Patent ID: 11901811
Assignee: DANMARKS TEKNISKE UNIVERSITET
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. An AC-DC power converter comprising:
an AC rectification circuit configured to convert an AC line voltage into a rectified line voltage,
a rectifying element connected between the rectified line voltage and a DC supply voltage of a resonant DC-DC converter; said resonant DC-DC converter comprising:
a resonant inverter configured to convert the DC supply voltage into a resonant inverter voltage at a fixed or controllable switching frequency, and
an output rectification circuit configured to generate a DC output voltage or DC output current from the resonant inverter voltage for supply to a converter load, and

a charge pump circuit connected to the rectified line voltage and the resonant inverter voltage, where said charge pump circuit is configured to draw current pulses at the switching frequency from the AC line voltage,
wherein electrical charges of the current pulses vary proportionally to instantaneous amplitude of the AC line voltage,
wherein the charge pump circuit comprises:
a smoothing capacitor connected to the DC supply voltage of the resonant DC-DC converter, and
a pump or flying capacitor connected from the resonant inverter voltage to the rectified line voltage,

wherein the charge pump circuit is configured to, during a cycle of the switching frequency, sequentially cycle through states of:
a first state where each of the rectifying element and the AC rectification circuit is non-conducting/off and a voltage across the pump/flying capacitor remains substantially constant,
a second state where the AC rectification circuit is conducting/on and the rectifying element is non-conducting/off to charge the pump/flying capacitor by line current drawn from the AC line voltage,
a third state where each of the rectifying element and the AC rectification circuit is non-conducting/off and the voltage across the pump/flying capacitor remains substantially constant, and
a fourth state where the AC rectification circuit is in a non-conducting/off state and the rectifying element is in a conducting/on state such that discharge current flows from the pump/flying capacitor into the smoothing capacitor to increase the DC supply voltage of the resonant inverter and decrease the voltage across the pump/flying capacitor;

wherein the charge pump circuit is further configured to:
cycle through its second state during a rising edge of a waveform of the resonant inverter voltage, and
cycle through its fourth state during a falling edge of the waveform of the resonant inverter voltage; and

wherein a capacitance of the smoothing capacitor and a capacitance of the pump/flying capacitor are selected such that the DC supply voltage of the resonant inverter is higher than the AC line voltage across an entire cycle of the AC line voltage.