Capacitive Sensor Subsystem for Non-Contact Voltage Magnitude Measurement
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Solution Overview
Problem
Conventional voltmeters require galvanic contact for measuring AC voltage, posing safety risks and failing to provide accurate magnitude measurements, while non-contact devices only indicate the presence of AC voltage without measuring its magnitude.
Innovation Solution
A non-contact voltage measurement system using capacitive sensors that measure AC voltage in insulated conductors without galvanic contact, employing a capacitive sensor subsystem with multiple sensors polled to compensate for position and distance variations, and a common mode reference voltage source to determine the AC voltage magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional voltmeters use galvanic contact to measure AC voltage, then accurate voltage magnitude measurement is achieved, but safety risks increase and operation becomes complex
Solution Approach 1:
The patent introduces an insulated probe as an intermediary between the user and the circuit being measured. The probe includes an insulating body that electrically isolates the user from the conductor, allowing safe galvanic contact measurement. The probe tip makes contact with the conductor while the user holds the insulated portion, eliminating direct exposure to electrical hazards.
Solution Approach 2:
The patent replaces the traditional two-probe galvanic contact method with a single-probe capacitive coupling system. Instead of requiring two probes to establish a complete circuit for measurement, the system uses one probe that capacitively couples to the conductor, with the user's body serving as the reference ground. This substitution eliminates the need for stripping insulation or creating exposed terminals.
2Ease of operation
If non-contact voltage detectors are used to detect AC voltage presence, then safety is improved and operation is simplified, but voltage magnitude measurement capability is lost
Solution Approach 1:
The patent creates a universal measurement tool that combines both contact and non-contact measurement capabilities in a single device. The system can operate in galvanic contact mode for accurate magnitude measurements or in capacitive coupling mode for non-contact measurements, making it adaptable to different measurement scenarios and eliminating the need for separate detection and measurement devices.
Solution Approach 2:
The patent enables the measurement system to switch between different operating modes by changing the coupling parameter. In capacitive coupling mode, the probe operates without direct contact for safety and convenience. In galvanic contact mode, the probe establishes direct electrical connection for precise magnitude measurement. The system dynamically adjusts its operation based on the measurement requirements.
3Measurement precision
If galvanic contact is required for voltage measurement, then accurate magnitude data is obtained, but device complexity and preparation time increase
Solution Approach 1:
The patent replaces the complex two-probe galvanic contact system with a simplified single-probe capacitive coupling system. The user's body capacitance serves as the reference ground, eliminating the need for a second probe or complex circuit setup. This substitution dramatically reduces device complexity and preparation time while maintaining measurement capability.
4Object-affected harmful factors
If insulated conductors are measured with conventional meters, then safety is improved, but measurement capability is reduced to binary detection only
Solution Approach 1:
The patent uses the insulated probe as an intermediary that bridges the gap between safety and measurement precision. The probe's insulation provides safety by preventing direct user contact with live conductors, while its capacitive coupling capability enables it to extract voltage magnitude information from insulated conductors without compromising safety.
Solution Approach 2:
The patent changes the measurement parameter from binary detection (presence/absence) to continuous measurement (magnitude). By using capacitive coupling through the insulated probe, the system can measure the actual voltage magnitude on insulated conductors rather than simply detecting whether voltage is present, providing quantitative data while maintaining safety.
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 safe and accurate measurement of AC voltage magnitude in insulated conductors without physical contact, providing reliable data through capacitive coupling and signal processing techniques.
Implementation Method 1
A non-contact voltage measurement system using capacitive sensors that measure AC voltage in insulated conductors without galvanic contact
Data Source
AI summary
Systems and methods for measuring AC voltage of an insulated conductor are provided, without requiring a galvanic connection between the conductor and a test electrode. A non-galvanic contact voltage measurement system includes a sensor subsystem, an internal ground guard and a reference shield. A common mode reference voltage source is electrically coupled between the internal ground guard and the reference shield to generate an AC reference voltage which causes a reference current to pass through the conductive sensor. Control circuitry receives a signal indicative of current flowing through the sensor subsystem due to the AC reference voltage and the AC voltage in the insulated conductor, and determines the AC voltage in the insulated conductor based at least in part on the received signal. The sensor subsystem includes a plurality of sensors that are polled to compensate for conductor position while allowing for measurement of physical characteristics of the conductor.