Frequency Converter Parameter Optimization via Finite Element Analysis
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Solution Overview
Problem
Existing frequency converter systems struggle to accurately identify and adapt to changing parameters of rotating electrical machines, especially at operating points outside typical ranges, leading to suboptimal control due to reliance on manual input and limited identification techniques that do not account for temperature and saturation effects.
Innovation Solution
The method involves using an electro-mechanical model of the machine, including geometry and material information, to calculate the state of the machine using a finite element method, allowing for parameter identification and correction across various operating points without disrupting the controller's operation, enabling more accurate control and optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If parameter identification is performed using traditional methods (manual input or identification run), then the controller operation is simple and fast, but the parameter accuracy deteriorates when operating points change due to temperature and saturation effects
Solution Approach 1:
The system dynamically adapts parameters by performing identification runs at multiple operating points and using interpolation to estimate parameters at intermediate operating points. This allows the control system to maintain accuracy across varying temperature and saturation conditions without requiring continuous real-time identification.
Solution Approach 2:
The system performs parameter identification in advance at several predetermined operating points before actual operation. These pre-identified parameters are stored and selected based on the current operating conditions, avoiding the need for real-time identification during critical control operations.
2Measurement precision
If signal injection or MRAS tuning methods are used to adapt parameters, then parameter accuracy improves at the current operating point, but the controller operation is impeded and tuning cannot be performed at desired operating points
Solution Approach 1:
Parameter identification and tuning are performed in advance at multiple operating points during system setup or maintenance phases. The identified parameters are stored in memory and retrieved during operation based on current conditions, eliminating the need for real-time tuning that would interrupt controller operation.
Solution Approach 2:
The parameter identification process is segmented into discrete operating points that are identified separately. This allows the system to build a comprehensive parameter set across the operating range without requiring continuous interruption of controller operation during normal use.
3Productivity
If parameters are identified only at typical operating points, then the identification process is fast and simple, but control optimality deteriorates when operating points go outside the typical range
Solution Approach 1:
The system performs detailed parameter identification at specific critical operating points (such as nominal, maximum torque, and maximum power points) where local accuracy is most important. For other operating points, parameters are estimated through interpolation, allocating computational resources efficiently while maintaining control optimality where it matters most.
Data Source
AI summary
A method is provided for optimizing a parameter used in a frequency converter connected to an electrical rotating machine. The method includes identifying a parameter of the machine using electrical quantities, the identified parameter being used in the frequency converter and being identified in a first operating point, providing an electro-mechanical model of the rotating electrical machine to the frequency converter, and calculating when a processor capacity of the frequency converter is available, (i) a state of the rotating electrical machine in the first operating point using a finite element method with the electro-mechanical model of the rotating electrical machine, (ii) a state of the rotating electrical machine in a selected operating point using the finite element method with the electro-mechanical model, correcting the calculated state of the rotating electrical machine, and calculating, from the corrected state, parameter(s) of the electrical machine to be used in the frequency converter.