Power Module Gate Bypass Circuit for Erroneous Turn-On Suppression

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Solution Overview

Problem

Existing power conversion devices experience erroneous turn-on due to resonance phenomena between power modules caused by variations in switching timing and impedance, leading to potential differences in drain-source voltage and increased gate voltage, which can damage the modules.

Innovation Solution

Incorporation of a bypass circuit with semiconductor switching elements to divert resonance currents away from the control terminals of power modules, using resistance elements to manage impedance and suppress resonance currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If power modules are connected in parallel to increase power capacity, then the power capacity of the power conversion device is increased, but switching timing deviation between modules causes resonance phenomena and erroneous turn-on

Engineering Contradiction:

Improvepower capacityVSAvoidswitching timing synchronization

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

A damping resistor is introduced as an intermediary element connected in series with the gate line of each power module. This resistor acts as a mediator that suppresses resonance currents caused by switching timing deviations between parallel power modules, preventing erroneous turn-on while allowing the parallel configuration to maintain increased power capacity

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If gate wiring line impedance is reduced to control gate current, then switching timing deviation is suppressed, but resonance currents still cause voltage differences and erroneous turn-on

Engineering Contradiction:

Improveswitching timing synchronizationVSAvoidresonance voltage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The damping resistor serves as an intermediary that specifically targets and suppresses resonance currents in the gate circuit. By placing the resistor in series with the gate line, it dampens the resonance phenomenon caused by parasitic inductance and capacitance, preventing voltage spikes that lead to erroneous turn-on

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If high-speed switching is implemented to improve efficiency, then productivity is increased, but resonance phenomena due to switching timing deviation cause erroneous turn-on and module destruction

Engineering Contradiction:

Improveswitching speedVSAvoidmodule safety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The damping resistor is strategically placed in the gate circuit as an intermediary element that suppresses resonance without significantly impacting the main switching performance. It allows high-speed switching to maintain productivity while preventing resonance-induced erroneous turn-on that would compromise module safety

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The bypass circuit effectively reduces resonance currents, preventing erroneous turn-on and protecting the power modules from damage.

Implementation Method 1

a potential difference occurs due to the deviation. The potential difference between the power modules causes a resonance phenomenon due to an inductance between the power modules and a parasitic capacitance thereof

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

a resistance element connected between the controller and the control terminal of each of the power modules

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentUS12494721B2Power conversion device with bypass of a gate current

Publication Date: 2025.12.09 MITSUBISHI ELECTRIC CORP

AI summary

The power conversion device includes: a control unit that switches between the on state in which a power module is made conductive between a drain terminal and a source terminal of the power module and the off state in which the power module is made non-conductive; a resistance element connected between the control unit and a gate terminal of the power module; and a bypass circuit in which a drain terminal of a semiconductor switching element provided for each power module is connected to the gate terminal of the power module, and a source terminal of the semiconductor switching element is connected to the source terminal of the power module, in which the control unit switches the semiconductor switching element of the bypass circuit to the on state when the power module is switched to the off state, thereby reducing occurrence of an erroneous turn-on of the power module.