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US 2020/0007032 A1Published application
Dc/dc resonant converters and power factor correction using resonant converters, and corresponding control methods
AssigneeSignify Holding B.V.
InventorsREINHOLD ELFERICH, DAVID LLEWELLYN JOHN, WILLIAM PETER MECHTILDIS MARIE JANS, JOHANNES HUBERTUS GERARDUS OP HET VELD
Life of this patent
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Abstract
Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.
Claims13
An AC/DC PFC converter, comprising:
- an AC input for providing an input voltage and an input current to an input of a rectifier, wherein the rectifier is arranged for rectifying the input voltage to obtain a rectified input voltage;
- a half bridge inverter for receiving the rectified input voltage and comprising a first switch and a second switch, wherein a first output is defined from a node between the first and second switches;
- an LLC circuit coupled to the first output and having a second output for supplying a converter output voltage and current, wherein a voltage across a capacitor of the LLC circuit is provided as an electrical feedback parameter, wherein the electrical feedback parameter is representative of the input current, wherein the capacitor is arranged for acting as a resonance capacitor;
- and
- a control circuit for generating a gate drive signal for controlling the switching of the first switch and the second switch in dependence on the electrical feedback parameter, wherein a high gate drive signal turns on one switch of the first and seconds switches and turns off another switch of the first and seconds switches and a low gate drive signal turns off the one switch and turns on the other switch,
- a correction unit for modifying a relationship between the threshold level for the electrical feedback parameter and the rectified input voltage to the circuit,
- wherein the control circuit comprises an outer control loop for setting a threshold level for the electrical feedback parameter proportional to the converter output voltage or current and the rectified input voltage without measurement of the input current, and an inner control loop for comparing the electrical feedback parameter with the threshold level to derive the gate drive signal and to provide power factor correction.
4 more elements
An AC/DC PFC conversion method, comprising:
- rectifying an AC input;
- operating a half bridge inverter comprising a first switch and a second switch using a gate drive signal and providing an output from a node between the first and second switches, wherein a high gate drive signal turns on one switch of the first and second switches and turns off another one of the first and second switches and a low gate drive signal turns off the one switch and turns on the other switch;
- providing a voltage across a capacitor of an LLC circuit as an electrical feedback parameter which is representative of an input current;
- controlling a switching of the first switch and the second switch in dependence on the electrical feedback parameter, by:
- setting a threshold level for the electrical feedback parameter in an outer control loop in dependence on a converter output voltage or current and the rectified AC input voltage without measurement of the input current;
- and
- comparing the electrical feedback parameter with the threshold level in an inner control loop to derive the gate drive signal.
4 more elements
Dependencies are inferred from the claim text.