Motor Driving Amplifier Timing Control for Distortion-Free Sampling
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Solution Overview
Problem
Conventional motor driving apparatuses face challenges in improving detection resolution due to distortion in signal waveforms when changing amplification factors, leading to deteriorated detection accuracy, especially when amplification exceeds the input range of A/D conversion circuits.
Innovation Solution
A motor driving apparatus that includes an amplifier circuit, an A/D converting part, and an amplification factor setting part, where the amplification factor set timing is commanded to avoid overlapping with the waveform stabilization period, ensuring distortion-free sampling by the A/D converting part, particularly using the Z phase signal as a trigger for accurate A/D conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If amplification factor is increased to improve detection resolution, then detection resolution is improved, but waveform distortion occurs when amplification exceeds A/D conversion input range
Solution Approach 1:
The patent applies dynamics by making the amplification factor adjustable rather than fixed. The amplification factor setting part dynamically changes the amplification factor based on signal amplitude conditions, allowing the system to adapt between high amplification (for low amplitude signals) and low amplification (for high amplitude signals), thus resolving the contradiction between detection resolution and waveform accuracy
Solution Approach 2:
The patent changes the parameter of amplification factor based on signal characteristics. When signal amplitude is below a threshold, higher amplification is applied to improve detection resolution; when amplitude exceeds the threshold, lower amplification is used to prevent waveform distortion, thereby maintaining both detection resolution and waveform accuracy under different operating conditions
2Adaptability or versatility
If amplification factor is changed using analog switch to adapt to different signal amplitudes, then amplification adaptability is improved, but waveform distortion occurs during switching transition
Solution Approach 1:
The patent applies preliminary action by performing A/D conversion at specifically timed moments when the amplification factor has already stabilized after changing. The amplification factor set timing command part commands A/D conversion timing to occur after the waveform stabilizing period, ensuring that sampling does not occur during the distorted transition phase, thus maintaining waveform stability while preserving amplification adaptability
Solution Approach 2:
The patent introduces an intermediary timing control mechanism (amplification factor set timing command part) that mediates between the amplification factor changing part and the A/D converting part. This intermediary ensures that A/D conversion is timed to occur only after waveform stabilization, preventing direct interference from switching distortion while maintaining the benefits of variable amplification
3Productivity
If A/D conversion is performed at regular sampling intervals, then sampling efficiency is maintained, but distorted waveforms are sampled when amplification factor changes occur
Solution Approach 1:
The patent applies dynamics by making the A/D conversion timing adaptive rather than purely periodic. The amplification factor set timing command part dynamically adjusts A/D conversion timing based on the state of amplification factor changing, commanding conversion to occur after waveform stabilization. This dynamic timing adjustment maintains sampling efficiency by minimizing interruptions while preventing distortion sampling
Data Source
AI summary
A motor driving apparatus includes an amplifier receiving, from a detector, a sine wave shaped signal detected in response to rotation of a motor, and amplifying the signal with a set amplification factor, an A/D converter for performing digital conversion by sampling the signal amplified by the amplifier at a sampling timing in a predetermined cycle, an amplification factor setting part for changing setting of the amplification factor of the amplifier, and an amplification factor set timing command part for issuing a command with respect to a timing for changing the setting of the amplification factor by the amplification factor setting part. The amplification factor set timing command part issues the command with respect to the timing so that a waveform stabilizing period until distortion in a waveform of the signal occurring when the amplification factor setting part changes the setting is stabilized does not overlap with the sampling timing.