Abstract: An electric machine is provided. The electric machine includes at least one stator, a shaft, movable in rotation around an axis of rotation, two rotors, each being interdependent of the shaft, at least two bearings, able to support both rotors and the shaft. A single bearing is located between both rotors along the axis of rotation.

Abstract: A reactive energy compensator that can be electrically connected to an AC electrical network, including at least one input direct voltage bus, at least one voltage inverter including switches and first and second capacitors having first and second voltages at their terminals, control means for the switches, including computation means capable of generating a target control current, means for combining the target control current and the output current from the inverter, means for transmitting a control signal capable of driving the switches, and correction means for the control signals of the switches, the correction means being capable of adding a balancing current to the target control current, the balancing current being able to correct the target control current so as to reduce the difference between the values of the first and second voltages, the target control current being increased for an even harmonic of the network frequency.

Abstract: A dc energy store system includes a dc energy store, an AC/DC power converter having ac terminals connected to an ac power supply and dc terminals connected to the dc energy store, and at least one auxiliary unit associated with the dc enemy store. The dc energy store system is adapted to be operated in a number of different operating modes including: (i) a first mode to supply power from the ac power supply to the dc energy store; (ii) a second mode to supply power from the dc energy store to the ac power supply; (iii) a third mode to supply power from the ac power supply to the auxiliary unit(s); and (iv) a fault mode where there is a fault in the ac power supply, and power is supplied from the dc energy store to the auxiliary unit(s).

Abstract: A reactive energy compensator (10) comprising: an input DC voltage (Vc) bus (13) capable of providing reactive energy; an inverter (18) connected to the DC voltage bus (13) and including controllable electronic switches (34) capable of converting the input DC voltage (Vc) into an intermediate alternating voltage, a device (22) for controlling the electronic switches, regulation means (22) for determining a value of a target active current circulating between the inverter and the network, capable of regulating the input direct current voltage (Vc) relatively to a set reference value; the device for controlling the switches, determining control signals according to the value of said target active current, determined from the error between the reference value and the square of the DC voltage of the bus via a transfer function, the definition of which varies according to the current value of said DC voltage.

Abstract: This method determines the value of a characteristic quantity (U1dc, U2dc) of a system for powering a load which comprises M DC-DC converters, connected in series to the terminals of the load and at the output of a DC current power supply, and at least one storage capacitor. This determination method comprises the measurement of a plurality of values of a first characteristic quantity (Ic) with a first high resolution, the measurement with a low resolution of a value of a second characteristic quantity (U1dc, U2dc), and a determination with a second high resolution of a value of the second characteristic quantity (U1dc, U2dc) from the plurality of values measured with the first high resolution of the first characteristic quantity (Ic) and from the value with the low resolution of the second characteristic quantity (U1dc, U2dc). The first and second high resolutions are at least 10 times greater than the low resolution.

Abstract: An ac synchronous electrical machine includes a stator and a multi-phase stator winding that defines a plurality of stator poles. The stator winding has two or more coil groups, each coil group including a plurality of coils for each phase that are received in winding slots in the stator. The stator winding is connected to a power source/sink. The coil groups are connected in series and each coil group is connected to a power source/sink by a respective switch (26a, 26b . . . ). This allows one or more of the coil groups to be selectively supplied with power from the associated power source/sink or selectively supply power to the associated power source/sink. The switches are operated by a controller. The coils in each coil group are arranged substantially symmetrically around the circumference of the stator to define selected poles of the electrical machine and to produce a constant and balanced rotating torque when any particular coil group or combination of coil groups is active.

Abstract: Device for balancing voltage on terminals of at least one capacitor of a set of N?1 capacitors connected in series between a positive terminal and a negative input terminal and connected through intermediate points, comprising at least one balancing module connected between both input terminals; each balancing module including means for determining the amount of excess or lacking charges in the intermediate points, a temporary electric energy storage element including two terminals, first current guiding means to extract electric charges from an intermediate point towards a terminal of the storage element, second current guiding means to inject electric charges from the other terminal of the storage element towards an intermediate point, and a member able to control the first means so as to extract charges from at least one intermediate point and able to control the second means so as to inject the charges to at least one intermediate point.

Abstract: The present invention relates a rotor assembly for an electrical machine (e.g. motor or generator) where a tuned vibration absorber adapted to provide radial damping is mounted directly to the rotor shaft.

Abstract: The present invention relates to a retaining band which provides outer reinforcement for the rotor assembly of a high speed electrical machine. The rotor assembly includes a plurality of circumferentially-spaced permanent magnet assemblies. A retaining band is fitted around the rotor assembly and applies a pre-load to the permanent magnet assemblies in the radial direction. The retaining band has a plurality of voids that are sized and shaped to provide the retaining band with a progressive spring stiffness in the radial direction. The voids are open before the retaining band is fitted and during the fitting process the retaining band is deflected in the radial direction so that the voids close up and the retaining band becomes substantially solid.

Abstract: A rotor (or a stator) for a superconducting electrical machine includes a mounting that is maintained at substantially ambient temperature during operation of the electrical machine and a field coil support structure. A plurality of superconducting field coils are maintained at cryogenic temperatures during operation of the electrical machine and are supported by the field coil support structure. A plurality of coupling elements are used to fix the field coil support structure to the mounting. The coupling elements can be linear struts and carry substantially of the torque that is experienced during operation of the electrical machine.