IGCT Gate Unit With Nonlinear Inductor for Low-Loss Switching
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Solution Overview
Problem
Existing gate units for integrated-gate commutated thyristors (IGCTs) are complex and costly due to separate hardware stages for various functions, leading to increased size and mechanical constraints, and high switching losses limit their efficiency in high-power applications.
Innovation Solution
Integration of turn-on, retrigger, positive-gate-voltage backporch, and negative-gate-voltage backporch functions into a single power stage using a nonlinear saturable inductor and a transistor-switched voltage selector, allowing for reduced component count and simplified circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate processing of gate finger regions is used, then manufacturing precision can be improved, but device complexity and processing time increase
Solution Approach 1:
The gate structure is segmented into multiple gate fingers arranged in parallel, where each gate finger can be processed independently through separate diffusion zones. This allows precise control of each gate finger region while maintaining overall device functionality.
Solution Approach 2:
Multiple gate finger regions are combined into a single integrated device structure where they share common processing steps and diffusion zones. The gate fingers are merged through a unified fabrication process that treats them as a collective unit rather than separate components.
2Manufacturing precision
If separate processing of gate finger regions is used, then manufacturing precision can be improved, but productivity decreases
Solution Approach 1:
Mask layers are pre-formed to define multiple gate finger regions before diffusion processing begins. This preliminary patterning allows subsequent processing steps to simultaneously address multiple gate fingers with precise positioning, improving both precision and throughput.
Solution Approach 2:
The fabrication process employs continuous diffusion zones that extend across multiple gate finger regions without interruption. This continuous processing approach maintains constant manufacturing precision across all gate fingers while maximizing production efficiency through uninterrupted processing.
3Device complexity
If integrated processing of gate finger regions is used, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
Different regions of the gate structure are assigned different local properties through selective doping concentrations and diffusion depths. Each gate finger region can have tailored electrical characteristics while being processed through the same integrated fabrication steps, achieving both simplicity and precision.
Data Source
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AI summary
The invention relates to a gate unit (22) for controlling a gate commutated thyristor (21), comprising: - a voltage selector (26) for selectively applying a high supply potential (Vpos), a middle supply potential (Vmid), and a low supply potential (Vneg); - a nonlinear inductor (27) serially coupled between the output of the voltage selector (26); - a gate control unit (23) configured to control the voltage selector (26) to control switching of the gate commutated thyristor (21) in its turn-on state comprising a turn-on pulse generation, a positive-gate-voltage backporch operation, a negative-gate-voltage backporch operation and a retrigger pulse generation; wherein the nonlinear inductor (27) has a nonlinearity to have a high inductance during any of the backporch operations and to have a low inductance during the turn-on pulse generation and retrigger pulse generation.