Bi-directional DC-DC Converter Partial Power Segmentation
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Solution Overview
Problem
Existing bi-directional DC-DC voltage converters in electric and hybrid electric vehicles suffer from inefficiencies, leading to increased volume, weight, and cost due to full power rating requirements, which result in higher losses and thermal management challenges.
Innovation Solution
A bi-directional DC-DC power converter operates as a partial power converter, processing a portion of the power while delivering another portion directly without processing, utilizing a first and second converter section with transformers to achieve efficient power transfer in both boost and buck modes, reducing the overall power rating and associated losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a full power rating DC-DC converter is used to carry full power, then the power conversion capability is sufficient, but the converter generates higher losses and requires higher thermal management
Solution Approach 1:
The power flow is segmented into two paths: a processed path through the DC-DC converter for voltage matching and an unprocessed path bypassing the converter for direct power transfer. This segmentation allows only the necessary differential power to be converted, reducing losses while maintaining full power capability.
Solution Approach 2:
The patent introduces an intermediary control mechanism that dynamically determines the split between processed and unprocessed power based on voltage differential and power demand, optimizing the balance between conversion capability and loss reduction.
2Power
If a full power rating DC-DC converter is used, then the converter can handle full power, but the volume and weight of the system increase
Solution Approach 1:
By segmenting power flow into processed and unprocessed paths, the converter only needs to handle the differential power portion, allowing for a smaller, lighter converter design while maintaining full system power handling capacity.
Solution Approach 2:
The converter operates at partial power rating (only processing the differential portion), which is sufficient for voltage matching while avoiding the weight penalty of a full power rating converter.
3Power
If a full power rating DC-DC converter is used, then the power conversion is comprehensive, but the cost of the system increases
Solution Approach 1:
Segmenting power flow allows the use of a lower power rating converter, which reduces component costs and manufacturing expenses while still achieving comprehensive power conversion through the combination of processed and unprocessed paths.
Solution Approach 2:
The system dynamically changes the power rating parameter of the converter based on operating conditions, using only the necessary conversion capacity required at any given moment, thereby reducing overall system cost.
4Power
If switches carry full power in the DC-DC converter, then the power conversion is complete, but higher current conduction increases losses
Solution Approach 1:
The switch current is segmented into two components: processed current through the converter switches (lower magnitude) and unprocessed current bypassing the switches (higher magnitude). This reduces switch conduction losses while maintaining complete power conversion.
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
This approach reduces the volume and weight of the converter system while improving efficiency to nearly 100% for unprocessed power transfer, achieving increased efficiency without additional cost, thereby enhancing the overall performance of electric and hybrid electric vehicle systems.
Implementation Method 1
a first converter section coupled to the energy storage device and a second converter section coupled to the DC link
Implementation Method 2
a first converter section coupled to the energy storage device and a second converter section coupled to the DC link
Data Source
AI summary
A bi-directional DC-DC converter assembly that processes and transfers differential power in a variable manner is disclosed. The converter assembly is coupled to an energy storage device and DC link, with the converter assembly including a first converter section coupled to the energy storage device and a second converter section coupled to the DC link and to the energy storage device. The converter assembly processes a first portion of the DC power output of the energy storage device and provides an unprocessed second portion of the DC power output of the energy storage device to the second converter section when providing power to the load, and processes a first portion of a regenerative power from the load and provides an unprocessed second portion of the regenerative power from the load to the first converter section when providing regenerative power to the energy storage device.