine.The compatibility between the control strategy and mine permanent magnet direct drive integrated machine is improved.In this thesis,the control strategy is optimized by improving the whale algorithm and fuzzy PI controller,and it is proved that the optimization strategy can improve the observation accuracy of the control system under different working conditions,and reduce the impact caused by the switching of working conditions to the all-in-one machine.It provides some reference significance and value for optimizing control strategy of mine permanent magnet direct drive all-in-one machine.