Semiconductor Radiated Noise Evaluation via Voltage Variation

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Solution Overview

Problem

Current methods for evaluating electromagnetic noise in power conversion apparatuses, such as inverters and PWM rectifiers, require detailed circuit board and housing structure analysis, and can only be measured after the apparatus is completed, leading to potential non-compliance with EMC standards, necessitating redesign and increased costs.

Innovation Solution

An evaluation method and apparatus that measure voltage variations during switching operations of semiconductor devices, allowing for the estimation and benchmarking of radiated noise before apparatus completion, using a configuration with a power supply, capacitive units, and a signal supplying unit to perform turn-on, turn-off, and recovery operations, and detect voltage variations to output evaluation benchmarks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If electromagnetic noise evaluation is performed by simulation or simple measurement after apparatus completion, then the evaluation can be conducted, but the evaluation occurs too late requiring redesign and increasing costs

Engineering Contradiction:

Improveevaluation timingVSAvoidmanufacturing cost

Core Design Contradiction:

Loss of timeVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by performing electromagnetic noise evaluation on semiconductor devices before they are integrated into the complete power conversion apparatus. The evaluation is conducted on individual devices during the manufacturing process, allowing early detection of noise issues and enabling corrective actions before final assembly, thus avoiding costly redesigns later

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If detailed circuit board and housing structure analysis is performed, then accurate electromagnetic noise evaluation can be achieved, but the evaluation process becomes complex and time-consuming

Engineering Contradiction:

Improveelectromagnetic noise evaluation accuracyVSAvoidevaluation process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the electromagnetic noise evaluation from the complex system-level analysis and applies it to individual semiconductor devices. By measuring voltage variations across specific terminals of individual devices during switching operations, the method achieves accurate noise characterization without requiring detailed analysis of the entire circuit board and housing structure

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses voltage variation measurements as an intermediary parameter to evaluate electromagnetic noise. Instead of directly measuring complex electromagnetic fields from the complete apparatus, the method measures voltage variations across device terminals, which serve as a proxy indicator for radiated noise generation, simplifying the evaluation process while maintaining accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If semiconductor device switching operations are monitored for voltage variation, then radiated noise can be evaluated early, but additional measurement equipment and procedures are required

Engineering Contradiction:

ImproveEMC standard complianceVSAvoidmeasurement setup complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex electromagnetic field measurement systems with electrical voltage variation measurements. Instead of using antennas and electromagnetic field sensors to evaluate radiated noise, the method uses standard electrical measurement equipment to measure voltage variations across device terminals, which correlates with noise generation and can be measured with conventional test equipment

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 pre-completion evaluation of radiated noise, reducing manufacturing troubles and costs by assessing electromagnetic noise earlier in the process, ensuring compliance with EMC standards and optimizing semiconductor device selection and EMC filter design.

Implementation Method 1

causing a semiconductor device to perform a switching operation

Methodology Applied

Scientific EffectSwitching operation:

Implementation Method 2

measuring voltage variation occurring between main terminals of the semiconductor device during the switching operation

Methodology Applied

Scientific EffectVoltage variation measurement:

Data Source

PatentUS11143691B2Evaluation method, estimation method, evaluation apparatus, and combined evaluation apparatus

Publication Date: 2021.10.12 FUJI ELECTRIC CO LTD

AI summary

The radiated noise of a semiconductor device is conveniently evaluated, and the radiated noise of an apparatus equipped with the semiconductor device is estimated. An evaluation method and an evaluation apparatus are provided, including: causing a semiconductor device to perform a switching operation; measuring voltage variation occurring between main terminals of the semiconductor device during the switching operation; and outputting an evaluation benchmark for radiated noise of the semiconductor device based on the voltage variation. The outputting the evaluation benchmark may include calculating the voltage variation in the semiconductor device for each frequency component as the evaluation benchmark.