Simulation Study On Control Scheme Of The Hydraulic Speed Governing System Based On Variable Frequency Technology

The hydraulic speed governing system based on variable frequency technology is one new hydraulic speed governing way. It uses the inverter, the ordinary electrical motor and the constant displacement pump. It omits the complex changing displacement organization, it changes the electrical motor rotational speed through the power supply frequency changing, thus realizes that current displacement of the hydraulic system is adjusted. This kind of new hydraulic speed governing system mainly applies to the large-scale precise hydraulic lathe, the hydraulic promoting organization, the moulding plastics machine, the hydraulic crane and so on. The motor revolution axis in these systems all has a greater inertia moment, the system power is also big, the system must control motor rotational speed real-time. The hydraulic speed governing system based on the variable frequency technology is the typical big inertia, strong load interfere and multi- coupling nonlinear system. this makes it difficult for the traditional control scheme based on the linear theory very difficult to satisfy control request of the high-performance hydraulic speed governing system.. The new intellectual control theory offers the new mentality for us that we can design the new-type controller. Under this kind of situation, this article unifies the actual project background need, develops the research work of the following several aspects.According to the actual request of the hydraulic speed governing system based on the variable frequency technology, this article first introduces the basic principle about the hydraulic variable frequency speed governing system, establishes the mathematical model;Provids the foundation for the choice of control plan through carring on the system frequency range analysis and the analysis of stability. Next analyses each kind of interfere factor of the variable frequency hydraulic speed governing system, produces the system parameter and the load factor to influence about the motor rotational speedand the system pressure;The paper analyses the control strategy, proposes the speed closed loop control plan;In order to enhance the stablity and the response rapidity of the hydraulic variable frequency speed governing system, puts forward the Fuzzy-PID compound control plan. Finally utilizes MATLAB simulink software to carry on the simulation of the system in the changeable loading, the changeable temperature, the changeable leakage and different speed, under the changeable situation, obtains the corresponding response curve chart about motor rotational speed and the system pressure.Through analyzing the simulation results, system dynamic performance is stable, response is rapid, Thus Fuzzy-PID compound control plan is feasible.