Research On Speed Control Of Mining Traction Motor Based On Fractional Sliding Mode

The mining electric locomotive is an important transportation tool for the mine surface and tunnels.Its operating conditions are complex,and the environment is bad.The domestic mining traction motor vehicle basically adopts a DC series excitation motor as a traction motor.However,the AC asynchronous traction motor's speed control technology has become more and more mature with the development of power electronics,intelligent control and other related subjects.It is the best choice for AC asynchronous motors to replace traditional DC motors as traction devices.In mining traction motor vector control system,the control performance of the rotary speed controller determines the static and dynamic performance of the traction control system.In recent years,the fractional sliding mode control has gradually attracted the attention of the majority of scholars.According to mining traction motor vehicle's operating requirements on the speed control,the FOSMC control strategy is used to design the speed controller and to improve the control performance of the field-weakening region.Finally,it aims to improve the speed control performance of the system.In this dissertation,the application of fractional calculus theory,sliding mode variable structure control,the design of speed controller and load observer,the FOSMC controller and the field-weakening controller in mining traction motor control system are researched.The main research contents include:(1)The theory of fractional calculus is introduced,including its definition and basic properties.Meanwhile,The response characteristics of the fractional unit step and its digital implementation is analyzed.Moreover,the sliding mode variable structure control's theory,design goals,dynamic quality and chattering are also introduced.(2)For different and severe operating conditions of the mining traction motor vehicle,Fractional PI,integer and fractional-order sliding mode speed controllers and load disturbance observers are designed,which could feedback the observed values into the speed controller.Hence,it can achieve the purpose of improving the speed control performance of asynchronous traction motor.(3)The vector control method of mining asynchronous traction motor is studied,The vector control system model of asynchronous traction motors is established based on the Matlab/Simulink simulation platform.The fractional-order sliding mode speed controller and load observer are applied into control systems.The simulation results are compared and analyzed.(4)The basic theory of field-weakening control system,the voltage and current limiting conditions are researched.Based on the speed regulation of high-speed operation of mining traction motor,the field-weakening controller is improved.The simulation results are compared with the traditional PI field-weakening control strategy.The simulation results of different operating conditions of the mining traction motor show that the load observer can accurately and quickly observe the load torque.The FOSMC speed controller with load observer can improve the speed control performance and system's reliability when the mining traction motor load's changed.Based on the fractional-order voltage closed-loop field-weakening control system can effectively reduce the fluctuation of the stator current and enlarge the speed range of asynchronous traction motors...