IGBT Bond Wire Aging Detection via Gate Voltage Overshoot
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Solution Overview
Problem
Existing methods for monitoring IGBT module bond wire failures in power electronic converters are inadequate, as they either require complex setups, interfere with normal operation, or have low resolution, making it difficult to detect slight failures and aging effectively.
Innovation Solution
An IGBT-module condition monitoring equipment and method that samples gate voltage signals to identify bond wire failures by comparing actual gate turning-on voltage overshoot with a reference threshold, using a voltage sampling circuit, driving circuit, bond wire state judging module, and signal acquisition module, allowing for early warning of failures without invasive procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bond wire monitoring method based on short-circuit current is used, then measurement precision is improved, but device complexity increases due to complicated gate driving circuit and regular short-circuit monitoring interfering with normal operation
Solution Approach 1:
The patent extracts the monitoring function from the gate driving circuit by using the existing gate voltage signal that is already present during normal IGBT operation. Instead of adding a separate monitoring circuit, the method utilizes the natural voltage overshoot phenomenon that occurs during gate turn-on, thereby achieving bond wire condition monitoring without increasing device complexity or interfering with normal operation
Solution Approach 2:
The gate driving circuit serves dual purposes: it drives the IGBT during normal operation and simultaneously provides the voltage signal for bond wire monitoring. The voltage overshoot that naturally occurs during gate turn-on is utilized as the monitoring signal source, making the system self-monitoring without requiring additional external monitoring equipment
2Ease of operation
If method based on on-state voltage drop is used, then ease of operation is improved, but measurement precision deteriorates due to low resolution for slight bond wire failures and difficulty in accurate measurement during operation
Solution Approach 1:
The patent performs preliminary action by capturing the gate voltage overshoot signal at the moment of gate turn-on, before the IGBT enters its on-state. This allows measurement of the bond wire condition during the switching transient when the voltage signal is most pronounced, rather than during steady-state operation where the signal is less distinct and harder to measure accurately
3Reliability
If method based on gate Miller platform time is used, then reliability is improved for IGBT aging evaluation, but device complexity increases due to requirement of large driving resistance that limits switching frequency
Solution Approach 1:
The patent performs preliminary action by measuring the gate voltage overshoot duration and magnitude during the turn-on transient, which occurs before the Miller platform phase. This allows assessment of bond wire condition and IGBT aging without requiring the IGBT to operate at reduced switching frequencies or use large driving resistances that would limit productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-resolution, non-invasive, real-time monitoring of IGBT module bond wire conditions, effectively detecting slight failures and enabling early warning of IGBT failures, thus improving the reliability of power electronic converters.
Implementation Method 1
a voltage sampling circuit for measuring a voltage between the gate and the emitter of IGBT module to monitor an actual gate turn on voltage overshoot
Data Source
AI summary
Disclosed are an IGBT-module condition monitoring equipment and method. The IGBT-module condition monitoring equipment includes an IGBT module, a gate turning-on voltage overshoot monitoring module, a driving circuit, a bond wire state judging module, and a signal acquisition module. The breakage condition of bond wires is obtained by comparing a monitored actual gate turning-on voltage overshoot with a preset reference gate turning-on voltage overshoot threshold. The present invention solves the problem encountered in monitoring the aging of IGBT bond wires in power electronic converters. By characterizing the bond wire detachment with the gate turning-on voltage overshoot, the slight aging of the detached bond wires can be monitored without disturbing the operation, which is high in resolution and free of invasiveness and enables real-time online monitoring at high sampling rate and low cost, showing great significance in the monitoring of the IGBT and the reliability evaluation of power electronic converters.