The invention generally relates to a machine with an electric drive and an energy storage system for the intermediate storage of recovered energy. The invention relates in particular to machines that function statically or quasi-statically with a primary electric drive and a secondary hydraulic drive that function in cyclical movements, such as in the form of a material-transferring device like an excavator or crane, having an electric drive with at least one electric motor for driving the drive train of the machine and with an energy storage system for the intermediate storage of reverse power released during towing and/or braking operation and transferred from the drive train to the electric motor. The invention also further relates to a method for operating a machine with an electric drive, in which energy recovered during a towing or braking operation is used to compensate for system losses or is stored temporarily. It is proposed that at least most of the energy transferred from the drive train back to the electric motor not be converted into electric energy, but rather that it be stored in the form of kinematic energy and that, to this end, the electric motor be put into a state with regard to its electromagnetic resistance and/or its torsional or drag torque in which the drag resistance or the electromagnetic torque of the motor is largely eliminated or at least significantly reduced relative to regular motor and/or generator operation.

A an energy storage system includes a crane and a plurality of blocks, where the crane is operable to move blocks from a lower elevation to a higher elevation (via stacking of the blocks) to store electrical energy as potential energy of the blocks, and then operable to move blocks from a higher elevation to a lower elevation (via unstacking of the blocks) to generate electricity based on the kinetic energy of the block when lowered (e.g., by gravity). The energy storage system can, for example, store electricity generated from solar power as potential energy in the stacked blocks during daytime hours when solar power is available, and can convert the potential energy in the stacked blocks into electricity during nighttime hours when solar energy is not available, and deliver the converted electricity to the power grid.

A motor assembly includes a three-phase asynchronous machine equipped with three stator phases, a capacitor assembly to establish self-excited generator operation of the asynchronous machine, a load resistor assembly to establish resistive load for self-excited generator operation of the asynchronous machine, and a load resistor switch which is arranged to connect the load resistor assembly to the stator phases. The load resistor assembly is asymmetrical.

A motor assembly includes a three-phase asynchronous machine equipped with three stator phases, a capacitor assembly to establish self-excited generator operation of the asynchronous machine, a load resistor assembly to establish resistive load for self-excited generator operation of the asynchronous machine, and a load resistor switch which is arranged to connect the load resistor assembly to the stator phases. The load resistor assembly is asymmetrical.

A an energy storage system includes a crane and a plurality of blocks, where the crane is operable to move blocks from a lower elevation to a higher elevation (via stacking of the blocks) to store electrical energy as potential energy of the blocks, and then operable to move blocks from a higher elevation to a lower elevation (via unstacking of the blocks) to generate electricity based on the kinetic energy of the block when lowered (e.g., by gravity). The energy storage system can, for example, store electricity generated from solar power as potential energy in the stacked blocks during daytime hours when solar power is available, and can convert the potential energy in the stacked blocks into electricity during nighttime hours when solar energy is not available, and deliver the converted electricity to the power grid.

A an energy storage system includes a crane and a plurality of blocks, where the crane is operable to move blocks from a lower elevation to a higher elevation (via stacking of the blocks) to store electrical energy as potential energy of the blocks, and then operable to move blocks from a higher elevation to a lower elevation (via unstacking of the blocks) to generate electricity based on the kinetic energy of the block when lowered (e.g., by gravity). The energy storage system can, for example, store electricity generated from solar power as potential energy in the stacked blocks during daytime hours when solar power is available, and can convert the potential energy in the stacked blocks into electricity during nighttime hours when solar energy is not available, and deliver the converted electricity to the power grid.

A an energy storage system includes a crane and a plurality of blocks, where the crane is operable to move blocks from a lower elevation to a higher elevation (via stacking of the blocks) to store electrical energy as potential energy of the blocks, and then operable to move blocks from a higher elevation to a lower elevation (via unstacking of the blocks) to generate electricity based on the kinetic energy of the block when lowered (e.g., by gravity). The energy storage system can, for example, store electricity generated from solar power as potential energy in the stacked blocks during daytime hours when solar power is available, and can convert the potential energy in the stacked blocks into electricity during nighttime hours when solar energy is not available, and deliver the converted electricity to the power grid.

A an energy storage system includes a crane and a plurality of blocks, where the crane is operable to move blocks from a lower elevation to a higher elevation (via stacking of the blocks) to store electrical energy as potential energy of the blocks, and then operable to move blocks from a higher elevation to a lower elevation (via unstacking of the blocks) to generate electricity based on the kinetic energy of the block when lowered (e.g., by gravity). The energy storage system can, for example, store electricity generated from solar power as potential energy in the stacked blocks during daytime hours when solar power is available, and can convert the potential energy in the stacked blocks into electricity during nighttime hours when solar energy is not available, and deliver the converted electricity to the power grid.

The disclosure relates to a work machine, comprising a primary energy source for feeding electric energy into a link, a gear for performing a task of the work machine, at least one electric drive connected to the link in order to operate the gear of the work machine, a holding brake for fixing or releasing the gear, and an energy store which is connected to the link in order to provide electric energy demanded from the link upon actuation of a gear and/or to absorb electric energy fed into the link. According to the disclosure, during an emergency lowering of the gear, the at least one electric drive to convert the kinetic energy into electric energy and to feed it into the link. In the event of an unavailability or failure, the primary energy source is configured to absorb the energy fed into the link by the electric drive.

An electric winch device includes a required braking force estimation section which estimates a required braking force required to stop a free-falling object at a position at an allowable stopping height; a braking force determination section which determines, out of an operational braking force, each of a first braking force to be borne by a braking device and a second braking force to be borne by a braking force which is generated in an electric motor due to consumption of regenerative power; and a control section which causes the braking device to apply the first braking force to a winch drum. The braking force determination section determines the first braking force to be a braking force equal to or greater than the required braking force when, at a time of stopping of the free-falling object, the operational braking force is equal to or greater than the required braking force.