Research On Characteristics Of Frequency Conversion Driving Flywheel Pump Power Unit

At present,hydraulic press adopts motor and pump direct driving mode universally,and accords to maximum power to configure installed capacity.hydraulic press works in the full load stage shortly,most time works in the light load stage,the energy utilization of the motor is not sufficient during the operation,the system wastes energy heavily,the system transmission efficiency is low,but investment costs is high.The dissertation combines the frequency control technology and flywheel energy storage technology,and puts forward a kind of frequency conversion driving flywheel pump power unit system.The power unit uses frequency conversion to control three-phase induction motor and flywheel,motor drives the pump to work,controller controls the flywheel to store energy and releases energy.Flywheel stores energy in the light load stage,and releases energy in the full load phase.In this dissertation,the design and experiments of the power system are researched deeply.According to the working characteristics of the hydraulic press and the work principle of power unit,comparative analysis of the existing motor flywheel pump system's flywheel design methods,the flywheel design principle of the new hydraulic power unit is proposed,and a hydraulic power unit experimental device is designed.The power unit experimental device control system is designed.The control system is made of pressure sensors,proximity switches,frequency converters and microcontroller,microcontroller uses AT89S52 chip for the CPU,and microcontroller is expanded by A / D module,D / A module circuit,serial communication module circuit and display module circuit.The dissertation used C language to write function programs.The power unit mathematical model is established,and the simulation of the power unit is carried out by MATLAB.The change of the motor speed of the power unit with or without flywheel under unload is analyzed,and the change of power and speed in working stage are analyzed.The experimental study of the device is carried out.By controlling the proportional valve output pressure to simulate the load pressure change,the dissertation analyzes the actual change of motor speed,motor power and load power in the same work condition and different work speed,and analyzes the energy saving effect of the power unit.The experiments indicate that,under the same operating conditions,compared to the maximum power configuration of the motor pump system,the new hydraulic power unit can reduce installed power by 30% at least,and works stably.