Drive Device for Power Semiconductor Elements Using Gate Current Analysis
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Solution Overview
Problem
Existing drive devices for power semiconductor elements connected in parallel require large and costly current detectors to detect overcurrent states, leading to increased size and cost.
Innovation Solution
A drive device with a control command unit, current detector, differentiator, integrator, and determination unit that detects overcurrent states by analyzing gate current differentiation and integration, allowing for simple and cost-effective detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current detector is used to detect main current in each power semiconductor element, then overcurrent detection capability is improved, but device size and cost increase
Solution Approach 1:
The patent uses gate current as an intermediary parameter to indirectly detect main current status. Instead of directly measuring the large main current through expensive amperemeters, the system measures the much smaller gate current and uses mathematical processing (differentiation and integration) to infer the main current state, thereby achieving overcurrent detection without large-sized current detectors
Solution Approach 2:
The patent replaces the direct electrical measurement system (amperemeter for main current detection) with a mathematical processing system. By substituting the physical measurement of main current with mathematical operations on gate current signals, the system achieves the same detection function with smaller, less expensive components
2Measurement precision
If a current detector is used to detect main current in each power semiconductor element, then overcurrent detection capability is improved, but device cost increases
Solution Approach 1:
The patent replaces expensive, large-sized amperemeters with cheaper alternative components (gate current detectors and mathematical processing units). This substitution uses lower-cost components to achieve the same functional outcome, significantly reducing device manufacturing cost while maintaining overcurrent detection capability
Solution Approach 2:
By using gate current as an intermediary measurement parameter, the system avoids the need for expensive main current detectors. The gate current is much smaller and easier/cheaper to measure accurately, and through mathematical transformation it provides equivalent information about main current status
Data Source
AI summary
A plurality of drive circuits each drive a corresponding one of a plurality of power semiconductor elements connected in parallel. Each of the drive circuits includes a control command unit, a current detector, a differentiator, and an integrator. The current detector detects a gate current that flows into a gate terminal of a corresponding one of the power semiconductor elements after the control command unit outputs a turn-on command. The differentiator performs time differentiation of the gate current detected by the current detector. The integrator performs time integration of the gate current detected by the current detector. Based on a differential value and an integral value in each of the drive circuits, the determination unit determines whether an overcurrent state occurs or not in any of the plurality of power semiconductor elements.