Pockels Crystal 3D Surface Potential Measurement

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Solution Overview

Problem

Existing surface potential measurement technologies, such as those using metal probes, struggle to accurately measure the high-frequency components of inverter pulse voltage in electric field relaxation systems due to interference and corona discharge, particularly at coil corners, leading to unreliable measurements of the three-dimensional surface potential distribution.

Innovation Solution

A three-dimensional surface potential distribution measurement apparatus utilizing a Pockels crystal, laser light source, and light detector, which maintains a controlled gap with the test object to measure the surface potential distribution without physical contact, enabling high-frequency component detection and accurate mapping of potential gradients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a metal probe is used to measure surface potential, then the measurement structure is simple, but the measurement precision deteriorates due to interference and corona discharge at high-frequency components

Engineering Contradiction:
Improvemeasurement structureVSAvoidsurface potential measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical contact-based metal probe measurement system with an optical measurement system using a Pockels crystal. The Pockels crystal utilizes the electro-optic effect to convert electrical field information into optical signal changes, allowing non-contact measurement of surface potential distribution. This substitution eliminates the interference and corona discharge problems inherent in metal probe contact measurement while maintaining measurement capability.

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

Solution Approach 2:

The Pockels crystal serves as an intermediary between the electric field and the measurement device. Instead of directly contacting the high-voltage surface with a metal probe, the Pockels crystal indirectly senses the electric field through its electro-optic properties, translating electrical information into optical changes that can be detected without physical contact or electrical interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a surface electrometer is used to measure surface potential, then the device is simple to operate, but the measurement precision deteriorates due to inability to follow high-frequency components

Engineering Contradiction:
Improvemeasurement operation simplicityVSAvoidhigh-frequency component detection capability
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the electrical measurement system (surface electrometer) with an optical measurement system. By using the Pockels crystal's electro-optic effect and detecting optical intensity changes with a light detector, the system achieves high-frequency response capability that electrical electrometers cannot provide, while maintaining ease of operation through optical detection methods.

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

3Device complexity

If a probe is brought into contact with the electric field relaxation system, then the measurement structure is simple, but harmful factors increase due to potential variation and corona discharge

Engineering Contradiction:
Improvemeasurement structureVSAvoidpotential variation and corona discharge
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent eliminates the mechanical contact between probe and measurement object by substituting optical fields for electrical contact. The Pockels crystal detects electric field distribution through optical intensity changes without physical contact, thereby completely avoiding potential variation and corona discharge that occur with metal probe contact.

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

Solution Approach 2:

The Pockels crystal acts as an intermediary that translates electric field information into optical signals without requiring direct electrical contact. This intermediary approach allows measurement of the electric field relaxation system without introducing harmful effects such as corona discharge or potential variation that would result from direct probe contact.

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

This solution allows for precise measurement of the three-dimensional surface potential distribution in electric field relaxation systems, effectively addressing the limitations of previous technologies by ensuring high responsiveness and avoiding interference, thus enhancing measurement accuracy and reliability.

Implementation Method 1

a Pockels crystal (11) configured to receive, at a first end face thereof, the laser light emitted from the laser light source

Methodology Applied
Scientific EffectPockels effect: Pockels Effect

Data Source

PatentEP3153870B1A device for measuring 3D surface potential distribution
Publication Date: 2019.09.25 TOSHIBA MITSUBISHI ELECTRIC IND SYST CORP
  • EP3153870B1 patent drawingFigure 1
  • EP3153870B1 patent drawingFigure 2
  • EP3153870B1 patent drawingFigure 3

AI summary

A three-dimensional surface potential distribution measurement apparatus (70) has: a laser light source (13); a Pockels crystal (11); a mirror; a light detector (16); a support structure (31) which supports the aforementioned elements while maintaining a relative positional relationship therebetween; a movement driver which can move the support structure (31) three-dimensionally; a rotary driver (35) which supports the test object (8) and can rotate the test object (8) about an axis extending in a longitudinal direction of the test object (8) ; and a drive controller (37) which controls the movement driver and the rotary driver (35). The drive controller (37) coordinates a driving operation by the movement driver and by the rotary driver (35) while maintaining a gap between the second end face of the Pockels crystal (11) and a surface of the test object (8) at a predetermined value such that the second end face of the Pockels crystal (11) approaches all the surfaces of the electric field relaxation system (3) on the test object (8) .