关键词: 液压机, 节能, 变频, 蓄能器, 传动效率

Abstract:

The transmission efficiency of a hydraulic press fast forging is less than 5%, it causes a great waste of energy. In view of this, a new hydraulic system of accumulator with compound power producer was proposed herein, which combined a direct-driven pump of variable frequency with accumulator. In order to control the pressure of the pump output, a  fuzzy self-turning closed-loop control strategy was adopted, thus making it possible stable pressure outputs without overflow under the low installed power, and providing stable power inputs for electro-hydraulic proportional control of the hydraulic forging press. Differential circuit was applied during down-stroke stage to reduce throttling loss. The mathematic model of pump unit was founded and working parameters' calculation principles were given.The experimental results show that the position error of  the new fast forging hydraulic system is lower to 0.2mm, and the total energy consumption is reduced by 65.3% compared with the traditional electro-hydraulic proportional system. Meanwhile, the results also prove that transmission efficiency is increased by 13.4%.

Key words: hydraulic press, saving energy, variable frequency, accumulator, transmission efficiency