Patent attributes
A control system for a hybrid construction machine includes first and second main pumps for supplying working oil, a boom cylinder extending by supply of the working oil to a piston-side chamber and raising a boom and contracting by discharge of the working oil from the piston-side chamber and lowering the boom, a regenerative spool valve controlled by a pressure of pilot pressure oil and adjusting a flow rate of the working oil discharged from the piston-side chamber, a regenerative motor for regeneration rotating by the working oil discharged from the piston-side chamber, a rotary electric machine connected to the regenerative motor, and a failsafe switching valve switching with a pressure of a regenerative passage between the regenerative control spool valve and the regenerative motor as a pilot pressure and lowering the pressure of the pilot pressure oil to the regenerative control spool valve so that a flow rate of the working oil discharged from the piston-side chamber is narrowed if the pressure of the regenerative passage is less than a set pressure.
