Abstract: A system for producing electrical power based on wind energy is capable of predicting its power output. The system includes a set of wind turbine units, a first plurality of sensors each adapted to sense at least one wind characteristic at some of the wind turbine units, and a second plurality of sensors remotely located. At least one wind characteristic is estimated at the wind turbines not having one of the first plurality of sensors based on sensing by the first plurality of sensors and an estimate of changes in wind characteristic at wind turbine units caused by presence of other wind turbine units. The magnitude of electrical power production by the set of wind turbine units at at least one predefined point in time in the future is predicted based on the estimated wind characteristics and sensed wind characteristics.

Abstract: A rotor disk for a rotor of a synchronous reluctance machine consists of a disk body material with high magnetic permeability. In order to improve the ability of the rotor disk to stand centrifugal and thermal loads, spokes extending in radial direction between a shaft opening and a disk periphery are provided with spoke openings. These openings extend over a wide distance both in circumferential direction and in radial direction to worsen the heat conducting properties of the spokes and to render the spokes less stiff.

Abstract: A synchronous reluctance machine includes a rotor having a plurality of rotor disks with longitudinal flux barriers. When the rotor disks are stacked together to form a rotor core, the flux barriers define channels extending in an axial direction of the rotor core. Air is forced to flow through these channels in order to improve a temperature distribution within the machine.

Abstract: A rotor disk for a rotor of a synchronous reluctance machine consists of a disk body material with high magnetic permeability. In order to improve the ability of the rotor disk to stand centrifugal and thermal loads, spokes extending in radial direction between a shaft opening and a disk periphery are provided with spoke openings. These openings extend over a wide distance both in circumferential direction and in radial direction to worsen the heat conducting properties of the spokes and to render the spokes less stiff.

Abstract: A method for finding an operating point of an electric motor which includes the steps of generating a perturbation signal, combining the perturbation signal with a current magnitude related to a drive system of the motor or combining the perturbation signal with a power magnitude related to the motor, yielding a combined signal, and sending, based on the combined signal, a flux adjustment signal to adjust a flux of the motor. An apparatus for finding an operating point of an electric motor comprising is also presented.

Abstract: A synchronous reluctance machine includes a rotor having a plurality of rotor disks with longitudinal flux barriers. When the rotor disks are stacked together to form a rotor core, the flux barriers define channels extending in an axial direction of the rotor core. Air is forced to flow through these channels in order to improve a temperature distribution within the machine.

Abstract: A softstarter for starting and stopping an asynchronous motor having three phases, including two pairs of semiconductor devices of the type turning off at zero-crossing of the current therethrough, wherein each of the two pairs of semiconductor devices is connected in anti-parallel, and the first pair of the semiconductor devices is adapted to control the voltage of one of the phases of the motor and the second pair of the semiconductor devices being adapted to control the voltage of another of the phases of the motor, a DC reducing unit associated with the two pairs of semiconductor devices, a first voltage measuring unit for measuring voltages across the two pairs of semiconductor devices, and a first zero-crossing detecting unit configured for detecting zero-crossings of the measured voltages across the two pairs of semiconductor devices and providing zero-crossing signals to the DC reducing unit.

Abstract: A softstarter for starting and stopping an asynchronous motor having three phases, including two pairs of semiconductor devices of the type turning off at zero-crossing of the current therethrough, wherein each of the two pairs of semiconductor devices is connected in anti-parallel, and the first pair of the semiconductor devices is adapted to control the voltage of one of the phases of the motor and the second pair of the semiconductor devices being adapted to control the voltage of another of the phases of the motor, a DC reducing unit associated with the two pairs of semiconductor devices, a first voltage measuring unit for measuring voltages across the two pairs of semiconductor devices, and a first zero-crossing detecting unit configured for detecting zero-crossings of the measured voltages across the two pairs of semiconductor devices and providing zero-crossing signals to the DC reducing unit.

Abstract: For identifying the machine type of an alternating current machine, a direct current is first applied to the stator for aligning the d-axis of the rotor and the magnetic field direction of the stator. Secondly, a direct current is applied to the stator at a current angle which causes the rotors of a permanent magnet machine and a synchronous reluctance machine to exert torque in different directions. The torque direction of the rotor is detected and the machine type is identified based on the torque direction information. The machine type is recognized as a permanent magnet machine or a synchronous reluctance machine depending on the torque direction. If no torque is detected, then the machine type is recognized as an induction machine.

Abstract: A cooling system for a brushed electrical machine includes a cooler configured to cool down a rotor and a commutator of the machine. There is a controller configured to adjust the cooling effect of the cooler in response to monitored rotor and commutator temperatures. The cooler includes a fan and an auxiliary motor configured to rotate the fan.

