The Study Of The Power Balance Of Long-distance Belt Conveyor Multi-motor Drive System

Long-distance belt conveyor is widely used in power plants，mining ports and otherindustrial and mining enterprises with the characteristics of large transmissioncapacity,little pollution and long life.It mainly includes the decives of steel coreconveyor belt, AC motor, reducer, brakes, hydraulic tension, frequency, deviationand tear protection. To reduce the tension belt produced during start and running, thesystem typically uses multiple high-power AC motor drives which mounted ondifferent places such as head,end,and middle.As the steel core conveyor belt has alarge viscoelastic, the system will produce a greater capillary wave during the periodof start and running. Capillary wave which propagates along the conveyor belt causesvibration which affects the start-up smooth, the operation safety.T o be serionsly, itwill lead to frequency stop accidents. Because of the difference of the motor andreducer and the round corner angle, the system will produce uneven motor powerdistribution. The unbalanced nature of these motors will have a more severe course ofthe tension fluctuations. Therefore, the study of multi-motor power balance hascrucial theoretical significance and application value for the safe operation of theconveyor.This thesis first describes the components of the long-distance belt conveyor andthe mathematical model of the key parts which includes tensioning device, electricmotor,inverter and conveyor belts. It analyses the dynamic model of conveyor beltby finite element method. To simplify the complexity of the simulation, it uses theequivalent model of the inverter and motor.Then it analyses the causes and phenomena of power imbalance,and discusses thepower imbalance characteristic of the dynamic process based on the steady-state ofpower distribution. It has also designed a power balance control strategy,and gives apower balance controller whose structure and calculation process of power balancehas been discussed.Finally, the thesis gives the simulation result based on the simulation model whichindicates that the power balancer has solved the problem of the balance distributionand has good dynamic properties. At the end of the thesis, a project application hasalso been discussed.The main innovation of this thesis is that the design of the steady-state model anddynamic model of the conveyor system of power distribution. The model can not only analyse the reasons for the power imbalance qualitatively, but also simulate thedynamic characteristic during the power distribution process dynamically.