In a system and method for operating a system, which includes a first inverter which feeds a first electric motor, and a second inverter which feeds a second electric motor, the DC-voltage side connection of the first inverter is connected to the DC-voltage side connection of a rectifier which is supplied from an electrical AC-voltage supply network, the DC-voltage side connection of the second inverter is connected to the DC-voltage side connection of the rectifier, in particular, the two DC-voltage side connections of the inverters are switched in parallel, and a controller is provided, in particular in the first inverter, which controls the current accepted and acquired by the first inverter at its DC-voltage side terminal toward a setpoint value in that the torque of the first electric motor fed by the first inverter is the controlled variable.

The invention relates to a system (36) for an electrically driven vehicle (10), in particular a utility vehicle (10), comprising at least one first energy store (38) of the type of a battery (38), and at least one second energy store (40) of a type different from the type of a battery (38). The second energy store (40) has an energy density (54) that is lower than an energy density (56) of the first energy store (38), and a power density (58) that is higher than a power density (60) of the first energy store (38). The first energy store (38) and the second energy store (40) are furthermore configured so as to provide energy for an electric drive (12) of the vehicle (10). The invention furthermore relates to a vehicle (10) having a system (36), and to a method for operating a system (36).

An electric power-regulating system includes an electric-load end, a power-supply end, a power regulator, a DC-bus device, a flywheel energy-storage device, a switch device and a controller. The flywheel energy-storage device connects the DC-bus device. The switch device is connected between the flywheel energy-storage device and the DC-bus device. The switch device provides at least one current-flow direction between the DC-bus device and the flywheel energy-storage device. The controller controls the power regulator and the flywheel energy-storage device. When a voltage of the DC-bus device exceeds a operation range, the controller selectively limits the current-flow direction of the switch device. Further, when a voltage-bias direction of the switch device and the current-flow direction are the same, the controller allows a current of the DC-bus device to flow into or out of the flywheel energy-storage device in the current-flow direction. In addition, an electric power-regulating method is also provided.

A motor drive system includes a converter configured to convert power between AC power in a power source and DC power in a DC link, an inverter for drive configured to convert power between the DC power in the DC link and AC power serving as drive power or regenerative power for a servomotor for drive, a motor control unit for drive configured to control the servomotor for drive connected to the inverter for drive, a power storage device configured to store the DC power from the DC link or to supply the DC power to the DC link, and a base holding energy change unit configured to change a base holding energy defined as a reference value of a holding energy of the power storage device, in accordance with the holding energy of the power storage device.

A motor drive system includes a converter configured to convert power between AC power in a power source and DC power in a DC link, an inverter for drive configured to convert power between the DC power in the DC link and AC power serving as drive power or regenerative power for a servomotor for drive, a motor control unit for drive configured to control the servomotor for drive connected to the inverter for drive, a power storage device configured to store the DC power from the DC link or to supply the DC power to the DC link, and a base holding energy change unit configured to change a base holding energy defined as a reference value of a holding energy of the power storage device, in accordance with the holding energy of the power storage device.

A motor drive system includes a converter configured to convert power between AC power in a power source and DC power in a DC link, an inverter for drive configured to convert power between the DC power and AC power in a servomotor for drive, a motor control unit for drive configured to control the servomotor for drive, a power storage device configured to store the DC power from the DC link or supplies the DC power to the DC link, and a determination unit configured to determine whether the holding energy of the power storage device is lower than a threshold for energy shortage determination, wherein when the holding energy is lower than the threshold for energy shortage determination, the motor control unit for drive controls the servomotor for drive by setting an additional standby period in which the servomotor for drive is inactive in a predetermined operation pattern.

A power transfer system includes a series of energy storage modules (ESMs) or energy storage devices (ESDs) that are coupled together to be able to transfer power between one another, as well as receive power from a power source, such as an onshore power generator. The energy storage modules may be hybrid energy storage modules, each including an electrical-machine-inertial energy store and an electro-chemical energy store. The energy storage modules are configured to receive constant-current DC or AC input from the power source, and are able to provide constant-current and constant-voltage output, either sequentially or simultaneously. The power transfer system allows the modules to operate independently or in conjunction with one another, should some of the connections of the system be broken. The energy storage modules may be used to provide power to underwater systems, for example sonar systems, weapons systems, or underwater vehicles.

A gas turbine engine includes first and second electrical machines coupled to the gas turbine engine, each of the first and second electrical machines electrically coupled to both a primary electrical bus and a secondary electrical bus. The gas turbine includes a first controller configured to control operation of the gas turbine engine, and a second controller coupled to the first controller, the second controller configured to respond to control inputs from the first controller and control an electrical output of the first and second electrical machines to the primary and secondary electrical busses. A converter controller is coupled to an energy storage system, the second controller, the primary electrical bus, and the secondary electrical bus.

A DC voltage network includes at least three energy storage networks, each having an energy store supplying a DC voltage, and at least three power converters implemented as DC voltage converters. The energy store and the power converters are electrically connected at a common point, At least three DC voltage sub-networks are each connected to a respective power converter of the energy storage networks. A feed device connects a respective DC voltage sub-network to an AC voltage network. The DC voltage network may be installed in a vehicle, in particular a ship. In a method of controlling the DC voltage network in the event of a fault, at least one of the power converters is switched off to protect the DC voltage network, depending on the location of the fault.

The present invention discloses a control system for monitoring and control of a micro-grid (100). The control system comprises a first controller for controlling of at least one of a power generation source and an electrical load, and a second controller (245) for controlling a rotating electrical machine (246). The rotating electrical machine (246) is electrically connectable to an electrical bus (205) of the micro-grid (100) for one of receiving electrical power and supplying electrical power. The second controller (245) is configured to coordinate with the first controller for operating the rotating electrical machine (246) by engaging the clutch (244) to couple the rotating electrical machine (246) to the prime mover (242), for supplying power.