Abstract: A method of operating a dual fed system is described where power is supplied to a electrical load from first and second ac busbars at a ratio that achieves a desired level of exhaust emissions such as nitrogen oxides (NOx), carbon dioxide (CO2) and other pollutants produced by the prime movers associated with generators. Preferably, the method may be used to operate a dual fed marine propulsion system wherein the electrical load is a thruster. Operating a dual fed marine propulsion system using the method of the present invention makes it possible to optimize thrust allocation between thrusters in a way that is similar to that used in conventional dynamic positioning (DP) systems and then share or allocate the required power between generators to minimize exhaust emissions.

Abstract: A method of balancing voltages in a group of capacitors of a power electronic device, such as a multilevel power inverter, includes making a balancing determination regarding whether to (i) inject energy into the selected one of the capacitors from an energy storage element, or (ii) extract energy from the selected one of the capacitors into the energy storage element based on the voltage of a selected one of the capacitors, and either injecting energy into the selected one of the capacitors from the energy storage element, or extracting energy from the selected one of the capacitors into the energy storage element based on the balancing determination. Also, a voltage balancing circuit that implements the method. In one particular implementation, a spatial second derivative algorithm is used. In another particular implementation, a comparison to an average capacitor voltage is used.

Abstract: A method of controlling a plurality of power converters 1a, 1b and 1c can be used to interface to a supply network, ac busbar etc. Each power converter includes a network bridge 14 operating in accordance with a pulse width modulation (PWM) strategy having the same switching period and which causes at least one unwanted harmonic in the supply network voltage. The method includes the step of providing the switching period of the PWM strategy of each network bridge with a different time offset relative to a time datum such that the at least one unwanted harmonic in the supply network voltage is at least partially cancelled. Two alternative ways of providing the time offset are described.

Abstract: The invention relates to a component such as a rotor or stator for an electrical machine. The component includes a plurality of axially adjacent stacks of laminations. At least one pair of adjacent stacks are spaced apart in the axial direction by spacer means such that a passageway or duct for cooling fluid, e.g. air, is formed therebetween. The spacer means comprises a porous structural mat of metal fibers. The cooling fluid may flow through the spaces or voids between the fibers.

Abstract: An electrical circuit, in particular a circuit used for generating electric power, wherein this circuit comprises a generator with n phases, a converter and a transformer to which a p-phase load can be connected. The converter comprises m partial converters, each of the partial converters is composed of p units and each of these units is provided with n/m switching circuits. The switching circuits of the individual units are connected symmetrical to the generator.

Abstract: A power supply system for supplying electrical power to a load is capable of delivering an output voltage to the load from an input voltage coming from an electric power network. The power supply system includes: at least two input terminals and at least two output terminals, the input terminals being adapted to be connected to the electric power network and the output terminals being adapted to be connected to the load, a converter capable of converting the input voltage into the output voltage, the converter being connected between the input terminals and the output terminals, and a device for limiting the homopolar current that is likely to flow between the electric power network and the load. The device for limiting the homopolar current comprises a transformer connected in parallel with respect to the converter, between the input terminals and the output terminals, the transformer having a first electromagnetic coil and a second electromagnetic coil.

Abstract: The present invention provides a permanent magnet rotor arrangement for a rotating electrical machine including a rotor body having an outer rim. A circumferential array of magnet carriers is mounted to the rotor body by fixing members and support members and is spaced apart from the rotor body in the radial direction to define a series of axially gaps or spaces which can optionally be used as passages for cooling air. At least one pole piece made of permanent magnet material is located adjacent to a surface of each magnet carrier. The magnet carriers and pole pieces preferably have a laminated or divided construction to virtually eliminate eddy currents that may be particularly problematic in certain types and construction of electrical machine. The flux path between adjacent pole pieces flows in the circumferential direction within the magnet carriers and does not use the rotor body.

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: An electric circuit is described for generating electric power. In this circuit, an asynchronous generator includes a stator and a rotor. On the stator side, the asynchronous generator is coupled to a power grid. The rotor current flowing to the rotor of the asynchronous generator can be measured. A control device is designed such that, in case of a fault in the power grid, the stator current flowing to the stator of the asynchronous generator is calculated from the measured rotor current as a function of parameters of the asynchronous generator.

Abstract: A circuit breaker comprising a first dc line electrically connectable to first incoming and first outgoing dc lines, wherein the first dc line comprises a first fault-interrupting switch contact system and a first switching aid network. The first switching aid network comprises first and second rectifier strings, wherein each rectifier string comprises one or more series connected reverse blocking power electronic devices that define a first H-bridge rectifier. The first switching aid network further comprises a snubber string, the snubber string comprising at least one series connected power electronic devices capable of being turned on by gate control and a capacitor. The first switching aid network further comprises a pre-charge string comprising at least one series connected power electronic devices capable of being turned on by gate control and a resistor, and a surge arrester connected between the first and second dc output terminals of the first H-bridge rectifier.

