Tracking Loop Angle Converter with Quadrant-Based 180° Correction
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Solution Overview
Problem
Existing tracking loop type digital angle converters experience a drop in response control when the angle error between input and output angles approaches 180°, leading to potential hang-up states due to small control deviations.
Innovation Solution
Incorporating a detected signal sign judging section and an output angle correcting section that phase-shifts the output angle by 180° when an excessive angle error is detected, ensuring the converter operates within a range that quickens convergence by comparing the quadrant of the input angle with the output angle and inverting the most significant bit of the counter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the tracking loop uses sin(θ−φ) as control deviation, then the converter operates with simple arithmetic operations, but the control response drops when angle error approaches 180°
Solution Approach 1:
The patent applies preliminary action by detecting the quadrant of the input angle θ in advance and comparing it with the quadrant of the output angle φ before the angle error reaches 180°. When a large angle error is predicted, the system preemptively corrects the output angle by adding or subtracting 180°, preventing the control response drop before it occurs. This is implemented through the quadrant detecting section (41) and output angle correcting section (42) that operate proactively rather than reactively.
Solution Approach 2:
The patent introduces an intermediary mechanism (quadrant detecting section and angle error judging section) that mediates between the simple sin(θ−φ) control deviation calculation and the control response quality. This intermediary detects angular position information and triggers corrective actions (adding/subtracting 180° to output angle) without fundamentally changing the simple arithmetic operations, thus maintaining low complexity while improving response speed.
2Reliability
If the angle error becomes large (close to 180°), then the control deviation sin(θ−φ) becomes small, but the actual angle error remains large causing hang-up states
Solution Approach 1:
The patent applies dynamics by making the output angle φ dynamic and adjustable based on the detected quadrant information. When the angle error is judged to be large, the system dynamically corrects the output angle by adding or subtracting 180° through the output angle correcting section (42). This dynamic adjustment ensures that the control deviation sin(θ−φ) always corresponds to a meaningful angle error, preventing hang-up states while maintaining reliable operation.
Solution Approach 2:
The patent strengthens the feedback mechanism by adding quadrant detection and angle error judgment to the existing feedback loop. The quadrant detecting section (41) continuously monitors the angular positions, and when a large angle error is detected, the system provides corrective feedback by adjusting the output angle (adding/subtracting 180°). This enhanced feedback ensures that the control system maintains accuracy and reliability even when large angle errors occur.
Data Source
AI summary
A tracking loop type digital angle converter that operates so that a deviation between input and output angles always becomes zero by feeding back the output angle to the input angle, wherein in order to eliminate a case where a control deviation decreases an angle error between the input and output angles is in the vicinity of 180°, i.e., where response becomes low, there are provided a detected signal sign judging section (41) that judges signs of rotation detection signals to determine a quadrant where the input angle exists, and an output angle correcting section (42) for comparing an angle region of the output angle and the quadrant of the input angle to detect a state where the angle error is excessive, judging that the control response is low and carrying out a process for compensating the output angle.