Patent ID: 11901826
Assignee: DELTA ELECTRONICS, INC.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G  Y | IPC G  H

Claim 0:
1. A power converter that receives an input signal from a voltage source to provide an output voltage or an output current to at least one load, characterized in that the power converter comprises:
(a) a primary-side circuit comprising:
(i) series-connected first and second pairs of series-connected switching devices, each switching device of the first and second pairs of switching devices being controlled by a switch control signal, wherein the input signal is provided across the series-connected first and second pairs of switching devices;
(ii) an LC resonant circuit connected between a first electrical node in the first pair of switching devices and a second electrical node in the second pair of switching devices; and
(iii) an isolation transformer having first and second windings, wherein the first winding is connected between third and fourth electrical nodes in the LC resonant circuit;

(b) a secondary-side circuit connected in parallel with the second winding of the isolation transformer, the secondary-side circuit comprising a filter capacitor providing the output voltage or output current to the at least one load; and
(c) a control circuit, wherein the control circuit selects, at any given time, one of two or more modulating schemes and provides the switch control signals to operate the first and second pairs of switching devices of the primary-side circuit under the selected modulation scheme, based on at least one of the output voltage, the output current, the input signal, and one or more external control signals,
wherein the control circuit operates the first and second pairs of switching devices based on the output voltage or the output current, the control circuit being configured to operate in a first modulation mode and a second modulation mode, wherein under the first modulation mode, the first and second pairs of switching devices are operated to generate the output voltage comprising three different voltage levels, and wherein under the second modulation mode, the first and second pairs of switching devices are operated to generate the output voltage comprising two different voltage levels,
wherein the control circuit is further configured to operate in a third modulation mode, under the third modulation mode, the first and second pairs of switching devices are operated to generate a zero voltage level, wherein the control circuit operates in the third modulation mode between operating in the first modulation mode and operating in the second modulation mode, and
wherein the control circuit is further configured to operate in a fourth modulation mode, under the fourth modulation mode, the duty ratio of one of every two pulses of one of the first pair of switching devices is increased and the duty ratio of one of every two pulses of one of the second pair of switching devices is increased, or the duty ratio of one of every two pulses of one of the first pair of switching devices is decreased and the duty ratio of one of every two pulses of one of the second pair of switching devices is decreased.