DC-DC Converter Segmentation for EV Efficiency
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Solution Overview
Problem
DC-DC converters in electric vehicles experience poor efficiency at low power requirements, leading to significant energy losses due to their design optimized for higher power ratings, resulting in high energy wastage during prolonged low-power operations such as charging.
Innovation Solution
Incorporating multiple independently usable converter circuits with different maximum power ratings within the DC-DC converter, allowing the control unit to select the most efficient combination based on the current power requirement, enabling cascading or exclusive operation to optimize efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single DC-DC converter is designed for high rated power to meet maximum power requirements, then the maximum power capability is sufficient, but the efficiency deteriorates significantly during low power operation
Solution Approach 1:
The DC-DC converter is divided into multiple converter circuits with different power ratings (e.g., a first converter circuit for high power and a second converter circuit for low power). Each converter circuit operates independently and can be selected based on the current power requirements, ensuring high efficiency across different operating conditions.
2Loss of energy
If multiple converter circuits with different power ratings are provided, then efficiency is improved across different power requirements, but the device complexity increases
Solution Approach 1:
Multiple converter circuits with different power ratings are integrated into a single DC-DC converter unit, sharing common infrastructure such as control units, sensors, and housing. This merging approach improves efficiency across different power requirements while minimizing the increase in overall device complexity through resource sharing.
3Power
If a single high-power DC-DC converter is used, then the maximum power delivery is adequate, but the manufacturing costs and complexity increase without benefit for low power applications
Solution Approach 1:
Instead of manufacturing a single high-power converter, the system uses multiple lower-power converter circuits with different ratings that can be selectively activated. This segmentation allows for simpler manufacturing of individual converter circuits while achieving the same maximum power delivery capability through selective operation.
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 significantly reduces energy losses by selecting the appropriate converter circuit combination for varying power demands, improving overall efficiency and reducing complexity and costs by utilizing existing infrastructure.
Implementation Method 1
DC-DC converters are used to supply the low-voltage network in order to convert from the high voltage in the high-voltage network
Data Source
AI summary
A motor vehicle, including an electric machine as a drive machine, a high-voltage battery, a high-voltage network to which the electric machine and the high-voltage battery are connected, a low-voltage network having a lower voltage than the high-voltage network, and a DC-DC converter, which connects the low-voltage network and the high-voltage network and is designed for a maximum deliverable rated voltage. The DC-DC converter includes at least two independently usable converter circuits having different maximum power and a control unit. The control unit selects at least one converter circuit to be operated in dependence on a power requirement value of the low-voltage network.