Abstract: A method of and system for controlling a DC midpoint of a multi-level inverter. The method includes receiving an input power signal from an AC power source at a multi-level motor control system that includes a DC bus and a multi-level inverter configured to supply a load, the DC bus having a DC midpoint, connecting a DC midpoint of a DC bus to a neutral point of the AC power source, while isolating a neutral point of a load supplied by the multi-level inverter from the DC midpoint, monitoring a voltage on the DC midpoint of the DC bus. In addition, the method may include controlling a voltage of the neutral point of the AC load based on imbalances in the load supplied by the multi-level inverter.

Abstract: A system for controlling inrush current between a power source and a load includes an output capacitor configured to be coupled in parallel with the load. The system also includes a transistor having a gate, a collector configured to be coupled to the power source, and an emitter configured to be coupled to the load. The system also includes a collector resistor coupled between the collector of the transistor and the gate of the transistor. The system also includes an emitter capacitor coupled between the gate of the transistor and the emitter of the transistor to facilitate current flow from the power source through the collector resistor and the emitter capacitor to charge the output capacitor.

Abstract: A method of and system for controlling a DC midpoint of a multi-level inverter. The method includes receiving an input power signal from an AC power source at a multi-level motor control system that includes a DC bus and a multi-level inverter configured to supply a load, the DC bus having a DC midpoint, connecting a DC midpoint of a DC bus to a neutral point of the AC power source, while isolating a neutral point of a load supplied by the multi-level inverter from the DC midpoint, monitoring a voltage on the DC midpoint of the DC bus. In addition, the method may include controlling a voltage of the neutral point of the AC load based on imbalances in the load supplied by the multi-level inverter.

Abstract: A system for controlling inrush current between a power source and a load includes an output capacitor coupled in parallel with the load, and a transistor having a gate, a collector configured to be coupled to the power source, and an emitter configured to be coupled to the load. The system also includes a supply resistor configured to be electrically coupled between the power source and the load and to provide a resistor charging current from the power source to the output capacitor to charge the output capacitor in response to initial power being provided by the power source. The system also includes a gate resistor having a first terminal coupled to the gate of the transistor to cause the transistor to operate in a linear mode in response to the initial power being provided by the power source to increase a speed of charging the output capacitor.

Abstract: An inductor includes a printed wiring board (PWB) and a plurality of electrically-conductive heat pipes operatively connected to the PWB. The PWB includes electrically conductive traces electrically connected to the plurality of electrically-conductive heat pipes. The traces and plurality of electrically conductive heat pipes form an inductor winding. A method of manufacturing an inductor includes mounting a plurality of electrically conductive heat pipes to a printed wiring board (PWB), wherein the PWB includes electrically conductive traces to connect the plurality of electrically-conductive heat pipes to form an inductor winding.

Abstract: A transformer assembly includes a housing with a sealed housing interior, a transformer disposed within the housing interior and having a core with windings wrapped about the core, and a condenser mounted to the housing. The condenser is in fluid communication with the housing interior. A surface of the windings bounds a coolant channel extending between the windings and the condenser to convey coolant of a first phase to the condenser and receive coolant of a second phase from the condenser.

Abstract: A parallel semiconductor switching system includes an input filter circuit, a plurality of switching circuits, and a current-sharing filter inductor. The switching circuits receive the filtered voltage generated by the input filter circuit, and each switching circuit outputs a respective current. The current-sharing filter inductor includes a plurality of windings. Each winding has a winding input and a winding output. The winding input of each winding is connected to a switching output of a respective switching circuit, and the winding output of each winding is connected to one another to form a common node. The node common node is connected directly to a load such that the current-sharing filter inductor shares each current output from the plurality of switching circuits so as to deliver a combined current to the load.

Abstract: A Litz wire terminal assembly includes a wire bundle having a plurality of electrically conductive strands extending between a first end and a second end to define a length. Each strand includes an insulative cover having a proximate cover end at the first end and a distal cover end at the second end. The distal cover end is flush with the second end. The Litz wire terminal assembly further includes a ferrule on the wire bundle. The ferrule has a distal ferrule end at the second end of the conductive strands.

Abstract: A transformer assembly includes a housing with a sealed housing interior, a transformer disposed within the housing interior and having a core with windings wrapped about the core, and a condenser mounted to the housing. The condenser is in fluid communication with the housing interior. A surface of the windings bounds a coolant channel extending between the windings and the condenser to convey coolant of a first phase to the condenser and receive coolant of a second phase from the condenser.

