Hybrid Inverter Thermal Management via Torque Reduction
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Solution Overview
Problem
Existing methods for detecting and managing the operating state of propulsion systems in alternatively powered vehicles fail to effectively prevent overheating, leading to reduced drivability due to inadequate cooling of transaxle components.
Innovation Solution
A propulsion system that includes an electric machine, power electronics, and a coolant, where the actual temperature difference between the coolant and power electronics is monitored, and the maximum output torque is reduced if this difference exceeds an expected threshold, allowing for torque reduction strategies to manage cooling and prevent component overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the maximum output torque of the electric machine is maintained at full capacity, then the vehicle productivity is improved, but the power electronics may overheat leading to reduced reliability
Solution Approach 1:
The control system continuously monitors the temperature difference between the coolant and power electronics, using this feedback to dynamically adjust the maximum output torque. When the actual temperature difference exceeds the expected temperature difference, the system reduces torque to prevent overheating, thereby maintaining reliability while optimizing productivity under varying thermal conditions.
2Reliability
If the maximum output torque is reduced to prevent overheating, then the reliability of power electronics is improved, but the vehicle productivity deteriorates
Solution Approach 1:
The system dynamically adjusts the maximum output torque based on real-time thermal conditions rather than using a static torque limit. By continuously monitoring the actual temperature difference and comparing it to the expected temperature difference, the control system optimizes torque output at each moment, maintaining high productivity when cooling is sufficient while preventing overheating when cooling capacity is exceeded.
3Temperature
If the cooling system is designed with high cooling capacity, then the temperature control is improved, but the device complexity increases
Solution Approach 1:
The system controls temperature by changing operational parameters (maximum output torque) rather than modifying the physical cooling system infrastructure. By adjusting the torque parameter based on thermal feedback, the system achieves effective temperature control without adding complex cooling components, maintaining simplicity while ensuring reliable thermal management.
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 ensures the transaxle components do not exceed their functional limits, maintaining vehicle drivability by effectively managing temperature differences and reducing torque output when necessary, thereby preventing overheating and ensuring safe operation.
Implementation Method 1
a coolant to cool the electric machine and power electronics
Implementation Method 2
a coolant to cool the electric machine and power electronics
Data Source
AI summary
Inverters of a hybrid electric vehicle are cooled by a coolant. Expected temperature differences between the inverters and the coolant are determined based on vehicle parameters. Actual temperature differences between the inverters and the coolant are compared to the expected temperature differences. A maximum output torque is reduced if the actual temperature differences exceed the expected temperature differences.