| Multi-motor drive is widely used in conveyor belt, which is high power, long distance and high speed. For the actual operation because of different characteristics of a single motor and the installation error and other causes making drive motor at different speeds. It's make the two drive motors endure different moment, which causes serious overloading of motor and even burning. These problems affect the belt conveyor safe operation. From this paper, in order to solve the problem research the synchronous multi-machine drive motor control method, and design the synchronous multi-machine control system based on the programmable logic controller.According to the multi-machine synchronization control system hardware requirements built test rig, design the method of multi-machine synchronization control method as follows: the programmable logic controller inputs speed pulse signal of motor and driven motors, which outputted by rotary encoder. PLC PID control circuit according to speed error controls the signal outputted to the inverter. Multi-machine synchronization control system by adjusting the frequency of the inverter to change the speed of the driven motor in order to achieve the purpose of multi-machine synchronization. The system can run real-time monitoring parameters such as: motor current, motor speed, inverter operating frequency and so on. Through the PID screen can change the PID control loop parameters to achieve the best results. Data show that speed run in a variety of circumstances the stability of the system can control the speed accuracy within 0.2%. Experiment shows that when the gain is 0.7 times, the integration time is 0.1 min, the system performs best.In order to verify the system's PID parameters, load 20%, 30%, and 50% of the maximum speed of the step signal to observe the response of the driven motor speed. Experiments show that the driven motor is able to follow the command motor, which meets the requirements of practical application.
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