De-Energized Power Converter Testing Using Driver-Induced Residual Voltage

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Solution Overview

Problem

Existing fault diagnostic methods for power converter systems require energization of the power circuit or complex sensing systems, leading to significant test and hardware complexity, especially in cascaded systems with many modular cells.

Innovation Solution

A method and apparatus for de-energized circuit testing using driver-induced electrical quantities, such as gate driver-induced residual voltage (GIRV), to detect and locate failures in insulated-gate power semiconductor devices without energizing the converter, utilizing a driver circuit, measurement device, and signal processing circuit to evaluate the health of the circuit based on induced voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fault diagnostic methods are used, then detection reliability is improved, but hardware complexity and test complexity increase significantly

Engineering Contradiction:

Improvefault detection reliabilityVSAvoidhardware complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The circuit under test generates its own test signal through the interaction of the driver circuit and the capacitor. The driver circuit complementarily switches the series-connected transistors, and the capacitor's inherent properties generate the electrical quantity that reveals circuit health status, eliminating the need for external complex test equipment

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The driver circuit serves dual purposes: it normally drives the transistors during operation and simultaneously functions as a test signal generator during de-energized testing. The capacitor also serves both as an energy storage element and as a signal generation element that produces measurable electrical quantities for fault detection

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If conventional fault diagnostic methods are used, then detection reliability is improved, but test time and efficiency worsen

Engineering Contradiction:

Improvefault detection reliabilityVSAvoidtest time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The testing is performed in a de-energized state before the circuit is activated for normal operation. The driver circuit complementarily drives the transistors and the capacitor generates the test signal in advance, allowing fault detection to occur before the circuit is energized, thereby preventing potential failures and reducing downtime

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The driver circuit continuously complementarily switches the transistors during the test period, maintaining a continuous test signal generation process. This continuous action ensures that the electrical quantity is constantly available for measurement and evaluation without interruption

Inventive Principle:

Principle #20Continuity of useful action

3Device complexity

If de-energized testing is implemented, then hardware complexity is reduced, but measurement precision may be compromised

Engineering Contradiction:

Improvehardware complexityVSAvoidelectrical quantity detection precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The invention measures electrical quantities (voltage or current) generated in the de-energized state, which are naturally present due to the capacitor's interaction with the complementarily driven transistors. By changing the measurement parameter to these naturally occurring electrical quantities rather than requiring external test signals, the system achieves both simplicity and sufficient precision for fault detection

Inventive Principle:

Principle #35Parameter changes

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

Enables efficient detection of open-circuit, short-circuit, and gate failures in power converters with low hardware complexity and computational effort, reducing the risk of cascading failures by identifying faulty components before energization.

Implementation Method 1

a capacitor coupled between the two terminals and a plurality of serially connected transistors coupled in parallel with the capacitor between the two terminals

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS20250389787A1Methods and apparatuses for de-energized circuit testing based on driver-induced electrical quantity

Publication Date: 2025.12.25 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

A method and an apparatus for testing a circuit is described. The circuit includes two terminals, a capacitor coupled between the two terminals and a plurality of serially connected transistors coupled in parallel with the capacitor between the two terminals. The method includes complementarily driving the plurality of serially connected transistors with the two terminals being in a de-energized state, detecting an electrical quantity of the circuit, and determining, using the electrical quantity, whether or not the circuit is healthy.