A generator system can include a generator configured to produce an output of alternating current (AC), a rectifier connected to the generator to rectify the AC into direct current (DC) rectifier output, an inverter connected to the rectifier to receive the DC rectifier output and configured to output three phase AC inverter output, and a plurality of output lines connected to the inverter to receive the three phase AC inverter output. The system can include a control module configured to control the output of the inverter. The control module can be operatively connected to one or more of the output lines via one or more local sense leads to receive a local feedback. The control module can be configured to control the inverter as a function of the local feedback to provide one or more of protection, voltage regulation, or harmonic correction.

A line interface filter apparatus to couple a drive or group of drives to a shared multiphase AC bus, including individual phase circuits having an inductor coupled between a respective bus and drive phase lines, a tapped resistor coupled to the respective drive phase line, and a capacitor coupled between the resistor and a common connection of the capacitors of the individual phase circuits, where the capacitance of the capacitors is 5 to 15 times a per-phase equivalent capacitance of the drive or group of drives, and the resistance of the resistors is two times a damping ratio times a square root of a ratio of the filter inductance to the filter capacitance, where the damping ratio ζ is greater than or equal to 1.0 and less than or equal to 2.0.

A system has a DC bus circuit with first and second terminals, an intermediate node, first and second capacitors, first and second depletion mode FETs, and first and second switching control circuits, where the first depletion mode FET has a drain coupled to the first bus terminal, a source, and a gate coupled to the intermediate node, the second depletion mode FET has a drain coupled to the intermediate node, a source, and a gate coupled to the second bus terminal, the first switching control circuit turns the first depletion mode FET off responsive to a first capacitor voltage of the first bus capacitor being less than or equal to a second capacitor voltage of the second bus capacitor, and the second switching control circuit turns the second depletion mode FET off responsive to the first capacitor voltage being greater than or equal to the second capacitor voltage.

In accordance with one or more embodiments, a method for implementing a PMG variable speed constant frequency generating system on an aircraft including an aircraft engine is provided. The method includes receiving AC power from a PMG at an AC/DC conversion stage, the received power being proportional to a rate of rotation of the aircraft engine and converting the AC power to DC power in the AC/DC conversion stage. The method further includes sensing a DC voltage output by the AC/DC conversion stage and providing the DC voltage to a DC/AC conversion stage. The method includes providing a control signal to the DC/AC conversion stage to control a frequency and a voltage of an output signal of the DC/AC conversion stage without varying an electrical signal provided to the PMG.

A flexible intelligent electrical switching device with multi-function capability, and methods of use are presented herein which provide an autonomous, reconfigurable switching device. The present disclosure is specifically designed to reduce space, cost of manufacture, efficiency, installation reduction time and ease of implementation.

A method and line interface filter apparatus to couple a drive or group of drives to a shared multiphase AC bus, including individual phase circuits having an inductor coupled between a respective bus and drive phase lines, a resistor coupled to the respective drive phase line, and a capacitor coupled between the resistor and a common connection of the capacitors of the individual phase circuits, where the capacitance of the capacitors is 5 to 15 times a per-phase equivalent capacitance of the drive or group of drives, and the resistance of the resistors is two times a damping ratio times a square root of a ratio of the filter inductance to the filter capacitance, where the damping ratio is greater than or equal to 1.0 and less than or equal to 2.0.

A power conversion apparatus capable of supplying a required reactive power while dynamically changing a dead band near 0 reactive current and maintaining a balance of DC voltage is provided. The power conversion apparatus including a three-level converter, a PWM controller for the three-level converter, an input current detector of the three-level converter, a coordinate converter that converts the current into a d-axis and q-axis current feedback, the reactive power control unit that controls a reactive power and outputs an reactive current reference, a d-axis current control unit having a dead band part for setting the d-axis current reference with hysteresis characteristics in the q-axis current feedback, and outputs the d-axis voltage reference, a q-axis current control unit that outputs a q-axis voltage reference based on the q-axis current reference, an inverse coordinate converter that outputs a three-phase AC voltage command based on the d-axis and q-axis voltage reference.

A method of controlling a variable speed constant frequency (VSCF) power converter is provided. The method includes receiving a determination that a sensed AC current output has exceeded a predetermined limit. The AC current output is converted from a DC voltage and has a constant frequency. The DC voltage is converted from a variable frequency AC voltage. The variable frequency AC voltage is generated in response to a mechanical energy input having a varying parameter. The method further includes decreasing the DC voltage in response to a determination that the sensed AC current output has exceeded the predetermined limit.

A motor drive that outputs a sinusoidal waveform utilizes power switching devices operable at high switching frequencies. The switching devices may be operated, for example, between twenty kilohertz and one megahertz. A first filter is included at the output of the motor drive which has a bandwidth selected to attenuate voltage components at the output which are at the switching frequency or multiples thereof such that the output voltage waveform is generally sinusoidal. Additional filtering is included within the motor drive to establish a circulation path for common mode currents within the motor drive. Further, a shield is provided adjacent to those components within the motor drive that may experience voltage or current waveforms at the switching frequency or multiples thereof to cause radiated emissions to establish eddy currents within the EMI shield rather than passing through the shield into the environment.

A line interface filter apparatus to couple a drive or group of drives to a shared multiphase AC bus, including individual phase circuits having an inductor coupled between a respective bus and drive phase lines, a tapped resistor coupled to the respective drive phase line, and a capacitor coupled between the resistor and a common connection of the capacitors of the individual phase circuits, where the capacitance of the capacitors is 5 to 15 times a per-phase equivalent capacitance of the drive or group of drives, and the resistance of the resistors is two times a damping ratio times a square root of a ratio of the filter inductance to the filter capacitance, where the damping ratio ζ is greater than or equal to 1.0 and less than or equal to 2.0.