Abstract: A DC power supply apparatus and method of supplying DC power for mission critical applications utilizes multiple power circuits in one unit, the power circuits being optimizable for efficiency as the load increases or decreases. The individual power supplies may use a multiphase topology within the power circuits, with logic phase shifts between multiphase, and two types of power management circuits arranged in parallel, or an equivalent controller, for implementing: (a) a variable linear or variable exponential precision droop algorithm, and (b) a “virtual bus” or current averaging/active current sharing circuit, the current sharing being provided by a low bandwidth communications link between droop controllers in each of the power circuits.

Abstract: A DC power supply apparatus and method of supplying DC power for mission critical applications utilizes multiple power circuits in one unit, the power circuits being optimizable for efficiency as the load increases or decreases. The individual power supplies may use a multiphase topology within the power circuits, with logic phase shifts between multiphase, and two types of power management circuits arranged in parallel, or an equivalent controller, for implementing: (a) a variable linear or variable exponential precision droop algorithm, and (b) a “virtual bus” or current averaging/active current sharing circuit, the current sharing being provided by a low bandwidth communications link between droop controllers in each of the power circuits.

Abstract: A method and device for connecting a load to an AC power source is arranged to ensure that the volt-second ratings of magnetic devices in the load are not exceeded, in order to limit in-rush currents resulting from saturation of the magnetic devices. In the case where the load is being disconnected from a first AC source and connected to a second AC source, the volt-seconds of the load can be measured and/or calculated during disconnect, in order to delay connection of the load to the second AC source by an amount sufficient to prevent saturation of magnetic devices and thereby ensure volt-second synchronization of the sources.

Abstract: A method and device for connecting a load to an AC power source is arranged to ensure that the volt-second ratings of magnetic devices in the load are not exceeded, in order to limit in-rush currents resulting from saturation of the magnetic devices. In the case where the load is being disconnected from a first AC source and connected to a second AC source, the volt-seconds of the load can be measured and/or calculated during disconnect, in order to delay connection of the load to the second AC source by an amount sufficient to prevent saturation of magnetic devices and thereby ensure volt-second synchronization of the sources.

Abstract: A branch circuit monitor includes a plurality of non-contact current sensors arranged to sense current on each of a plurality of branch circuits, the non-contact current sensors being connected to a common digital signal processor (DSP) module having as inputs the outputs of the current sensors and also voltage inputs from each power source. The digital signal processor is arranged to calculate not only overall energy consumption, but also RMS voltage, RMS current, power factor, real power, and/or apparent power for each branch circuit. Preferably, the non-contact current sensors are in the form of miniature non-contact Rogowski coils or induction transducers. Data from the digital signal processor may be made available via communications protocols such as Modbus RTU or RS232/RS485/422, to any number of remote sites. The individual branch circuit monitors can be wired in a daisy chain or star network configuration and even connected to the Internet via an appropriate interface device.

Abstract: A harmonic current filtering transformer includes a three-phase input winding and at least two wye-connected three-phase output windings. Windings for each of the phases includes an in-phase coil connected between a common neutral and vector coils for each of the other two phases, the output windings thereby being phase shifted relative to each other by an amount which causes harmonic currents generated by a non-linear load to magnetically cancel in the transformer core. The harmonic current filtering transformer may be used as part of a harmonic cancelling power system which includes multiple linear and nonlinear loads, and protective devices, switches, filters and other components on both the input and output sides of the transformer as in a conventional power system since the harmonic cancelling transformer does not require additional secondary windings or other electrical components previously thought necessary to achieve harmonic cancellation.

Abstract: A harmonic current filtering transformer includes a three-phase input winding and at least two wye-connected three-phase output windings. The output windings are phase shifted relative to each other by an amount which causes harmonic currents generated by a non-linear load to magnetically cancel in the transformer core.

Abstract: A harmonic current filtering transformer includes a three-phase input winding and at least two wye-connected three-phase output windings. The output windings are phase shifted relative to each other by an amount which causes harmonic currents generated by a non-linear load to magnetically cancel in the transformer core.