Battery-Less Rotary Encoder Using Wiegand Wire at Low Speeds
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Solution Overview
Problem
Existing encoders face inefficiencies in generating power using magnetic fields from magnets, particularly at low rotational speeds, necessitating the use of batteries or external power sources.
Innovation Solution
The encoder employs a power generation element with magnetic plates configured to efficiently capture magnetic flux changes from magnets, utilizing a Wiegand wire to generate power through Barkhausen characteristics, and includes magnetic sensors to detect position and rotation information without requiring a battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional power generation element is used, then the encoder can operate, but power generation efficiency is insufficient especially at low rotational speeds
Solution Approach 1:
The power generation element is divided into multiple independent Wiegand wires (first, second, third, and fourth Wiegand wires) arranged in different orientations. Each wire segment responds to different components of the magnetic field, allowing efficient power generation across various rotational speeds including low speeds where conventional single-element designs fail.
Solution Approach 2:
Different portions of the power generation element have different magnetic response characteristics. The Wiegand wires are oriented at different angles (e.g., 0° and 90°) to capture different components of the rotating magnetic field, optimizing local power generation efficiency for each spatial direction and ensuring consistent performance across all rotational speeds.
2Loss of energy
If magnetic flux is not efficiently captured, then power generation is insufficient, but adding more components increases device complexity
Solution Approach 1:
Multiple Wiegand wires with different orientations are combined within a single power generation element structure. This merging approach captures both radial and tangential components of the magnetic field simultaneously, achieving efficient magnetic flux capture without requiring separate sensing elements or complex additional structures.
Solution Approach 2:
The power generation element serves multiple functions: it generates power for the encoder's operation and simultaneously provides magnetic field sensing capability. The same Wiegand wires that generate power also respond to magnetic field variations, eliminating the need for separate power generation and sensing systems.
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
The solution enables a battery-less encoder that generates stable power efficiently at various rotational speeds, including low speeds, by effectively harnessing magnetic field variations to power the encoder's operations.
Implementation Method 1
utilizing a Wiegand wire to generate power through Barkhausen characteristics
Implementation Method 2
configured to efficiently capture magnetic flux changes from magnets
Data Source
AI summary
An encoder includes a power generation element including a first end portion and a second end portion spaced apart from the first end portion in a first direction, the power generation element being configured to generate power upon occurrence of a condition in which a magnetic field generated by one or more magnets fixed to a rotary shaft varies between the first end portion and the second end portion. The encoder includes a first member including a first vertical plate portion that is provided facing the first end portion and extends in a second direction intersecting the first direction, the first member being formed of a magnetic material; and a second member spaced apart from the first member, and including a second vertical plate portion that is provided facing the second end portion and extends in the second direction, and the second member being formed of the magnetic material.