A/B-Phase Signal Generation for Reliable Polarity Reversal Detection
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Solution Overview
Problem
Conventional RD converters generate A/B-phase pulse signals with pulse widths that are too short for the upward system to detect when the rotation polarity is reversed, leading to failed detection, and halving the clock signal frequency is not preferable for high-speed rotation or precision.
Innovation Solution
An A/B-phase signal generator with an up/down count unit, angle comparison unit, and count request comparison unit that generates up-count or down-count commands only when both requests are the same, ensuring the generation of A-phase and B-phase pulse signals with a minimum pulse width that is not too short, preventing missed detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the clock signal frequency is maintained high for high-speed rotation and high-precision detection, then detection precision and speed are improved, but the pulse width becomes too short for the upward system to detect when rotation polarity reverses
Solution Approach 1:
The count request comparison unit performs preliminary comparison of consecutive count requests before generating pulse signals. When a polarity reversal is detected (previous request differs from current request), the unit prevents generation of abnormally short pulses in advance, ensuring reliable pulse detection by the upward system while maintaining high clock frequency for precise angle detection
2Reliability
If the clock signal frequency is halved to ensure minimum pulse width for reliable detection, then pulse detection reliability is improved, but high-speed rotation and high-precision detection are compromised
Solution Approach 1:
The count request comparison unit applies local quality control by selectively managing pulse generation based on rotation polarity conditions. Instead of uniformly reducing clock frequency, the system maintains high clock frequency locally during normal operation and only intervenes when polarity reversal is detected, thus preserving high-speed rotation capability while ensuring reliable pulse detection
Data Source
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AI summary
An A/B-phase signal generator wherein an up/down count unit 52C counts up by an up-count command or counts down by a down-count command at fixed intervals, an angle comparison unit 51 compares the count result ACNT of up/down count unit 52C with an input rotation angle θ and generates a count request, which is an up-count request or a down-count request, a count request comparison unit 52B compares a previous count request with a next count request and generates an up-count command or a down-count command only when the previous count request and the next count request are both up-count requests or down-count requests, respectively, and an A/B-phase pulse generator 53 receives a least significant bit and a second least significant bit of up/down count unit 52C and generates and outputs an A-phase pulse signal and a B-phase pulse signal.