Abstract: A position sensorless control methodology for electrical machines using high frequency flux vector signal injection in the estimated rotor flux rotational reference frame is provided. In one aspect, the estimated position error function is derived directly from the stator flux equation without any simplification. The method is applicable for electrical generator motoring mode operation from standstill and power generation mode operation.

Abstract: A method for controlling a variable speed wind turbine generator is disclosed. The generator is connected to a power converter comprising switches. The generator comprises a stator and a set of terminals connected to the stator and to the switches of the power converter. The method comprises: determining a stator flux reference value corresponding to a generator power of a desired magnitude, determining an estimated stator flux value corresponding to an actual generator power, determining a difference between the determined stator flux reference value and the estimated stator flux value, and operating said switches in correspondence to the determined stator flux reference value and the estimated stator flux value to adapt at least one stator electrical quantity to obtain said desired generator power magnitude.

Abstract: A position sensorless control methodology for an electrical machine is provided. In particular, one aspect provides a method for position sensorless operation of an electrical machine using direct position error computation from stator flux observation results and stator current measurement.

Abstract: A method for controlling a variable speed wind turbine generator is disclosed. The generator is connected to a power converter comprising switches. The generator comprises a stator and a set of terminals connected to the stator and to the switches of the power converter. The method comprises: determining a stator flux reference value corresponding to a generator power of a desired magnitude, determining an estimated stator flux value corresponding to an actual generator power, determining a difference between the determined stator flux reference value and the estimated stator flux value, and operating said switches in correspondence to the determined stator flux reference value and the estimated stator flux value to adapt at least one stator electrical quantity to obtain said desired generator power magnitude.

Abstract: A method for controlling a variable speed wind turbine generator is disclosed. The generator is connected to a power converter comprising switches. The generator comprises a stator and a set of terminals connected to the stator and to the switches of the power converter. The method comprises: determining a stator flux reference value corresponding to a generator power of a desired magnitude, determining an estimated stator flux value corresponding to an actual generator power, determining a difference between the determined stator flux reference value and the estimated stator flux value, and operating said switches in correspondence to the determined stator flux reference value and the estimated stator flux value to adapt at least one stator electrical quantity to obtain said desired generator power magnitude.

Abstract: A method of controlling a wind turbine generator is provided, the wind turbine generator converting mechanical energy to electrical. The method comprises: determining an electromagnetic power reference representing the electromagnetic power generated by the wind turbine generator, wherein the electromagnetic power reference is determined based on a desired output of the wind turbine generator; controlling the electrical power generated by the wind turbine generator using a control signal, wherein the control signal is derived from the electromagnetic power reference and is modified in dependence on an inverse power function of the wind turbine generator by incorporating minimal copper loss constraint and stator voltage limiting constraint such that non-linearity of the wind turbine generator plant is compensated in the control loop and it operates at its maximum efficiency. One effect of the method is that classical linear control loop design can be employed in spite of the plant being a non-linear identity.

Abstract: A variable speed wind turbine is provided. The wind turbine comprises a generator, a power converter for converting at least a portion of electrical power generated by the generator, an energy management arrangement coupled to the power converter, the energy management arrangement comprises an energy storage unit, and a controller. The controller is adapted to detect a power imbalance event and to transfer at least a portion of excess electrical energy generated by the generator to the energy storage unit to be stored therein when the power imbalance event is detected.

Abstract: A method for operating an electromechanical generator is provided, the method comprising: determining a magnetic field reference parameter based on an electromagnetic power reference representing a desired output of the electromechanical generator, determining a scaling factor for adjusting an air-gap magnetization level of the electromechanical generator to reduce loss in operating the electromechanical generator, modifying the magnetic field reference parameter with the scaling factor; and operating the electromechanical generator based on at least the modified magnetic field reference parameter.

Abstract: A method for validating and initializing a control system for an electrical generator connected to a power converter in a wind turbine. The method may include generating a first parameter value representing control signal for controlling the stator flux of a stator of the electrical generator, measuring a second parameter value specifying an electrical operational characteristic of the electrical generator, and determining an accuracy level of the control signal based on the first parameter value and the second parameter value, wherein the accuracy level of the control signal has to fall within a predefined threshold for the control system to be validated.

Abstract: A method for determining a rotor position of an electrical generator in a wind turbine is described comprising determining a voltage of the electrical generator, determining a rotor position angle estimate based on the voltage of the electrical generator, determining a subsequent rotor position angle estimate through a feedback loop, based on a combination of the voltage of the electrical generator and the rotor position angle estimate. Further, a method to real time track encoder health is described comprising determining the phase angle of a reference voltage, determining the angle difference between the rotor position and the reference voltage, and determining the differentiation of the angle difference.

