Dual Active Bridge Converter Switching for Thermal Loss Balancing
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Solution Overview
Problem
Conventional dual active bridge converters have power ratings limited by unbalanced thermal performance in switches due to dissimilar switching characteristics and thermal differences among bridge legs, leading to inefficient loss distribution.
Innovation Solution
Implementing a control mechanism that enables certain switches of a dual active bridge converter to have uneven inactive states during a switching cycle, distributing losses among switches by using a switching sequence that alternates between top and bottom switches to drive voltages towards zero volts, thereby balancing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional PWM switch control signal patterns are used, then the dual active bridge converter can operate with balanced control, but switching losses and thermal performance become unbalanced among bridge legs, limiting power rating
Solution Approach 1:
The patent applies asymmetry by implementing uneven inactive states for top switches versus bottom switches within the same converter. Specifically, top switches are enabled concurrently during certain inactive stages while bottom switches are prevented from being enabled concurrently during other stages, creating an asymmetric switching pattern that deliberately unbalances the switching characteristics to achieve balanced thermal performance across all bridge legs.
Solution Approach 2:
The patent implements dynamics by making the switching sequence adaptive and variable. The control circuitry dynamically adjusts which switches are enabled concurrently during inactive stages based on real-time operational conditions, allowing the system to optimize loss distribution and thermal management across different operating points and load conditions.
2Device complexity
If equal number of inactive stages are provided for top switches and bottom switches, then switching control is simplified, but thermal differences among bridge legs increase, limiting power rating
Solution Approach 1:
The patent deliberately introduces asymmetry in the switching control by providing different numbers of inactive stages for top switches compared to bottom switches. This asymmetric control strategy is designed to compensate for inherent thermal differences among bridge legs, ensuring that all switches operate within acceptable thermal limits despite the increased control complexity.
3Adaptability or versatility
If switches operate with dissimilar switching characteristics, then the converter can handle different load conditions, but thermal performance becomes unbalanced, reducing overall efficiency
Solution Approach 1:
The patent applies local quality by implementing switch-specific control strategies where each switch or group of switches (top vs. bottom) receives customized switching sequences tailored to their specific thermal and electrical characteristics. This localized optimization ensures that each switch operates efficiently under its specific conditions while contributing to overall system balance.
Data Source
AI summary
Systems, methods, and computer-readable media for controlling a dual active bridge converter to distribute switching losses are disclosed herein. A plurality of switch control signals are provided to a plurality of switches, respectively, of at least one bridge of a dual active bridge converter. The plurality of switches comprises top switches and bottom switches. Control circuitry causes the plurality of switch control signals to switch according to a switching sequence comprising a plurality of stages. During at least one of the plurality of stages, the top switches are enabled concurrently with one another or the bottom switches are enabled concurrently with one another.