Digital Phase Tracking Filter With Adaptive Bandwidth for Position Sensing
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Solution Overview
Problem
Existing position sensor technologies face limitations in accuracy and speed due to analog processing, noise interference, and the need for complex filtering techniques, especially at high angular velocities and accelerations.
Innovation Solution
A digital processing approach for position sensor signals using a phase-locked loop filter with a filter selector that adjusts bandwidth based on error signals, allowing for efficient calculation of position, velocity, and acceleration, while minimizing noise and computational resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analog filtering techniques are used to reduce noise and improve signal quality, then measurement precision is improved, but device complexity and processing time increase
Solution Approach 1:
The patent replaces analog filtering mechanisms with digital signal processing techniques. The phase-locked loop operates in the digital domain, using computational algorithms rather than physical analog components to achieve noise reduction and signal conditioning, thereby simplifying the hardware while maintaining measurement precision.
Solution Approach 2:
The patent dynamically adjusts the bandwidth parameter of the loop filter based on operating conditions (angular velocity and acceleration). By changing the filter bandwidth parameter adaptively, the system optimizes noise reduction effectiveness while minimizing processing overhead and avoiding excessive complexity for all operating conditions.
2Reliability
If complex filtering techniques are applied to achieve smooth and robust angular position estimates, then reliability is improved, but processing speed decreases
Solution Approach 1:
The patent implements a dynamic bandwidth adjustment mechanism where the loop filter bandwidth is automatically adapted based on the measured angular velocity and acceleration. During high-dynamic periods, the bandwidth increases to maintain tracking speed, while during stable periods, it decreases to enhance noise filtering, thus balancing reliability and processing speed adaptively.
Solution Approach 2:
The system performs preliminary estimation of angular velocity and acceleration before optimizing the filter parameters. This preliminary analysis allows the system to pre-adjust the loop filter bandwidth to appropriate levels, ensuring that the filtering is optimized for upcoming signal conditions rather than reacting with excessive processing delay.
3Measurement precision
If multiple sensor elements are used to improve signal-to-noise ratio through averaging, then measurement precision is improved, but device complexity and computational resources increase
Solution Approach 1:
The patent combines the outputs of multiple sensor elements (sine and cosine channels from multiple Hall sensors) within the phase-locked loop processing. By merging these signals through the common loop filter and phase detector, the system achieves noise averaging and improved signal-to-noise ratio without requiring separate processing chains for each sensor, thus reducing overall device complexity.
4Device complexity
If fixed bandwidth loop filter is used, then device complexity is reduced, but adaptability to different dynamic conditions deteriorates
Solution Approach 1:
The patent transforms the fixed bandwidth loop filter into a dynamic system where the bandwidth parameter is automatically adjusted based on real-time measurements of angular velocity and acceleration. This dynamic adaptation allows the filter to respond appropriately to different operating conditions without requiring multiple fixed configurations or complex manual tuning.
Solution Approach 2:
The system employs feedback mechanisms where the measured angular velocity and acceleration are continuously fed back to the bandwidth adjustment logic. This feedback loop enables the filter bandwidth to self-adjust to optimal values for current dynamic conditions, providing adaptability while maintaining relatively simple filter hardware architecture.
Data Source
AI summary
A position sensor device includes position sensor elements for generating analog sense signals. A digitization circuit is provided for a digital signal representative of the input phase based on the analog sense signals and a digital processing unit. An output signal is indicative of the position based on the first output of the processing unit. The processing unit comprises an error signal generator for computing an error signal indicative of a phase difference between the digital signal and a feedback signal. A digital filter filters the error signal to generate the first output. A feedback path provides the feedback signal based on the first output and a filter selector to select a filter to be applied from different filters. At least one input on which a common filter circuit operates is scaled differently for each of the different filters to select different filter bandwidths.