In-Vehicle DC-DC Converter Temperature-Based Power Limiting
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Solution Overview
Problem
Existing in-vehicle DC-DC converters face challenges in determining optimal power limitation values for input and output powers based on the temperature of power storage units, leading to inefficient voltage management and potential overcharging or undercharging issues.
Innovation Solution
An in-vehicle DC-DC converter system that adjusts power limitation values based on temperature-specific voltage ranges, using a control unit to determine input and output power limitations by associating voltage ranges with temperature ranges, allowing for dynamic adjustment of power limits to prevent overcharging or undercharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed threshold value is set for voltage conversion operation, then the control logic is simple, but the power storage unit cannot be fully utilized across different temperature conditions
Solution Approach 1:
The patent implements dynamic threshold adjustment by switching between a first threshold value (for lower temperature ranges) and a second threshold value (for higher temperature ranges) based on the detected temperature of the power storage unit. This allows the voltage conversion operation to adapt to different temperature conditions, optimizing power utilization while preventing overcharging or undercharging across varying thermal environments.
Solution Approach 2:
The patent changes the voltage threshold parameter based on temperature conditions. When the power storage unit temperature is below a predetermined threshold, a first threshold value is used; when the temperature is at or above the threshold, a second threshold value is used. This parameter change approach enables the system to optimize charging/discharging operations for different temperature scenarios.
2Adaptability or versatility
If the threshold value is set too low, then the available charging voltage range is maximized, but the charging voltage easily reaches the limit voltage when large current is output at low temperature
Solution Approach 1:
The patent dynamically adjusts the voltage threshold based on temperature detection. At lower temperatures, a higher first threshold value is applied to prevent the charging voltage from reaching the limit voltage when large currents are output. At higher temperatures, a lower second threshold value is used to maximize the charging voltage range. This dynamic adjustment resolves the contradiction between voltage range and voltage stability.
3Reliability
If the threshold value is set too high, then the charging voltage is protected from reaching the limit, but the available charging voltage range becomes too small and there is excessive leeway when temperature is high
Solution Approach 1:
The patent changes the voltage threshold parameter according to temperature conditions. When the power storage unit temperature is below the predetermined threshold, a first threshold value is used that allows broader voltage range. When the temperature is at or above the threshold, a second threshold value is applied that provides appropriate protection while avoiding excessive conservatism. This resolves the contradiction between protection and utilization.
4Device complexity
If a single power limitation value is used for all temperatures, then the control system is simple, but optimal power management cannot be achieved across different temperature conditions
Solution Approach 1:
The patent implements a dynamic power limitation system that adjusts the power limitation value based on detected temperature. When the power storage unit temperature is below a predetermined threshold, a first power limitation value is applied. When the temperature is at or above the threshold, a second power limitation value is used. This dynamic approach optimizes power management efficiency across different temperature conditions while maintaining relatively simple control logic.
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 system effectively manages power by limiting input power as the input voltage decreases and output power as the output voltage increases, ensuring safer and more efficient charging/discharging operations based on temperature conditions, thereby preventing voltage extremes.
Implementation Method 1
a voltage conversion unit that includes a switching element that performs an on/off operation in accordance with being supplied with a control signal, and steps up or down a voltage applied to the input-side conductive path through an on/off operation by the switching element, and outputs the voltage to the output-side conductive path
Data Source
AI summary
Provided is a configuration in which, in an in-vehicle DC-DC converter, a limitation value of input power or output power can be determined according to the temperature of a power storage unit. In an in-vehicle DC-DC converter (1), a determination unit uses a scheme for determining whether or not input power of an input-side conductive path has reached an input power limitation value that is determined according to an input voltage of the input-side conductive path and a temperature range to which the temperature of an input-side power storage unit belongs, or a scheme for determining whether or not output power of an output-side conductive path has reached an output power limitation value that is determined according to an output voltage of the output-side conductive path and a temperature range to which the temperature of an output-side power storage unit belongs.