An AC-DC converter circuit can include a plurality of passive components configured to convert AC to DC and to non-linearly regulate output DC voltage to about a selected maximum throughout an AC input voltage range and/or generator frequency. The plurality of passive components can be configured to also limit power loss as a function of load on a DC side.

A power factor correction (PFC) controller applied to a primary side of a power converter includes a feedback pin, a sensing pin, a current detecting circuit, an output voltage detecting circuit, and a determination circuit. The current detecting circuit is coupled to the feedback pin and the sensing pin for detecting an output current of a secondary side of the power converter according to a feedback voltage of the feedback pin and a sensing voltage of the sensing pin. The output voltage detecting circuit is coupled to the feedback pin for detecting an output voltage of the secondary side of the power converter according to the feedback voltage. The determination circuit is coupled to the current detecting circuit and the output voltage detecting circuit for turning on or turning off a PFC circuit coupled to the power converter according to the output current and the output voltage.

A power system includes first and second power supplies, and a control circuit. The control circuit is configured to control the first power supply to regulate its output voltage at a first value, enable the second power supply, increase the output voltage of the first power supply to a second value in response to the second power supply being enabled, increase an output voltage of the second power supply to a third value, and decrease an output current of the first power supply and increase an output current of the second power supply to transition between electrically powering the load with the first power supply and electrically powering the load with the second power supply. Other example power system and methods for controlling a power transition between power supplies are also disclosed.

A switched-capacitor converter has a first and second terminal; a switched-capacitor ladder network having a plurality of serially connected first capacitors defining a plurality of flying capacitor nodes; a plurality of serially connected second capacitors defining a plurality of output capacitor nodes, wherein nodes of the flying capacitor nodes can be connected to nodes of the output capacitor nodes in a plurality of ladder converter configurations to perform a switched-capacitor ladder power conversion; and a switch matrix to connect the first terminal to different flying capacitor nodes and/or to connect any flying capacitor node to any other flying capacitor node or output capacitor node according to different switch configurations. Also, a switched-capacitor converter assembly may have a plurality of serially and/or parallel connected switched-capacitor reconfigurable switched-capacitor ladder converters. Methods for converting an input into an output voltage using a converter and for operating an assembly of converters are also provided.

A multi-phase shift transformer based AC-DC converter includes a single transformer that reflects a negative portion of an AC voltage to become a positive voltage by generating multiple phases from a poly-phase input. The multiple phases generated can be separated by as little as 1° to create a well-approximated DC output without the need for a smoothing circuit. The primary and second windings of the transformer are flat wire conductors structured to provide a larger number of windings per core including a larger number of secondary coils, which provides for a large number of output phases.

In this work, it is shown for the first time that the power and the impedance in a transformer circuit depend on the phase of the flux, hence the phase of the current. There is a phase change when the flux travels the magnetic core, and formulas for the effect of the phase change in the power and the impedance are derived. Therefore, the power factor can be adjusted so that the power is delivered more at the load than that, at the primary supplied by the source.

A method and apparatus for detection of a failure of a rectifier connected to a passive harmonic filter with a tuned circuit reactor, or of the filter itself, and for generating system currents in the filter, using low cost voltage sensing, modeling of reactor resistance and saturable inductance, and a mathematical integration. The harmonic spectrum of the rectifier current is used to determine an estimate of the rectifier impedance. A template of expected rectifier current is calculated, and compared against a rectifier current calculated on the basis of sensed voltages, to generate a difference signal. The difference signal is compared against a predetermined fault threshold to determine if an error has occurred. The apparatus includes a DSP obtaining the voltages of the source and load, and the tuned circuit reactor voltage, calculating the template, and comparing the actual voltages with the template, to annunciate a fault.

A UPS comprising an input, an output, a battery circuit, a PFC stage, a switch configured to selectively couple an interface of the PFC stage to the input in an online mode and to the battery circuit in a backup mode, a positive DC bus, a negative DC bus, and a controller configured to operate, in the online mode, the PFC stage to provide DC power, derived from the input AC power, to the DC busses, to operate, in the backup mode, the PFC stage to provide DC power, derived from the backup DC power, to the DC busses, to operate, in a first stage of the backup mode, the battery circuit to couple a positive terminal of a DC source to the interface, and to operate, in a second stage of the backup mode, the battery circuit to couple a negative terminal of the DC source to the interface.

A bidirectional power factor correction (PFC) module is coupled to an AC power source, an energy storage unit, and a DC bus. The bidirectional PFC module includes a bridge arm assembly and a control unit. The bridge arm assembly includes a first bridge arm, a first inductor, a second inductor, and a second bridge arm. The control unit provides a plurality of control signals to control the first bridge arm and the second bridge arm to make the bidirectional PFC module operate in an AC power supply mode, a DC power supply mode, or a power feed mode.

An AC-DC converter circuit can include a plurality of passive components configured to convert AC to DC and to non-linearly regulate output DC voltage to about a selected maximum throughout an AC input voltage range and/or generator frequency. The plurality of passive components can be configured to also limit power loss as a function of load on a DC side.