Research On The Control System Of Controlled Starting Transmission In Heavy Scraper Conveyor

With the rapid development of coal industry and the fully mechanized technology, heavy scraper conveyors for overloading starting, power balance, the chain blocked overload protection attach more and more attention, therefore, soft start control in heavy scraper conveyor start-up process is particularly important. Valve control liquid type hydraulic coupler, double speed motor, frequency control of motor speed drive and controllable starting transmission(CST) are currently used in the soft start of scraper conveyors. The CST, which is especially suitable for scraper conveyor overload start, is the ideal soft start device. However, the current domestic use of CST are imported from abroad, the core control technology has also been monopolised by DBT company in Germany, and theoretical research and design in the domestic scientific research institutions and related enterprises are still in the initial stage.Based on the KP-45 CST, designed and manufactured by DBT, the system composition, function and working principles of its control system have been studied in the theoretical research.The CST control strategy, which are the CST in single motor drive load, double motor drive load and overload protection blocked chain under different work requirements, were analyzed. The heavy conveyor machine simulation models, including motor model, CST and electro-hydraulic servo control system model and scraper conveyor load model were built through AMESim, and the simulation model parameters were determined. Finally, the characteristic of CST electro-hydraulic servo control system under the single motor drive and double motor drive had been carried on the simulation analysis.For a single motor drive control system model, the control characteristic of CST in scraper conveyor no-load start, loading start and blocked chain protection condition were analysed. For a double motor drive power balance control system model, analyzed the scraper conveyor running resistance and CST startup latency time influence on motor output power, and by introducing power PID control link, the characteristics of CST power balance adjustment control were analysed.It is shown that the control system model set up by the AMESim simulation software can accurately simulate control characteristic of CST control system under different working conditions. The CST control strategies can meet heavy scraper conveyor controllable starting under different working conditions such as single motor driven load, double motor driven load and protection against blocked chains. Therefore, CST has good controllable starting characteristics, and can achieve acceleration starting of large inertia load according to the given speed curve, at the same time also has the function of protection against blocked chains with higher response speed. By selecting the appropriate percentage of power balance adjustment threshold can realize output power balance adjustment under the condition of heavy scraper conveyor running smoothly driven by double motor.