Modulation to extend zero-voltage switching margin for dual-active bridge converter

Patent metadata

Field	Value
Publication number	US-12316233-B2
Application number	US-202217984092-A
Country	US
Kind code	B2
Filing date	Nov 9, 2022
Priority date	Nov 9, 2022
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

Systems and methods for controlling a dual active bridge converter are disclosed herein. A bus voltage of a dual active bridge (DAB) converter is detected and a first duty ratio of a primary bridge and a second duty ratio of a secondary bridge are determined, at least one of the first duty ratio and the second duty ratio are modified by adjusting at least one of a differential mode (DM) adjustment variable and a common mode (CM) adjustment variable based on the detected bus voltage. A plurality of switch control signals, which are provided to respective switches of the primary bridge and the secondary bridge, are caused to switch according to a time-based switching sequence based on the first duty ratio and the second duty ratio.

First claim

What is claimed is:

1. A method comprising:
detecting a bus voltage of a dual active bridge (DAB) converter, wherein the DAB comprises a primary bridge, a secondary bridge, and a transformer coupling the primary bridge to the secondary bridge;
determining a first duty ratio of the primary bridge and a second duty ratio of the secondary bridge;
modifying at least one of the first duty ratio and the second duty ratio by adjusting at least one of a differential mode (DM) adjustment variable and a common mode (CM) adjustment variable based on the detected bus voltage; and
causing a plurality of switch control signals, which are provided to respective switches of the primary bridge and the secondary bridge, to switch according to a time-based switching sequence based on the first duty ratio and the second duty ratio.

2. The method of claim 1 , wherein modifying at least one of the first duty ratio and the second duty ratio comprises modifying at least one of the first duty ratio and the second duty ratio such that a current of the transformer changes polarity before the secondary bridge switches off.

3. The method of claim 1 , wherein:
the DM adjustment variable is based on the detected bus voltage, a leakage inductance of the transformer, and a first gain; and
the CM adjustment variable is based on a deadtime of the DAB converter and a second gain.

4. The method of claim 1 , wherein the DM adjustment variable is a product of a first gain and a ratio of a leakage inductance of the transformer to the detected bus voltage.

5. The method of claim 1 , wherein the CM adjustment variable is a product of a second gain and a dead time between interlocked switches of the primary bridge or the secondary bridge.

6. The method of claim 1 , wherein the secondary bridge switches off before the primary bridge while a polarity of a current of the transformer is opposite to a polarity of a secondary bus voltage of the secondary bridge.

7. The method of claim 1 , wherein modifying at least one of the first duty ratio and the second duty ratio comprises modifying at least one of the first duty ratio and the second duty ratio to avoid zero current switching (ZCS) of the DAB converter.

8. The method of claim 1 , wherein modifying at least one of the first duty ratio and the second duty ratio comprises modifying at least one of the first duty ratio and the second duty ratio such that:
at each rising edge of a primary side voltage of the transformer, a current of the transformer is negative;
at each falling edge of the primary side voltage of the transformer, the current of the transformer is positive;
at each rising edge of a secondary side voltage of the transformer, the current of the transformer is positive; and
at each falling edge of the secondary side voltage of the transformer, the current of the transformer is negative.

9. The method of claim 1 , wherein detecting the bus voltage comprises:
detecting a primary bus voltage of the primary bridge;
detecting a secondary bus voltage of the secondary bridge; and
selecting, as the detected bus voltage, the bus voltage having smaller voltage fluctuations among the primary bus voltage and the secondary bus voltage.

10. A method comprising:
detecting a bus voltage of a dual active bridge (DAB) converter, wherein the DAB comprises a primary bridge, a secondary bridge, and a transformer coupling the primary bridge to the secondary bridge;
determining when to turn off the primary bridge and the secondary bridge based on the detected bus voltage such that zero voltage switching (ZVS) is achieved for one or more switches of the primary bridge and the secondary bridge, comprising:
determining a differential mode (DM) adjustment variable and a common mode (CM) adjustment variable; and
modifying at least one of a first duty ratio of the primary bridge and a second duty ratio of the secondary bridge based on the DM adjustment variable and the CM adjustment variable; and

causing a plurality of switch control signals, which are provided to respective switches of the primary bridge and the secondary bridge, to switch according to a time-based switching sequence based on the determination of when to turn off the primary bridge and the secondary bridge.

11. The method of claim 10 , further comprising switching off the secondary bridge before switching off the primary bridge.

12. A system for controlling a dual active bridge (DAB) converter having a primary bridge, a secondary bridge, and a transformer coupling the primary bridge to the secondary bridge, the system comprising:
a port of the DAB converter;
a plurality of output ports coupled to switches of the DAB converter; and
control circuitry coupled to the port and the plurality of output ports and configured to:
detect a bus voltage of the DAB converter via the port;
determine a first duty ratio of the primary bridge and a second duty ratio of the secondary bridge;
modify at least one of the first duty ratio and the second duty ratio by adjusting at least one of a differential mode (DM) adjustment variable and a common mode (CM) adjustment variable based on the detected bus voltage; and
cause a plurality of switch control signals, which are provided to respective switches of the primary bridge and the secondary bridge, to switch according to a time-based switching sequence based on the first duty ratio and the second duty ratio.

13. The system of claim 12 , wherein the control circuitry is configured to modify at least one of the first duty ratio and the second duty ratio by modifying at least one of the first duty ratio and the second duty ratio such that a current of the transformer changes polarity before the secondary bridge switches off.

14. The system of claim 12 , wherein each of the switches of the DAB converter is a gallium nitride (GaN) based semiconductor or a silicon carbide (SiC) based semiconductor.

15. The system of claim 12 , wherein:
the DM adjustment variable is a product of a first gain and a ratio of a leakage inductance of the transformer to the detected bus voltage; and
the CM adjustment variable is a product of a second gain and a deadtime between interlocked switches of the primary bridge or the secondary bridge.

16. The system of claim 12 , wherein the secondary bridge switches off before the primary bridge while a polarity of a current of the transformer is opposite to a polarity of a secondary bus voltage of the secondary bridge.

17. The system of claim 12 , wherein the control circuitry is configured to modify at least one of the first duty ratio and the second duty ratio by modifying at least one of the first duty ratio and the second duty ratio to avoid zero current switching (ZCS) of the DAB converter.

18. The system of claim 12 , wherein the control circuitry is configured to modify at least one of the first duty ratio and the second duty ratio by modifying at least one of the first duty ratio and the second duty ratio such that:
at each rising edge of a primary side voltage of the transformer, a current of the transformer is negative;
at each falling edge of the primary side voltage of the transformer, the current of the transformer is positive;
at each rising edge of a secondary side voltage of the transformer, the current of the transformer is positive; and
at each falling edge of the secondary side voltage of the transformer, the current of the transformer is negative.

19. The system of claim 12 , wherein the control circuitry is configured to detect the bus voltage by:
detecting a primary bus vol

Assignees

• Rivian Ip Holdings Llc

Inventors

• Shi Yanjun
• Mohajerani Zahra
• Wei Lixiang
• Marwali Mohammad Nanda R

Classifications

• H02M1/123

  Suppression of common mode voltage or current · CPC title

• H02M3/33573

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

• H02M3/3353 Primary

  having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter · CPC title

• H02M3/33584 Primary

  Bidirectional 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