An energy storage and delivery system includes a crane elevator cage, where the crane or elevator cage is operable to move one or more blocks from a lower elevation to a higher elevation to store energy (e.g., via the potential energy of the block in the higher elevation) and operable to move one or more blocks from a higher elevation to a lower elevation (e.g., by gravity) to generate electricity (e.g., via the kinetic energy of the block when moved to the lower elevation). 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 electrical grid.

A lifting device includes a motor designed as a three-phase asynchronous motor via which the lifting device can be driven to lift and lower a load, and includes a brake resistor via which a power output resulting from a motor generator operation that is carried out when lowering the load at a lowering speed can be converted into heat. The brake resistor is designed for a rated power which is less than the power resulting with a nominal load and a nominal speed. A method for operating a lifting device includes lowering a load at a lowering speed while taking into consideration at least one load capacity characteristic value of the brake resistor for the lowering speed, a threshold is set such that while lowering the load at the lowering speed corresponding to the threshold, the resulting power output is limited to the at least one load capacity characteristic value.

A lifting device includes a motor designed as a three-phase asynchronous motor via which the lifting device can be driven to lift and lower a load, and includes a brake resistor via which a power output resulting from a motor generator operation that is carried out when lowering the load at a lowering speed can be converted into heat. The brake resistor is designed for a rated power which is less than the power resulting with a nominal load and a nominal speed. A method for operating a lifting device includes lowering a load at a lowering speed while taking into consideration at least one load capacity characteristic value of the brake resistor for the lowering speed, a threshold is set such that while lowering the load at the lowering speed corresponding to the threshold, the resulting power output is limited to the at least one load capacity characteristic value.

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 mobile lifting apparatus, comprising at least one truck, provided with a first drive device comprising at least one internal combustion engine connected by power transmission means to one or more user devices of the truck hydraulically actuated, and at least one boom provided with a second drive device.

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.

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 drive apparatus that can continue operation within the upper limit of system control even if a voltage drop of an AC power source occurs during operation of a motor used for a hoist or a crane is provided. The inverter control unit of the motor drive apparatus includes a speed reference setting means for setting the rotation speed of the motor, means for detecting a speed deviation between the output of the rotation speed detection means for detecting the rotation speed of the motor and the output of the speed reference setting means, means for controlling the output current of the inverter according to the output of the speed deviation. The speed reference setting means includes a correction circuit for correcting an external speed command given from outside. The correction circuit corrects the external speed command according to a deviation between a detection value of a DC voltage and a first reference value when a voltage drop signal is received from the voltage drop detection means, and makes the corrected speed command as the output of the speed reference setting means.

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 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.