A/B-Phase Signal Generation for Reliable Polarity-Reversal Pulse 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 potential failure in high-speed rotation and high-precision angle detection.
Innovation Solution
An A/B-phase signal generator that includes an up/down count unit, an angle comparison unit, and a count request comparison unit to ensure that only valid up-count or down-count commands are generated, preventing the generation of short pulses by comparing previous and next count requests, and using these to control the up/down count unit, which outputs A-phase and B-phase pulse signals based on the least significant bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the clock signal frequency is increased to support high-speed rotation and high-precision detection, then the detection precision and rotation speed capability are improved, but the pulse width becomes too short for the upward system to detect when rotation polarity is reversed
Solution Approach 1:
The count request comparison unit performs preliminary comparison of consecutive count requests before generating pulse signals. By checking whether the current count request matches the previous one, the system proactively prevents generation of invalid short pulses before they occur, ensuring reliable pulse detection even at high clock frequencies
Solution Approach 2:
The count request comparison unit acts as an intermediary between the angle comparison unit and the up/down count unit. It filters and validates count requests by comparing consecutive requests, allowing only valid transitions to pass through, thereby preventing short pulse generation without reducing clock frequency
2Reliability
If the clock signal frequency is reduced to ensure adequate pulse width for upward system detection, then the pulse detection reliability is improved, but the high-speed rotation support and high-precision detection capability are degraded
Solution Approach 1:
The system performs preliminary validation of count requests by comparing consecutive requests before generating pulses. This proactive filtering ensures that only valid, sustained count requests trigger pulse generation, maintaining adequate pulse widths for reliable detection while preserving high clock frequency for high-speed rotation support
Solution Approach 2:
The count request comparison unit serves as an intermediary that validates count requests without affecting clock frequency. By filtering invalid transitions, it ensures adequate pulse widths for reliable upward system detection while allowing the high-frequency clock to continue operating, thus maintaining high-speed rotation capability
3Device complexity
If the pulse width is set to the minimum required by the upward system, then the system complexity is reduced, but short pulses generated during polarity reversal are not detected
Solution Approach 1:
The count request comparison unit performs preliminary comparison of consecutive count requests before pulse generation. By validating that current and previous requests match, the system prevents generation of short polarity-reversal pulses before they occur, ensuring reliable detection without increasing minimum pulse width requirements or system complexity
Solution Approach 2:
The count request comparison unit uses feedback from previous count requests to validate current requests. By comparing the current count request with the previous one and only allowing valid transitions, the system prevents short pulse generation during polarity reversal while maintaining minimal system complexity
Data Source
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.