Motor Wiring Temperature Estimation Using Detector Thermal Data
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Solution Overview
Problem
Existing motor control systems face challenges in accurately monitoring wiring temperature as an absolute value, especially in small-size, low-cost motors, where temperature detection elements are not feasible due to spatial constraints and cost considerations, leading to potential wiring damage from incorrect protection thresholds.
Innovation Solution
A control apparatus that estimates the absolute wiring temperature by using a detector to measure the rotor's rotational position and speed, calculating the change in detector temperature, and then determining environmental temperature to accurately estimate the wiring temperature without a dedicated temperature detection element for the wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature detection element is provided on the wiring to directly monitor wiring temperature, then wiring temperature monitoring reliability is improved, but device complexity and cost increase due to additional components and spatial requirements
Solution Approach 1:
The patent uses the detector temperature as an intermediary parameter to indirectly estimate the wiring temperature. Instead of directly measuring wiring temperature with a dedicated temperature detection element, the system measures the detector temperature (which is thermally coupled to the wiring) and uses this as a proxy to infer the wiring temperature state, thereby avoiding the need for additional temperature detection components on the wiring itself.
Solution Approach 2:
The detector serves multiple functions: it detects rotational position and speed of the rotor, and simultaneously its temperature detection element provides wiring temperature monitoring information. By making the detector multi-functional, the patent eliminates the need for separate dedicated temperature detection elements on the wiring, reducing device complexity while maintaining monitoring reliability.
2Measurement precision
If a temperature detection element is provided on the wiring to directly monitor wiring temperature, then accurate wiring temperature measurement is improved, but manufacturing cost increases due to additional components
Solution Approach 1:
The detector is designed to perform multiple functions including rotational position detection, speed detection, and temperature monitoring. By integrating these functions into a single component, the patent reduces the total number of parts needed, simplifying manufacturing and reducing costs while maintaining accurate temperature measurement capability through the detector's temperature detection element.
Solution Approach 2:
The system uses the detector temperature as an intermediary measurement to infer wiring temperature. This indirect measurement approach eliminates the need for expensive dedicated wiring temperature sensors, reducing manufacturing costs while still providing accurate wiring temperature monitoring through thermal coupling between the detector and wiring.
3Device complexity
If temperature detection element is not used and wiring temperature change is estimated based on current or torque command value, then device complexity and cost are reduced, but measurement precision of wiring temperature deteriorates
Solution Approach 1:
The patent introduces the detector temperature as a physical intermediary that provides direct thermal information about the wiring environment. This temperature measurement serves as a more accurate basis for estimating wiring temperature compared to using only electrical parameters like current or torque command values, thereby improving measurement precision while keeping the device simple.
Solution Approach 2:
The patent replaces purely electrical estimation methods (using current or torque command values) with a thermally-based measurement approach using the detector temperature detection element. This substitution provides more accurate wiring temperature information because it directly reflects the thermal state of the motor components rather than inferring temperature from electrical parameters.
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
Enables accurate estimation of wiring temperature as an absolute value, considering environmental conditions, thereby preventing overheating and motor failure by adjusting protection thresholds based on actual conditions.
Implementation Method 1
a temperature detection element that detects a temperature of the detector
Implementation Method 2
A wiring temperature is monitored by these temperature detection elements
Implementation Method 3
the model calculates an amount of generated heat due to copper loss calculated by (square of current)×(resistance)
Data Source
AI summary
A temperature detection element that detects a temperature of a detector is provided in a detector that detects a rotational position and/or a rotational speed of a rotor of a motor. An estimated value of a change of a wiring temperature is calculated based on a current supplied to the wiring of the motor. An estimated value of a change of the detector temperature is calculated based on the estimated value of the change of the wiring temperature. A difference between the detector temperature detected by the temperature detection element and the estimated value of the change of the detector temperature is set as an environmental temperature. The environmental temperature is added to the estimated value of the change of the wiring temperature, to estimate an absolute value of the wiring temperature. The wiring temperature is monitored based on the estimated absolute value of the wiring temperature.