Auxiliary Voltage Source for Serial IGBT Overvoltage Equalization
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Solution Overview
Problem
IGBT voltage equalization technologies face challenges due to uneven voltage distribution caused by inconsistent IGBT parameters, peripheral circuit inconsistencies, and delayed driving signals, leading to potential overvoltage, reduced service life, and system instability.
Innovation Solution
A method and system utilizing an auxiliary voltage source to detect dynamic overvoltage in serial IGBTs, supplying an emergency high-level signal followed by a constant voltage to stabilize the gate voltage, determining the signal amplitude and width based on voltage diagnostics, and calculating the constant voltage amplitude to prolong IGBT off-time and synchronize other IGBTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If IGBT serial technology is used to solve low voltage level, then voltage level is improved, but voltage distribution uniformity deteriorates
Solution Approach 1:
The patent implements real-time detection of each IGBT's port dynamic voltage and compares it with reference voltage to generate feedback signals. When overvoltage is detected, the system dynamically adjusts the gate voltage of the affected IGBT through auxiliary voltage sources, creating a closed-loop feedback control system that maintains voltage distribution uniformity while operating at high voltage levels.
Solution Approach 2:
The patent dynamically changes the gate voltage parameter of IGBTs to compensate for voltage distribution unevenness. By adjusting the gate voltage magnitude and duration based on real-time voltage detection, the system modifies the IGBT switching characteristics to achieve uniform voltage distribution across all serial IGBTs during operation.
2Reliability
If dynamic overvoltage diagnosis is implemented, then overvoltage protection is improved, but system complexity increases
Solution Approach 1:
The patent divides the voltage equalization control into independent modules for each IGBT. Each IGBT has its own voltage detection and auxiliary voltage source, allowing parallel processing of overvoltage diagnosis and control without requiring complex centralized coordination. This modular segmentation reduces overall system complexity while maintaining comprehensive overvoltage protection.
3Stability of the object's composition
If auxiliary voltage source is used for voltage equalization, then voltage distribution uniformity is improved, but device complexity increases
Solution Approach 1:
The patent introduces auxiliary voltage sources as intermediary devices between the control system and IGBT gates. These intermediaries provide precise voltage adjustment capability without requiring direct modification of the main power circuit, thereby achieving voltage equalization with minimal impact on the overall system structure and complexity.
Data Source
AI summary
A serial IGBT voltage equalization method and system based on an auxiliary voltage source is disclosed. The method includes the following steps. (1) Detect a port dynamic voltage of each serial IGBT. (2) Perform dynamic overvoltage diagnosis respectively on the port dynamic voltage of each IGBT. (3) Supply emergency high level signal to the gate of the IGBT when there is dynamic overvoltage. (4) Stop supplying emergency high level signal to the gate of the IGBT, supply a constant voltage at the gate of the IGBT through the auxiliary voltage source. The invention provides a constant voltage through the auxiliary voltage source, prolongs the off time of the faulty IGBT, and turns off other IGBTs simultaneously, thereby achieving the purpose of serial IGBT voltage equalization.