Direct-current-to-direct-current converter with transformer thermal management

Patent metadata

Field	Value
Publication number	US-12348148-B2
Application number	US-202318360996-A
Country	US
Kind code	B2
Filing date	Jul 28, 2023
Priority date	Dec 19, 2022
Publication date	Jul 1, 2025
Grant date	Jul 1, 2025

Abstract

An electronic controller is configured to adjust the duty cycle, between a respective pairs of semiconductor switches of the primary converter of a direct-current-to-direct-current converter based on reducing or minimizing one or more of the first estimated line-to-line DC offset voltage, the second estimated line-to-line DC offset voltage, and the third estimated line-to-line DC offset voltage. Further, the electronic controller is configured determines duty cycle adjustments based on oversampling (e.g., enhanced data processing with interpolation) of smoothed or integrated representation of the first estimated line-to-line DC offset voltage, the second estimated line-to-line DC offset voltage, and the third estimated line-to-line DC offset voltage.

First claim

The following is claimed:

1. A dual-active-bridge converter comprising:
a primary converter having a plurality of primary switch pairs that operate at different phases or phase offsets with respect to each other; each primary switch pair comprising a first switched terminal of low-side semiconductor switch coupled to a corresponding second switched terminal of high-side semiconductor switch at a primary alternating current node, each primary switch pair comprising the low-side semiconductor switch having a second switched terminal coupled to one terminal of a primary direct current bus; the high-side semiconductor switch having a first switched terminal coupled to another terminal of the primary direct current bus;
a secondary converter having a plurality of secondary switch pairs that operate at different phases or phase offsets with respect to each other; each secondary switch pair comprising a first switched terminal of low-side semiconductor switch coupled to a corresponding second switched terminal of high-side semiconductor switch at an secondary alternating current node, each secondary switch pair comprising the low-side semiconductor switch having a second switched terminal coupled to one terminal of a secondary direct current bus; the high-side semiconductor switch having a first switched terminal coupled to another terminal of the secondary direct current bus;
a first DC offset detector to measure a first observed DC offset line-to-line voltage, associated with the primary alternating current nodes, between a first respective phase and a second respective phase;
a second DC offset detector to measure a second observed DC offset line-to-line voltage, associated with the primary alternating current nodes, between a third respective phase and the second respective phase;
an estimator or summer for determining or estimating a third estimated line-to-line DC offset voltage based upon a difference between the first observed line-to-line DC offset voltage and the second line-line DC offset voltage;
a transformer coupled between the primary alternating current node and the secondary alternating current node; and
an electronic controller configured to provide control signals to the control terminals of the semiconductor switches of the primary converter and the secondary converter based on a commanded current or target output current; the electronic controller configured to adjust the duty cycle through a duty cycle adjustment, between a respective pairs of semiconductor switches of the primary converter and second converter based on reducing or minimizing one or more of the first estimated line-to-line DC offset voltage, the second estimated line-to-line DC offset voltage, and the third estimated line-to-line DC offset voltage.

2. The dual active bridge converter according to claim 1 further comprising:
the electronic controller being configured to determine duty-cycle adjustments for each phase based on oversampling of a smoothed or integrated representation of the first estimated line-to-line DC offset voltage, the second estimated line-to-line DC offset voltage, and the third estimated line-to-line DC offset voltage.

3. The dual active bridge converter according to claim 1 further comprises:
the electronic controller being configured to determine duty-cycle adjustments for each phase based on oversampling at a supplemental rate of a smoothed or integrated representation of the first estimated line-to-line DC offset voltage, the second estimated line-to-line DC offset voltage, and the third estimated line-to-line DC offset voltage provided at a preliminary rate of one or more proportional integral controller, where the supplemental rate is greater than the preliminary rate.

4. The dual active bridge converter according to claim 1 wherein the first DC offset detector comprises:
a first low-pass filter configured to receive the first alternating current voltage at a first alternating current node for a first respective phase;
a second low-pass filter configured to receive the second alternating current voltage a second alternating current node for a second respective phase;
a differential amplifier coupled to the outputs of the first low-pass filter and the second low-pass filter, the differential amplifier providing a first line-to-line DC offset voltage.

5. The dual active bridge converter according to claim 4 wherein the second DC offset detector comprises:
a first low-pass filter configured to receive the second alternating current voltage at a second alternating current node for a second respective phase;
a second low-pass filter configured to receive the third alternating current voltage a third alternating current node for a third respective phase;
a differential amplifier coupled to the outputs of the first low-pass filter and the second low-pass filter, the differential amplifier providing the second line-to-line DC offset voltage.

6. The dual active bridge converter according to claim 1 wherein the controller comprises a duty-cycle control module; the duty-cycle module comprising:
a first summer for receiving a negative inputs of the first line-to-line DC offset voltage and the target zero line-to-line DC offset voltage;
a second summer for receiving a negative inputs of the second line-to-line DC offset voltage and the target zero line-to-line DC offset voltage;
a first controller configured to receive an output of the first summer;
a second controller configured to receive an output of the second summer;
a time modulation and duty-cycle assignment module configured to provide a dynamic duty cycle adjustment in a corresponding time slot on a time-division multiplex basis for each corresponding phase of the primary converter that differs from an approximately fifty percent duty cycle.

7. The dual active bridge converter according to claim 1 wherein the duty-cycle adjustment comprises decreasing the duty cycle of the low-side switch below approximately 50 percent duty cycle, while simultaneously increasing the duty cycle of the high-side switch above approximately 50 percent duty cycle for a corresponding phase of the primary inverter to attenuate any direct current or low frequency alternating current flowing between the primary winding and secondary winding of the transformer.

8. The dual active bridge converter according to claim 1 wherein the duty-cycle adjustment comprises adjusting the duty cycle for a first pair of switches of a corresponding first phase of the primary converter on a time division multiplex basis with respect to a second pair of switches for a corresponding second phase of the primary converter and with respect to a third pair of switches for a third phase of the primary converter.

9. The dual active bridge converter according to claim 1 wherein the duty-cycle adjustment comprises adjusting the duty cycle for a first pair of switches of a corresponding first phase of the primary converter on a time division multiplex basis with respect to a second pair of switches for a corresponding second phase of the primary converter and with respect to a third pair of switches for a third phase of the primary converter.

10. The dual active bridge converter according to claim 1 wherein each duty cycle adjustment is provided to a respective pair of switches during a respective time slot among successive time slots that are provided in a recurring rotational sequence that provides a control signal to the control terminal of each switch with a minimum time slot duration that is based on the clock speed of the electronic data processor.

11. The dual active bridge converter according to claim 10 wherein the respective time slot has a duration or interval wi

Assignees

• Deere & Co

Inventors

• Wu Yuheng
• Fu Tianjun
• Wu Long
• Oelmann Dustin E
• Wainwright Richard E

Classifications

• H02M3/33573

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

• H02M1/327

  against abnormal temperatures · CPC title

• H02M1/0064

  Magnetic structures combining different functions, e.g. storage, filtering or transformation · CPC title

• H02M3/33576 Primary

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

• H02M3/33584 Primary

  Bidirectional converters · CPC title