IGBT Gate Voltage Control for Short-Circuit Shutdown
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Solution Overview
Problem
Existing low-voltage protective devices face issues with reduced service life due to heavy loading of IGBT circuits during short circuits, leading to thermal overload and increased power loss, and complex constructions with high loop inductance that prolong commutation times.
Innovation Solution
A low-voltage protective device using a single power semiconductor component, such as an IGBT or MOSFET, with a controlled gate voltage strategy to manage short-circuit and overcurrent conditions, preventing desaturation and reducing thermal stress, allowing for faster commutation and extended service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single IGBT is used to de-energize short-circuit currents, then the device complexity is reduced, but the IGBT experiences thermal overload and reduced service life
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the gate voltage of the IGBT beyond its peak rated voltage during short-circuit conditions. This temporary parameter change enables the IGBT to handle high short-circuit currents without saturation, preventing thermal overload while maintaining single-component simplicity. The control unit monitors collector-emitter voltage and increases gate voltage when desaturation is detected, resolving the contradiction between simplicity and reliability.
2Temperature
If multiple IGBTs are connected in parallel to handle high currents, then thermal overload is prevented, but the loop inductance increases and commutation time is prolonged
Solution Approach 1:
Instead of using multiple parallel IGBTs, the patent changes the operating parameter of a single IGBT by temporarily exceeding its peak gate voltage rating during short-circuit events. This approach maintains low loop inductance and fast commutation while preventing thermal overload through controlled parameter deviation. The single IGBT configuration with dynamic voltage control achieves both thermal protection and fast response.
3Duration of action of stationary object
If the IGBT operates at peak gate voltage continuously, then the service life is maximized, but the maximum current carrying capacity is limited
Solution Approach 1:
The patent implements periodic action by applying elevated gate voltage only during brief short-circuit events rather than continuously. The control unit temporarily increases gate voltage above the peak rating when desaturation is detected, then returns to normal operating voltage. This periodic, conditional parameter change enables high current handling capacity while maintaining long service life through minimal stress exposure.
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
The device effectively de-energizes high short-circuit currents without thermal issues, maintaining the semiconductor's lifespan and enabling operation in both AC and DC networks with reduced loop inductance and power loss.
Implementation Method 1
A low-voltage protective device using a single power semiconductor component, such as an IGBT or MOSFET, with a controlled gate voltage strategy to manage short-circuit and overcurrent conditions
Data Source
AI summary
A low-voltage protective device, comprising a first semiconductor circuit arrangement with a power semiconductor, a control and driver unit to drive the first semiconductor circuit arrangement with a control voltage, the control and driver unit configure the first semiconductor circuit arrangement: —in a switching-on process for a switching-on time with a first voltage value, which is a threshold control voltage, of the control voltage, and —increase the control voltage from the first voltage value to a second voltage value, which is a peak control voltage, after the switching-on time, and —increase the control voltage to a third voltage value, which is greater than the peak control voltage, upon detection of a short-circuit current or an overcurrent in a first shut-down step, and to de-energize the first semiconductor circuit arrangement in a second shut-down step.