Research On Power Balance Of Multi-motor Drive In Belt Conveyer

Multi-motor drive method was widely used in Belt conveyers, which were high power, long distance and high speed. The distribution ratios of power and drive force among motors were usually departure from the original designed point in practicality, and this brought imbalance of belt tension and motor power, further more, this may cause the overload or damage of motor. In this paper, the power balance of multi-motor drive Belt conveyer was researched to solve the problem mentioned above. The speed regulation hydrodynamic coupling, which was controlled by PLC, was adopt to achieve the power balance of multi-motor, and the composition of the control system was also determined.The method to achieve power balance was determined according to the control principle of power balance, and it can be described as following. To detect the currents of motors which drive Belt conveyer, then import the currents to PLC and compare with the reference current, the dispersion of reference current and current detected was regarded as controlled quantity to control the step-servomotor. By this way, the flux of hydrodynamic coupling can be controlled and the aim to control the power of motor can achieved.According to the drive character of motors used in Belt conveyer, four methods was mentioned to acquire the reference current, which was used to obtain controlled quantity after compare with the currents detected. The mean of currents detected was chosen as the reference current.The input and output quantities of fuzzy control was selected based on fuzzy control principle, the input quantities were also changed to fuzzy variable. The membership grade, the control rule and the control decision table were gained in this paper. The algorithm pattern which adopted PLC to achieve the power balance of multi-motor drive Belt conveyer was given. The simulation models of speed regulation hydrodynamic coupling and motor were established in the simulation circumstance of Matlab, combining with the fuzzy control algorithm, the simulation model of the control system was also established. The results of the simulation can be described as following. When the system started, the motor can reach the steady situation in about one second, and avoided the damage of motor caused by the high starting current. When the motor was disturbed and the power was imbalance, the system can adjust to re-distribute the power among motors, and achieve the balance of power. The adjust time was about one second, and this can avoid the accident caused by power imbalance.The result of simulation indicated that the control method introduced in this paper can used to achieve power balance of multi-motor drive Belt conveyer..