Electric Valve Rotor Restriction Detection Using Dual Hall Sensors

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Solution Overview

Problem

Existing electric valve control systems require complex processes to detect when the rotor reaches a reference position, making it difficult to simply determine if the rotation of the magnet rotor is restricted.

Innovation Solution

The electric valve control device uses a configuration with a magnet rotor and two magnetic sensors positioned outside the can, where the output signals of the sensors and expected value information are used to detect the restriction of the magnet rotor's rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single Hall IC is used to detect rotor position, then the detection function is achieved, but the control process becomes complex requiring flags and counting mechanisms

Engineering Contradiction:
Improvecontrol process complexityVSAvoid rotor position detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from single-dimension detection (one Hall IC) to two-dimension detection (two Hall ICs positioned at different angular locations). This dimensional expansion allows simultaneous detection of rotor position and rotation restriction status, eliminating the need for complex flag-based control processes while maintaining detection accuracy.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The dual Hall IC configuration enables the system to self-diagnose rotation restriction by comparing expected signal patterns with actual readings. The system automatically detects abnormal states without requiring external intervention or complex control logic, making the detection process simpler and more autonomous.

Inventive Principle:
Principle #25Self-service

2Reliability

If multiple detection mechanisms are implemented to accurately detect rotor restriction, then detection reliability is improved, but device complexity increases

Engineering Contradiction:
Improverotation restriction detection reliabilityVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detection function is segmented into two independent Hall ICs positioned at different angular locations around the rotor. Each sensor independently monitors magnetic field changes, and their combined signals provide reliable detection of rotation restriction. This segmentation distributes the detection function across multiple simple components rather than requiring a single complex mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements feedback by continuously monitoring the output signals from both Hall ICs and comparing them against expected patterns during normal rotation. When the rotor encounters restriction, the feedback mechanism detects the abnormal signal pattern, enabling reliable identification of the restricted state without additional complex hardware.

Inventive Principle:
Principle #23Feedback

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 configuration allows for a simple detection of the rotor's restricted rotation by comparing the output signals with expected values, thereby simplifying the detection process.

Implementation Method 1

The Hall IC is disposed outside the case. An output signal of the Hall IC is a signal (a binary signal) corresponding to the magnetic field generated by the detection magnet drum.

Methodology Applied
Scientific EffectMagnetic field detection: Hall Effect

Data Source

PatentEP4538571A1Electric valve control device and electric valve device
Publication Date: 2025.04.16 FUJIKOKI CORP
  • EP4538571A1 patent drawingFigure 1
  • EP4538571A1 patent drawingFigure 2
  • EP4538571A1 patent drawingFigure 3

AI summary

[Object] To provide an electric valve control device and an electric valve device that are capable of detecting in a relatively simple way that rotation of a magnet rotor is restricted. [Solution] An electric valve control device controls an electric valve. The electric valve includes a first magnetic sensor (91) and a second magnetic sensor (92). Output signals of the first magnetic sensor (91) and the second magnetic sensor (92) are each a binary signal. Where n represents the total number of north poles and south poles of a magnet rotor (31), N represents a natural number, and θ represents an angle between a line (M1) connecting an axis (L) to the first magnetic sensor (91) and a line (M2) connecting the axis (L) to the second magnetic sensor (92), the following expression (1) is satisfied. θ=360/n×N+360/2n The electric valve control device is configured to detect that the rotation of the magnet rotor (31) is restricted using the output signals and output-signal expected value information.