Dual Active Bridge Switching Delay for DC Link Resonance Control
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Solution Overview
Problem
Dual active bridge (DAB) power converters experience DC link power resonance across components like snubber capacitors, leading to potential early failure due to energy accumulation, which is costly to mitigate by increasing component sizes.
Innovation Solution
A control method is implemented to reduce DC link resonance by sending specific control signals to toggle pairs of switches in the DAB converter, with temporal delays based on the resonance time of the bridge, minimizing ripple currents on snubber capacitors without reducing power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of snubber capacitors is increased to reduce energy accumulation, then component reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent changes the timing parameters of switch toggling by introducing a temporal delay based on resonance time. This parameter change in the control signals minimizes ripple currents and energy accumulation in snubber capacitors without requiring larger component sizes, thereby improving reliability while avoiding increased device complexity
Solution Approach 2:
The patent replaces the mechanical approach of increasing component size with a control-based solution. By using temporal delay control signals instead of physically larger capacitors, the system achieves the same energy management goal through electrical control rather than mechanical enlargement
2Reliability
If the size of snubber capacitors is increased to reduce energy accumulation, then component reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent modifies operational parameters (temporal delay based on resonance time) rather than physical parameters (capacitor size). This allows the system to achieve improved reliability through control optimization, avoiding the increased manufacturing cost associated with larger components
3Reliability
If temporal delay based on resonance time is applied to minimize ripple currents, then component reliability is improved, but power output may be reduced
Solution Approach 1:
The patent applies a partial temporal delay (half of the resonance time) rather than a complete resonance cycle delay. This partial action is sufficient to minimize ripple currents and improve reliability while maintaining near-maximum power output, avoiding the excessive delay that would significantly reduce power
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively minimizes ripple currents across snubber capacitors, reducing the risk of component failure while maintaining near-maximum power output, thus avoiding the need for oversized components.
Implementation Method 1
the temporal delay is based on a resonance time for the bridge... the resonance time for the bridge is based on a capacitance of at least two capacitors coupled to the bridge and an inductance between the at least two capacitors
Data Source
AI summary
Systems and methods for operating dual active bridge (DAB) converters are provided herein. The systems and methods include sending a first control signal to toggle a first pair of switches of a bridge of the DAB converter and sending a second control signal to toggle a second pair of switches of the bridge, where a temporal delay, based on a resonance time for the bridge, separates the toggling caused by the first control signal from the toggling caused by the second control signal.