Anticipatory Field Current Control for Synchronous Machines
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Solution Overview
Problem
Current methods for testing large-capacity rotating electric machines require significant on-site load tests, making it difficult to predict machine characteristics before installation, which is undesirable for quality assurance, especially for underutilized systems like three-phase synchronous reluctance machines.
Innovation Solution
A field control device and method for synchronous rotating machines that includes a target operating condition input unit, subtraction units, a final-control-quantity control computation unit, an anticipatory computation unit, and a field-current regulation device, which uses dependence characteristics derived from a no-load test to predict and adjust field current settings based on operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If actual load test is performed only after on-site installation, then the rotating electric machine can be tested in actual environment, but the characteristics cannot be confirmed before installation which is undesirable for quality assurance
Solution Approach 1:
The patent performs a no-load test and derives dependence characteristics before on-site installation, allowing prediction of machine characteristics in advance. This preliminary action enables quality assurance activities to occur during the factory testing phase rather than waiting until after installation, thus resolving the contradiction between early characteristic confirmation and actual environment testing.
2Reliability
If significant-scale load test equipment is used for actual load test, then the rotating electric machine can be tested, but the testing requires on-site installation which increases complexity and cost
Solution Approach 1:
The patent extracts the essential characteristic derivation process from the complex actual load test by performing a simplified no-load test that captures the dependence characteristics. This extracted information is then used to predict performance under various operating conditions, eliminating the need for significant-scale load test equipment and reducing testing complexity while maintaining test accuracy.
3Loss of information
If no-load test is performed to derive dependence characteristics, then machine characteristics can be predicted before on-site test, but additional testing steps are required
Solution Approach 1:
The patent introduces dependence characteristics as an intermediary that connects the simple no-load test results to the prediction of complex operating conditions. By deriving these intermediate characteristics during the no-load test, the system can accurately predict machine behavior under various loads without requiring complex control structures or additional extensive testing.
Data Source
AI summary
A field control device for a synchronous rotating machine includes: a target operating condition input unit; a first subtraction unit; a final-control-quantity control computation unit that accepts the final-control-quantity deviation and outputs a field-current correction demand value; an anticipatory computation unit that outputs a field-current anticipatory demand value based on the operating condition demand values input; an addition unit that adds the field-current correction demand value and the field-current anticipatory demand value; a second subtraction unit; and a field-current regulation device that adjusts the field current based on the field current deviation. The anticipatory computation unit includes: a dependence characteristic data storage unit that stores dependence characteristics predicted on the basis of the results of a no-load test; and a circuit calculation unit that performs a circuit calculation by using the dependence characteristics and outputs a field-current anticipatory demand value.