Abstract: Method and apparatus for determining a ground fault impedance. In one embodiment the apparatus comprises a voltage divider and a ground fault detection module for (i) determining a first voltage based on at least one voltage measurement of the voltage divider while the voltage divider is coupled between the first AC line and the DC line; (ii) determining a second voltage based on at least one voltage measurement of the voltage divider while the voltage divider is coupled between the second AC line and the DC line; (iii) determining a differential voltage based on at least one voltage measurement between the first AC line and the second AC line; and (iv) computing the ground fault impedance based on the first voltage, the second voltage, and the differential voltage.

Abstract: A method and apparatus for converting DC input power to DC output power with reactive power control. The apparatus includes a plurality of flyback circuits, coupled in parallel, and a DC-AC inversion circuit coupled across an output of each flyback circuit of the plurality of flyback circuits. The apparatus also including a reactive power control circuit coupled to an output of one flyback circuit of the plurality of flyback circuits, and across an output of the DC-AC inversion circuit; and a controller operative to coordinate timing of switches in each flyback circuit of the plurality of flyback circuits and the reactive power control circuit to generate AC output power of a desired power factor.

Abstract: A method and apparatus for power conversion. In one embodiment, an apparatus includes a power conversion module for converting a first current to a second current, where the first current or the second current is an AC current having at least two phases. The apparatus also includes a waveform modification module, coupled to the power conversion module, for modifying the AC current to generate a modified AC current, where each phase of the modified AC current has a value of zero at the beginning of an AC line cycle.

Abstract: Method and apparatus for converting DC input power to DC output power. In one embodiment, the apparatus comprises a plurality of flyback circuits, coupled in parallel, for providing DC-to-DC conversion; and a controller for automatically adjusting activation timing of each flyback circuit in said plurality of flyback circuits to achieve a balanced operation.

Abstract: The present invention is directed towards a serially connected micro-inverter (SCMI) system comprising a plurality of power sources for producing DC power, a plurality of micro-inverters, where each micro-inverter is coupled to at least one power source of the plurality of power sources, for converting the DC power into AC power, an AC bus for coupling the plurality of micro-inverters in series to form a string and for coupling the AC power an AC line; and a controller, coupled to the string, for measuring an output signal of one or more strings of series coupled micro-inverters, comparing the measured output signal to a desired signal for the string; and adjusting a phase angle of an output from each micro-inverter in the one or more strings until a difference between the measured output signal and the desired signal is less than a predetermined threshold value.

Abstract: A method and apparatus for power converter current control. In one embodiment, the method comprises controlling an instantaneous current generated by a power converter that is part of an AC battery such that (i) the power converter appears, from the perspective of an AC line coupled to the power converter, as a virtual AC voltage source in series with a virtual impedance, wherein real and reactive phasor currents for the power converter are indirectly controlled by modifying amplitude and phase of a virtual AC voltage waveform that defines the virtual AC voltage source, and (ii) active power flow is prioritized while the AC battery is operating in a charge mode.

Abstract: A method and apparatus for autonomously operating a microgrid power generator. In one embodiment, the method comprises obtaining a first measurement of at least one grid parameter of a microgrid transmission line coupled to a power generator in a microgrid; comparing the first measurement to a turn-on threshold; initiating, when the first measurement is less than the turn-on threshold, power generation by the power generator; obtaining, after initiation of the energy generation, a second measurement of the at least one grid parameter of the microgrid transmission line; comparing the second measurement to a shut-down threshold that is greater than the turn-on threshold; and stopping, when the second measurement exceeds the shut-down threshold, the power generation by the power generator.

Abstract: Method and apparatus for generating a power line communication (PLC) signal. In one embodiment, the method comprises generating a first modulation signal based on at least one data stream; modulating a first carrier signal by the first modulation signal to generate a first signal; generating a second signal by performing a phase shift based on the first signal; and coupling a balanced three-phase PLC signal comprising the first signal, the second signal and a third signal to a three-phase power line.

Abstract: System and apparatus for electrically coupling a microgrid to and from a power distribution grid. In one embodiment, the apparatus comprises an interconnect device, coupled to the microgrid and the power distribution grid, comprising (i) an overcurrent protection component (OPC) for interrupting a circuit during an overcurrent condition; and (2) a contactor component, coupled in series with the OPC and independently operable from the OPC, comprising (a) a set of contacts movable between a first position and a second position; (b) a first coil energizable to move the set of contacts from the first position into the second position; and (c) a second coil energizable, independently of the first coil, to maintain the contacts in the second position after the first coil is de-energized until a level of current flowing through the set of contacts is less than a lower current level.

