MOSFET Gate Control via Characteristic Blocks

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Solution Overview

Problem

Wide-Bandgap Semiconductor MOSFETs face challenges in maintaining predictable switching behavior under fluctuating operating conditions, such as varying operating voltage and temperature, which affects their performance in applications like traction converters.

Innovation Solution

A method and control arrangement that utilize characteristic blocks to adjust control variables like turn-on and turn-off voltages and gate resistances based on actual operating parameters, stabilizing the switching behavior by compensating for changes caused by operating voltage and temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If MOSFET is used under highly variable operating conditions (voltage and temperature fluctuations), then the MOSFET can operate in demanding applications like traction converters, but the switching behavior becomes unpredictable and inconsistent

Engineering Contradiction:
Improveoperating condition rangeVSAvoidswitching behavior consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of control parameters (gate voltage, gate resistance) based on real-time operating conditions (temperature, voltage). The control arrangement continuously adapts the MOSFET switching characteristics by selecting from multiple characteristic curves corresponding to different operating ranges, ensuring consistent switching behavior across highly variable conditions in traction converter applications

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes control parameters (gate voltage magnitude, gate resistance value) as a function of operating temperature and voltage. By storing multiple sets of control parameters in the control arrangement and selecting appropriate sets based on current operating conditions, the system maintains predictable switching behavior while adapting to a wide range of operating environments

Inventive Principle:
Principle #35Parameter changes

2Reliability

If PWM signal modulation is applied to control switching behavior (as in US 2017/0155250 A1), then switching consistency improves, but the control system complexity increases

Engineering Contradiction:
Improveswitching behavior consistencyVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent stores multiple pre-calculated characteristic curves in the control arrangement, each representing optimal control parameters for specific operating conditions (temperature ranges, voltage levels). Instead of computing adjustments in real-time, the system selects the appropriate pre-stored curve based on current sensors readings, reducing computational complexity while maintaining switching consistency across varying operating conditions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex real-time computational control with a lookup-based control mechanism. By storing characteristic curves in memory and using simple comparison logic to select the appropriate curve based on temperature and voltage thresholds, the system achieves consistent switching behavior without requiring complex real-time calculations or advanced control algorithms

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3769418B1Control of a metal oxide semiconductor field effect transistor
Publication Date: 2022.03.23 SIEMENS AG
  • EP3769418B1 patent drawingFigure 1
  • EP3769418B1 patent drawingFigure 2~3
  • EP3769418B1 patent drawingFigure 4~5

AI summary

The invention relates to a method and an actuation assembly (3) for actuating a MOSFET (1), in particular a MOSFET (1) based on a semiconductor with a wide band gap. According to the invention, a characteristic block is generated in which a change (ΔU1, ΔU2, ΔR1, ΔR2) in at least one actuation variable (U1, U2, R1, R2) for actuating the MOSFET (1) with respect to a reference actuation value of the actuation variable (U1, U2, R1, R2) is stored on the basis of at least one operating characteristic variable (U, T) which influences the switching behavior of the MOSFET (1), said change counteracting a change in the switching behavior as a result of the at least one operating characteristic variable (U, T). During the operation of the MOSFET (1), an actual value of the at least one operating characteristic variable (U, T) is ascertained, and the reference actuation value of the at least one actuation variable (U1, U2, R1, R2) is changed according to the characteristic block depending on the actual value of the at least one operating characteristic variable (U, T).