Power Converter Diagnostic System Using Current Change Amount
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Solution Overview
Problem
Existing power converter diagnostic techniques face challenges in accurately detecting abnormality and deterioration in power semiconductors, particularly in high-voltage, large-capacity systems, due to difficulties in implementing voltage divider circuits and early detection of current abnormalities before system failure occurs.
Innovation Solution
A diagnostic system that calculates the current change amount per unit time using a current change amount calculation circuit, compares it with reference values, and outputs determination results to detect abnormality and deterioration in power semiconductors, allowing for remote monitoring and control of power converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage divider circuits are used to detect power semiconductor temperature, then temperature abnormality detection is achieved, but device complexity and manufacturing difficulty increase due to high voltage requirements
Solution Approach 1:
The patent introduces a current sensor as an intermediary device to indirectly detect power semiconductor temperature through current characteristics rather than directly measuring voltage. The current sensor outputs a voltage signal proportional to the detected current, which is then processed to determine temperature, avoiding the need for complex high-voltage divider circuits while achieving accurate temperature monitoring
Solution Approach 2:
The patent replaces the traditional voltage-based measurement system with a current-based measurement system. Instead of using voltage divider circuits to directly measure high voltage for temperature detection, the system uses a current sensor to detect current characteristics that correlate with temperature, substituting voltage measurement with current measurement to simplify the overall system
2Measurement precision
If multiple voltage divider circuits are provided for three-phase AC control, then all power semiconductor voltages are evaluated, but device complexity and noise susceptibility increase
Solution Approach 1:
The patent makes the current sensor serve multiple functions: it detects both current magnitude and current change rate, and these measurements are used to evaluate temperature and diagnose abnormalities across all power semiconductors in the three-phase system. This single multi-functional sensor replaces multiple separate voltage measurement circuits, reducing noise susceptibility while maintaining comprehensive monitoring capability
Solution Approach 2:
The patent combines multiple measurement functions into a single current sensor system. The same current sensor is used to monitor all phases by detecting current characteristics, merging what would have been separate voltage measurement circuits into one unified current-based monitoring system that is less susceptible to noise
3Reliability
If current abnormality detection is implemented, then overcurrent protection is achieved, but early detection of deterioration before failure is not possible
Solution Approach 1:
The patent performs preliminary detection of power semiconductor deterioration by monitoring current change rate before actual failure occurs. The abnormality determination unit analyzes the rate of current change to detect early signs of degradation, allowing maintenance to be scheduled before catastrophic failure happens, thus preventing unplanned system downtime
Solution Approach 2:
The patent implements a feedback mechanism where the current change rate is continuously monitored and fed back to the abnormality determination unit. This feedback loop enables real-time detection of deterioration trends, allowing the system to identify problems early and trigger maintenance alerts before the deterioration progresses to complete failure
Data Source
AI summary
A diagnostic system for a power converter which includes a semiconductor device, and which performs a switching operation between conduction and interruption of the principal current flowing through a main circuit. The diagnostic system includes a current change amount calculation circuit for obtaining numeric data which reflects a current change amount of the principal current per unit time, a determination circuit for determining a state of the power converter by comparing the numeric data with a reference value, and an output circuit for outputting a determination result of the determination circuit.