Patent ID: 9725879
Date: 2017-08-08
CPC Classifications: B60L,E02F,H02P,Y02T

Claim:
1. A portable power supply system for an electrically driven work machine, the electrically driven work machine comprising a propulsion means with continuous tracks with which the work machine can be driven, a maneuverable arm coupling a tool at a free end of said maneuverable arm, wherein the electrically driven work machine is connected to a primary source of power during normal operation via an electrical cable and said primary source of power including a fixed alternating current (AC) electricity distribution grid at a job site, the portable power supply system comprising: an electric motor connected to a hydraulic pump to supply the operating means of the work machine with a hydraulic medium, a secondary source of power comprising a direct current (DC) energy-storage arrangement with the ability to store and to supply electrical energy, a rectifier for the conversion of AC from the fixed electricity distribution grid at the job site to DC for the energy-storage arrangement, and a coupling arrangement arranged between the primary source of power, the secondary source of power and the electric motor such that when necessary, said coupling arrangement allows the secondary source of power to be connected to the electric motor in order to drive the electrically driven work machine, temporarily, wherein the coupling arrangement comprises a DC bus to which the rectifier is connected in order to supply DC from the primary source of power to the DC bus, a control circuit which is connected to the DC bus and controls and monitors the levels of voltage that are supplied from the DC bus to the electric motor through continuously sending and receiving signals from the rectifier, an inverted rectifier, and the secondary source of power that are connected to the DC bus, and the secondary source of power provides sufficient power such that it alone can supply the electrical power that is required to the work machine in the absence of power from the primary source of power, and can also serve as a supplemental source of power to the primary source of power when the primary source of power lacks sufficient power required to operate the work machine.