Study On Frequency Control System Of Bridge Crane Based On PLC Fuzzy Control

The bridge crane plays an important role in the national economy as a typical material handling device, so it is important to raise the bridge crane operational efficiency and make the operation system to be secure. The electric control system of the traditional bridge crane adopts rotor circuit applying series resistor in step speed regulation, and it makes the system have many disadvantages, for example: poor reliability, complex operation, high failure rate, high waste of energy, low efficiency ect. So the research on the control system of the bridge crane has practical significance, and it is also a subject for the domestic and foreign experts.With the development of power electronic technology, microelectronics and modern control theory,frequency control technique has been widely used in every field as high-tech and energy-saving technology. The whole performance of the crane could have been improved immensely by frequency control technique, and it could also solve many problems in the control system of the bridge crane.In this paper, a fuzzy control method applied to the system with PLC is presented and the fuzzy control algorithm to be realized with PLC is given according to conditions of variable frequency speed control system. We first research into the design of variable frequency speed control system, and then the communication between PLC and PC and the communication between PLC and inverter are mainly discussed. Furthermore, it pays more attention to introduce the principle and structure of fuzzy controller, and a fuzzy controller of motor speed is researched and designed. The engineering application and actualization of fuzzy control is researched and the key program is given, based on SIEMENS S7-200 PLC.The variable-frequency regulating system of the bridge crane in this paper, can realize the motor speed regulation, and meet the demand of energy saving and production. The system not only has the characteristics of reliability, flexibility, and adaptability, but also has higher intelligent degree and static and dynamic character. The results show the system has good performance and applicable value.