Abstract: A method for determining a rotor position of an electrical generator in a wind turbine is described comprising determining a voltage of the electrical generator, determining a rotor position angle estimate based on the voltage of the electrical generator, determining a subsequent rotor position angle estimate through a feedback loop, based on a combination of the voltage of the electrical generator and the rotor position angle estimate. Further, a method to real time track encoder health is described comprising determining the phase angle of a reference voltage, determining the angle difference between the rotor position and the reference voltage, and determining the differentiation of the angle difference.

Abstract: A method for providing dynamic load sharing between a first and a second three phase system is disclosed, wherein the first and second three phase system are connected to a first and second three phase interleaved winding in a generator. The method comprises determining a first q-axis control signal for the first three phase system and a second q-axis control signal for the second three phase system based on a torque and/or power demand for the generator, determining a first d-axis control signal for the first three phase system and a second d-axis control signal for the second three phase system based on a coupling effect between the first and second three phase systems, and adjusting the q-axis control signals and d-axis control signals by including at least one feed forward compensation signal, wherein said at least one feed forward compensation signal is based on a coupling effect between the first and second three phase systems.

Abstract: A power conversion system for converting electrical power from at least one power source includes a plurality of converter chains which couple the at least one power source to at least one load. At least two of the converter chains comprise an associated dissipating unit. The dissipating units are coupled via at least one switch. A controller is arranged to control the at least one switch to route power to be dissipated from one of the converter chains to the converter chain's associated dissipating unit, or to at least one of the other dissipating units, or to the converter chain's associated dissipating unit and to at least one of the other dissipating units, to cause corresponding dissipation of the power to be dissipated.

Abstract: A method for determining a rotor position of an electrical generator in a wind turbine is described comprising determining a voltage of the electrical generator, determining a rotor position angle estimate based on the voltage of the electrical generator, determining a subsequent rotor position angle estimate through a feedback loop, based on a combination of the voltage of the electrical generator and the rotor position angle estimate. Further, a method to real time track encoder health is described comprising determining the phase angle of a reference voltage, determining the angle difference between the rotor position and the reference voltage, and determining the differentiation of the angle difference.

Abstract: A controller arrangement of an electrical power transfer system (1) of a wind turbine is described. The wind turbine has an electrical generator and is connected to an electrical power grid, wherein the power transfer system (1) is arranged to transfer electrical power from the generator to the grid. The power transfer system (1) has at least two electrical elements (2-6), e.g. converters, and at least two controllers (15-17) each arranged to control at least one element (2-6).

Abstract: A method for validating and initializing a control system for an electrical generator connected to a power converter in a wind turbine. The method may include generating a first parameter value representing control signal for controlling the stator flux of a stator of the electrical generator, measuring a second parameter value specifying an electrical operational characteristic of the electrical generator, and determining an accuracy level of the control signal based on the first parameter value and the second parameter value, wherein the accuracy level of the control signal has to fall within a predefined threshold for the control system to be validated.

Abstract: A method for determining a rotor position of an electrical generator in a wind turbine is described comprising determining a voltage of the electrical generator, determining a rotor position angle estimate based on the voltage of the electrical generator, determining a subsequent rotor position angle estimate through a feedback loop, based on a combination of the voltage of the electrical generator and the rotor position angle estimate. Further, a method to real time track encoder health is described comprising determining the phase angle of a reference voltage, determining the angle difference between the rotor position and the reference voltage, and determining the differentiation of the angle difference.

Abstract: A design method for an integrated circuit adds spare cells in a System-on-Chip to allow for Engineering Change Orders (ECOs) to be performed at a later stage in the design. This method can be used to provide a second version of the chip having minimal alterations performed in a short cycle time. The spare cells can be divided into combinational and sequential cells. There is an optimum spread of combinational cells in the design for post placement repairs of the chip with just metal layer changes. The method takes into account the drive strength of the spare cells as the main factor in their placement on the chip.

Abstract: A rotor structure for an interior permanent magnet (IPM) electromotive machine is provided. The rotor structure includes at least one rotor lamination including a first group of slots and a second group of slots arranged to form a magnetic pole. The first group of slots may be arranged to form a magnetic flux along a direct axis of the magnetic pole resulting from the first and second group of slots. At least some of the first group of slots is arranged to receive a respective permanent magnet. The second group of slots is arranged to provide a separation for the magnetic flux from adjacent magnetic poles and lying along a quadrature axis of said magnetic pole. At least some of the second group of slots is arranged without a permanent magnet. The rotor structure further includes a magneto-mechanical barrier arranged to reduce a peak level of mechanical stress occurring by the first and/or the second group of slots and/or impede a flow of magnetic flux through the barrier.

Abstract: Various systems and methods for forming a polymer part with utilizing heating fluid are provided. In one embodiment of the present invention a method for forming polymer includes heating the mold apparatus with a first heat energy source comprising heating fluid to a first mold temperature, and then heating the mold apparatus with a second energy source which is different than the first energy source. The second energy source heats the mold surface to a second mold temperature greater than the first mold temperature to form the part to achieve a desired surface finish of the polymer part.