Permanent Magnet Direct Drive Scraper Conveyor Research On Dynamic Characteristics And Control Strategy Of Chain Drive System

Scraper conveyor is mainly responsible for coal loading,transportation,and unloading in underground mining to improve mining efficiency and reduce its failure rate.This thesis proposes a direct-drive method for scraper conveyor using a permanent magnet synchronous motor(PMSM),omitting the intermediate vulnerable transmission mechanism.Since the intermediate transmission mechanism is eliminated,any vibration or impact on the scraper conveyor end will be directly transmitted to the motor shaft.The PMSM direct-drive system for scraper conveyor operates under complex working conditions,including intermittent operation and frequent impact,which can cause internal parameter perturbations,inertia,and large load changes,seriously affecting the stability of the PMSM system.To ensure high system reliability,this thesis conducts research on the dynamic characteristics of the PMSM direct-drive scraper conveyor chain transmission system under typical operating conditions,and the speed control strategy of the PMSM system under the load characteristics of the scraper conveyor,through theoretical analysis,mathematical modeling,and experimental verification.The main research work is as follows:(1)This thesis describes the structure of a permanent magnet direct drive scraper conveyor system,which employs a permanent magnet synchronous motor,a coupling,and a scraper conveyor as its driving components.The mathematical model of the system is established,and a double-loop control system(speed loop and current loop)based on motor vector control method is constructed for the permanent magnet motor.The critical steps of the control system,such as coordinate transformation and vector pulse width modulation,are analyzed.In addition,the kinematic and mechanical characteristics of the end load of the permanent magnet direct drive system are studied.The structural features of the mining scraper conveyor chain transmission system are considered,and the polygonal effect of the chain and tension distribution between chains during chain wheel and chain ring transmission are analyzed.The overall system parameters are determined,and multi-body dynamic analysis is used to study the kinematic and dynamic characteristics of the scraper conveyor chain transmission system.(2)To study the dynamic characteristics of the scraper conveyor chain transmission system in the permanent magnet direct drive system,a simplified model of the scraper conveyor chain transmission system components is created using Solidworks 3D software and assembled.The virtual prototype model of the scraper conveyor chain transmission system is established in ADAMS software using the multibody dynamics research method,and constraints are applied according to its operating conditions.The kinematic and dynamic analysis of the empty load stable operation condition and the chain breakage and chain card failure operating condition of the chain transmission system are performed based on contact and collision theory.In addition,to study the dynamic characteristics of the entire system,an electromechanical coupling model of the entire machine is established using ADSMS and MATLAB/Simulink for numerical simulation analysis,exploring the impact of the end load on the speed control of the permanent magnet direct drive system.(3)Considering the parameter uncertainty,external load fluctuations,and large load impact in the scraper conveyor system,a sliding mode control method that is insensitive to internal parameters and has strong anti-interference ability is introduced for the speed control strategy of the permanent magnet direct drive system.A permanent magnet direct drive system sliding mode speed controller(SMC)is established.To reduce the chattering caused by the sliding mode control,a smooth switching function is used instead of the traditional switching function.Based on the fuzzy control principle,the parameters of the sliding mode controller are dynamically adjusted to establish a permanent magnet direct drive system fuzzy sliding mode speed controller(FUZZY-SMC).PI,SMC,and FUZZY-SMC speed controllers are simulated and compared under step load and simulated working conditions.The results show that the designed FUZZY-SMC speed controller has the characteristics of small overshoot and good robustness.(4)In order to verify the experimental performance of the permanent magnet direct drive scraper conveyor chain transmission system,based on the load characteristic simulation principle and the parameter equivalence scaling principle,a small-scale permanent magnet direct drive system load simulation experimental platform consisting of a "permanent magnet synchronous motor","coupling" and "magnetic powder dynamometer" is built.The dynamic characteristics of the electromechanical coupling system in Chapter 3 are experimentally verified by loading the simulated operating condition on the dynamometer.The experimental curves of motor speed,current,and electromagnetic torque obtained from the experiment are relatively consistent with the simulation results,which demonstrates the validity of the smallscale experimental platform and the correctness of the simulation results.Furthermore,the speed control strategy of the permanent magnet direct drive system in Chapter 4 is experimentally verified,and the experimental results are consistent with the simulation results,verifying that the designed speed control strategy of the permanent magnet direct drive system has better performance.This dissertation has 99 figures,12 tables and 94 references.