IGBT Deterioration Estimation in Inverters Without Special Sensors
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Solution Overview
Problem
Existing power conversion devices lack means to measure switching element characteristics, necessitating special sensors for detecting deterioration, which is costly and resource-intensive.
Innovation Solution
A deterioration estimation device and program that calculate variations in switching element characteristics from voltage commands and output voltages, determining changes beyond a threshold to issue warnings without requiring special sensors, using existing DC voltage and output current measuring means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If special sensors are provided to measure switching element characteristics, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The power conversion device uses its own existing voltage and current measuring means to detect switching element characteristics, eliminating the need for external special sensors. The control device calculates characteristic variations using internally available electrical quantity data, making the system self-diagnostic.
Solution Approach 2:
Existing voltage and current measuring means, originally designed for power conversion control, are repurposed to also measure switching element characteristics. This multi-functional use of standard components avoids adding dedicated sensing infrastructure.
2Reliability
If special sensors are installed for detecting switching element deterioration, then reliability is improved, but maintenance costs and resource requirements increase
Solution Approach 1:
The system performs self-diagnosis using existing measurement capabilities, eliminating the need for expensive special sensors and reducing both initial investment and ongoing maintenance costs for reliability monitoring.
Solution Approach 2:
The control device continuously monitors electrical quantities and calculates switching element characteristic variations, providing real-time feedback on element health status to enable proactive maintenance before failure occurs.
3Measurement precision
If leakage current measuring means are added to detect switching element abnormality, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The device uses its existing voltage measurement capabilities across the gate-emitter junction to infer leakage current status, avoiding the addition of dedicated current sensing circuits while still achieving effective abnormality detection.
Data Source
AI summary
Provided is a deterioration estimation device and a deterioration estimation program for a power conversion device that can estimate the deterioration of a switching element without providing a special sensor. A deterioration estimation device includes a calculating device calculating the variation of the characteristics of an IGBT in an inverter from a voltage command treated as a target of the output voltage of the power conversion device and the output voltage value of the power conversion device, a determining device determining whether the variation of the characteristics calculated by the calculating device has changed from an initial state by a threshold value or greater, and a notifying device issuing a warning when the determining device has determined that the change in the variation of the characteristics is equal to or greater than the threshold value.