Hall-Based Angle Detection for Startup-Ready High-Resolution Sensing
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Solution Overview
Problem
Conventional angle detectors for AC rotating machines face challenges in achieving high-resolution angle detection immediately after startup, due to complex signal processing and susceptibility to noise, which limits the resolution of the electric angular signal.
Innovation Solution
The proposed angle detector employs a configuration with a discoidal magnet and Hall devices arranged to output first and second Hall signals, allowing for a 15°-resolution stepped electric angular signal by dividing one electric-angle rotation into 24 sections, without requiring incremental signal processing, thus enabling high-resolution angle detection from the start.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an angle detector combines absolute angular signal and continuous-value relative angular signal to achieve high resolution, then measurement precision is improved, but device complexity increases and noise susceptibility increases requiring filter circuits
Solution Approach 1:
The patent segments the relative angular signal into discrete steps (4-step or 8-step signal) rather than using a continuous-value signal. This segmentation allows the signal processing unit to handle discrete values instead of continuous analog signals, reducing computational complexity while maintaining high resolution angle detection capability.
Solution Approach 2:
The patent replaces expensive and complex filter circuits with a simpler digital signal processing approach. By using discrete stepped signals and binary-coded representations, the system eliminates the need for analog filter circuits, reducing both cost and complexity while maintaining noise immunity.
2Measurement precision
If an angle detector uses incremental signal processing to achieve high resolution, then measurement precision is improved, but reliability decreases due to noise susceptibility
Solution Approach 1:
The patent replaces analog incremental signal processing with a digital encoding system. The angle detection result is directly encoded in binary form using multiple Hall devices, eliminating the need for analog-to-digital conversion and incremental processing. This substitution provides inherent noise immunity and improves reliability while maintaining high resolution.
Solution Approach 2:
The patent uses multiple Hall devices to detect the same magnetic field from different positions, creating redundant copies of the angle information. These multiple detections are combined through logical operations to produce a single, noise-resistant binary-coded angle value, improving reliability through redundancy.
3Reliability
If an angle detector uses complex filter circuits to reduce noise, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex analog filter circuits with a digital encoding scheme. By directly encoding the angle position in binary form using multiple Hall devices, the system achieves noise immunity through digital redundancy rather than analog filtering, eliminating complex filter circuits and reducing overall device complexity.
4Measurement precision
If an angle detector achieves high resolution by dividing one electric-angle rotation into many sections, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the detection function across multiple Hall devices positioned at different angular locations. Each Hall device detects the magnetic field at its specific position, and the combined binary-coded output directly represents the angle with high resolution. This segmentation distributes the complexity across simple, identical sensor elements rather than requiring complex processing of fewer sensors.
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 immediate high-resolution angle detection, reducing noise susceptibility and eliminating the need for complex incremental processing, thereby enhancing the accuracy and reliability of angle detection in AC rotating machines.
Implementation Method 1
a first Hall device group that detects a magnetic field from the magnet and outputs first Hall signals and a second Hall device group that detects the magnetic field from the magnet and outputs second Hall signals
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
There is provided an angle detector including a magnet (3) that is mounted on a rotation axle and that has a first track (11) magnetized in P pole-pairs and a second track (12) magnetized in Q pole-pairs, a first hole device group (13) that senses magnetic flux from the first track (11) and then outputs a first hole signal, a second hole device group (14) that senses magnetic flux from the second track (12) and then outputs a second hole signal, a first detection unit (15) that outputs an M-step absolute angular signal through division of one electric-angle rotation into M sections, based on the first hole signal, a second detection unit (16) that outputs an N-step relative angular signal through division of each of the M divided sections into N sections, based on the second hole signal, an angle calculation unit (17) that divides the one electric-angle rotation into[M × N] sections and calculates an[M × N] -step electric angular signal, based on the absolute angular signal and the relative angular signal, and an angle correction unit (18) that outputs a correction angle supplemented so as to smooth the electric angular signal.