Abstract: A direct current (DC) transmission and distribution system (10) includes a system DC link (12) configured for carrying power from a source (14) to a plurality of loads (16) and DC to alternating current (AC) power converter modules (18, 118, 218, 318, 418) coupled in series to the system DC link on a load side of the system DC link.

Abstract: A power system for providing an output power to a load is provided. The system comprises a generator configured to generate an alternating current input power and an power converter system coupled to the generator and configured to generate an output power and provide the output power to the load through at least one transformer. The system further comprises a converter control system coupled to the converter system and configured to drive the converter system in an interleaved pattern to reduce harmonic components in the output power and the alternating current input power.

Abstract: A collection and transmission system (10) includes: a system direct current (DC) link (12) configured for carrying power from a source (13) to a grid (16); and alternating current (AC) to DC power converter modules (19, 119, 219, 319) coupled in series to the system DC link on a source side of the system DC link, each power converter module configured for being coupled to one or more sources (114, 214, 314, 414) on the source side, wherein each power converter module is configured to short circuit the DC terminals of the power converter module upon receipt of a respective command signal.

Abstract: A power converter for coupling an electrical machine to an electrical grid, the power converter including a machine side converter and a grid side converter, each side having a plurality of corresponding stages for converting a three-phase electrical signal of the electrical machine to a three-phase electrical signal of the electrical grid; wherein the machine side converter includes a plurality of single-phase bridges coupled in a series and has at least one coupling for coupling with the electrical machine; wherein the grid side converter includes a plurality of three-phase bridges, each three-phase bridge corresponding to one of the single-phase bridges of the machine side converter; wherein each three-phase bridge is coupled to the primary windings of a respective transformer while the secondary windings of the respective transformer are phase-shifted from the primary windings thereof and are coupled to secondary windings of another respective transformer, thus providing for coupling of the plurality of t

Abstract: Methods and apparatus for converting power from a power source are described. In one example embodiment, the method includes controlling multiple transformer and switchgear units coupled to a power source, and controlling multiple converter units connected in parallel. Each converter unit is coupled to a respective one of the transformer and switchgear units to form an individual thread. The transformer and switchgear unit and power converters are controlled so that the carrier waveforms for each individual thread are interleaved between each other over a carrier cycle.

Abstract: A gradient amplifier arrangement is described that comprises a gradient amplifier power stage. The device may be employed to provide a current to a gradient coil, as in a MRI system. The circuitry disclosed includes a series coupling of a first bridge amplifier operating at a first voltage, a second bridge amplifier operating at a second voltage, a third bridge amplifier operating at a third voltage, and a gradient amplifier control stage. The amplifiers may provide output voltages at different levels, and may be switched at different times and frequencies to provide a range of output voltage and current levels.

Abstract: An AC ripple current reduction circuit for an AC converter having: an AC voltage source at the input; a first capacitor across which the circuit output voltage is provided; a first, main inductor in series with the first capacitor and the input; an auxiliary circuit including a second capacitor and a transformer coupled to the main inductor, the secondary of the transformer being in series with the second capacitor; and a means for enabling the flow of a time varying voltage across the first and second capacitors that has a frequency much less than the ripple frequency of the current in the main inductor.

Abstract: A cross current control system for multiple, parallel-coupled power converters includes common mode chokes, local cross current feedback controllers, and local converter controllers. Each common mode choke is coupled to a respective power converter. Each local cross current feedback controller is configured for receiving common mode cross currents from a respective local cross current detector, calculating a resultant cross current, and generating a local feedback control signal. Each local converter controller is configured for using a respective local feedback control signal to drive the respective power converter in accordance with a coordinated switching pattern. An integral choke assembly includes a common mode choke and a differential mode choke with common and differential mode choke cores configured with at least one magnetic flux path being shared by magnetic flux generated by common mode coils and differential mode coils.

