Inductive Sensor Harmonic Distortion Compensation

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Solution Overview

Problem

Inductive sensors face accuracy reduction due to harmonic components, which distort the electrical angle information and lead to errors in position detection, particularly in mechanical systems like gear positions in automated control applications.

Innovation Solution

The method involves using inductive sensors with transmit and receive coils to detect mechanical angles by processing harmonic component information, removing distortion from higher-order harmonics through sinusoidal amplitude modulation, and applying harmonic compensation to correct sine and cosine signals, thereby enhancing sensor accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If inductive sensors are used to detect mechanical angle, then position detection capability is provided, but harmonic components cause accuracy reduction

Engineering Contradiction:
Improveposition detection accuracyVSAvoidharmonic distortion
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes harmful harmonic components from the sensor signal through signal processing. By identifying and eliminating higher-order harmonics (2nd, 3rd, 4th, etc.) while retaining the fundamental frequency, the system achieves accurate position detection without the distortion caused by harmonic components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements feedback through harmonic compensation using stored harmonic information. The system continuously monitors the sensor output, compares it with expected sinusoidal behavior, and applies compensation factors to correct deviations caused by harmonics, thereby maintaining high measurement precision.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If harmonic compensation is applied to correct sine-cosine signals, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvesensor accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by pre-storing harmonic information and compensation factors in memory before actual measurement. During operation, the system simply retrieves pre-computed compensation data and applies it through straightforward signal processing, avoiding complex real-time calculations and reducing operational complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes parameters by adjusting the sine and cosine signal values through harmonic compensation. By modifying the amplitude and phase parameters of the sensor output based on pre-determined compensation factors, the system corrects harmonic distortion without requiring complex structural changes or additional hardware.

Inventive Principle:
Principle #35Parameter changes

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 effectively increases the accuracy of inductive sensors by removing harmonic-based errors, providing precise mechanical angle detection and reducing unwanted harmonic components, leading to improved performance in automated control systems.

Implementation Method 1

A signal injected by the transmitting coil results in the receiving coil(s) sensing a signal at the carrier frequency of the signal transmitted by the transmitting coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A signal injected by the transmitting coil results in the receiving coil(s) sensing a signal at the carrier frequency

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4012352B1Position sensor having harmonic distortion compensation
Publication Date: 2023.10.04 ALLEGRO MICROSYSTEMS LLC
  • EP4012352B1 patent drawingFigure 1
  • EP4012352B1 patent drawingFigure 2
  • EP4012352B1 patent drawingFigure 3~4

AI summary

Methods and apparatus for determining a mechanical angle of a target from sine and cosine signals generated by inductive sensing elements by applying harmonic compensation on the sine and cosine signals using possible mechanical angles and analyzing results of the applied harmonic compensation. One of the mechanical angles can be selected based on the results of the applied harmonic compensation. In embodiments, a cost function can be used to select the mechanical angle.