IGBT Gate Drive Protection via Thermistor Temperature Detection
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Solution Overview
Problem
Existing drive circuits for semiconductor devices like IGBTs face challenges in protecting against short circuit breakdowns, leading to increased size and cost due to the need for fuses to detect and manage high currents, and prolonged failure recovery times in large systems.
Innovation Solution
The integration of thermistors in gate resistors to detect temperature rises and automatically turn off switching elements, eliminating the need for fuses and enabling faster failure recovery without increasing circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuses are used to detect and protect against short circuit breakdowns in semiconductor devices, then the drive circuit can be protected from high currents, but the circuit size and cost increase
Solution Approach 1:
The patent extracts the protection function from the traditional fuse-based system and implements it through temperature detection using thermistors integrated into the gate resistors. This removes the need for separate fuse components while maintaining protection capability, thereby reducing circuit size.
Solution Approach 2:
The patent merges the temperature detection function with the existing gate resistors by integrating thermistors directly into them. This combination eliminates the need for separate fuse components and reduces overall circuit complexity and size while maintaining protection functionality.
2Reliability
If fuses are used to detect short circuit breakdowns, then protection is achieved, but failure recovery time increases due to the need to replace fuses
Solution Approach 1:
The patent implements a self-diagnostic system where the control circuit automatically detects short circuit conditions through thermistor temperature monitoring and autonomously controls the switching elements to protect the circuit. This self-service capability eliminates the need for manual fuse replacement, significantly reducing failure recovery time.
Solution Approach 2:
The patent employs feedback through temperature detection by thermistors, which continuously monitor the thermal state of gate resistors. When a short circuit is detected via temperature rise, the control circuit receives feedback and automatically responds by turning off switching elements, enabling rapid protection without manual intervention.
3Reliability
If larger capacity biasing power sources and gate resistors are used to tolerate high currents during short circuit, then protection is achieved, but the drive circuit size and cost increase
Solution Approach 1:
The patent implements preliminary protection action by continuously monitoring the temperature of gate resistors through integrated thermistors. When a short circuit begins to occur, the temperature rise is detected early, and the control circuit proactively turns off the switching elements before excessive current can damage the circuit, eliminating the need for oversized components.
Solution Approach 2:
The patent replaces the mechanical/fuse-based protection system with an electronic temperature monitoring and control system. Instead of relying on physical fuses or oversized components to tolerate high currents, the system uses thermistor-based temperature detection and electronic control to prevent excessive current flow, reducing component size requirements.
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
This solution reduces the size and cost of drive circuits by eliminating the need for fuses and allows for quicker failure recovery by automatically cutting off power when a short circuit is detected, improving user-friendliness through signal output for control and display.
Implementation Method 1
a first thermistor th1 whose resistance value changes depending on temperature is thermally joined to and installed in the turn-on gate resistor R1
Implementation Method 2
the source S2 and drain D2 of the MOSFET Tr4 are connected between the gate and source of the N-channel type MOSFET Tr2, which is a reverse biasing switching element
Data Source
AI summary
When there is a short circuit failure between the gate and emitter of a main switching element such as an IGBT, the temperature of a turn-on gate resistor or turn-off gate resistor is detected by a thermistor, and a drive circuit is protected by turning off a turn-on gate drive switching element or a turn-off gate drive switching element. Furthermore, instead of detecting the temperature of the turn-on gate resistor or turn-off gate resistor, a thermistor is connected in series with the turn-on gate drive switching element or turn-off gate drive switching element, the resistance change corresponding to a change in temperature of the thermistor is detected, and the drive circuit is protected by turning off the turn-on gate drive switching element or turn-off gate drive switching element.