One-sided parallel LLC power converter

Patent metadata

Field	Value
Publication number	US-11146175-B2
Application number	US-202016800276-A
Country	US
Kind code	B2
Filing date	Feb 25, 2020
Priority date	Feb 25, 2020
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

A power converter includes a primary circuit and a secondary circuit. The primary circuit includes two primary LC circuits that are in parallel electrically with each other. A first node of each primary LC circuit is electrically coupled to a high-voltage input. A second node of each primary LC circuit is coupled to a respective terminal of a primary inductor that forms a transformer with a secondary inductor in the secondary circuit. Each primary LC circuit is electrically coupled to a primary switch that operates at approximately the resonance frequency of the primary LC circuits to output an alternating current that passes through the primary inductor. The terminals of the secondary inductor are coupled to respective secondary switches. The switches operate at the resonance frequency of the primary LC circuit to rectify the power. A low-pass filter outputs the mean of the received voltage.

First claim

What is claimed is:

1. A power converter comprising:
a primary circuit comprising:
a common node electrically coupled to a high-voltage source;
a first primary LC circuit electrically coupled to the common node and to a first primary node;
a second primary LC circuit electrically coupled to the common node and to a second primary node, the second primary LC circuit in parallel electrically with the first primary LC circuit, the first and second primary LC circuits having the same or about the same primary LC resonance frequency;
a primary inductor having a first terminal electrically coupled to the first primary node and a second terminal electrically coupled to the second primary node;
a first primary circuit switch electrically coupled to the first primary node, the first primary circuit switch having a closed state where the first primary switch is electrically coupled to the first primary node and to ground, the first primary circuit switch having an open state where the first primary circuit switch is electrically decoupled from the first primary node; and
a second primary circuit switch electrically coupled to the second primary node, the second primary circuit switch having a closed state where the second primary switch is electrically coupled to the second primary node and to ground, the second primary circuit switch having an open state where the second primary circuit switch is electrically decoupled from the second primary node;

a secondary circuit in electrical communication with the primary circuit, the secondary circuit comprising:
a secondary inductor electromagnetically coupled to the primary inductor to form a transformer;
a first secondary circuit switch electrically coupled to a first secondary inductor node, the first secondary node electrically coupled to a first terminal of the secondary inductor, the first secondary circuit switch having a closed state where the first secondary switch is electrically coupled to the first secondary node and to ground, the first secondary circuit switch having an open state where the first secondary circuit switch is electrically decoupled from the first secondary node;
a second secondary circuit switch electrically coupled to a second secondary inductor node, the second secondary node electrically coupled to a second terminal of the secondary inductor, the second secondary circuit switch having a closed state where the second secondary switch is electrically coupled to the second secondary node and to ground, the second secondary circuit switch having an open state where the second secondary circuit switch is electrically decoupled from the second secondary node;
a low-pass filter electrically coupled to the first and second secondary nodes;
a low-voltage output node electrically coupled to an output of the low-pass filter; and

a controller in electrical communication with the first and second primary circuit switches and with the first and second secondary circuit switches, the controller configured to:
operate the first and second primary circuit switches at about the primary LC resonance frequency; and

operate the first and second secondary circuit switches at about the primary LC resonance frequency,
wherein the low-pass filter comprises:
a first low-pass filter electrically coupled to the low-voltage output node and the first secondary node; and
a second low-pass filter electrically coupled to the low-voltage output node and the second secondary node.

2. The power converter of claim 1 , wherein the controller includes a frequency-locked loop circuit that is locked to the primary LC resonance frequency.

3. The power converter of claim 1 , wherein:
the first low-pass filter comprises a first LP inductor and a common output capacitor, and
the second low-pass filter comprises a second LP inductor and the common output capacitor.

4. The power converter of claim 1 , wherein the first and second low-pass filters output a mean of a voltage at the first and second secondary nodes, respectively.

5. The power converter of claim 1 , wherein the first and second primary LC circuits output an alternating current, the alternating current passing through the primary circuit inductor.

6. The power converter of claim 5 , wherein the alternating current is received by the secondary circuit via the transformer.

7. The power converter of claim 6 , wherein the first and second secondary switches rectify the alternating current.

8. The power converter of claim 1 , wherein the controller includes a charge-sharing circuit that is electrically coupled to a charge-sharing switch, the charge-sharing switch electrically coupled to the first and second secondary circuit switches.

9. The power converter of claim 8 , wherein:
the charge-sharing circuit is configured to close the charge-sharing switch to form an electrical path between the first and second secondary circuit switches, and
when the charge-sharing switch is closed, a charge in a parasitic gate capacitor of the first secondary circuit switch is used to partially charge a parasitic gate capacitor of the second secondary circuit switch.

10. The power converter of claim 1 , further comprising a secondary circuit capacitor in parallel electrically with the secondary inductor to form a secondary LC circuit.

11. The power converter of claim 10 , wherein the secondary circuit capacitor comprises a variable capacitor.

12. The power converter of claim 11 , wherein:
the controller includes a voltage regulation circuit that compares an output voltage at the low-voltage output node with a reference voltage,
the voltage regulation circuit increases a capacitance of the variable capacitor when the output voltage is greater than the reference voltage, and
the voltage regulation circuit decreases a capacitance of the variable capacitor when the output voltage is less than the reference voltage.

13. The power converter of claim 12 , wherein the controller includes a primary zero-voltage switching circuit that adjusts a duty cycle of the first and second primary circuit switches so that the first and second primary circuit switches are in phase with the first and second secondary circuit switches, respectively, when the capacitance of the variable capacitor is adjusted.

14. The power converter of claim 1 , wherein the controller is configured to operate the first and second primary circuit switches at about a 50% duty cycle.

15. The power converter of claim 1 , wherein the controller is configured to operate the first and second secondary circuit switches at about the 50% duty cycle.

16. A power converter comprising:
a primary circuit comprising:
a common node electrically coupled to a high-voltage source;
a first primary LC circuit electrically coupled to the common node and to a first primary node;
a second primary LC circuit electrically coupled to the common node and to a second primary node, the second primary LC circuit in parallel electrically with the first primary LC circuit, the first and second primary LC circuits having the same or about the same primary LC resonance frequency;
a primary inductor having a first terminal electrically coupled to the first primary node and a second terminal electrically coupled to the second primary node;
a first primary circuit switch electrically coupled to the first primary node, the first primary circuit switch having a closed state where the first primary switch is electrically coupled to the first primary node and to ground, the first primary circuit switch having an open state where the first primary circuit switch is electricall

Assignees

• Ferric Inc

Inventors

• Zaliasl Samira
• Sturcken Noah
• Shishkov Denis
• Lekas Michael

Classifications

• H02M3/01 Primary

  Resonant DC/DC converters · CPC title

• Y02B70/10

  Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes · CPC title

• H02M1/0058

  by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826) · CPC title

• H02M3/33592

  having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer · CPC title

• H02M3/33576

  having at least one active switching element at the secondary side of an isolation transformer · CPC title