The invention concerns a portable power supply system (30) intended to supply a remotely controlled, electrically driven work machine (1) with electrical power, where the work machine is of the type that demonstrates a propulsion means that includes continuous tracks (8b) and is equipped with a maneuverable arm (10) intended to carry a tool at its free end, and electric motor (19) that is connected to a hydraulic pump (20) and is intended to supply the operating means (8c, 10a) of the machine with a hydraulic medium, whereby the work machine is intended to be connected under normal operation to a primary source of power (30a) via an electrical cable (2′), which primary source of power includes a fixed alternating current electricity distribution grid at the location. In order to be able to supply the current that is required it comprises a DC energy-storage arrangement (29) that, including a secondary source of power (30b), can store energy and, when necessary, supply energy in electrical form; a coupling arrangement (31, 33, 34, 34′) that makes it possible to choose between connecting the primary (30a) or the secondary (30b) source of power to the electric motor in order to drive the same.

The present invention relates to an apparatus for controlling a cascaded hybrid construction machine system and a method therefor, which apparatus includes: a control part for controlling an electric motor for driving an actuator differently according to whether or not the actuator performs a recovery action and whether or not an energy storage device can be recharged; and a motor driver for driving or stopping the electric motor by switching under the control of the control unit, wherein when the actuator performs a recovery action for both the overcharged state and the failure state of the energy storage device, the motor for driving the actuator is temporarily stopped by the switching of the motor driver so as to restrain the recovery energy generated, thus protecting the hybrid power source system and keeping the operator safe as well as resolving the problem of the working time being increased due to the system's shutting off.

The present disclosure relates to a charging system for an energy storage device of hybrid construction machinery, and more particularly, to a charging system for an energy storage device of hybrid construction machinery which is capable of computing an amount of regenerable energy predicted according to an operational situation of an actuator, calculating a target charging rate of the energy storage device by reflecting the computed amount of the regenerable energy, and finally, computing an amount of power generated by an engine auxiliary motor in order to compensate for a difference between a target voltage and an actual voltage of the energy storage device, in the case of charging the energy storage device of the electric hybrid construction machinery.

An exemplary embodiment suggested in the present specification provides an apparatus and a method of controlling a voltage of a direct current terminal of construction machinery equipped with a motor, which are capable of improving energy efficiency of a power conversion apparatus, such as an inverter and a converter by changing a voltage of the direct current terminal to an optimum voltage size in consideration of operation conditions of a swing motor, an engine auxiliary motor, and an energy storage apparatus.

A hybrid construction machine detects the voltage of each cell that forms a battery, calculates a difference voltage between the detected voltage and a predetermined upper-limit working voltage, selects the lower one of the calculated difference voltage and a stored difference voltage, corrects an upper-limit working charging rate to decrease as the selected difference voltage decreases, and controls charging of the battery, based on the corrected upper-limit working charging rate.

A power transmission device of a work vehicle includes a generator, a motor, and an energy storage unit. The energy storage unit stores electricity generated by the generator. A forward/backward travel switch operation device receives an instruction for forward or backward travel from an operator. A vehicle speed detection unit detects the speed of the vehicle. A control unit includes an energy management requirement determination unit. The energy management requirement determination unit determines, on the basis of the difference between a target electricity storage amount and a current electricity storage amount in the energy storage unit, the energy management required power required by the power transmission device for charging the energy storage unit. The energy management requirement determination unit increases the target electricity storage amount when a first travel direction according to the instruction and a second travel direction determined from the vehicle speed are different.

A mobile mining machine includes a plurality of traction elements, a plurality of motors, a power source in electrical communication with the plurality of motors, and an energy storage system in electrical communication with the plurality of motors and the power source. Each of the motors is coupled to an associated one of the plurality of traction elements. Each of the motors is driven by the associated traction element in a first mode, and drives the associated traction element in a second mode. The energy storage system includes a shaft, a rotor secured to the shaft, a stator extending around the rotor, and a flywheel coupled to the shaft for rotation therewith. In the first mode, rotation of the motors causes rotation of the flywheel to store kinetic energy. In the second mode, rotation of the rotor and the flywheel discharges kinetic energy to drive the motors.

A power supply system can be used for an electric motor that drives a hydraulic pump in a demolition robot. The system provides a DC current from a source of power, controls and monitors the voltage level (VDCnom) of the DC current, can be activated, and supplies a pre-determined load current (I.sub.L) from the source of power to the electric motor. In order to offer improved operational availability and flexibility, the load current (I.sub.L) can be constituted by a DC current, and the electric motor can be a DC motor.

An electricity storage device (20) includes voltage detectors (25A) to (25C) detecting cell voltages (VcA) to (VcC) and a controller (26) controlling the cell voltages (VcA) to (VcC). The controller (26) includes a balancing control section (27) performing balancing control reducing deviations of the cell voltages (VcA) to (VcC), a maximum cell voltage calculating section (28) calculating a maximum cell voltage (Vmax) in the cell voltages (VcA) to (VcC), a minimum cell voltage calculating section (29) calculating a minimum cell voltage (Vmin) in the cell voltages (VcA) to (VcC), and an abnormality detecting section (34) detecting an abnormality of the electricity storage device (20) in accordance with whether or not a differential voltage (ΔV) between the maximum cell voltage (Vmax) and the minimum cell voltage (Vmin) is within a range of a reference differential voltage (ΔVstd1) calculated based on a history of the balancing control performed.

The available power surge capacity of a battery is detected. The available steady state regeneration energy capacity of the battery is also detected. The available battery generation power, available from an electric motor, is detected as well. The generation power available from the electric motor is applied to regenerate (or recharge) the battery based upon the available power surge capacity, and the available steady state capacity of the battery.