Abstract: A gearless drive for a rotating electrical machine comprises a rotor in the form of a hollow rotatable body and having an axis of rotation and a stator surrounding the rotor. A plurality of pole bodies are independently mounted circumferentially around the rotor by a pole mounting arrangement. The stiffness of the pole mounting arrangement in the radial direction is greater than the stiffness of the pole mounting arrangement in the circumferential direction.

Abstract: A system for generating electrical power is described. In at least one embodiment, the system includes a turbine that is mechanically connected to a generator, wherein the generator is electrically connected via a first converter to a load. The first converter generates a first output current. A second output current is generated by a second converter and is added to the first output current. The second output current is generated such that an actual current over the load follows a desired current.

Abstract: A method for operating an electrical circuit, in particular of a converter is described. The circuit, in at least one embodiment, includes a line-side converter that is coupled to a capacitor. The line-side converter includes at least two series connections, each including at least two power semiconductor elements, and each of the at least two series connections being connected parallel to the capacitor. The line-side converter is coupled to an energy supply system. The DC voltage that is present at the capacitor is determined. A maximum voltage is predetermined. If the DC voltage present at the capacitor is determined to be greater than the maximum voltage, then at least two of the power semiconductor elements are switched into their conductive state in such a manner that the capacitor is discharged in the direction of the energy supply system.

Abstract: This hydrokinetic rotor is arranged to be rotated by a flow of a liquid. This rotor comprises of an inner ring, an outer ring and at least one blade (24) extending between the inner ring and the outer ring in a radial direction (R), the inner rings and the external rings being centered on a same longitudinal axis (X). This rotor comprises of at least one radial axis (26) extending radially between the inner ring and the outer ring, and at least one blade (24) is movable around the respective radial axis (26). The rotor (14) comprises of the limitation means (28) of the movement in rotation of at least one blade (24) mentioned above around its respective radial axis (26).

Abstract: The present invention provides an improved architecture for integrating an inertial navigation system (INS) into a dynamic positioning (DP) system for a vessel. The architecture includes an INS unit and a DP system having a Kalman filter or other algorithm for combining data supplied by a plurality of position measuring equipment (PME) and the INS unit to derive an estimate of the position or speed of the vessel. A switch array and a switch array controller are also provided. These may optionally form a part of the DP system. The switch array is operable under the control of the switch array controller to supply data supplied by one or more of the plurality of position measuring equipment to the INS unit for the purposes of correcting drift. The selection of which of the one or more PME is/are to be combined with the INS unit is made automatically, in real time, to dynamically optimise the DP system.

Abstract: A semi-conductor electronic device for mounting in a pressed stack assembly. The device comprises a box comprising a lower plate, an upper plate and a lateral wall mechanically connecting the lower plate to the upper plate, the lower and upper plates being electrically conductive, several semi-conductor components, each component comprising a first electrode and a second electrode, the first electrodes being electrically connected to the lower plate and the second electrodes being electrically connected to the upper plate, and elastic parts positioned between the components and a supporting plate chosen from the lower plate and the upper plate.

Abstract: Described is a method for testing a power producer or a power consumer that can be connected to a power grid. The power producer or the power consumer is connected to a terminal point. A converter circuit is provided for influencing a voltage that is present at the terminal point. The converter circuit is connected via a transformer to the terminal point. In at least one embodiment, a series connection is configured with a choking coil and a first switch and connected to the terminal point. In a time coordinated manner, the first switch is initially closed and the converter circuit is influenced such that the voltage has the desired value at the terminal point, whereupon the second switch is then opened.

Abstract: The present invention relates to armature windings for DC electrical machines, and in particular to those that use electronic commutation and have relatively few slots per pole-pair. The armature windings are particularly well suited for use with rotating DC electrical machines that have a large diameter and a large number of poles such as those that might be directly coupled to the turbine blade assembly of a wind turbine. The armature winding is arranged in relation to the magnetic field generated by a field winding or by permanent magnets such that a number of commutation events during the time taken for the relative movement between the armature and the field system of one pole-pair is much larger than the number of coils per pole-pair.

Abstract: This system for converting a direct input voltage into an alternating output voltage comprises two input terminals, two voltage generators connected in series between the input terminals and connected to one another by a middle point, as well as, for each phase of the alternating voltage, an output terminal, two switching branches each connected between the output terminal and a respective input terminal, each switching branch comprising N first switching cells connected in series and N?1 intermediate points, the first switching cells successively being connected to one another by a corresponding intermediate point, N being an integer greater than or equal to 2, and control means for controlling the first switching cells. The system includes, for each phase of the alternating voltage, N?1 pair(s) of capacitors, each pair of capacitors being connected between intermediate points of one of the two switching branches and the other of the two switching branches.

Abstract: A method determines the value of a characteristic quantity (U1dc, U2dc) of a system for powering a load which includes 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 and includes 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.