Rotating Machine Flux Detection via Temperature-Current Compensation
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Solution Overview
Problem
In rotating electrical machines with permanent magnets, temperature changes and irreversible demagnetization due to overheating lead to torque fluctuations, making accurate detection of interlinkage magnetic flux challenging for existing flux estimation and measurement techniques.
Innovation Solution
A controller system that uses a processing unit with sensors for current, temperature, and magnetic pole position, incorporating a flux observer model and proportional integrator to detect interlinkage magnetic flux, correcting armature winding resistance values based on temperature and considering changes due to both temperature and current-induced magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If flux table for temperature is used to detect magnetic flux, then temperature-based flux detection is simplified, but accuracy deteriorates because current-induced magnetic field changes are not considered
Solution Approach 1:
The patent transitions from using only temperature as a parameter to using both temperature and current as parameters for flux detection. The flux table is expanded to include current information, allowing the system to accurately determine magnetic flux by considering both temperature-based and current-based magnetic field changes simultaneously.
2Measurement precision
If motor model or flux estimator is used to detect magnetic flux, then current-induced magnetic field changes are considered, but accuracy deteriorates because voltage drop changes due to temperature are not sufficiently accounted for
Solution Approach 1:
The patent applies preliminary temperature compensation to the armature winding resistance before using it in flux calculations. By pre-adjusting the resistance value based on detected temperature and storing it in the flux table, the system eliminates the need for real-time voltage drop calculations, simplifying the detection process while maintaining accuracy.
3Measurement precision
If voltage drop in armature winding is subtracted from terminal voltage to calculate magnetic flux, then flux calculation is performed, but accuracy deteriorates because resistance magnitude changes with temperature are not considered
Solution Approach 1:
The patent changes the resistance parameter from a fixed value to a temperature-dependent variable. By detecting temperature and selecting appropriate resistance values from the flux table based on temperature ranges, the system automatically compensates for resistance changes, eliminating the need for separate voltage drop calculations.
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 approach enables accurate detection of interlinkage magnetic flux, ensuring stable torque control and preventing irreversible demagnetization, thereby maintaining desired output in rotating electrical machines.
Implementation Method 1
a current sensor to detect current passed between the power converter and the winding of the armature
Implementation Method 2
a temperature sensor to detect temperature of the winding of the armature
Implementation Method 3
a magnetic pole position sensor to detect magnetic pole position of the magnetic field system
Implementation Method 4
detects a magnetic flux that interlinks with the winding of the armature from the permanent magnet
Data Source
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AI summary
A controller for rotating electrical machines comprises a processing unit, to which a plurality of parameters are input, for generating a switching instruction to control a switching operation of a switching semiconductor device and outputting a signal corresponding to the switching instruction to a power converter. The processing unit includes at least a function to input thereto signals having been output from each of sensors such as a current sensor (250) to detect current passed between the power converter and a winding of an armature, a temperature sensor (140) to detect temperature of the winding of the armature, and a magnetic pole position sensor (130) to detect magnetic pole position of a magnetic field system, and, based upon information on current, temperature, and rotation speed of the rotating electrical machines, having been obtained from those sensor signals, detects a magnetic flux that interlinks with the winding (111) of the armature (110) from a permanent magnet (121).