Motor Speed Detection Using Dual-Path Signal Processing
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Solution Overview
Problem
Conventional sine-wave encoders for motor speed detection experience a decline in accuracy at high motor speeds due to limitations in processing frequency ranges, leading to inaccurate speed calculations.
Innovation Solution
An apparatus comprising an amplifier, a first conversion unit to convert two-phase sine-wave signals to digital data, a second conversion unit to convert them to square-wave signals, and a speed determination unit that calculates motor speed using the digital data and accumulated counts, enhancing resolution through arc-tangent calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a high frequency signal is used in a conventional sine-wave encoder for motor speed detection, then the detection range is extended to higher motor speeds, but the accuracy of the detected speeds is declined
Solution Approach 1:
The patent segments the signal processing into two independent paths: one path converts the sine-wave signal to digital data for high-resolution position angle calculation using arc-tangent function, while the other path converts it to square-wave signal for frequency counting. This segmentation allows each path to optimize for its specific function, resolving the contradiction between speed range and accuracy.
Solution Approach 2:
The patent introduces a new dimension of processing by converting the analog sine-wave signal into both digital data (adding a digital dimension) and square-wave signal (adding a frequency dimension). This multi-dimensional approach enables simultaneous achievement of high-speed detection capability and high-precision measurement by combining results from different dimensional processing paths.
2Productivity
If the motor speed is increased, then the productivity is improved, but the accuracy of speed detection is declined due to high frequency signal limitations
Solution Approach 1:
The patent introduces digital data as an intermediary between the analog sine-wave signal and the final speed calculation. The digital data enables precise arc-tangent calculation for position angle determination, serving as a mediator that preserves measurement accuracy even when the motor operates at high speeds that would otherwise cause frequency-related accuracy degradation.
3Measurement precision
If conventional speed detection methods are used, then the device complexity is kept simple, but the measurement precision is insufficient at high speeds
Solution Approach 1:
The patent makes the signal processing system multi-functional by implementing two conversion paths from a single sine-wave encoder output. The same input signal is processed simultaneously for both high-precision position measurement (via digital conversion and arc-tangent calculation) and frequency measurement (via square-wave conversion and counting), achieving enhanced accuracy without requiring multiple separate encoders or sensors.
Data Source
AI summary
An apparatus for detecting speed of a motor is disclosed, the apparatus including an amplifier configured to amplify a two-phase sine-wave signal inputted from an encoder based on rotation of a motor; a first conversion unit configured to convert the two-phase sine-wave signal to a digital data; a second conversion unit configured to convert the two-phase sine-wave signal to a square-wave signal; a counter unit configured to accumulate by counting the square-wave signal; and a speed determination unit configured to determine a speed of the motor, by receiving the digital data from the first conversion unit and the accumulated count from the counter unit.