Bidirectional DC-DC Converter Topology Switching for Circulation Currents
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Solution Overview
Problem
Existing bidirectional DC to DC converters face challenges in managing circulation currents and efficiency when switching between low and high current applications, leading to oversizing of transformers and inductors, which affects thermal management and conversion efficiency.
Innovation Solution
A hybrid, high-power bidirectional DC to DC converter that dynamically switches between a delta-wye configuration for low to mid-current inputs and a straight interleaved configuration for high-current applications, using sets of switches to alter the topology and manage circulation currents effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a delta-wye configuration is used to double the boost ratio and minimize transformer size, then conversion efficiency is improved at low to mid-current inputs, but circulation currents increase significantly at high input currents requiring substantial oversizing and inductance devices
Solution Approach 1:
The patent implements dynamic switching between delta-wye and interleaved configurations based on real-time current detection. The controller monitors input current levels and automatically reconfigures the transformer connections, transitioning from delta-wye at low currents to interleaved at high currents, thereby optimizing efficiency while preventing circulation current damage
Solution Approach 2:
The patent changes the topological configuration parameter of the transformer connections based on operating conditions. By altering the connection mode (delta-wye vs. interleaved) according to current levels, the system adapts its electrical characteristics to maintain high efficiency across varying load conditions without suffering from circulation current issues
2Volume of stationary object
If transformer size is minimized through delta-wye configuration, then packaging and thermal management are improved, but the ability to handle high current transients deteriorates without substantial oversizing
Solution Approach 1:
The system dynamically adjusts transformer configuration based on load conditions. During high-current transients, the controller switches to interleaved configuration which provides better transient handling capability while maintaining compact transformer sizing during normal operation, thus achieving both compact size and reliable transient response
3Object-generated harmful factors
If the converter operates in interleaved configuration to avoid circulation currents, then high current handling is improved, but the boost ratio is reduced compared to delta-wye configuration
Solution Approach 1:
The converter dynamically switches between interleaved and delta-wye configurations based on current levels. At low currents where high boost ratio is needed, the system uses delta-wye configuration. At high currents where circulation current avoidance is critical, it switches to interleaved configuration, thereby achieving both high boost ratio when needed and circulation current elimination when required
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 converter maintains high efficiency and a compact size across varying power levels by actively switching configurations based on current size and boost ratio, doubling the boost ratio in delta-wye mode and minimizing circulation currents in interleaved mode.
Implementation Method 1
A bidirectional DC to DC converter includes transformers with windings that determine the boost ratio or reduction ratio of voltages across the converter
Implementation Method 2
a plurality of rectifiers, wherein each of the plurality of rectifiers is associated with a respective one of the plurality of transformers
Data Source
AI summary
A hybrid, high-power, bidirectional DC to DC converter includes switches between a delta-wye configuration and a straight interleaved configuration. In this way, the converter can operate in a delta-wye configuration for low to mid-current input applications and in a straight interleaved configuration for high-current applications. This allows the converter to have high efficiency while maintaining a small size for a wide range of applications.