Optical Waveguide Sensor for Galvanically Isolated Field Measurement
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Solution Overview
Problem
Existing methods for measuring electrical parameters such as current, voltage, and temperature in power electronics are complex, expensive, difficult to miniaturize, and require direct physical contact, which is unsafe and impractical for existing installations, lacking effective galvanic isolation.
Innovation Solution
A sensor using optical transmitters and receivers with deflectable optical waveguides, integrated on a bridge with functional elements, measures physical influencing factors like magnetic fields, electric fields, and temperature changes through optical attenuation changes, ensuring galvanic isolation and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inductive or capacitive couplers are used for galvanic isolation, then reliable isolation between power and control sides is achieved, but device complexity and cost increase
Solution Approach 1:
The patent replaces inductive or capacitive couplers with a purely optical measurement system. Optical transmitters convert electrical signals to optical signals that travel through optical waveguides to optical receivers, eliminating the need for complex electromagnetic coupling components and achieving galvanic isolation through optical rather than electrical means.
Solution Approach 2:
The patent introduces optical waveguides as intermediary elements between the measurement point and the evaluation unit. These waveguides serve as the coupling medium that transfers optical signals while maintaining galvanic isolation, replacing the need for direct electrical contact or complex electromagnetic couplers.
2Reliability
If toroidal transformers are used for current measurement, then reliable galvanic isolation is achieved, but miniaturization becomes difficult or impossible
Solution Approach 1:
The patent replaces bulky toroidal transformers with integrated optical components. The optical transmitters, waveguides, and receivers can be miniaturized and integrated directly into the sensor housing, enabling compact sensor designs that maintain galvanic isolation without requiring large magnetic cores and windings.
Solution Approach 2:
The patent integrates multiple functional elements (optical transmitter, optical receiver, optical waveguides) into a compact, nested arrangement within the sensor housing. This allows the entire optical measurement system to be miniaturized and integrated into small components, eliminating the need for large external toroidal transformers.
3Ease of operation
If contact methods are used for current measurement, then direct measurement in the circuit is possible, but safe galvanic isolation cannot be ensured
Solution Approach 1:
The patent replaces direct electrical contact measurement methods with optical measurement. Optical transmitters detect electrical parameters through electromagnetic field interactions without requiring physical contact with live conductors, and optical waveguides transmit this information to evaluation units while maintaining galvanic isolation throughout the measurement chain.
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 non-contact, miniaturized, and cost-effective measurement of electrical parameters with galvanic isolation, suitable for retrofitting existing systems and integrating into components without structural modifications, providing reliable and efficient monitoring.
Implementation Method 1
an arrangement of at least one optical waveguide between the optical transmitter and the optical receiver
Implementation Method 2
This optical coupling point is only passable for a reduced optical power when the bridge is deflected. The deflection changes the optical attenuation at the coupling point between the flexible bridge and the optical receiver.
Implementation Method 3
The change in optical power is measured at the receiver
Data Source
Figure 1~2
AI summary
The invention relates to a sensor and a method for detecting a physical influencing variable with at least one optical transmitter (TX) and at least one optical receiver (RX). Furthermore, the invention relates to a manufacturing method for an optical sensor and an electrical component with an optical sensor. The proposed sensor comprises at least one optical transmitter (TX) and at least one optical receiver (RX), as well as an arrangement of at least one optical waveguide (OF) between the optical transmitter (TX) and the optical receiver (RX). The optical waveguide (OF) is arranged with a functional element on a mechanically deflectable bridge (ST, SE, SM). The functional element can be a bimetal, a ferroelectric coating, or a magnetic coating.Depending on the physical influencing factor, such as a temperature to be measured, an electric field, or a magnetic field, the functional element experiences a force and causes a deflection of the bridge (ST, SE, SM). The optical received signal correlates with the physical influencing factor via an optical coupling point in the optical waveguide (OF) between the mechanically deflectable bridge (ST, SE, SM) and the optical receiver (RX), which is only passable for a reduced optical power when the bridge (ST, SE, SM) is deflected.