High Voltage Relay Hall Sensor Flux Alignment
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Solution Overview
Problem
High-current relays face measurement accuracy issues due to remanence effects and magnetic field interference, which cause errors in current detection using Hall sensors, especially when current direction is reversed.
Innovation Solution
A relay design featuring a ferromagnetic body that surrounds the main contact terminals and creates a free space for Hall sensors, concentrating the magnetic flux and reducing remanence, combined with a microcontroller for processing and safety features like overcurrent shutdown and digital conversion of measured currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Hall sensors are used to detect current indirectly via magnetic field, then galvanic isolation is achieved, but measurement accuracy deteriorates due to remanence effects and magnetic field interference from the relay itself
Solution Approach 1:
A ferromagnetic body is introduced as an intermediary component between the current-carrying main contacts and the Hall sensors. This mediator concentrates and directs the magnetic flux generated by the current through a defined path to the sensors, while isolating the sensors from interfering magnetic fields generated by the relay's own magnetization. The ferromagnetic body acts as a flux guide that separates the useful magnetic signal from harmful magnetic interference.
Solution Approach 2:
The ferromagnetic body creates a localized region of enhanced magnetic flux density specifically at the sensor location. By concentrating the magnetic field lines through the ferromagnetic material's high permeability, the local magnetic field strength at the Hall sensors is significantly increased, improving signal-to-noise ratio and measurement accuracy without affecting the overall relay structure.
2Measurement precision
If the relay structure is modified to include ferromagnetic bodies and flux alignment devices, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The ferromagnetic body is integrated into the existing relay structure, combining the current measurement function with the relay's mechanical components. The ferromagnetic material is incorporated into the contact assembly or housing, merging multiple functions (structural support, magnetic flux guidance, and sensor mounting) into a single integrated component rather than adding separate discrete parts.
Solution Approach 2:
The ferromagnetic body serves multiple functions simultaneously: it provides structural support for the contacts, guides and concentrates the magnetic flux for measurement, and provides mounting support for the Hall sensors. This multi-functionality reduces the need for additional separate components, offsetting the complexity increase with functional consolidation.
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
Significantly improves current measurement accuracy and allows for precise detection of currents in both directions, enabling enhanced reliability and safety features such as automatic shutdown and prevention of measurement errors from inrush currents.
Implementation Method 1
The magnetic flux is concentrated on the Hall sensor or sensors by means of the device for aligning the magnetic flux. The ferromagnetic body which flows around the main contact connections and is provided with a free space for the Hall sensor or sensors. A strong magnetic field is induced in the ferromagnetic body by the current flowing through the main contact terminals.
Implementation Method 2
Hall sensors are usually used so that the flowing currents do not have to be measured directly, but indirectly, i. H. to be able to detect galvanically isolated via the magnetic field induced by the current.
Implementation Method 3
The ferromagnetic body or bodies are formed from a stack of ferromagnetic sheets. By dividing the ferromagnetic body into a bundle of individual sheets, the remanence of the ferromagnetic body can be significantly reduced.
Data Source
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AI summary
The relay (10) has a movable armature permitting or interrupting current flow via two main contact terminals (16.1, 16.2) by a magnetic flux generated in a coil. A current-measuring instrument measures current flowing via the main contact terminals by a Hall sensor. An aligning device (20) aligns the magnetic flux with the hall sensor around the main contact terminals. The aligning device comprises a ferromagnetic body that surrounds the main contact terminals and provided with a free space for the hall sensor. The ferromagnetic body is made of ferromagnetic metal sheets.