Synchronous Machine Internal Temperature Estimation via State Observers
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Solution Overview
Problem
Current methods for determining internal temperatures in synchronous electrical machines are inaccurate, as they rely on surface temperature measurements and cannot simultaneously and accurately measure the temperatures of coils and magnets, leading to inefficiencies in control and diagnosis.
Innovation Solution
A method using state observers to estimate the resistance of coils and magnetic flux, allowing for the accurate determination of internal temperatures through measurements of rotor speed, voltages, and currents, and applying preprocessing to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are placed within the electrical machine to measure internal temperatures, then measurement accuracy is improved, but device complexity and cost increase due to additional sensors and instrumentation
Solution Approach 1:
The patent replaces physical temperature sensors with a mathematical observer-based system that estimates internal temperatures from electrical measurements. The observer uses a thermal model combined with measured currents and voltages to calculate coil and magnet temperatures without requiring direct thermal sensing, thereby eliminating the need for complex sensor instrumentation while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces an intermediary thermal model that acts as a mediator between electrical measurements and temperature estimation. The thermal model uses measured electrical quantities (currents, voltages) as inputs and produces temperature estimates as outputs, serving as a mathematical intermediary that translates electrical domain measurements into thermal domain information without direct thermal contact.
2Device complexity
If surface temperature sensors are used to measure coil and carcass temperatures, then device complexity is reduced, but measurement precision deteriorates because internal temperatures cannot be measured
Solution Approach 1:
The patent replaces surface temperature sensors with a mathematical observer that estimates internal temperatures from electrical measurements. The observer uses a thermal model combined with measured currents and voltages to calculate coil and magnet temperatures without requiring direct thermal sensing, thereby eliminating the need for complex sensor instrumentation while maintaining measurement accuracy.
Solution Approach 2:
The patent enables the electrical machine to self-diagnose its internal temperature state using its own operational electrical measurements (currents, voltages) and a built-in thermal model. The system serves itself by using its normal operating data to estimate temperatures, eliminating the need for external sensing infrastructure while providing accurate internal temperature information.
3Measurement precision
If separate algorithms are used to estimate coil temperature and magnet temperature, then measurement precision for each component is improved, but device complexity increases due to multiple independent estimation systems
Solution Approach 1:
The patent merges the estimation of coil temperature and magnet temperature into a single unified observer framework. The thermal model simultaneously processes electrical measurements to estimate both temperatures in one integrated system, using shared thermal parameters and a unified mathematical structure, thereby reducing algorithmic complexity while maintaining precision for both component temperature estimates.
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 precise determination of internal temperatures, enhancing control and diagnosis by accurately measuring coil and magnet temperatures, and subsequently the casing temperature, thereby improving the operational efficiency of synchronous electrical machines.
Implementation Method 1
the resistance is estimated R̂ coils by implementing the following steps: i) the voltages are determined u d,q and currents i d,q in Park's landmark by a transformation of the tensions a m and currents i m measures
Implementation Method 2
the intensity of the magnetic flux is estimated φ̂ of the magnet by means of said measurements and said currents î d and î q estimated by a state observer
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a method for determining the internal temperatures (2) (temperatures of the coils and the magnet) of a synchronous electrical machine (4) by means of state observers of the coil resistance and the magnetic flux of the magnet. The invention further relates to a diagnostic method, a method, and a control system (3) of a synchronous electrical machine based on the determined internal temperatures.