Abstract: A Litz wire terminal assembly includes a wire bundle having a plurality of electrically conductive strands extending between a first end and a second end to define a length. Each strand includes an insulative cover having a proximate cover end at the first end and a distal cover end at the second end. The distal cover end is flush with the second end. The Litz wire terminal assembly further includes a ferrule on the wire bundle. The ferrule has a distal ferrule end at the second end of the conductive strands.

Abstract: A motor controller has a direct current input, inverter, common mode filter, differential mode filter, and an output terminal. The direct current input is electrically connected to the common mode filter. The common mode filter is electrically connected to the inverter. The inverter is electrically connected in to the differential mode filter. The differential mode filter is electrically connected to the output terminal. The common mode filter is configured to attenuate common mode noise and is located on the input side of the inverter. The differential mode filter attenuates differential mode noise and is located on the output side of the inverter. A motor system having a motor controller, a direct current source, a feeder cable, and an electric motor.

Abstract: A three phase step-up autotransformer construction is discussed herein. The passive 12-pulse AC-DC converter offers simplicity, high reliability and low cost solution to AC-DC power conversion. The autotransformer is a component of the passive 12-pulse AC-DC converter. The autotransformer converts three-phase AC power into six-phase AC power. With appropriate vector design, the autotransformer may be configured to draw a near sinusoidal 12-pulse current waveform from the three-phase voltage source. The six-phase output may be configured to drive a rectifier (non-linear) load.

Abstract: A three phase step-up autotransformer construction is discussed herein. The passive 12-pulse AC-DC converter offers simplicity, high reliability and low cost solution to AC-DC power conversion. The autotransformer is a component of the passive 12-pulse AC-DC converter. The autotransformer converts three-phase AC power into six-phase AC power. With appropriate vector design, the autotransformer may be configured to draw a near sinusoidal 12-pulse current waveform from the three-phase voltage source. The six-phase output may be configured to drive a rectifier (non-linear) load.

Abstract: A dual-input 18-pulse autotransformer rectifier unit for more electric aircraft AC-DC converter uses an autotransformer with a nine-phase output to condition AC power prior to DC rectifying the AC power.

Abstract: A dual-input nine-phase autotransformer converts first and second three-phase AC inputs to a nine-phase AC output. The autotransformer includes input terminals for connection to a first three-phase AC input and a second three-phase AC input smaller than the first three-phase AC input. The autotransformer includes a first plurality of coils, a second plurality, and a third plurality of coils wound on respective phase legs of the autotransformer. The autotransformer includes a plurality of output terminals for providing a plurality of AC output voltages, and a plurality of internal terminals for connecting the first, second, and third plurality of coils in a configuration that provides a 40° phase shift in the AC outputs provided by the dual-input nine-phase autotransformer.

Abstract: An AC-AC power converter supplies AC power to an AC motor having a plurality of motor windings and a case connected to a ground. The AC-AC power converter architecture includes an asymmetric phase shift autotransformer/rectifier unit (ATRU) that converts an AC input to a DC output, wherein the asymmetric phase shift ATRU generates a common-mode AC voltage across the asymmetric phase shift ATRU. The common mode voltage is diverted to ground through motor case parasitic capacitance via a common-mode voltage pull-down circuit connected between each phase of the ATRU AC input and the ground.

Abstract: An AC-DC power converter has a phase-shifting autotransformer based rectifiers and DC capacitors. Soft start of the AC-DC power converter is achieved by designing the autotransformer to operate at a low peak flux density at a point of AC voltage step application (initial turn on). The addition of a controlled impedance segregates capacitor charging from the initial magnetizing process of the autotransformer.

Abstract: A dual-input 18-pulse autotransformer rectifier unit for more electric aircraft AC-DC converter uses an autotransformer with a nine-phase output to condition AC power prior to DC rectifying the AC power.

Abstract: An electrical apparatus includes a magnetic core, and a bobbin extending about and partially covering the magnetic core. The bobbin is formed from a thermally conductive material. An electrical conductor forms a winding that wraps about the bobbin.

Abstract: An AC-AC power converter supplies AC power to an AC motor having a plurality of motor windings and a case connected to a ground. The AC-AC power converter architecture includes an asymmetric phase shift autotransformer/rectifier unit (ATRU) that converts an AC input to a DC output, wherein the asymmetric phase shift ATRU generates a common-mode AC voltage across the asymmetric phase shift ATRU. The common mode voltage is diverted to ground through motor case parasitic capacitance via a common-mode voltage pull-down circuit connected between each phase of the ATRU AC input and the ground.