Abstract: A surge blocking inductor. In one embodiment, the surge blocking inductor includes a core; a first winding wound about the core in a first direction; and a second winding wound about the core in a second direction, wherein the first winding and the second winding are magnetically independent when the core is in a non-saturated state, and wherein the first winding and the second winding are coupled magnetically when the core is in a saturated state.

Abstract: A method and apparatus for regulating an input voltage to a power conversion module. In one embodiment, the method comprises computing a voltage regulation threshold based on an output voltage for the power conversion module; comparing an input voltage of the power conversion module to the voltage regulation threshold; and generating, when the input voltage satisfies the voltage regulation threshold, an average input voltage less than the voltage regulation threshold, wherein the average input voltage is generated from the input voltage.

Abstract: A method and apparatus for providing multi-phase power. In one embodiment, the apparatus comprises a cycloconverter controller for determining a charge ratio based on a reference waveform; and a cycloconverter, coupled to the cycloconverter controller and to a multi-phase AC line, for selectively coupling an alternating current to each line of the multi-phase AC line based on the charge ratio.

Abstract: A method and apparatus for monitoring maximum power point tracking (MPPT) by measuring, external to a device that performs the MPPT, a DC current and a DC voltage to obtain a DC current value and a DC voltage value, wherein the DC current and the DC voltage are from a distributed generator (DG) coupled to the device. The method determining, external to the device, a constellation of data points, wherein each data point of the constellation comprises a DC voltage change and a corresponding DC current change resulting from an AC waveform, and determining, a dynamic resistance of the DG based on the constellation. The method computes a ratio of the DC voltage value to the DC current value, compares the dynamic resistance to the ratio, and determines, based on the comparison of the dynamic resistance to the ratio, if the DG is biased at a maximum power point (MPP).

Abstract: A method and apparatus for harmonic distortion compensation in power line communications. In one embodiment, the method comprises analyzing a waveform generated by a transmitter of a power line communications transceiver (PLCT), wherein the waveform is analyzed to determine harmonic information for one or more harmonics of a carrier waveform of the PLCT; computing, based on the harmonic information, one or more harmonic compensation coefficients; and pre-distorting, based on the one or more harmonic compensation coefficients, the carrier waveform such that the one or more harmonics are reduced below a threshold.

Abstract: A method and apparatus for correcting a locally measured inverter voltage. In one embodiment, the method comprises determining a voltage compensation to compensate for a voltage drop along an AC bus between an inverter and a remotely located point on the AC bus; obtaining a voltage measurement at the inverter; applying the voltage compensation to the voltage measurement to determine a corrected voltage measurement; comparing the corrected voltage measurement to a voltage requirement; and performing a corrective action at the inverter when the corrected voltage measurement does not meet the voltage requirement.

Abstract: Method and apparatus for generating a power line communication (PLC) signal. In one embodiment, the method comprises generating a first modulation signal based on at least one data stream; modulating a first carrier signal by the first modulation signal to generate a first signal; generating a second signal by performing a phase shift based on the first signal; and coupling a balanced three-phase PLC signal comprising the first signal, the second signal and a third signal to a three-phase power line.

Abstract: A method and apparatus for providing multi-phase power. In one embodiment, the apparatus comprises a cycloconverter controller for determining a charge ratio based on a reference waveform; and a cycloconverter, coupled to the cycloconverter controller and to a multi-phase AC line, for selectively coupling an alternating current to each line of the multi-phase AC line based on the charge ratio.

Abstract: A method and apparatus for managing DC arc faults. At least a portion of the method is performed by a controller comprising at least one processor. In one embodiment, the method comprises identifying, based on a first signature of a power converter, an arc fault; determining, based on the first signature, a type of the arc fault; and performing an action on the power converter based on the type of the arc fault.

Abstract: Method and apparatus for extending a zero voltage switching (ZVS) range during power conversion. In one embodiment, the apparatus comprises a DC/DC converter, operated in a quasi-resonant mode, comprising a transformer; a primary switch, coupled to a primary winding of the transformer, for controlling current flow through the primary winding; and a component coupled to the transformer, wherein the component has a capacitance that varies with voltage across the component, and wherein during a downswing in voltage across the primary switch the component is passively tuned by a change in the voltage across the component that changes the capacitance of the component, and wherein the passive tuning of the component causes a resonant frequency of the DC/DC converter to change, and wherein the change in the resonant frequency causes the downswing to accelerate.

Abstract: A method and apparatus for converting a first power to a second power. In one embodiment, the apparatus comprises a power conversion circuit for receiving the first power and a controller, coupled to the power conversion circuit, for dynamically selecting between a regular mode and a quasi-resonant mode for operating the power conversion circuit to convert the first power to the second power.