Study On The Longitudinal Oscillation Characteristics Of Hoist Wire Rope In High-power Deep Mine Hoist And Its Suppression

In order to achieve deep and large-scale coal mining,it is necessary to use modern mine hoist which can hoist deeper,faster and heavier.Modern mine hoist is a precise system in which mechanical part and electrical part are highly integrated.The existing shallow mine hoist technology can no longer meet the needs of deep mine hoist system.As the connection between mine hoist motor and load,hoist wire rope is responsible for lifting and lowering load,but its longitudinal oscillation problem has not been solved effectively.The longitudinal oscillation of the hoist wire rope will directly affect the stability and safety of hoist motor and hoist load.At the same time,modern hoists put forward higher requirements for the performance of hoist wire ropes.However,higher performance wire rope manufacturing technology can't achieve a key breakthrough in a short time.Therefore,the thesis studies the longitudinal oscillation characteristics of the hoist wire rope and the torque ripple law of the high-power synchronous motor.Then the thesis designs control strategies to effectively suppress the longitudinal oscillation of the hoist wire rope,thereby improving the performance of the wire rope and the stability and safety of the hoist system.In addition,the thesis used a high-power permanent magnet synchronous motor as the power source of hoist system.Firstly,Taking the energy conversion characteristics between deep mine hoist load and motor as the research objective,the thesis established and numerically solved the longitudinal oscillation mathematical model and dynamic tension equation of mine hoist system by generalized coordinates and Lagrange equation.Then the thesis established the longitudinal oscillation model of hoist wire rope based on generalized Hamilton principle and verified the rationality and accuracy of the corresponding model by numerical calculation.Finally,from two aspects of the operating state parameters and external excitation,the thesis simulated and analyzed the longitudinal oscillation characteristics of the hoist system which provides a theoretical basis for further study of its longitudinal oscillation suppression strategy.In order to master the torque ripple characteristics of high-power permanent magnet synchronous motor at low switching frequency.Through establishing models,the thesis derived and analyzed important causes of motor torque ripple,including design structure of motor body,drive device-inverter non-linearity,controller-PWM modulation mode and load fluctuation.Based on the above results,the thesis established a torque ripple characteristic model of permanent magnet synchronous motor.To suppress the motor torque ripple,the thesis designed the specific harmonic current suppression strategy at the multi-synchronous rotating frame.The simulation results show that the controller based on this strategy could effectively reduce the specified subharmonic current,as well as the torque ripple caused by the fluctuating load of fixed frequency.However,the longitudinal oscillation of hoist wire rope is slow time-varying oscillation,so the thesis designed the longitudinal oscillation suppression strategy of hoist wire rope based on acceleration feedback compensation.The simulation results show that the strategy could eliminate the time varying longitudinal oscillation basically which guarantees hoist load safe and stable.Finally,through establishing the experimental platform of the motor speed control system,the thesis completed the experimental verification of related research.