Based On Four Quadrant Worked Variable Frequency Hydraulic Closed Circuit And Its Application Research

With the development of the advanded control technic and power electrics and electronics, variable frequency speed control technology has become more and more outstanding and has been used in more and more abroad field.Using variable frequency technology in hydraulic drived system can help reduce the hydraulic component, make the structure of the hydraulic system be simple, reliable worked,what's more,the whole system will be more energy-saving. Now the variable frequency hydraulic technology has an extensive potential application in many kinds of equipments such as hydraulic elevator , hydraulic elevating mechanism ,machine tool and injection machine. In this paper, some components of the variable frequency closed circuit system are choosed ,the installation structure of them in the system is designed. Also, the data-collected and control output system of the experimental system is built. To develop research on the system,the model of the whole system is founded in AMESim, a kind of simulation software.Then the simulation research on the openloop and closeloop PID controlled system is carried out. The result suggests that when uses closeloop PID control mode, the whole system will have well static and dynamic characteristic.The main research contents are as follows.In chapter 1, the development course, research actuality and application field of variable frequency hydraulic technology home and abroad are summarized. The main research subjects are summarized in the paper.In chapter 2, the power component and actuate component of the variable frequency colsed hydraulic system are designed and built; The data-collect system is also built to carry out experiments on the system ;the software of the control system is written in turbo C.In chapter 3, mathematic models of the variable frequency hydraulic power unit are built, simulation models are also set up using AMESim. The values of model's parameters are selected and determined, and the simulation research is carried out. The results are verified by Experimental Research.In chapter 4, the application of the frequency conversion and close circuit hydraulic system in hydraulic oil pumping unit. According to design and application research, the characteristics of the hydraulic oil pumping unit are improved by using the system above. The installed power and energy consumption are reduced, and the structure of the application system is simplified.In chapter 5, some conclusions are given and some new views are put forward in the future.