Transmission-Cooled Inductor Control for EV Power Conversion
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Solution Overview
Problem
In electric vehicles, inductors used in power networks can overheat due to increased current, leading to power loss and reduced efficiency, as existing temperature monitoring systems rely on direct contact sensors which may not effectively manage heat dissipation.
Innovation Solution
The automotive propulsion system incorporates a variable voltage converter with an inductor housed within a transmission, where transmission fluid cools the inductor, and a controller regulates the current through the inductor based on speed and switching frequency to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If current through the inductor is increased to improve power conversion capability, then the power conversion efficiency is improved, but the inductor temperature increases causing power loss
Solution Approach 1:
The system performs preliminary cooling of the inductor using transmission fluid before the inductor reaches its temperature threshold. The controller proactively reduces current magnitude when approaching thermal limits, preventing overheating rather than reacting after temperature exceeds safe levels.
Solution Approach 2:
Transmission fluid serves as an intermediary cooling medium between the inductor and the surrounding environment. The fluid absorbs heat from the inductor and transfers it away, enabling the inductor to maintain higher current levels without excessive temperature rise.
2Temperature
If current magnitude is reduced to prevent overheating, then inductor temperature is controlled, but power conversion capability is reduced
Solution Approach 1:
The system dynamically adjusts the current magnitude through the inductor based on real-time temperature conditions and transmission fluid cooling capacity. The controller continuously modulates current levels to maintain optimal balance between power conversion capability and thermal management, rather than using fixed current limits.
Solution Approach 2:
The system changes operating parameters (current magnitude, switching frequency) based on thermal conditions. When the inductor approaches temperature thresholds, the controller adjusts these parameters to reduce heat generation while maintaining acceptable power conversion performance.
3Measurement precision
If direct contact temperature sensors are used to monitor inductor temperature, then temperature measurement is achieved, but the system cannot effectively manage heat dissipation
Solution Approach 1:
The transmission fluid serves a dual function: it cools the inductor and simultaneously provides temperature information to the controller. The fluid's temperature and flow characteristics enable the system to self-regulate current levels without requiring separate temperature sensing and cooling control systems.
Solution Approach 2:
The transmission fluid performs multiple functions: it acts as a cooling medium, a temperature sensor, and a heat transfer intermediary. This multi-functionality eliminates the need for separate temperature measurement devices and integrates thermal management directly into the existing transmission fluid system.
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 solution effectively maintains the inductor's temperature within safe limits, reducing power loss and enhancing the efficiency of the vehicle's power network by utilizing transmission fluid for cooling and intelligent current regulation.
Implementation Method 1
transmission fluid within the housing contacts the inductor to cool the inductor
Implementation Method 2
transmission fluid within the housing contacts the inductor to cool the inductor
Data Source
AI summary
An automotive propulsion system has a transmission including an output shaft, a variable voltage converter including an inductor disposed within a housing of the transmission such that transmission fluid within the housing contacts the inductor to cool the inductor, and a controller that maintains a magnitude of current through the inductor to less than a limit value that is defined by a speed associated with the output shaft and a switching frequency of the variable voltage converter.