Current Detection Apparatus Synchronizing Phase Currents
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Solution Overview
Problem
Conventional current detection apparatuses in power systems suffer from deviations in peak detection timing between arm and bus current detectors, leading to reduced correction accuracy of phase currents, which can result in ripples and inaccuracies in current control.
Innovation Solution
A current detection apparatus that includes multiple detectors to synchronize and correct phase currents by obtaining multiple values of corrective phase and bus-based currents, ensuring phase alignment and eliminating deviations, thereby improving correction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional arm current detector and bus current detector are used separately, then the detection structure is simple, but the peak detection timing deviates and correction accuracy deteriorates
Solution Approach 1:
The patent combines the arm current detection function and bus current detection function into a single integrated detection apparatus. The detection unit simultaneously detects both arm currents and bus currents, and the correction unit uses both current types together to calculate corrected phase currents. This merging eliminates the timing deviation between separate detectors while maintaining structural simplicity.
Solution Approach 2:
The bus current serves as an intermediary reference signal in the correction process. The correction unit uses the bus current waveform as a reference to identify peak timing, then applies this timing information to correct the arm current measurements. This intermediary approach enables accurate synchronization without requiring multiple independent peak detection systems.
2Measurement precision
If peak detection timing is not synchronized, then detection operation is simple, but ripples in phase currents differ and correction accuracy deteriorates
Solution Approach 1:
The correction unit implements a feedback mechanism where the detected bus current waveform is used as a reference to verify and adjust the timing of arm current peak detection. The system continuously compares the timing information from both current types and applies corrective calculations to ensure synchronized peak detection timing, thereby eliminating timing deviation losses.
Solution Approach 2:
The detection unit performs preliminary detection of both arm currents and bus currents simultaneously before the correction calculation. By capturing both current waveforms at the same time instances, the system establishes a common time reference that enables accurate peak timing identification and synchronization in the subsequent correction process.
3Measurement precision
If separate detection switches are used for each phase, then phase current detection is accurate, but the detection system becomes complex
Solution Approach 1:
The detection unit is designed with multi-functionality to detect both arm currents and bus currents using the same detection circuitry. The single detection unit can measure multiple current types by switching its measurement target based on the operational mode, eliminating the need for separate detection switches for each current type while maintaining detection accuracy.
Data Source
AI summary
In a current detection apparatus, a corrector obtains first current-value pairs of the plural values of the corrective first phase current and the respective plural values of the corrective first phase bus-based current synchronized with the plural values of the corrective first phase current. The corrector obtains second current-value pairs of the plural values of the corrective second phase current and the respective plural values of the corrective second phase bus-based current synchronized with the plural pairs of the corrective second phase current. The corrector corrects at least target first and second phase currents detected by a first current detector based on the obtained first current-value pairs and the second current-value pairs to thereby align amplitudes of the respective target first and second phase currents with each other.