Inductive Position Sensor Pulsed Excitation Energy Efficiency
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Solution Overview
Problem
Inductive position measuring devices, such as rotary encoders, face challenges in maintaining accurate position counting and energy efficiency, especially during power failures or when operating without a mains voltage supply.
Innovation Solution
A position measuring device with a carrier body and a capacitor forming an LC resonant circuit, using pulsed excitation currents and a switching element to induce voltages in detector arrangements, which are measured after the switch-off edge of the pulse to determine position information, reducing energy consumption and enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous excitation current is applied to the excitation coil, then the position measurement function is maintained, but energy consumption increases
Solution Approach 1:
The patent applies periodic pulsed excitation instead of continuous excitation current. The excitation coil receives periodic pulse signals that generate corresponding magnetic fields, allowing the system to maintain position measurement functionality while significantly reducing energy consumption during battery operation mode.
Solution Approach 2:
The patent ensures continuous position measurement capability by using periodic pulses that maintain the necessary magnetic field presence. The evaluation unit continuously monitors the induced voltages in receiver coils, ensuring uninterrupted position information acquisition despite the pulsed excitation approach.
2Duration of action of moving object
If pulsed excitation current is applied to reduce energy consumption, then battery life is extended, but measurement accuracy may deteriorate
Solution Approach 1:
The patent optimizes pulse parameters including width, amplitude, and frequency to ensure accurate position measurement. By carefully adjusting these parameters, the system achieves reliable detection of induced voltages in receiver coils while maintaining energy efficiency and extending battery operation duration.
Solution Approach 2:
The evaluation unit processes the voltages induced in receiver coils through correlation evaluation, comparing received signals with reference signals. This feedback mechanism enables accurate position determination even with pulsed excitation by analyzing the temporal and amplitude characteristics of the induced signals.
3Reliability
If switch-on duration TP is extended to improve signal strength, then measurement reliability improves, but energy consumption increases
Solution Approach 1:
The patent uses pulse widths that are sufficient to generate detectable induced voltages in receiver coils but not excessively long. This partial action approach provides just enough excitation to maintain measurement reliability while avoiding unnecessary energy consumption that would occur with longer pulse durations.
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 solution enables efficient energy use, extends battery life, and improves measurement accuracy and immunity to interference, ensuring reliable position counting even without a mains voltage supply.
Implementation Method 1
an excitation current is generated in an excitation coil by switch-on pulses of a specific duration. The resulting magnetic field induces voltages in receiver coils that correspond to a damped oscillation.
Implementation Method 2
a capacitor, which forms an LC resonant circuit together with the exciter winding
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The device has a support body with an exciter winding (2.21) for conducting an excitation current (I) to generate an electromagnetic field, which is scanned by a detector system. A capacitor (2.24) forms an inductor capacitor-oscillation circuit together with the winding. A switch device (2.25) is switchable by an evaluation device (2.23). The current is generatable by switching the switch device with switch-on pulses including an on-time period. Voltages (U1-U4) induced in the detector system are measurable in an area after a cut-off edge of the pulses for ascertaining position information. An independent claim is also included for a method for operating a position-measuring device.