Motor Thermoanalysis Coupling Temperature Field with Thermal Circuit
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Solution Overview
Problem
Current motor thermoanalysis simulation software relies solely on thermal circuit methods, which fail to accurately model temperature distribution in complex geometric structures and uneven heat source distributions, and cannot effectively simulate heat convection within enclosed motors, leading to inaccuracies and long calculation times.
Innovation Solution
A method that integrates finite element and thermal circuit approaches by directly coupling a temperature field with a thermal circuit, using equivalent convection and temperature boundaries to overlay element matrices and solve for simultaneous temperature distributions in both domains, allowing for more accurate and efficient modeling of motor temperature fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermal circuit method is used for motor thermoanalysis, then calculation speed is improved, but temperature distribution accuracy in complex geometric structures deteriorates
Solution Approach 1:
The motor model is divided into two distinct regions: a thermal circuit region for efficient calculation and a finite element region for high-precision temperature distribution analysis. This segmentation allows each method to be applied where it is most effective, resolving the contradiction between calculation speed and accuracy.
Solution Approach 2:
The patent combines thermal circuit method and finite element method into a unified hybrid model. The thermal circuit region uses lumped parameter models for fast calculation, while the finite element region provides detailed temperature distribution, and they are coupled through interface boundaries to achieve both speed and accuracy.
2Measurement precision
If finite element method is used for motor thermoanalysis, then temperature distribution accuracy is improved, but calculation time increases
Solution Approach 1:
Instead of applying finite element method to the entire motor model, the patent segments the model and applies finite element method only to regions requiring high-precision temperature distribution analysis, while using thermal circuit method for other regions, thereby reducing overall calculation time.
Solution Approach 2:
The patent applies different analysis methods to different regions based on their specific requirements: finite element method is applied locally to regions with complex geometries or critical thermal behavior where high precision is needed, while thermal circuit method is used in regions where average temperature is sufficient.
3Ease of manufacture
If thermal circuit model is used, then modeling simplicity is improved, but ability to represent parts with complicated geometric structures deteriorates
Solution Approach 1:
The patent segments the motor model into thermal circuit regions (for simple modeling) and finite element regions (for complicated geometries), allowing each method to handle the types of structures it is best suited for while maintaining overall modeling efficiency.
Solution Approach 2:
By merging thermal circuit modeling and finite element modeling in a hybrid approach, the patent achieves both modeling simplicity (from thermal circuit) and accuracy for complicated geometries (from finite element) in the same overall model.
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 integrated approach provides a quicker and more accurate motor thermoanalysis by leveraging the strengths of both methods, effectively handling complex geometries and heat convection within motors, resulting in a more efficient and precise thermal modeling platform.
Implementation Method 1
confirming a weak solution form of a differential equation of heat conduction containing the equivalent convection boundary and the equivalent temperature boundary
Implementation Method 2
the heat convection between an end winding and a motor shell, and the heat convection bet a stator and a rotor
Data Source
AI summary
A motor thermal analysis method with a temperature field directly coupled with a thermal circuit is used for modeling partial parts of the motor, and a thermal circuit method is used for modeling other parts. A temperature field is contacted with a thermal circuit through an equivalent temperature boundary and an equivalent convection boundary. The thermal circuit part is composed of one-dimensional finite elements, and two connecting boundaries are deemed as two boundary elements. An element stiffness matrix, an element loading matrix and an element mass matrix corresponding to the one-dimensional finite elements and the boundary elements are respectively overlaid to a global stiffness matrix, a global loading matrix and a global mass matrix, and the distribution of temperature in the temperature field and the distribution of temperature in the thermal circuit are obtained simultaneously by solving a whole system of linear equations.