Winding Temperature Estimation Using Coolant Heat Transfer
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Solution Overview
Problem
Existing winding temperature estimation devices for rotating electric machines struggle to accurately estimate winding temperatures due to the high space factor of windings, which complicates cooling and temperature distribution analysis, especially during complex operating conditions and non-driving states.
Innovation Solution
A winding temperature estimation device that includes a coolant supply system, temperature sensors, and calculation components to determine heat reduction and heating values, allowing for precise temperature calculations using heat models and coolant flow rates, and accounting for copper and eddy current losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a winding with high space factor is used to increase power density, then productivity and power output are improved, but temperature distribution becomes more complex and measurement precision deteriorates
Solution Approach 1:
The patent introduces a coolant temperature as an intermediary parameter to estimate winding temperature. By measuring the coolant temperature and using heat transfer models, the system indirectly determines the winding temperature without direct sensors inside the winding, thus maintaining high space factor while improving temperature estimation accuracy
Solution Approach 2:
The patent replaces direct physical temperature measurement (mechanical contact sensors) with a thermal field model based on coolant temperature measurements and heat transfer equations. This substitution allows accurate temperature estimation in high space factor windings where direct measurement is difficult
2Temperature
If coolant cooling is applied to high space factor windings, then temperature control is improved, but temperature distribution becomes more complex and estimation accuracy deteriorates
Solution Approach 1:
The patent divides the thermal system into distinct segments (coolant, stator core, winding) with separate heat transfer paths. By modeling each segment independently and their interactions, the system can accurately estimate winding temperature even with complex coolant cooling patterns
Solution Approach 2:
The patent dynamically adjusts thermal model parameters based on operating conditions (coolant flow rate, ambient temperature, load). This allows the temperature estimation to adapt to varying cooling conditions and maintain accuracy across different operational states
3Device complexity
If simple temperature estimation methods are used for non-driving states, then device complexity is reduced, but measurement precision deteriorates under complex operating conditions
Solution Approach 1:
The patent creates a universal temperature estimation model that works across all operating states (driving, non-driving, cooling, heating). The same core thermal model adapts to different conditions by adjusting parameters, eliminating the need for separate estimation systems for each state while maintaining high accuracy
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 solution improves the precision of winding temperature estimation by considering the cooling path and state of the winding and stator, enabling accurate temperature calculations even under complex operating conditions.
Implementation Method 1
a coolant supply part configured to supply a coolant to the winding and the stator
Implementation Method 2
cooling of the winding by a coolant at the coil end or the like outside the slot
Implementation Method 3
heating value due to a loss of the winding
Implementation Method 4
heating value due to copper loss and eddy current loss of the winding
Implementation Method 5
heating value due to an iron loss of the stator
Data Source
AI summary
A winding temperature estimation device for a rotating electric machine includes a rotating electric machine including a stator, which has a winding, and a rotor, a coolant supply part configured to supply a coolant, a temperature sensor configured to detect a temperature of the coolant, a heat reduction amount calculation part configured to calculate a heat reduction amount of the winding using the temperature of the coolant and a heat resistance between the coolant and the winding, a heating value calculation part configured to calculate a heating value due to a loss of the winding, and a winding temperature calculation part configured to calculate a temperature of the winding using the heat reduction amount from the winding and the heating value due to the loss of the winding.