IGBT Gate Driver Feedback for Stable Negative Gate Voltage

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Solution Overview

Problem

Existing IGBT driver modules face challenges in accurately maintaining the Cs:Cg ratio for generating the required negative gate voltage, as capacitance variations can lead to insufficient voltage variance across the gate capacitance, affecting the switching performance.

Innovation Solution

The IGBT driver module incorporates a series capacitance charge adjustment component that dynamically adjusts the charge stored in the series capacitance based on the determined gate voltage error, using a comparator to control a current source and apply proportional current to compensate for capacitance variances between the series and gate capacitances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a series capacitor topology is used to generate negative gate voltage, then the gate voltage can be shifted to prevent cross conduction, but the capacitance variations cause insufficient voltage variance across the gate capacitance

Engineering Contradiction:
Improvegate voltage generationVSAvoidvoltage variance consistency
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the voltage across the series capacitor is continuously monitored and compared against a reference voltage. Based on this comparison, the charge on the series capacitor is dynamically adjusted to maintain the required voltage variance across the gate capacitance, compensating for capacitance variations and ensuring consistent switching performance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes the charge parameter of the series capacitor to compensate for capacitance variations. By adjusting the charge on the series capacitor based on feedback from voltage measurements, the system maintains the required voltage variance across the gate capacitance despite variations in capacitor values, thereby ensuring reliable operation.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the series capacitance value is increased to account for capacitance variations, then voltage variance consistency improves, but the device complexity and charge adjustment requirements increase

Engineering Contradiction:
Improvevoltage variance consistencyVSAvoidcharge adjustment mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Rather than simply increasing the series capacitance value, the patent uses a feedback-controlled charge adjustment mechanism. The system monitors the voltage across the series capacitor and dynamically adjusts its charge to maintain the required voltage variance, providing precision without requiring excessive capacitance values or overly complex hardware modifications.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from a static capacitance approach to a dynamic charge adjustment approach. The charge on the series capacitor is continuously adjusted based on real-time voltage measurements and feedback, allowing the system to adapt to capacitance variations without requiring a fixed, oversized capacitor or complex mechanical adjustments.

Inventive Principle:
Principle #15Dynamics

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 solution ensures a consistent and required voltage variance across the gate capacitance, enhancing the switching performance by dynamically adjusting the charge in the series capacitance to match the gate voltage reference, thereby maintaining efficient operation despite capacitance variations.

Implementation Method 1

a first series capacitance operably coupled between a driver component of the IGBT driver module and the at least one gate of the at least one IGBT device

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The at least one series capacitance charge adjustment component is arranged to compare a gate voltage of the IGBT device to a gate reference voltage to determine the gate voltage error

Methodology Applied
Scientific EffectVoltage comparison:

Implementation Method 3

The at least one series capacitance charge adjustment component is arranged to control at least one current source component operably coupled in parallel across the at least one series capacitance based on the determined gate voltage error

Methodology Applied
Scientific EffectElectrical current: Conduction (electrical)

Data Source

PatentEP3058656B1IGBT driver module and method therefor
Publication Date: 2019.11.06 NXP USA INC
  • EP3058656B1 patent drawingFigure 1
  • EP3058656B1 patent drawingFigure 2~3
  • EP3058656B1 patent drawingFigure 4~5

AI summary

The present invention relates to an insulated gate bipolar transistor, IGBT (200), driver module (605) for driving at least one gate (202) of at least one IGBT device (200), and method therefor. The IGBT driver module (605) comprises at least one series capacitance (210) operably coupled between a driver component (630, 640) of the IGBT driver module (605) and the at least one gate (202) of the at least one IGBT device (200). The IGBT driver module (605) further comprises at least one series capacitance charge adjustment component (205) controllable to determine a gate voltage error (ΔGerr) at the at least one gate (202) of the at least one IGBT device (200) and dynamically adjust a charge of the at least one series capacitance (210) based at least partly on the determined gate voltage error (ΔGerr).