Gate Drive Circuit Paths for Surge and Miller Period Control
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Solution Overview
Problem
Existing gate drive circuits for semiconductor breakers face reliability issues due to surge voltages caused by quick current interruptions, which can break the semiconductor breaker, while slow current interruptions lead to overcurrents, also reducing reliability.
Innovation Solution
A gate drive circuit with multiple parallel circuit paths, including a gate resistor, a capacitor-resistor series combination, and a capacitor-resistor series with higher capacitance and resistance values, to control surge voltages and shorten the Miller period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If current is quickly interrupted in semiconductor breaker, then current interruption speed is improved, but surge voltage breaks the semiconductor breaker
Solution Approach 1:
The gate drive circuit is segmented into multiple parallel paths with different resistance values. The first path has high resistance to limit surge current, the second path has medium resistance for controlled discharge, and the third path has low resistance for quick Miller period termination. This segmentation allows different phases of current interruption to be handled by appropriately sized resistance paths.
Solution Approach 2:
The patent changes the resistance parameter by providing multiple gate resistors with different resistance values in parallel paths. This allows the circuit to dynamically select appropriate resistance levels during different stages of switching, optimizing both surge voltage suppression and Miller period termination without requiring a single fixed resistance value.
2Reliability
If current is slowly interrupted in semiconductor breaker, then surge voltage is reduced, but Miller period extends causing overcurrent
Solution Approach 1:
The gate discharge process is segmented into multiple phases handled by different parallel paths. The high-resistance path handles initial surge suppression, while the low-resistance path takes over for rapid Miller period termination. This segmentation ensures that neither surge voltage nor Miller period duration exceeds safe limits.
Solution Approach 2:
The circuit dynamically transitions between different resistance paths during the switching process. Initially, the high-resistance path dominates to suppress surge voltage. As the switching progresses and surge voltage decreases, the low-resistance path becomes more effective at terminating the Miller period quickly, preventing overcurrent conditions.
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 proposed solution effectively reduces surge voltages and shortens the Miller period, enhancing the reliability of semiconductor breakers by decreasing current interruption speed.
Implementation Method 1
the second circuit path includes a first capacitor and a first resistor connected in series, the third circuit path includes a second capacitor and a second resistor connected in series
Implementation Method 2
the second capacitor has a capacitance value greater than a capacitance value of the first capacitor, the second resistor has a resistance value greater than a resistance value of the first resistor
Data Source
AI summary
A gate drive circuit includes: an input terminal; a first circuit path inserted into a line connecting the input terminal and a gate of a power transistor; a second circuit path connected in parallel to the first circuit path; and a third circuit path connected in parallel to the second circuit path. The first circuit path includes a gate resistor (Rgon). The second circuit path includes a first capacitor and a first resistor connected in series. The third circuit path includes a second capacitor and a second resistor connected in series. The second capacitor has a capacitance value greater than a capacitance value of the first capacitor. The second resistor has a resistance value greater than a resistance value of the first resistor. The gate resistor (Rgon) has a resistance value greater than the resistance value of the second resistor.