Encoder Turn Counting with Magnetic Sensors and Backup Power
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Solution Overview
Problem
Existing AC servomotor encoders fail to continuously count motor turns during power outages and require re-counting upon power recovery, leading to space, reliability, and cost issues with mechanical gear, external battery, and Wiegand rotary types, respectively.
Innovation Solution
A controlling method and encoder system that includes a switching unit, battery, and driving circuit to detect rotation angles and provide backup power for continuous turn counting, with a sleep mode to conserve energy and extend battery life, using hall sensors or TMR sensors for accurate counting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical gear type absolute encoder is used for turn number counting, then turn number counting capability is improved, but device space requirement increases and structure becomes more complex
Solution Approach 1:
The patent replaces the mechanical gear structure with a magnetic field-based detection system using Hall sensors or TMR sensors. The rotor includes a magnet and magnetic elements that detect rotation angle and generate counting trigger signals, eliminating the need for mechanical gears while maintaining turn number counting capability.
Solution Approach 2:
The patent extracts the turn number counting function from the mechanical gear structure and implements it through a separate controller that processes counting trigger signals generated by magnetic sensors. This separates the counting function from the mechanical transmission structure, reducing space requirements.
2Volume of moving object
If external battery type absolute encoder is used for turn number counting, then encoder size is reduced, but battery replacement frequency increases and reliability decreases
Solution Approach 1:
The patent implements a sleep mode where the encoder enters a low-power state when no counting trigger signals are detected for a predetermined period. The switching unit controls the battery to provide power only when needed, reducing overall power consumption and extending battery life from 1-3 years to over 10 years.
Solution Approach 2:
The patent changes the power consumption parameter by implementing dynamic power management. The encoder switches between active and sleep modes based on the presence of counting trigger signals, adjusting power consumption to match actual operational needs and thereby extending battery duration.
3Ease of manufacture
If Wiegand rotary type absolute encoder is used for turn number counting, then fabrication cost is reduced, but cogging torque increases and speed control precision deteriorates
Solution Approach 1:
The patent replaces the Wiegand rotary structure with a magnetic field-based detection system using Hall sensors or TMR sensors combined with a magnet on the rotor. This eliminates the cogging torque issue while maintaining accurate rotation detection and speed control capability.
4Speed
If encoder operates continuously without sleep mode, then turn number counting responsiveness is improved, but battery power consumption increases and battery life decreases
Solution Approach 1:
The patent implements periodic operation by switching between active and sleep modes. The switching unit activates the encoder only when counting trigger signals are present and keeps it in sleep mode otherwise, achieving both energy savings and rapid responsiveness when needed.
Solution Approach 2:
The patent uses a predetermined period timer to determine when to enter sleep mode. This preliminary timing mechanism ensures the encoder remains active long enough to capture valid counting signals while transitioning to sleep mode appropriately to conserve battery power.
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 continuous turn counting without restarting, reduces battery replacement frequency to over 10 years, and eliminates transient cogging torque issues, while optimizing space and cost, ensuring reliable operation and extended battery life.
Implementation Method 1
a battery (180) to provide a backup voltage when the driving circuit (240) fails to provide the operating voltage
Implementation Method 2
a switching unit (160) to switch between the operating voltage and the backup voltage according to a switching condition
Implementation Method 3
The sensor (120) is coupled to a rotor (220) of the motor (200)... the first magnetic element (124) detects the rotation angle of the magnet (122) so as to output a first counting trigger signal (S1)
Data Source
AI summary
A controlling method of an encoder includes: detecting a rotation angle of a rotor of a motor coupled to the encoder to generate a first counting trigger signal and a second counting trigger signal so as to perform a turn number counting procedure; determining whether a period that an operating voltage of a driving circuit of the motor is smaller than a threshold voltage exceeds a preset time; and when the period exceeds the preset time, controlling a switching unit of the encoder to allow a battery of the encoder to provide a backup voltage to the encoder such that the encoder enters a low power processing procedure.