Abstract: A method for controlling an electric motor with a softstarter. A softstarter device for control of electric motors. Motor torque is controlled in dependence of a torque error signal, based on a calculated difference between the motor torque and a reference torque value, so that the motor torque displays a rate of change with respect to time, during a stopping or starting time interval, that is adapted to follow a rate of change of the reference torque value, with respect to time, that varies between at least a first part of the time interval and a second part of the time interval, and thereby changing the speed of the motor. A system includes an electric motor, a device driven by the electric motor and a softstarter device for controlling the electric motor. A computer program product includes a computer readable medium and a computer program recorded thereon.

Abstract: A method for finding an operating point of an electric motor which includes the steps of generating a perturbation signal, combining the perturbation signal with a current magnitude related to a drive system of the motor or combining the perturbation signal with a power magnitude related to the motor, yielding a combined signal, and sending, based on the combined signal, a flux adjustment signal to adjust a flux of the motor. An apparatus for finding an operating point of an electric motor comprising is also presented.

Abstract: Epitaxial silicon carbide layers are fabricated by forming features in a surface of a silicon carbide substrate having an off-axis orientation toward a crystallographic direction. The features include at least one sidewall that is orientated nonparallel (i.e., oblique or perpendicular) to the crystallographic direction. The epitaxial silicon carbide layer is then grown on the surface of the silicon carbide substrate that includes features therein.

Abstract: Epitaxial silicon carbide layers are fabricated by forming features in a surface of a silicon carbide substrate having an off-axis orientation toward a crystallographic direction. The features include at least one sidewall that is orientated nonparallel (i.e., oblique or perpendicular) to the crystallographic direction. The epitaxial silicon carbide layer is then grown on the surface of the silicon carbide substrate that includes features therein.

Abstract: An epitaxial silicon carbide layer is fabricated by forming first features in a surface of a silicon carbide substrate having an off-axis orientation toward a crystallographic direction. The first features include at least one sidewall that is orientated nonparallel (i.e., oblique or perpendicular) to the crystallographic direction. A first epitaxial silicon carbide layer is then grown on the surface of the silicon carbide substrate that includes first features therein. Second features are then formed in the first epitaxial layer. The second features include at least one sidewall that is oriented nonparallel to the crystallographic direction. A second epitaxial silicon carbide layer is then grown on the surface of the first epitaxial silicon carbide layer that includes the second features therein.

Abstract: Epitaxial silicon carbide layers are fabricated by forming features in a surface of a silicon carbide substrate having an off-axis orientation toward a crystallographic direction. The features include at least one sidewall that is orientated nonparallel (i.e., oblique or perpendicular) to the crystallographic direction. The epitaxial silicon carbide layer is then grown on the surface of the silicon carbide substrate that includes features therein.

Abstract: Epitaxial silicon carbide layers are fabricated by forming features in a surface of a silicon carbide substrate having an off-axis orientation toward a crystallographic direction. The features include at least one sidewall that is orientated nonparallel (i.e., oblique or perpendicular) to the crystallographic direction. The epitaxial silicon carbide layer is then grown on the surface of the silicon carbide substrate that includes features therein.

Abstract: Epitaxial silicon carbide layers are fabricated by forming features in a surface of a silicon carbide substrate having an off-axis orientation toward a crystallographic direction. The features include at least one sidewall that is orientated nonparallel (i.e., oblique or perpendicular) to the crystallographic direction. The epitaxial silicon carbide layer is then grown on the surface of the silicon carbide substrate that includes features therein.

Abstract: An epitaxial silicon carbide layer is fabricated by forming first features in a surface of a silicon carbide substrate having an off-axis orientation toward a crystallographic direction. The first features include at least one sidewall that is orientated nonparallel (i.e., oblique or perpendicular) to the crystallographic direction. A first epitaxial silicon carbide layer is then grown on the surface of the silicon carbide substrate that includes first features therein. Second features are then formed in the first epitaxial layer. The second features include at least one sidewall that is oriented nonparallel to the crystallographic direction. A second epitaxial silicon carbide layer is then grown on the surface of the first epitaxial silicon carbide layer that includes the second features therein.

Abstract: An epitaxial silicon carbide layer is fabricated by forming first features in a surface of a silicon carbide substrate having an off-axis orientation toward a crystallographic direction. The first features include at least one sidewall that is orientated nonparallel (i.e., oblique or perpendicular) to the crystallographic direction. A first epitaxial silicon carbide layer is then grown on the surface of the silicon carbide substrate that includes first features therein. Second features are then formed in the first epitaxial layer. The second features include at least one sidewall that is oriented nonparallel to the crystallographic direction. A second epitaxial silicon carbide layer is then grown on the surface of the first epitaxial silicon carbide layer that includes the second features therein.