IGBT Switch Control via Inductive Voltage Feedback

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Solution Overview

Problem

High variation in power current during switching in IGBT switches can lead to excessive electric voltage at terminals, potentially damaging the switch.

Innovation Solution

Measuring the potential difference between two measurement points with inductance present allows for control of the power current variation, ensuring a reliable and optimal measurement of current changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If IGBT switches are used for power switching, then switching speed and power control capability are improved, but high variation in power current during switching creates excessive electrical voltage that can damage the switch

Engineering Contradiction:
Improveswitching speedVSAvoidexcessive electrical voltage
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an inductance element as an intermediary component between the power current source and the IGBT switch. This inductance acts as a mediator that limits and controls the rate of change of power current (di/dt) during switching operations, thereby preventing excessive voltage spikes while maintaining the high switching speed capability of the IGBT

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the electrical parameters of the switching circuit by introducing a specific inductance value (greater than 2nHenry) to change the current waveform characteristics. This parameter change transforms the abrupt current variation into a controlled ramp-like waveform, reducing peak voltage stress on the switch terminals

Inventive Principle:
Principle #35Parameter changes

2Reliability

If inductance is added to control current variation, then voltage spikes are reduced, but measurement of current variation becomes more challenging

Engineering Contradiction:
Improveswitch reliabilityVSAvoidcurrent variation measurement
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements a feedback control mechanism where the potential difference across the inductance is continuously measured and fed back to the control unit. The control unit uses this feedback information to adjust the gate control signal and regulate the power current variation in real-time, ensuring reliable operation while providing accurate measurement capability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The inductance element serves multiple functions simultaneously: it limits current variation to protect the switch, provides a measurable potential difference for current monitoring, and acts as part of the control feedback loop. This multi-functionality resolves the measurement difficulty by making the protective component itself the sensing element

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables effective control of power current variations, enhancing the reliability and performance of electronic devices by maintaining a constant potential difference during switching phases.

Implementation Method 1

an inductance 3 existing between these two measuring points is accompanied by a potential difference U, or voltage U, between the two points P

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3347987B1Electronic control device for a switch, in particular for an automotive vehicle
Publication Date: 2023.05.10 VALEO SIEMENS EAUTOMOTIVE FRANCE SAS
  • EP3347987B1 patent drawingFigure 1~5
  • EP3347987B1 patent drawingFigure 6~7

AI summary

Electronic control device for a switch, in particular for an automotive vehicle. The invention relates to an electronic device (1), in particular for an automotive vehicle, this device comprising a switch (2), and the device is designed to allow the control, in the switching phase, of the variation of the power current passing the switch with the aid of this difference in potentials.