Inductive Position Sensing with Adaptive Excitation Frequency
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Solution Overview
Problem
Inductive position sensors face challenges in achieving high precision due to noise interference, which limits the signal-to-noise ratio and temporal resolution of position information, especially in systems with unknown narrow-band interference sources.
Innovation Solution
The method involves forming a frequency functional dependent on the excitation frequency to minimize noise impact, optimizing the excitation frequency to operate in a range where noise is minimal, and using demodulation techniques like the IQ method to extract amplitude information and variance for noise assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed excitation frequency is used in inductive position sensors, then the device complexity is reduced and operation is simplified, but noise interference increases and measurement precision deteriorates
Solution Approach 1:
The patent performs preliminary noise analysis and excitation frequency optimization during the setup or calibration phase. The evaluation unit pre-determines the optimal excitation frequency by analyzing the noise spectrum and storing this information for subsequent position measurements, avoiding the need for continuous frequency adjustments during operation.
Solution Approach 2:
The patent introduces dynamic adaptation of the excitation frequency based on operating conditions. The evaluation unit continuously or periodically analyzes the measurement signal quality and adjusts the excitation frequency to optimize the signal-to-noise ratio, transforming a static system into a dynamically adaptive one.
2Measurement precision
If the excitation frequency is optimized to minimize noise, then the signal-to-noise ratio is improved, but the device complexity increases due to additional evaluation and frequency adjustment mechanisms
Solution Approach 1:
The evaluation unit performs multiple functions: it evaluates the measurement signal quality, analyzes the noise spectrum, determines the optimal excitation frequency, and controls the excitation signal generation. By consolidating these functions into a single multi-functional unit, the patent avoids the need for separate dedicated components for each function, thereby limiting the increase in device complexity.
Solution Approach 2:
The evaluation unit autonomously analyzes the measurement signal and self-adjusts the excitation frequency without requiring external intervention or complex external control systems. The system serves itself by using its own measurement signals to determine optimal operating parameters, reducing the need for additional external complexity.
3Measurement precision
If noise filtering is applied to improve position information precision, then measurement precision is improved, but temporal resolution is reduced due to processing delays
Solution Approach 1:
The patent performs noise analysis and excitation frequency optimization in advance, before actual position measurements are taken. By pre-determining the optimal excitation frequency based on noise spectrum analysis, the system avoids the need for time-consuming noise filtering operations during critical measurement phases, thereby preserving temporal resolution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the signal-to-noise ratio, allowing for improved precision and temporal resolution of position information by adapting the excitation frequency to reduce noise interference, thereby improving the accuracy of position detection in inductive position sensors.
Implementation Method 1
an excitation signal with an excitation frequency and excitation amplitude is fed into the excitation winding, generating an electromagnetic excitation field that induces a measurement signal in the secondary winding
Data Source
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AI summary
For a simple method for position determination with an inductive position sensor with increased precision of the position information, it is provided that the position sensor generates a measurement signal from which a frequency functional (Ff) dependent on the excitation frequency (ω) is formed, which represents a measure of the noise signal (RS) and the excitation frequency (ω) of the excitation signal (ES) is changed so that the frequency functional (Ff) is minimized or maximized and the excitation frequency (ω) that minimizes or maximizes the frequency functional (Ff) is used for the excitation signal (ES).