Gate Drive Circuit Dynamic Surge Suppression
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Solution Overview
Problem
Existing gate drive circuits using active gate drive technology face increased element losses due to surge voltage suppression, particularly during the switching off process of electrical power switching elements like IGBT and MOSFET, where the collector voltage approaches the power supply voltage, leading to excessive energy dissipation.
Innovation Solution
A gate drive circuit incorporating a main voltage detection unit, a control current source, and an adjustment unit that adjusts the control current based on detected main and gate currents, allowing for dynamic control of the surge voltage suppression, thereby reducing element losses by varying the clamp level of the collector voltage in response to collector current levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If active gate drive technology is used to suppress surge voltage, then surge voltage is suppressed, but element loss increases
Solution Approach 1:
The clamp level voltage is made dynamically adjustable based on the collector current magnitude. During turn-off, the clamp level is set higher when collector current is large and lower when collector current is small, optimizing the balance between surge suppression and loss reduction throughout the switching transition
Solution Approach 2:
The invention changes the parameter of clamp level voltage from a fixed value to a variable value that depends on collector current. This parameter change allows the system to adapt the surge suppression strength according to the actual switching conditions, reducing unnecessary energy dissipation
2Object-affected harmful factors
If clamp level is set high to suppress surge voltage effectively, then surge voltage suppression is improved, but energy dissipation increases
Solution Approach 1:
The clamp level is dynamically adjusted during the switching process based on real-time collector current feedback. The control unit increases clamp level when collector current is high and decreases it when collector current drops, maintaining effective surge suppression while minimizing energy dissipation during different phases of turn-off
Solution Approach 2:
Instead of applying full surge suppression throughout the entire turn-off period, the invention applies strong suppression (high clamp level) only when necessary (when collector current is large and surge risk is high), and reduces suppression strength when collector current decreases, avoiding excessive energy dissipation
Data Source
AI summary
The present invention includes: a main voltage detection unit for detecting a voltage applied between main electrodes of an electrical power switching element; a control current source for injecting a current into a gate electrode of the electrical power switching element in accordance with the voltage detected by the main voltage detection unit; a main current detection unit for detecting a main current flowing between the main electrodes of the electrical power switching element; and an adjustment unit for adjusting a current of the control power source in accordance with the main current detected by the main current detection unit.