Research On Radial Piston Constant Flow Pump With Digital Distribution Under Random Low Speed Driving

Nowadays,with the traditonal energy drying up and people’s attention to environment procection,wind and ocean power generation and other generation technology of the sustainable energy have gotten more and more attention.But as the motive power of wind and ocean power generation,wind and wave both have the characteristics of random and variable size.The characteristics increase the difficulty of collection and conversion of the motive power and the development of power system.In recent years,for the advantages of high power output,easy to automatic control and small compact structure,hydraulic technology begins to get application in wind and ocean power generation.Hydraulic pump can be as a key element of power collection and conversion.Now the most quantitative hydraulic pumps are designed on the principle of constant and high speed drive.So this kind of pump is hard to keep the need of random and variable size of wind and wave for long time and it is difficult to keep running in low speed for long time.In view of this,this paper designs a kind of radial piston hydraulic pump with digital distribution and constant flow output,in which high speed solenoid on/off valves are used to replace the traditional distribution mechanisms.Around the pump with digital distribution,this paper expands in many aspects: the principle of digital distribution and constant output flow,the design of mechanical structure,the static and dynamic mathematical model,the method of cosntant flow control and simulated analysis,the hardware and software design of control system,etc.The main concrete work is as follows:1)Compared the distribution characteristic of traditional piston pump,the paper analyses the distribution principle of the digital distribution pump.The distribution relationship tables and interval tables of piston cavity’s oil extraction under clockwise and counterclockwise rotating are given.Meanwhile,the paper analyses the flow control principle.There are two methods,duty cycle control and stroke ratio control.2)Based on the selected hydraulic pump ontology model,measurement and UG model are carried out.Then the selections of the high speed solenoid on/off valve and absolute value angular encoder are done.Based on these structures,the design and UG model of the digital distribution structure are finished.Finally the design and model of the whole pump are accomplished.3)On account of the kinematics analysis of piston,the static model is established.Based on the valve port flow equation of the high speed solenoid on/off valve and the torque balance equation,the whole dynamic model is established.Meanwhile,through the distribution relationship table and signal-piston equations,the angel section dynamic model is established.4)Because of the flow control principle of the digital pump,this paper introduces the methods of constant output flow.Through the methods,the simulated analyses of the static,whole dynamic and angel section dynamic models are done by the Matlab/Simulink software.Based on Matlab GUI,the simulation platform of the digital pump is compiled.5)Based on the distribution principle and constant output flow methods,the controller of the digital pump is designed.The PCB is designed by Altium Designer software and the ECU is made.The control software program and the simulation debug of the ECU are completed.The accomplished research work such as principle,theoretical models,methods and conclusions provide the basis for the manufacturing of the radial piston hydraulic pump with digital distribution and constant flow output and further theoretical and experimental analysis of characteristics.