DC-dC resonant converter and control method thereof

Patent metadata

Field	Value
Publication number	US-11799370-B2
Application number	US-202117363129-A
Country	US
Kind code	B2
Filing date	Jun 30, 2021
Priority date	Jun 30, 2020
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

The present disclosure provides a series resonant converter and its corresponding control method. In one aspect, the series resonant converter includes m (m=1,2,3, . . . ) sets of primary side stages in parallel, wherein each primary side stage is identical and includes n (n=2,3, . . . ) stacked element circuits, where the primary side stages receive an input voltage; n×m resonant networks coupled to the primary side stages; n×m transformers having n×m primary side windings and n×m secondary side windings, where the primary side windings are coupled to the n×m resonant networks; p (p=1,2,3, . . . ) sets of secondary side stages in parallel, wherein each secondary side stage is identical and includes q (q=n×m/p) stacked element circuits, where the secondary side stages are coupled to n×m secondary side windings; and a control block controlling the primary side switches according to the output voltage, input voltage and input capacitor voltages.

First claim

What is claimed is:

1. A DC-DC converter comprising:
a primary side comprising a serial stack of at least two half-bridge inverter cells, each comprising two active switches in series in one leg and an input capacitor in a parallel leg together forming a loop wherein each inverter cell is connected from a point between the active switches to a resonant tank circuit to a primary side winding wound on a transformer core, and through the other end of the winding to a common star connection of the corresponding ends of all the inverter cells, wherein one end of the loop connecting the legs of one inverter cell is directly connected to the opposite end of the corresponding loop in an inverter cell on which said one inverter cell is stacked and a primary side voltage is applied or produced between the two ends of the loops of the serial stack of inverter cells that are not directly connected to another inverter cell and wherein the transformer core is sharable with other inverter cells;
a secondary side comprising at least two sets of rectifier circuit elements each coupled to a secondary side winding wound on a transformer core shared with a corresponding primary side winding and is configured to rectify current induced at the secondary stage by current flowing in the corresponding primary side winding, and wherein a secondary side voltage is produced or applied; and
control circuitry configured to activate the active switches in the converter to vary the pulse frequency or width or phase shift angle of voltage or current through said serial stack of at least two half-bridge inverter cells;
wherein the control circuitry is configured to perform at least one of
(1) determining whether the voltage detected across the input capacitor of an inverter cell is greater than a reference voltage and, if so, adjusts the inverter cell duty cycles through the two active switches to balance the capacitor voltage; and
(2) determining whether any of the average voltages across the input capacitors of each inverter cell minus a reference voltage is greater than a threshold voltage and, if so, determines the greatest difference among the cells and adjusts the phase shift angle to each phase leg through the two active switches to balance the capacitor voltages.

2. The DC-DC converter of claim 1 , wherein the rectifier circuit elements are each a half-bridge rectifier cell comprising in a leg two diodes in series and oriented in the same direction between the two diodes being a connection to the corresponding secondary side winding to a common star connection of the corresponding ends of all the rectifier cells, wherein corresponding ends of the diode legs form common connections with a parallel capacitor legs such that the secondary side voltage is produced between the two ends of the parallel legs.

3. The DC-DC converter of claim 1 , wherein the rectifier circuit elements are each an active half-bridge rectifier cell comprising in a leg two active switches in series, each controlled by the control circuitry, between which active switches is a connection to the corresponding secondary side winding to a common star connection of the corresponding ends of all the rectifier cells, wherein corresponding ends of the legs of the rectifier circuit elements form common connections with a parallel capacitor leg such that the secondary side voltage is produced or applied between the two ends of the parallel legs.

4. The DC-DC converter of claim 1 , wherein the rectifier circuit elements are each a full-bridge rectifier cell comprising two parallel legs of two diodes in series oriented in the same direction wherein each rectifier cell is connected from a point between the diodes of one leg to one end of the corresponding secondary side winding wound on the transformer core and through the other end of the winding to a point between the diodes of the other leg, wherein corresponding ends of the diode legs form common connections with a parallel capacitor leg such that the secondary side voltage is produced between the two ends of the parallel legs.

5. The DC-DC converter of claim 1 , wherein the rectifier circuit elements are each a full-bridge rectifier cell comprising two parallel legs of two active switches in series, each controlled by the control circuitry, between the active switches in a leg being a connection to one end of the corresponding secondary side winding wound on the transformer core and through the other end of the winding to a point between the active switches of the other leg, wherein corresponding ends of the active switch legs form common connections with a parallel capacitor leg such that the secondary side voltage is produced or applied between the two ends of the parallel legs.

6. The DC-DC converter of claim 1 , wherein the rectifier circuit elements form a serial stack of half-bridge rectifier cells, each comprising two diodes in series oriented in the same direction in one leg and two capacitors in series in a parallel leg together forming a loop wherein each rectifier cell is connected from a point between the diodes to one end of the corresponding secondary side winding wound on the transformer core and through the other end of the winding to a point between the two capacitors, wherein one end of the loop connecting the parallel legs of one rectifier cell is directly connected to the opposite end of the corresponding loop in a rectifier cell on which said one rectifier cell is stacked and a secondary side voltage is produced between the two ends of the loops of the secondary stack of rectifier cells that are not directly connected to another rectifier cell.

7. The DC-DC converter of claim 1 , wherein the rectifier circuit elements form a serial stack of half-bridge rectifier cells, each comprising two active switches in series in one leg, each controlled by the control circuitry, and two capacitors in series in a parallel leg together forming a loop wherein each rectifier cell is connected from a point between the active switches to one end of the corresponding secondary side winding wound on the transformer core and through the other end of the winding to a point between the two capacitors, wherein one end of the loop connecting the parallel legs of one rectifier cell is directly connected to the opposite end of the corresponding loop in a rectifier cell on which said one rectifier cell is stacked and a secondary side voltage is produced or applied between the two ends of the loops of the serial stack of rectifier cells that are not directly connected to another rectifier cell.

8. The DC-DC converter of claim 1 , wherein the rectifier circuit elements form a serial stack of half-bridge rectifier cells, each comprising two diodes in series oriented in the same direction in one leg and a capacitor in a parallel leg together forming a loop wherein each rectifier cell is connected from a point between the diodes through a blocking capacitor to one end of the corresponding secondary side winding wound on the transformer core and through the other end of the winding to a common star connection of the corresponding ends of all the rectifier cells, wherein one end of the loop connecting the parallel legs of one rectifier cell is directly connected to the opposite end of the corresponding loop in a rectifier cell on which said one rectifier cell is stacked and a secondary side voltage is produced between the two ends of the loops of the serial stack of rectifier cells that are not directly connected to another rectifier cell.

9. The DC-DC converter of claim 1 , wherein the rectifier circuit elements form a serial stack of half-bridge rectifier cells, each comprising two active switches in series in one leg, each controlled by the control circuitry, and a capacitor in a

Assignees

• Delta Electronics Inc

Inventors

• Zhang Chi
• Shen Zhiyu
• Wang Ruxi
• Barbosa Peter Mantovanelli

Classifications

• H02M1/0074 Primary

  Plural converter units whose inputs are connected in series · CPC title

• H02M3/01

  Resonant DC/DC converters · CPC title

• H02M3/33571

  Half-bridge at primary side of an isolation transformer · CPC title

• H02M3/33592

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