Abstract: A cross current control system for multiple, parallel-coupled power converters includes common mode chokes, local cross current feedback controllers, and local converter controllers. Each common mode choke is coupled to a respective power converter. Each local cross current feedback controller is configured for receiving common mode cross currents from a respective local cross current detector, calculating a resultant cross current, and generating a local feedback control signal. Each local converter controller is configured for using a respective local feedback control signal to drive the respective power converter in accordance with a coordinated switching pattern. An integral choke assembly includes a common mode choke and a differential mode choke with common and differential mode choke cores configured with at least one magnetic flux path being shared by magnetic flux generated by common mode coils and differential mode coils.

Abstract: A method for damping an LC filter coupled to a converter and generating a filter signal. The method comprises sensing the filter signal and processing the filter signal to generate a corresponding feedback signal. The feedback signal is subtracted from a controller signal to generate a difference signal. The difference signal is used for damping the LC filter.

Abstract: A cross current control system for multiple, parallel-coupled power converters includes common mode chokes, local cross current feedback controllers, and local converter controllers. Each common mode choke is coupled to a respective power converter. Each local cross current feedback controller is configured for receiving common mode cross currents from a respective local cross current detector, calculating a resultant cross current, and generating a local feedback control signal. Each local converter controller is configured for using a respective local feedback control signal to drive the respective power converter in accordance with a coordinated switching pattern. An integral choke assembly includes a common mode choke and a differential mode choke with common and differential mode choke cores configured with at least one magnetic flux path being shared by magnetic flux generated by common mode coils and differential mode coils.

Abstract: A method for damping an LC filter coupled to a converter and generating a filter signal. The method comprises sensing the filter signal and processing the filter signal to generate a corresponding feedback signal. The feedback signal is subtracted from a controller signal to generate a difference signal. The difference signal is used for damping the LC filter.

Abstract: A cross current control system for multiple, parallel-coupled power converters includes common mode chokes, local cross current feedback controllers, and local converter controllers. Each common mode choke is coupled to a respective power converter. Each local cross current feedback controller is configured for receiving common mode cross currents from a respective local cross current detector, calculating a resultant cross current, and generating a local feedback control signal. Each local converter controller is configured for using a respective local feedback control signal to drive the respective power converter in accordance with a coordinated switching pattern. An integral choke assembly includes a common mode choke and a differential mode choke with common and differential mode choke cores configured with at least one magnetic flux path being shared by magnetic flux generated by common mode coils and differential mode coils.

Abstract: Imaginary orthogonal circuit state variables are established to enable transformation of real circuit state variables of a single-phase converter or the zero-sequence circuit of a three-phase converter from stationary coordinates to DQ rotating coordinates, thereby transforming the sinusoidal steady-state operating point of the real circuit into a DC operating point. A control provides the imaginary circuit state variables in a shifted queue comprising memory blocks for storing quarter-cycle shifted real circuit variables. Control of the converter is thus implemented in rotating DQ coordinates to achieve a theoretically infinite control loop gain at the fundamental frequency.

Abstract: Imaginary orthogonal circuit state variables are established to enable transformation of real circuit state variables of a single-phase converter or the zero-sequence circuit of a three-phase converter from stationary coordinates to DQ rotating coordinates, thereby transforming the sinusoidal steady-state operating point of the real circuit into a DC operating point. A control provides the imaginary circuit state variables in a shifted queue comprising memory blocks for storing quarter-cycle shifted real circuit variables. Control of the converter is thus implemented in rotating DQ coordinates to achieve a theoretically infinite control loop gain at the fundamental frequency.

Abstract: A resonant gate driver circuit suitable for driving MOS-gated power switches in high-frequency applications recovers gate drive energy stored in the gate capacitance of the power switches, resulting in substantially lossless operation. The resonant gate driver circuit provides bi-polar gate control signals that are compatible with PWM operation.

Abstract: A secondary-side controlled series resonant AC voltage controlled module (VRM) converts an AC distribution bus voltage to a low DC voltage for providing power to high speed microprocessors and integrated circuits, with minimal conduction and switching losses, providing high efficiency even at low output voltage, high current and high switching frequency.