DC-DC resonant converter and control method thereof

Patent metadata

Field	Value
Publication number	US-11652396-B2
Application number	US-202117363119-A
Country	US
Kind code	B2
Filing date	Jun 30, 2021
Priority date	Jun 30, 2020
Publication date	May 16, 2023
Grant date	May 16, 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 two input capacitors in series in a parallel leg, said one leg and said parallel leg being connected to form a loop wherein each half-bridge inverter cell is connected to a resonant tank circuit by connecting a first point between the active switches and a second point between the two input capacitors to a primary side winding wound on a transformer core, wherein an end of the loop connecting the legs of one of the inverter cells is connected to an opposite end of the loop connecting the legs of a neighboring one of the inverter cells on which said one of the inverter cells is stacked, and wherein a primary side voltage is applied or produced between two ends of the loops of the serial stack of inverter cells that are not connected to any inverter cell and wherein the transformer core is sharable among the inverter cells;
a secondary side comprising at least two rectifier circuit elements, each being coupled to a secondary side winding wound on the transformer core sharable with a corresponding primary side winding and is configured to rectify current induced at the secondary side 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 determines at least one of:
(1) whether an average of capacitor voltages detected across the two input capacitors of each one of the half-bridge inverter cells is greater than a first reference voltage and, if so, adjusts duty cycles of the two active switches of said each one of the half-bridge inverter cells to balance capacitor voltages among the half-bridge inverter cells; and
(2) 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 switches (S 1 , S 2 ) to balance capacitor voltages.

2. The DC-DC converter of claim 1 , wherein the rectifier circuit elements are each a half-bridge rectifier comprising two diodes in series and oriented in the same direction, wherein between the two diodes is a connection point connected to a first end of a corresponding one of the secondary side windings, wherein second ends of the secondary side windings are connected together, wherein corresponding ends of the rectifier circuit elements form common connections with a parallel capacitor such that the secondary side voltage is produced between two ends of the parallel capacitor.

3. The DC-DC converter of claim 1 , wherein the rectifier circuit elements are each an active half-bridge rectifier comprising two active switches in series, each being controlled by the control circuitry, wherein between the active switches is a connection point connected to a first end of a corresponding one of the secondary side windings, wherein second ends of the secondary side windings are connected together, wherein corresponding ends of the rectifier circuit elements form common connections with a parallel capacitor such that the secondary side voltage is produced or applied between two ends of the parallel capacitor.

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

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

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 a first leg and two capacitors in series in a second leg, said first and second legs being connected to form a loop, wherein each half-bridge rectifier cell is connected to a corresponding one of the secondary side windings wound on the transformer core by connecting a first point between the two diodes and a second point between the two capacitors respectively to two ends of said corresponding one of the secondary side windings wound on the transformer core, wherein one end of the loop connecting the first and second legs of one of the half-bridge rectifier cells is connected to one end of the loop connecting the first and second legs of a neighboring one of the half-bridge rectifier cells on which said one of the half-bridge rectifier cells is stacked, and wherein a secondary side voltage is produced between two ends of the loops of the serial stack of half-bridge rectifier cells that are not connected to any 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 a first leg, each being controlled by the control circuitry, and two capacitors in series in a second leg, said first and second legs being connected to form a loop, wherein each half-bridge rectifier cell is connected to a corresponding one of the secondary side windings wound on the transformer core by connecting a first point between the two diodes and a second point between the two capacitors respectively to two ends of said corresponding one of the secondary side windings wound on the transformer core, wherein one end of the loop connecting the first and second legs of one of the half-bridge rectifier cells is connected to one end of the loop connecting the first and second legs of a neighboring one of the half-bridge rectifier cells on which said one of the half-bridge rectifier cells is stacked, and wherein a secondary side voltage is produced between two ends of the loops of the serial stack of half-bridge rectifier cells that are not connected to any 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 a first leg and a capacitor

Assignees

• Delta Electronics Inc

Inventors

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

Classifications

• H02M7/06

  using discharge tubes without control electrode or semiconductor devices without control electrode · CPC title

• H02M1/0074 Primary

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

• H02M1/0009

  Devices or circuits for detecting current in a converter · CPC title

• Y02P80/10

  Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier · CPC title

• H02M3/33573 Primary

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