Voltage Sensor Calibration via Selective RC Network Deactivation

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Solution Overview

Problem

Conventional ohmic-capacitive voltage dividers face challenges in achieving accurate measurements of high alternating voltages due to manufacturing inaccuracies and complex resistance mismatches between the primary and secondary circuits, making calibration difficult, especially at high frequencies.

Innovation Solution

A voltage sensor with an ohmic-capacitive voltage divider featuring a resistor-capacitor network with selectively deactivatable components, including fuses in series with resistors and capacitors, allows for adaptation of the secondary circuit's complex resistance to match the primary circuit, enabling precise calibration and adjustment without on-site modifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional ohmic-capacitive voltage divider is used, then the voltage measurement function is provided, but manufacturing inaccuracies cause complex resistance mismatches between primary and secondary circuits, making calibration difficult

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidcomponent tolerance
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by providing multiple resistors and capacitors with different nominal values in the secondary circuit. These components can be selectively deactivated through fuses to adjust the complex resistance parameters, enabling calibration compensation for manufacturing inaccuracies in the primary circuit components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the secondary circuit into multiple parallel resistor-capacitor branches, where each branch contains components with different nominal values. This segmentation allows selective deactivation of specific components to achieve the desired complex resistance matching, transforming a single calibrated circuit into a multi-configurable calibration system.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the secondary circuit components are fixed, then the device structure is simple, but on-site adjustment and calibration are impossible

Engineering Contradiction:
Improvecalibration capabilityVSAvoidcircuit configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by pre-configuring multiple resistor and capacitor components with different nominal values during manufacturing, along with associated fuses. This preparation enables on-site calibration without requiring complex adjustment mechanisms or specialized equipment, as the desired configuration can be achieved by simply blowing appropriate fuses to deactivate specific components.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses fuses as disposable components to selectively deactivate resistors and capacitors. Once a fuse is blown, the corresponding component is permanently deactivated, providing a simple and reliable method for configuration selection. This approach avoids the need for complex switches or adjustable components, maintaining device simplicity while enabling adaptability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Speed

If high-frequency measurements are performed, then the measurement range is extended, but measurement accuracy decreases due to resistance mismatches

Engineering Contradiction:
Improvefrequency responseVSAvoidhigh-frequency accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent addresses high-frequency measurement accuracy by enabling adjustment of the secondary circuit's complex resistance parameters through selective component deactivation. By matching the resistance and capacitance values at different frequency ranges, the circuit can maintain accuracy across extended frequency spectra, including high-frequency harmonics analysis.

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

This solution enhances measurement accuracy and reliability by allowing for easy automation and remote adjustment of the voltage sensor, ensuring precise matching of the secondary circuit to the primary circuit, particularly at high frequencies, thereby improving measurement fidelity.

Implementation Method 1

a resistive-capacitive voltage divider is provided with a first resistor-capacitor parallel circuit and a second resistor-capacitor parallel circuit, wherein the resistor-capacitor parallel circuits are electrically connected in series

Methodology Applied
Scientific EffectVoltage division: Electrical Resistance

Implementation Method 2

an electrical capacitor with a predefined capacitance connected in parallel in the secondary circuit

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4241092B1Voltage sensor with ohmic capacitive voltage divider
Publication Date: 2024.07.24 GREENWOOD POWER GMBH
  • EP4241092B1 patent drawingFigure 1

AI summary

The invention relates to a voltage sensor (1) for measuring a high voltage, comprising a high-voltage primary side (2), a low-voltage secondary side (3), and an ohmic capacitive voltage divider with a first resistor-capacitor parallel circuit (4) and a second resistor-capacitor parallel circuit (4'), wherein the resistor-capacitor parallel circuits (4, 4') are electrically arranged in series, the voltage drop at the second resistor-capacitor parallel circuit (4') is in relation to the high voltage, and a resistor-capacitor network (5) is provided parallel to the second resistor-capacitor parallel circuit (4'), said resistor-capacitor network comprising a plurality of resistors (6, 6', 6) and capacitors (7, 7', 7), which are connected in parallel and can be selectively deactivated, in order to electrically balance the secondary side (3).