Patent ID: 8831805

Claim:
A construction machine or industrial vehicle comprising: a power supply system which includes a chargeable and dischargeable capacitor and a feeder circuit connecting a chargeable and dischargeable battery and the capacitor to a load capable of power running and regeneration, feeds energy stored in the capacitor through an inverter to the load and feeds regenerative energy of the load through the inverter to the capacitor, wherein: the load is an electric motor; the capacitor is connected through a DC/DC converter to the load; the DC/DC converter includes control means that controls energy charged or discharged by the capacitor through the DC/DC converter; and the control means includes: power running/regeneration operation estimating means which estimates an operation pattern including a point of change between power running and regeneration modes of the motor according to previously stored operation pattern information including a point of change between power running and regeneration in repetitive work and revolution speed and torque of the motor, or DC current supplied to the inverter, or control lever information; and capacitor target voltage calculating means which controls an output command value of the DC/DC converter according to the point of change and operation pattern estimated by the power running/regeneration operation estimating means so that a capacitor target voltage sequentially decreases in power running and sequentially increases in regeneration.