Abstract: An example, overvoltage protection device includes a switch and a surge protection device that is selectively activated by actuating the switch. The switch is actuated in response to a voltage. An example method of absorbing an overvoltage includes sensing a voltage, and selectively activating a surge protection device in response to the sensed voltage.

Abstract: A machine for generating electricity has an exciter rotor with a plurality of coils, and is associated with a shaft to be driven by a source of rotation. A diode bridge is connected downstream of the exciter rotor to provide a rectifier for an AC current generated by rotation of the exciter rotor. The diode bridge rectifies the AC generated current into DC current, which is passed downstream to windings for a main rotor. A snubber circuit is positioned intermediate said rectifier and said main rotor, said snubber circuit including both a resistor and a capacitor.

Abstract: An electric power supply system has a power bus for providing DC power, and a control unit for a source of power to supply the power bus. The power unit includes a damping algorithm to provide damping to power supplied on the power bus. A motor and a motor control include a compensation block for tapping power from the bus, and identifying a portion of a supplied signal due to the damping. The compensation block provides a signal to a summing block that addresses the damping on the power bus prior to the power being supplied to the motor. A method of utilizing such a system is also disclosed.

Abstract: An example, overvoltage protection device includes a switch and a surge protection device that is selectively activated by actuating the switch. The switch is actuated in response to a voltage. An example method of absorbing an overvoltage includes sensing a voltage, and selectively activating a surge protection device in response to the sensed voltage.

Abstract: An electric load damper assembly includes a synchronous generator operable to provide a plurality of phases of electrical output in response to a mechanical input from a rotating shaft. An electric load damper includes a phase leg for each of the plurality of phases. Each phase leg includes a resistive load, a snubber and at least one solid state switch. The at least one solid state switch is in parallel with the snubber, and the at least one solid state switch and snubber are collectively in series with the resistive load. A controller is operable to receive a signal indicative of a rotational speed oscillation of the synchronous generator, and is operable to selectively reduce a torsional oscillation of the shaft by diverting electrical current from the synchronous generator through the resistive load of each of the plurality of phases in response to the signal exceeding a predefined threshold.

Abstract: A low pass filter includes a differential mode filter and a common mode filter. The common mode portion of the filter includes at least one inductor and one capacitor, as well as a damping circuit with at least one capacitor. The low pass filter has a reduced weight, which is useful in circumstances in which weight is a significant factor, such as in aircraft.

Abstract: An electric power supply system has a power bus for providing DC power, and a control unit for a source of power to supply the power bus. The power unit includes a damping algorithm to provide damping to power supplied on the power bus. A motor and a motor control include a compensation block for tapping power from the bus, and identifying a portion of a supplied signal due to the damping. The compensation block provides a signal to a summing block that addresses the damping on the power bus prior to the power being supplied to the motor. A method of utilizing such a system is also disclosed.

Abstract: An electric load damper assembly includes a synchronous generator operable to provide a plurality of phases of electrical output in response to a mechanical input from a rotating shaft. An electric load damper includes a phase leg for each of the plurality of phases. Each phase leg includes a resistive load, a snubber and at least one solid state switch. The at least one solid state switch is in parallel with the snubber, and the at least one solid state switch and snubber are collectively in series with the resistive load. A controller is operable to receive a signal indicative of a rotational speed oscillation of the synchronous generator, and is operable to selectively reduce a torsional oscillation of the shaft by diverting electrical current from the synchronous generator through the resistive load of each of the plurality of phases in response to the signal exceeding a predefined threshold.

Abstract: A machine for generating electricity has an exciter rotor with a plurality of coils, and is associated with a shaft to be driven by a source of rotation. A diode bridge is connected downstream of the exciter rotor to provide a rectifier for an AC current generated by rotation of the exciter rotor. The diode bridge rectifies the AC generated current into DC current, which is passed downstream to windings for a main rotor. A snubber circuit is positioned intermediate said rectifier and said main rotor, said snubber circuit including both a resistor and a capacitor.

Abstract: A simulator system is connected to simulate the connection of a mechanically loaded motor to a motor controller/driver. The simulator system includes a current transformer circuit for monitoring AC output currents provided by the motor controller/driver. A simulation controller calculates, based on the monitored AC output currents, dynamic load voltages that simulate the response that would be generated by a mechanically loaded motor based on the AC output currents provided by the motor controller/driver. A number of power supplies amplify the dynamic loading calculated by the simulation controller to generate a dynamic loading that opposes the AC output currents provided by the motor controller/driver.

Abstract: A simulator system is connected to simulate the connection of a mechanically loaded motor to a motor controller/driver. The simulator system includes a current transformer circuit for monitoring AC output currents provided by the motor controller/driver. A simulation controller calculates, based on the monitored AC output currents, dynamic load voltages that simulate the response that would be generated by a mechanically loaded motor based on the AC output currents provided by the motor controller/driver. A number of power supplies amplify the dynamic loading calculated by the simulation controller to generate a dynamic loading that opposes the AC output currents provided by the motor controller/driver.

