Thyristor Startup Device Gate Pulse Abnormality Detection
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Solution Overview
Problem
Thyristor starting devices face challenges in detecting gate pulse abnormalities without increasing device size and cost, and simplifying the control circuit configuration.
Innovation Solution
A thyristor starting device with a timer-based abnormality detection unit that sets acceptable current ranges and measures signal duration to determine gate pulse abnormalities, preventing false positives during initial energization and sudden current changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated monitoring circuit is provided to detect gate pulse abnormalities, then detection reliability is improved, but device size and cost increase
Solution Approach 1:
The system uses its own existing DC current detection capability to monitor gate pulse abnormalities. The control circuit compares the actual DC current with the commanded DC current, and when a significant deviation occurs beyond a threshold value, it determines a gate pulse abnormality. This self-monitoring approach eliminates the need for separate dedicated monitoring circuits, thereby maintaining detection reliability while avoiding increased device size and cost.
2Reliability
If a determination circuit is provided to detect gate pulse abnormalities, then detection reliability is improved, but control circuit complexity increases
Solution Approach 1:
The control circuit performs multiple functions: it controls the converter and inverter operation, monitors DC current, detects gate pulse abnormalities, and manages system protection. By integrating the abnormality detection function into the existing control circuit's current monitoring capability, the system achieves reliable gate pulse monitoring without adding separate determination circuits, thus maintaining control circuit simplicity while improving overall reliability.
3Measurement precision
If DC current threshold monitoring is used to detect gate pulse abnormalities, then detection capability is improved, but false detection occurs during initial energization
Solution Approach 1:
The system implements a startup prohibition mechanism that prevents abnormality determination during a specified period after initial energization. During this startup phase, the control circuit prohibits the abnormality determination function, allowing the system to complete initial energization and reach stable operation before enabling abnormality detection. This preliminary action prevents false detections during transient startup conditions while maintaining accurate detection capability during normal operation.
Data Source
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AI summary
A thyristor starting device (100) includes: a converter (1) which converts AC power supplied from an AC power source (e1) into DC power; a DC reactor (3) which smooths a DC current; an inverter (2) which converts the DC power provided from the converter (1) through the DC reactor (3) into AC power, and supplies the AC power to a synchronous machine (4); a gate pulse generation circuit (40) which generates a gate pulse to be provided to thyristors of the converter (1) and the inverter (2); a control unit (20) which sets a phase control angle of the gate pulse to be provided to the thyristors of the converter (1), by controlling a current of the converter (1) such that the DC current flowing into the DC reactor (3) matches a current command value; and an abnormality detection unit (50) which compares a detection value of the DC current with the current command value, and determines an abnormality in the gate pulse based on a comparison result.