A system including: a journal bearing having a carrier, a rotor arranged rotatable about a rotational axis relative to the carrier, and a fluid in a clearance between the rotor and the carrier. A sensor measures a vibration signal of the rotor. A control system is adapted to determine a pressure set point for the fluid in the clearance based on the vibration signal, and to provide control signals generated based on the pressure set point. An active device is adapted to modify the pressure of the fluid in the clearance based on the control signals.

A double winding electric machine assembly including a double winding electric machine having a first stator winding and a second stator winding; a first converter including a first modulator and a first power unit whose output is electrically connected to the first stator winding; a second converter including a second modulator and a second power unit whose output is electrically connected to the second stator winding. The assembly includes a current determining system adapted to determine at least one instantaneous phase current in the output of the first power unit; and a synchronizing system adapted to analyse ripple in the at least one instantaneous phase current, and to synchronize the first modulator with the second modulator by adjusting a phase shift between the first modulator and the second modulator until a minimum peak-to-peak current is obtained.

A double winding electric machine assembly including a double winding electric machine having a first stator winding and a second stator winding; a first converter including a first modulator and a first power unit whose output is electrically connected to the first stator winding; a second converter including a second modulator and a second power unit whose output is electrically connected to the second stator winding. The assembly includes a current determining system adapted to determine at least one instantaneous phase current in the output of the first power unit; and a synchronizing system adapted to analyse ripple in the at least one instantaneous phase current, and to synchronize the first modulator with the second modulator by adjusting a phase shift between the first modulator and the second modulator until a minimum peak-to-peak current is obtained.

Control circuits control inverter circuits provided in correspondence to the control circuits by a drive mode selected from a plurality of drive modes. A cooperative drive mode is for controlling a current supply to motor windings by a plurality of systems by using a value acquired from the other control circuit via communication. An independent drive mode is for controlling the current supply to the motor windings by the plurality of systems without using the value acquired from the other control circuit. A one-system drive mode is for controlling the current supply to the motor winding by one system without using the value acquired from the other control circuit. The control circuits set the drive mode to a cooperative drive mode when inter-computer communication is normal. The control circuits set the drive mode to an independent drive mode or a one-system drive mode thereby differentiating an output characteristic of a motor from that in the cooperative drive mode.

Control circuits control inverter circuits provided in correspondence to the control circuits by a drive mode selected from a plurality of drive modes. A cooperative drive mode is for controlling a current supply to motor windings by a plurality of systems by using a value acquired from the other control circuit via communication. An independent drive mode is for controlling the current supply to the motor windings by the plurality of systems without using the value acquired from the other control circuit. A one-system drive mode is for controlling the current supply to the motor winding by one system without using the value acquired from the other control circuit. The control circuits set the drive mode to a cooperative drive mode when inter-computer communication is normal. The control circuits set the drive mode to an independent drive mode or a one-system drive mode thereby differentiating an output characteristic of a motor from that in the cooperative drive mode.

A motor controller integrated circuit (IC) includes a storage device containing software. The IC also includes a processor core coupled to the storage device. The processor core has an output adapted to be coupled to a motor. The processor core is configured to execute the software to implement a resonant controller at a frequency that is a harmonic of a speed of a motor.

The design of a novel digital controller for a motor driven aircraft arrestment system of the type used on aircraft carriers is described. The unique control and feedback design of the described controller has many advanced features, which provide many advantages over existing designs for controlling advanced arresting gear systems. Gain scheduling in engage/arrest controllers can be done based on estimated parameters such as speed, effective skew angle, and faults to allow optimized engage/arrest controllers, where the gain scheduling can be defined, discretely, for each “bin” as defined for a range of threshold values, or it can be defined, continuously, using interpolation and/or functions of speed and effective skew. Particularly, controller design gain values K.sub.ci and K.sub.fi are picked to shape control loop transfer functions and dampen resonances in the aircraft arrestment system.

The design of a novel digital controller for a motor driven aircraft arrestment system of the type used on aircraft carriers is described. The unique control and feedback design of the described controller has many advanced features, which provide many advantages over existing designs for controlling advanced arresting gear systems. Gain scheduling in engage/arrest controllers can be done based on estimated parameters such as speed, effective skew angle, and faults to allow optimized engage/arrest controllers, where the gain scheduling can be defined, discretely, for each “bin” as defined for a range of threshold values, or it can be defined, continuously, using interpolation and/or functions of speed and effective skew. Particularly, controller design gain values K.sub.ci and K.sub.fi are picked to shape control loop transfer functions and dampen resonances in the aircraft arrestment system.

The invention relates to a method (400) for regulating an electric machine (190), comprising a harmonic filter (150), said harmonic filter (150) comprising a second filter (142) and a filter output transformer (132). The method has the steps of: ascertaining (410) a feedback variable (Idq); determining (414) a filter specification variable (FV); filtering (415) the filter specification variable (FV); ascertaining (417) a filtered feedback variable without harmonic components (IdqFunda); and energizing (480) at least one winding of the electric machine (190) on the basis of the filtered feedback variable without harmonic components (IdqFunda).

The invention relates to a method (400) for regulating an electric machine (190), comprising a harmonic filter (150), said harmonic filter (150) comprising a second filter (142) and a filter output transformer (132). The method has the steps of: ascertaining (410) a feedback variable (Idq); determining (414) a filter specification variable (FV); filtering (415) the filter specification variable (FV); ascertaining (417) a filtered feedback variable without harmonic components (IdqFunda); and energizing (480) at least one winding of the electric machine (190) on the basis of the filtered feedback variable without harmonic components (IdqFunda).