IGBT Gate Wiring Fault Detection via Gate Voltage Timing
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Solution Overview
Problem
Existing fault detection methods for gate wiring disconnection in high-power IGBTs are not applicable due to the lack of a current-dividing structure and require large current sensors, leading to increased device size and complexity.
Innovation Solution
A fault detection device that monitors the timing of gate voltage changes using a gate voltage determination circuit, delay circuit, XOR circuit, and filter circuit to detect disconnection by comparing the rate of change in gate voltage with a threshold, without requiring special current detection structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current sensor is used to detect gate wiring disconnection, then detection reliability is improved, but device size increases
Solution Approach 1:
The patent replaces the mechanical/electrical current sensing system with an optical detection system. A light source emits light toward the gate wiring, and a light receiver detects light reflected from or transmitted through the wiring. When disconnection occurs, the optical path changes, enabling fault detection without physical contact or large current sensors.
Solution Approach 2:
The patent introduces light as an intermediary medium to detect gate wiring integrity. Instead of directly measuring electrical current, the system uses optical signals that interact with the wiring structure, providing indirect but reliable detection of disconnection while avoiding the size constraints of direct electrical sensing methods.
2Difficulty of detecting and measuring
If a current-dividing structure is used for fault detection, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent eliminates complex electrical current-dividing structures by substituting them with an optical detection system. The light-based method directly detects wiring continuity through optical path changes, removing the need for current sensors, resistors, and complex signal processing circuits.
Solution Approach 2:
The patent extracts the detection function from the electrical current path and places it in the optical domain. By separating the detection mechanism from the power transmission path, the system achieves fault detection capability without modifying the complex electrical circuit structure or adding current-dividing elements.
3Measurement precision
If existing fault detection methods are applied to high-power IGBTs, then detection accuracy is improved, but adaptability decreases
Solution Approach 1:
The patent creates a universal fault detection system that can be applied to various power semiconductor devices including high-power IGBTs. The optical detection method is device-agnostic, detecting wiring integrity through physical light interaction rather than electrical characteristics, making it adaptable across different power ratings and device types.
Solution Approach 2:
The patent replaces electrical detection methods with optical detection, enabling applicability to high-power IGBTs where current-based methods fail. The optical system detects mechanical/physical wiring integrity independent of electrical parameters, achieving both accuracy and adaptability to high-power applications.
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 reliable detection of gate wiring disconnection in high-power IGBTs with a simple configuration, preventing erroneous operation and ensuring system safety by stopping the power conversion circuit when disconnection is detected.
Implementation Method 1
a gate voltage determination circuit that compares an output voltage of the drive circuit with a reference voltage and outputs a gate voltage determination signal
Implementation Method 2
a delay circuit that delays an output signal of the control unit by a predetermined time
Implementation Method 3
an XOR circuit that performs an exclusive OR operation on an output signal of the delay circuit and an output signal of the gate voltage determination circuit
Implementation Method 4
a filter circuit that generates an abnormality detection signal based on an output signal of the XOR circuit
Implementation Method 5
a leakage current flows into the gate via a parasitic capacitance (feedback capacitance) between the collector and the gate of the IGBT
Data Source
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AI summary
A fault detection device 1 for detecting whether the connection state is normal or abnormal for control lines 119a, 119b, which electrically connect between auxiliary terminals 105a, 106a, 105b, 106b for controlling paths for main terminals 103a, 104a, 103b, 104b of semiconductor switching elements 101a, 101b and control units 110a, 110b for controlling driving of the semiconductor switching elements 101a, 101b, wherein, when the rate of change of an output voltage output from the control units 110a, 110b to the control lines 119a, 119b is greater than a prescribed value, it is determined that a connection abnormality has occurred in the control lines 119a, 119b, and an abnormality detection signal is output.