Study On Characteristic Of Digital Displacement Pumps Based On VVVF And High-speed On/Off Valve Control

Digital hydraulic control technology combines with computer technology, mechanical technology, microelectronic technology and hydraulic technology, with its high reliability, energy saving, anti-interference ability and easy communication with the computer, etc. It becomes the development trend of the hydraulic control system.Digital variable pump is a power component as digital hydraulic control system, which plays a central role in the system. There are two main control ways which are variable speed control and variable volume control, but they all have lack of dynamic response slow and variable range narrow, which seriously restrict the performance improvement of the hydraulic system control.The digital variable pump bases on a frequency control and high-speed on/off valve control is proposed. In the composite control system, digital variable pump bases on a variable speed control and a throttling control of the high-speed on/off valve by changing the input signal of the high-speed on/off valve and the input speed of the motor, and it will achieve combination with two ways.Firstly, the overview of the development of digital hydraulic control system and digital hydraulic components are introduced. For the deficiencies of the existing digital variable pump, a digital variable of the composite control is proposed. And through the analysis of the relevant characteristics of the VVVF control mode, mathematical model with U/f and slip frequency vector control mode is established, and their characteristics were respectively analyzed to using Simulink. In this way, using the slip frequency vector control as the digital variable frequency control mode has been determined. Secondly, the working principle of high-speed on/off valve control cartridge valves is described and the mathematical model of the high-speed on/off valve control cartridge valve is established. Through the comparative analysis of the characteristics of different programs under the control AMEsim software, the use of the two position three way high-speed on/offing valve controlling for cartridge valve has been identified, which was a control components as the digital variable pump. Finally, the overall structure of the digital variable pump has been designed. According to the working principle, the joint simulation model of AMEsim and Simulink has been established and the control performance of the digital variable pump under the different Parameters has been analyzed. And by optimizing control, the design requirements of the digital variable pump have been acheived.