Voltage Sensor Abnormality Diagnosis in Power Conversion Devices
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Solution Overview
Problem
Existing power conversion devices face challenges in accurately diagnosing voltage sensor failures due to reliance on external abnormal voltage generation and indirect calculation methods, resulting in poor diagnosis accuracy.
Innovation Solution
A power conversion device with a voltage boost converter, inverter, and abnormality diagnosis controller that measures and compares voltage values from primary, secondary, and intermediate sensors during a discharge operation to diagnose abnormality in voltage sensor characteristics, allowing for direct and accurate detection of voltage detection function abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external abnormal voltage generation means are used to diagnose voltage sensor failures, then diagnosis coverage is expanded, but device complexity and cost increase
Solution Approach 1:
The voltage boost converter performs self-diagnosis by utilizing its own existing voltage sensors to detect abnormalities in its voltage detection function, eliminating the need for external test equipment or additional diagnosis-specific hardware. The control unit orchestrates the discharge operation and compares sensor readings against expected values to identify failures.
Solution Approach 2:
The diagnosis method changes the operational state of the voltage boost converter from normal voltage boosting to controlled discharge mode. By switching the converter to discharge operation, the system creates a specific test condition where capacitor voltage decay can be monitored by existing sensors to detect abnormalities without requiring external voltage sources.
2Device complexity
If indirect calculation methods are used to diagnose voltage detection function, then diagnosis can be performed without additional hardware, but diagnosis accuracy deteriorates
Solution Approach 1:
The control unit continuously monitors the output voltage during discharge operation using the existing voltage sensor and compares it against expected discharge characteristics. This feedback mechanism enables direct detection of sensor abnormalities by observing deviations from the predicted voltage decay pattern, providing accurate diagnosis without indirect calculations.
3Productivity
If voltage sensor abnormalities are diagnosed during normal operation, then system continuity is maintained, but diagnosis accuracy across broad voltage range is limited
Solution Approach 1:
The system performs voltage sensor diagnosis during the discharge operation, which is a predetermined phase in the voltage boost converter's operational cycle. By utilizing this specific operational phase, the system can accurately diagnose sensor abnormalities across the full voltage range without compromising overall system productivity, as the discharge operation is already part of normal converter functionality.
Data Source
AI summary
A power conversion device provided with a DC power source, a voltage boost converter, an inverter, a primary smoothing capacitor, a secondary smoothing capacitor, an intermediate capacitor provided in the voltage boost converter and three voltage sensors which measure the voltages of the capacitors, further including an abnormality diagnosis controller which makes a diagnosis of the presence/absence of an abnormality in the detection characteristics of the voltage sensors, on the basis of the state of transition of the detection results of the voltage sensors which are monitored during a discharge operation by the respective capacitors.