1989 Volume 1989 Issue 1 Pages 95-102
From a view point of saving energy, power losses in hydraulic systems including power sources should be minimized as small as possible. In conventional hydraulic power units, the output power is adjusted by controlling a displacement of variable displacement pump to avoid a waste of excess power. In this study, it is proposed for adjustment of the output power that rotating speeds of a fixed displacement pump is controlled by making use of a inverter-motor drive. We apply a digital control scheme to the energy-saving hydraulic system. A pressure feedback control system and an estimated pressure feedback control system are discussed and the results are experimentally verified. Experimental results demonstrate that the studied systems are effective to save energy for constant pressure power sources.
