Abstract: A method and a high-voltage DC (HVDC) power system are provided. The system includes a plurality of sending-end (SE) modules coupled in electrical series and divided into at least two groups that each operate independently with respect to an electrical ground and a plurality of receiving-end (RE) power converter modules electrically coupled to the plurality of SE modules, the plurality of RE power converter modules including a fast ground-fault detection and control device, the plurality of RE power converter modules including a receiving-end front-end DC-DC converter controller, and an output current damping control.

Abstract: A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

Abstract: Methods for determining a ground fault or insulation degradation condition within energy conversion systems are described. A method for determining a ground fault within an energy conversion system may include, in part, a comparison of baseline waveform of differential current to a waveform of differential current during operation for a plurality of DC current carrying conductors in an energy conversion system. A method for determining insulation degradation within an energy conversion system may include, in part, a comparison of baseline frequency spectra of differential current to a frequency spectra of differential current transient at start-up for a plurality of DC current carrying conductors in an energy conversion system. In one embodiment, the energy conversion system may be a photovoltaic system.

Abstract: A power converter is provided. The power converter includes a converter leg including switches for converting power. The power converter also includes a controller for switching the switches using a pulse width modulation technique. The power converter further includes an interface inductor coupled to the converter leg for avoiding a reverse recovery of current in the switches during operation.

Abstract: A partial power converter includes a converter leg including an upper portion comprising at least one diode connected to a positive output node of an output terminal of the partial power converter and a lower portion comprising at least two switches connected in series with each other and with the at least one diode and to a negative output node of the output terminal of the partial power The partial power converter also includes at least one flying capacitor connected between the at least two switches at a first end and to either of the upper portion of the converter leg or the positive output node of the partial power converter at a second end.

Abstract: A system and method are provided for enabling a PV inverter to be connected to a string of series connected PV modules without exposing the inverter to elevated voltage stresses. The input voltage to the inverter is gradually built up by sequentially switching in more series PV modules. This system and method are simple to implement in both centralized and distributed PV power plants and in either case, it significantly increases the utilization of the PV inverter. The input switching elements can be implemented using a wide variety of parts including electro-mechanical switches, semiconductor switches (IGBTs, MOSFETs . . . , etc.) as well as MEMS devices depending on the current level and target cost. A mix of switches can also be used to assist in minimizing impedance of the final switching stage that remains connected during normal operation.

Abstract: A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.

Abstract: A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

Abstract: An apparatus and method for an electron beam manipulation coil for an x-ray generation system includes the use of a control circuit. The control circuit includes a first low voltage source, a second low voltage source, and a first switching device coupled in series with the first low voltage source and configured to create a first current path with the first low voltage source when in a closed position. The control circuit also includes a second switching device coupled in series with the second low voltage source and configured to create a second current path with the second low voltage source when in a closed position and a capacitor coupled in parallel with an electron beam manipulation coil and positioned along the first and second current paths.

Abstract: A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.

Abstract: An apparatus and method for an electron beam manipulation coil for an x-ray generation system includes the use of a control circuit. The control circuit includes a first low voltage source, a second low voltage source, and a first switching device coupled in series with the first low voltage source and configured to create a first current path with the first low voltage source when in a closed position. The control circuit also includes a second switching device coupled in series with the second low voltage source and configured to create a second current path with the second low voltage source when in a closed position and a capacitor coupled in parallel with an electron beam manipulation coil and positioned along the first and second current paths.

Abstract: An apparatus and method for magnetic control of an electron beam includes a control circuit having a first low voltage source and a second low voltage source. The control circuit also includes a first switching device coupled in series with the first low voltage source and configured to create a first current path with the first low voltage source when in a closed position and a second switching device coupled in series with the second low voltage source and configured to create a second current path with the second low voltage source when in a closed position. The control circuit further includes a capacitor coupled in parallel with an electron beam manipulation coil and positioned along the first and second current paths and a current source circuit electrically coupled to the electron beam manipulation coil and constructed to generate an offset current in the first and second current paths.

Abstract: A system that includes micro-electromechanical system switching circuitry is provided. The system may include a first over-current protection circuitry connected in a parallel circuit with the micro-electromechanical system switching circuitry for suppressing a voltage level across contacts of the micro-electromechanical system switching circuitry during a first switching event, such as a turn-on event. The system may further include a second over-current protection circuitry connected in a parallel circuit with the micro-electromechanical system switching circuitry for suppressing a current flow through the contacts of the micro-electromechanical system switching circuitry during a second switching event, such as a turn-off event.