Power Balance of Starting Process for Pipe Belt Conveyor Based on Master-Slave Control
An output power imbalance usually occurs in the driving motor of pipe belt conveyor due to the load disturbance and a variety of environmental interferences. This paper focuses on the operating condition of pipe belt conveyor where the head and tail with inclined angle are equipped with a motor separately. The discrete element method is used to propose a discrete model of the pipe belt conveyor, and its simulation model is established in the AMESim. According to the direct torque control method for the three-phase asynchronous motor, the principles for controlling the balance of dual-motor power are analyzed. A master-slave control strategy is proposed, where the master motor is controlled using a speed-given strategy and the slave motor is controlled using a torque-given strategy. A simulation model is built for the dual-motor driven system in the MATLAB-Simulink. After establishing a correlation between parameters through VS2010, a joint simulation model was established for the control system of the pipe belt conveyor. Simulation analysis and field test of the starting process are performed. Results of comparison with the traditional master-slave control strategy demonstrate the ability of the proposed method to balance the master-slave motor power of the pipe belt conveyor more effectively.
Research on Power Balance Control of Multi-Motor Driving Belt Conveyor System Based on Controlled Transmission Device
According to the existing problems of driving equipment for belt conveyor, a novel design scheme of controlled transmission which uses hydraulic transmission system driving worm gear to control the output speed of planetary gear mechanism is proposed. The control strategy of multi-motor drive power balance which adopts master-slave structure is designed. The master driver adopts speed closed-loop control with current limiting and the slave drivers adopt power closed-loop control. The given power signal of slave pulley is decided by the master motor. The control system offers multiple communication interfaces which enable the belt conveyor to integrate in coal mine information platform and realize information resource sharing. The controlled transmission device and its power balance control system have characteristics of compact, reliable and high efficiency.
Study on the Effect of WC Size on the Thermal Expansion Coefficient of WC/Cu Composites
Abstract: In order to study the effect of WC size on the thermal expansion coefficient of WC/Cu composites after anneal, WC/Cu composites with different WC particle size were prepared by powder metallurgy method. In this paper the thermal expansion coefficient of WC/Cu composites were measured by digital image correlation method. The results show that the thermal expansion coefficient increased with the increasing of temperature and the particle size.