Power Electronics Thermal Control Using Coolant-Aware Power Derating
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Solution Overview
Problem
Power electronic systems, such as those in electric vehicles, are overdesigned due to traditional thermal management approaches that maintain constant maximum power throughout a wide temperature range, leading to inefficiency and unused thermal headroom at lower temperatures.
Innovation Solution
A system and method that includes a power electronic system with a semiconductor switch, a temperature sensor, and a controller that adjusts power based on sensed semiconductor switch and coolant temperatures, allowing for increased power output below a threshold coolant temperature and power derating above it to prevent junction temperature exceeding maximum limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power electronic system is designed for maximum power at maximum coolant temperature, then the system can operate at rated maximum power across the entire temperature range, but the system becomes cost-inefficient with unused thermal headroom at lower temperatures
Solution Approach 1:
The patent implements dynamic power adjustment based on coolant temperature. The controller continuously monitors coolant temperature and adjusts the maximum permissible power output accordingly - allowing higher power at low temperatures and reducing power at high temperatures. This dynamic approach replaces the static overdesign with temperature-adaptive power management, optimizing both reliability and cost efficiency.
Solution Approach 2:
The system changes the operating parameter (maximum power) as a function of another parameter (coolant temperature). By establishing a relationship between coolant temperature and maximum permissible power, the system optimizes performance across the temperature range without requiring overdesign for maximum temperature conditions.
2Stability of the object's composition
If the system maintains constant maximum power throughout the temperature range, then the power output is stable, but thermal headroom is unused at lower temperatures leading to inefficiency
Solution Approach 1:
The patent transforms the static power output characteristic into a dynamic one by continuously adjusting the maximum power limit based on real-time coolant temperature measurements. This allows the system to utilize available thermal headroom at low temperatures while maintaining safety margins at high temperatures, thereby improving overall productivity without compromising stability.
Solution Approach 2:
The system employs feedback control by monitoring coolant temperature and using this information to adjust the maximum permissible power output. The controller receives temperature feedback and dynamically modifies the power limit to optimize efficiency while maintaining stable operation within safe boundaries.
3Reliability
If the maximum junction temperature is strictly limited even at low temperatures, then component safety is ensured, but the system cannot utilize available cooling capacity for higher power output
Solution Approach 1:
The patent changes the maximum junction temperature parameter from a fixed constant to a variable that depends on coolant temperature. At low coolant temperatures, the system allows higher junction temperatures (utilizing available cooling capacity), while at high coolant temperatures, it maintains stricter temperature limits. This parameter adaptation enables higher power output when cooling conditions permit while ensuring component safety when cooling is less effective.
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
Enables the power electronic system to operate closer to its maximum potential at low temperatures while preventing thermal damage, reducing the need for costly overdesign and optimizing performance across the temperature range.
Implementation Method 1
The cooling system is thermally coupled to the power electronic system and configured to carry heat away from the power electronic system using a cooling agent
Implementation Method 2
the power electronic components of the system are thermally connected to a cooling circuit, in which water or any other cooling agent (coolant) may recirculate to transport heat away from the power electronic system
Data Source
AI summary
A cooling system is thermally coupled to a power electronic system and configured to carry heat away from the power electronic system using a cooling agent. A system controller is configured to receive information concerning a sensed temperature of a semiconductor switch and a temperature of the cooling agent (coolant). The system controller is further configured to adjust a power of the power electronic system by controlling the switching operation of the semiconductor switch. When the temperature of the coolant is below a threshold temperature, then the controller adjusts the power of the power electronic system to a target value greater than the rated maximum power based on the sensed temperature of the semiconductor switch and the temperature of the cooling agent.