Three-Phase Discharge Detection With Phase-Domain Noise Localization

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Solution Overview

Problem

Conventional discharge detection structures for three-phase alternating current systems are impractical due to the need for multiple components and cannot accurately specify the source of discharge noise between different phase connections, leading to incorrect determinations.

Innovation Solution

A discharge detector with a single determination section that includes a filter, amplification, phase angle setting, phase division, and smoothing components to analyze noise in a high frequency band, allowing for precise identification of discharge occurrence and source in three-phase alternating current systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a camera is used to capture images of a patient's mouth for discharge detection, then image capture capability is provided, but the device becomes large and cumbersome requiring manual operation

Engineering Contradiction:
Improvedischarge detection accuracyVSAvoiddevice size and operation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical camera system with an optical sensor that directly detects light intensity changes. Instead of capturing full images and processing them digitally, the system uses photodetectors to measure light intensity variations caused by discharge particles, substituting a complex mechanical imaging system with a simpler optical detection mechanism.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the essential detection function from the complete camera system. Rather than using a full imaging system, it isolates and utilizes only the light detection capability, removing unnecessary components like lenses, shutters, and image processing hardware, thereby simplifying the device while maintaining discharge detection functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If an optical sensor is used to detect discharge, then the device can be simplified, but the sensor may be contaminated by saliva or food particles

Engineering Contradiction:
Improvedevice simplicityVSAvoidsensor reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a reflective member as an intermediary between the light source and the optical sensor. This reflective member reflects light toward the sensor without requiring the sensor to be in direct contact with the oral environment, thereby preventing saliva and food particles from contaminating the sensor while still enabling discharge detection through light intensity measurements.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent positions the optical sensor at a location that is spatially separated from the direct path of saliva and food particles. By arranging the sensor and reflective member in a specific geometric configuration, the system detects light reflections from discharge particles without placing the sensitive sensor components in the contaminated zone, thus maintaining reliability while keeping the device simple.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If the optical sensor is positioned to directly face the patient's mouth, then discharge detection is optimized, but saliva or food particles may attach to the sensor

Engineering Contradiction:
Improvedischarge detection sensitivityVSAvoidsensor contamination by saliva or food
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The reflective member serves as a mediator that indirects light from the discharge particles to the sensor. This arrangement allows the sensor to detect discharge effectively while being positioned away from the direct spray path of saliva and food particles, thus maintaining detection sensitivity without exposing the sensor to contamination.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of positioning the sensor to directly face the mouth (which causes contamination), the system inverts the approach by using a reflective member to redirect light. The sensor faces away from the mouth while still detecting discharge particles through the reflected light path, thereby solving the contamination problem while maintaining detection effectiveness.

Inventive Principle:
Principle #13The other way round (Inversion)

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 discharge detector effectively determines discharge occurrence and specifies the source in three-phase alternating current systems using a minimal number of components, reducing complexity and improving accuracy.

Implementation Method 1

a light source that emits light, and an optical sensor that receives the light reflected by the particles

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4403936B1Discharge detection device
Publication Date: 2026.04.22 NITTO KOGYO KK
  • EP4403936B1 patent drawingFigure 1
  • EP4403936B1 patent drawingFigure 2
  • EP4403936B1 patent drawingFigure 3A~3D

AI summary

A discharge detector 1 of the present invention includes: at least one filter section 21 electrically connected between two phases out of an R phase, an S phase, and a T phase of a power circuit of a three-phase alternating current and configured to extract a noise from the alternating current power source; an amplification section 22 configured to amplify an output of the filter section 21; a smoothing section 25 configured to smooth an output of the amplification section 22; a phase angle setting section 23 configured to set a starting point of noise measurement for each connection between the R phase - the S phase, between the S phase - the T phase, and between the T phase - the R phase; a phase division section 24 configured to define a plurality of domains by dividing one cycle of a voltage waveform or a current waveform of each connection between the R phase - the S phase, between the S phase - the T phase, and between the T phase - the R phase based on the starting point of noise measurement; and a determination section 26 configured to detect a noise included in an output of the smoothing section 25, configured to specify at least one domain coincident with a timing of detecting the noise out of the plurality of domains defined by the phase division section 24, and configured to specify which connection between the R phase - the S phase, between the S phase - the T phase, or between the T phase - the R phase is a source of the noise.