Relay Coil Circuit With Series EMI Filtering

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Solution Overview

Problem

High-voltage relays experience electromagnetic interference from signals of different frequencies conducted through magnetic components and air media, leading to mis-operation and signal interference in the coil end.

Innovation Solution

Incorporating anti-interference elements such as magnetic beads or inductors in series with the coil to form a loop within the control circuit, which shields and reduces interference signals of various frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If signals are transmitted through the relay's magnetic components and air medium, then the relay can control the load circuit, but electromagnetic interference is conducted to the coil end causing mis-operation

Engineering Contradiction:
Improverelay operation stabilityVSAvoidelectromagnetic interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an anti-interference element as an intermediary component connected in series with the coil. This element acts as a mediator that allows control signals to pass through while blocking high-frequency interference signals from the load end, thus resolving the contradiction between maintaining relay functionality and preventing electromagnetic interference

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts and separates the interference filtering function from the coil assembly by adding a dedicated anti-interference element. This element is specifically designed to remove harmful high-frequency signals while allowing the coil to maintain its primary function of controlling the relay switch

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If the frequency of signals input into the load circuit is increased, then the relay can control higher frequency loads, but the coupled interference signals become stronger and interfere with other control components

Engineering Contradiction:
Improvesignal frequency rangeVSAvoidsignal interference strength
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of high-frequency signals into a beneficial filtering mechanism. The anti-interference element is designed to specifically target and attenuate high-frequency interference signals while maintaining transparency to lower frequency control signals, thus allowing the system to handle high-frequency loads without proportional increase in interference

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

Effectively shields interference signals, ensuring normal operation of the relay by reducing electromagnetic interference from the load end to the control circuit.

Implementation Method 1

the anti-interference element is connected to the coil... significantly reduce and shield interference signals of various frequencies input from a load end and conducted to the coil

Methodology Applied
Scientific EffectElectromagnetic interference shielding: Absorption (EM radiation)

Implementation Method 2

A relay is an electronic control device that functions as a switch for controlling load circuits... the coil is electrically connected to an external control circuit

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4611019A1Relay, control device and control circuit module
Publication Date: 2025.09.03 XIAMEN HONGFA ELECTRIC POWER CONTROLS CO LTD
  • EP4611019A1 patent drawingFigure 1~2
  • EP4611019A1 patent drawingFigure 3~4
  • EP4611019A1 patent drawingFigure 5

AI summary

A relay, a control device and a control circuit module. The relay comprises a coil (11) and an anti-interference element (42). The anti-interference element (42) is connected to the coil (11), and when the coil (11) is used for electrical connection to an external control circuit (41), the coil (11) and the anti-interference element (42) are connected in series in the external control circuit (41). When the relay works, the anti-interference element (42) and the coil (11) are connected in series in the external control circuit (41), so that interference signals inputted from a load end and transmitted to the coil (11) can be significantly reduced and screened, thus ensuring the normal work of the relay