Abstract: A low pass filter includes a differential mode filter and a common mode filter. The common mode portion of the filter includes at least one inductor and one capacitor, as well as a damping circuit with at least one capacitor. The low pass filter has a reduced weight, which is useful in circumstances in which weight is a significant factor, such as in aircraft.

Abstract: A method of starting a gas turbine engine with a synchronous multiphase alternating current (AC) dynamoelectric machine with a rotor and a stator that allows re-engagement of a starting operation at non-zero rotor speeds comprises the steps of: applying electrical excitation to the rotor; measuring electromotive force (EMF) generated in the stator; determining rotor speed, acceleration and position from the measured EMF by sensorless means; initiating closed-loop sensorless position controlled power to the stator if the determined rotor speed is at least a pre-determined minimum closed-loop sensorless re-engagement speed; initiating open-loop position controlled power to the stator if the determined rotor speed is less than the pre-determined minimum closed-loop sensorless re-engagement speed but at least a predetermined minimum open-loop re-engagement speed and the determined rotor acceleration is no more than a pre-determined maximum open-loop re-engagement acceleration; and initiating open-loop zero-speed

Abstract: A polyphase alternating current (AC) active rectifier system converts polyphase AC from an AC source to direct current (DC) on a DC bus comprising a positive DC bus line and a negative DC bus line with a switching element for each phase configured to direct current from the AC source to the DC bus through four different conducting paths with three electrical potential levels, including a positive DC level on the positive DC bus line, a negative DC level on the negative DC bus line and a neutral DC level between the positive and negative DC level on a neutral DC bus line and suppresses AC common mode electrical potential from the DC bus, comprising: a ground path between the neutral DC bus line and a system ground coupled to a neutral point for the AC source that clamps the level of the neutral DC level to the AC source neutral.

Abstract: A motor control system for a wound field synchronous dynamoelectric machine used as an electrical starter and a generator for aeronautical engines that uses its integral auxiliary permanent magnet generator as an angular position sensor in its starting mode.

Abstract: A wound field synchronous (WFS) dynamoelectric machine comprises: a rotor assembly; an exciter generator section comprising a stationary multiphase exciter stator winding for receiving excitation power from a multiphase alternating current (AC) source to generate an exciter stator magnetic field, a multiphase exciter rotor winding in the rotor assembly for generating multiphase AC excitation power as it cuts through the exciter stator magnetic field and a rotating rectifier assembly in the rotor assembly for converting the multiphase AC excitation power to direct current (DC) excitation power; a synchronous machine section comprising a DC main rotor winding in the rotor assembly for generating a main rotor magnetic field and a stationary multiphase main stator winding for receiving a multiphase AC control signal to generate a rotating main stator magnetic field that interacts with the main rotor magnetic field to rotate the rotor assembly; and an impedance that selectively connects one phase of the exciter st

Abstract: An unbalanced current detection circuit determines when a multi-phase, normally-balanced load is unbalanced. The detection circuit of the present invention includes a plurality of current-squaring circuits, each squaring a sensed current of one of the phases. A summing circuit produces a sum of the squares of the currents. If the load is balanced, this sum should be relatively constant, perhaps changing only slowly over time, with little or no ripple from that relatively constant value. In an unbalanced current condition, the sum of the current squares would consist of an average (dc) component plus a ripple (ac) component. If the amplitude of the ripple current exceeds a threshold, it is determined that the currents are unbalanced.

Abstract: An improved motor controller for driving polyphase alternating current dynamoelectric machines from a direct current power source that employs two inverter bridges controlled with a state vector modulation symmetrical state sequence that has a desired “chop” frequency so that each of their outputs produce a fundamental component that is exactly in phase but chop frequency components that are exactly 180 degrees out of phase with each other, with their outputs combined through respective interphase transformers to average the potentials of the chop frequency components.

Abstract: A motor controller having a damper that dampens resonance in a motor drive of a common mode filter to prevent it from becoming over excited by operation of the motor drive at a resonant frequency of the common mode filter. The damper is connected to an output feeder line of a motor drive in the motor controller and provides a common mode path to ground for the common mode filter. Thus, even if the motor drive is operating at a resonant frequency of the common mode filter, the resulting resonance in the common mode filter is attenuated by rather than amplified by the common mode filter, thereby preventing the common mode filter from excessive excitation.

Abstract: An active rectifier circuit includes a rectifier bridge having a plurality of passive rectifiers and a switching element coupled across each passive rectifier. A control circuit is coupled to the switching elements and senses reactive current flow and includes a phase-locked loop responsive to the reactive current flow and a circuit for developing switching patterns for the switching elements.