Motor Thermal Model Correction for Aging Temperature Estimation
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Solution Overview
Problem
Conventional control devices for rotating electric machines cannot adjust thermal resistances, heat generations, and thermal capacities in their thermal circuit models after production, leading to decreased accuracy of temperature estimation due to aging deterioration over time.
Innovation Solution
A control device with a correction unit that adjusts thermal resistances, heat generations, and thermal capacities using measurement information from sensors, allowing for real-time corrections based on actual changes in the motor's thermal characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermal resistances and thermal capacities are fixed at production time, then device complexity is reduced and ease of manufacture is improved, but measurement precision deteriorates over time due to aging deterioration
Solution Approach 1:
The patent implements a correction unit that dynamically adjusts thermal resistance and thermal capacity values in the thermal circuit model based on actual temperature measurements from temperature detectors. This transforms the previously fixed parameters into dynamic, self-correcting values that adapt to aging deterioration, resolving the contradiction between ease of manufacture (fixed initial values) and long-term measurement precision (accurate temperature estimation after aging).
Solution Approach 2:
The system uses temperature detectors to measure actual temperatures and feeds this information back to the correction unit, which then adjusts the thermal circuit model parameters accordingly. This feedback mechanism enables continuous refinement of thermal resistance and thermal capacity values, maintaining temperature estimation accuracy despite aging effects while keeping the initial manufacturing process simple.
2Reliability
If thermal circuit model parameters are fixed after production, then reliability of the control logic is improved, but adaptability deteriorates as the motor ages and thermal characteristics change
Solution Approach 1:
The correction unit dynamically modifies thermal circuit model parameters based on actual temperature measurements, transforming static, reliable-but-inflexible values into adaptive parameters that evolve with the motor's aging process. This maintains reliability through systematic correction while gaining adaptability to changing thermal characteristics.
Solution Approach 2:
The system performs self-correction of thermal parameters using its own temperature measurement capabilities. The correction unit automatically adjusts thermal resistance and thermal capacity values based on discrepancies between measured and estimated temperatures, enabling the system to self-adapt to aging without external intervention, thus improving both reliability and adaptability.
Data Source
AI summary
A control device that can prevent the deterioration of temperature estimation accuracy in a rotating electric machine due to its aging deterioration is provided. The control device (10) includes a correction unit (13) to correct at least one of thermal resistance, heat generation, and thermal capacity, which are physical quantities to build a thermal circuit model (30-1) covering a thermal circuit of a rotating electric machine (1), wherein the correction unit (13) corrects at least one of the thermal resistance, the heat generation, and the thermal capacity at a measurement position by using measurement information including temperature (T31) or thermal flow (U32) measured by a sensing unit (8) at the measurement position in the rotating electric machine (1).