Dual Active Bridge PWM Swapping for Balanced Switching Losses
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Solution Overview
Problem
Conventional dual active bridge converters have limited power efficiency due to unbalanced thermal performance and turn-off switching losses among switches, primarily caused by conventional PWM switch control signal patterns that lead to dissimilar switching characteristics and thermal differences between bridge legs.
Innovation Solution
Implementing periodic or aperiodic swapping of PWM patterns to control switches of a dual active bridge converter, distributing switching losses among switches by alternating between two distinct switching sequences, and adjusting the swapping frequency based on temperature feedback to optimize thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional PWM switch control signal patterns are used, then the control system is simple, but switching losses and thermal performance are unbalanced among switches
Solution Approach 1:
The patent applies periodic action by implementing periodic swapping between two distinct PWM switching sequences (first and second switching sequences). The control circuitry alternates between these sequences at predetermined intervals, which periodically redistributes switching losses among the bridge legs and switches. This periodic alternation balances the thermal performance across all switches while maintaining a relatively simple control structure based on two predefined patterns.
2Temperature
If switching sequences are swapped periodically, then thermal performance is balanced, but control complexity increases
Solution Approach 1:
The patent implements dynamics by making the control signal pattern adaptive and variable over time. The control circuitry dynamically switches between two distinct PWM sequences based on predetermined criteria or feedback from temperature sensors. This dynamic adjustment allows the system to adapt to thermal conditions and balance switching losses across different bridge legs, transforming a static control approach into a dynamic one that responds to system state.
Solution Approach 2:
The patent employs feedback mechanisms where temperature sensors monitor the thermal state of switches and provide feedback to the control circuitry. Based on this feedback, the control circuitry adjusts the switching sequence selection and swapping timing to optimize thermal distribution. This closed-loop feedback ensures that thermal performance is actively managed and balanced across all switches.
3Use of energy by moving object
If PWM patterns are swapped to balance switching losses, then power efficiency improves, but system complexity increases
Solution Approach 1:
The patent applies periodic action by implementing periodic swapping between two distinct PWM switching sequences (first and second switching sequences). The control circuitry alternates between these sequences at predetermined intervals, which periodically redistributes switching losses among the bridge legs and switches. This periodic alternation balances the thermal performance across all switches while maintaining a relatively simple control structure based on two predefined patterns.
Solution Approach 2:
The patent implements parameter changes by varying the switching sequence parameters (which switches are turned on/off and when) to optimize power efficiency. By changing the temporal and spatial distribution of switching events across different bridge legs, the system redistributes thermal stress and reduces overall switching losses, thereby improving power efficiency without requiring fundamental changes to the converter architecture.
Data Source
AI summary
Systems and methods for controlling a dual active bridge converter are disclosed herein. Switch control signals are provided to respective switches of at least one bridge of a dual active bridge converter. Control circuitry causes the switch control signals to switch according to a first switching sequence. After causing the switch control signals to switch according to the first switching sequence, the control circuitry causes the switch control signals to switch according to a second switching sequence, distinct from the first switching sequence, to distribute switching losses among the switches.