Rotary Transformer Decoding With Error-Model Signal Compensation

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Solution Overview

Problem

Rotary transformers suffer from lower decoding accuracy due to incomplete orthogonality of their signal windings, leading to manufacturing process errors.

Innovation Solution

Generate sine and cosine reference signals based on preset amplitudes, ratios, and phases, calculate difference signals, and use an error model to regenerate reference signals if errors exceed a threshold, determining the decoding result only when errors are within tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional decoding methods are used with standard reference signals, then the decoding process is simple, but the decoding accuracy is reduced due to manufacturing errors in signal windings

Engineering Contradiction:
Improvedecoding accuracyVSAvoiddecoding process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameters of reference signals (amplitude, phase, frequency) based on actual measured values from the rotary transformer. The amplitude ratio and phase difference between sine and cosine reference signals are adjusted to match the actual transformer characteristics, thereby compensating for manufacturing errors and improving decoding accuracy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the actual output signals from the rotary transformer are measured and used to regenerate optimized reference signals. The system continuously adjusts the reference signal parameters based on the measured amplitude ratio and phase difference, creating a closed-loop system that improves decoding accuracy through iterative refinement

Inventive Principle:
Principle #23Feedback

2Measurement precision

If reference signals are regenerated through iterative optimization, then decoding accuracy is improved, but the processing time increases

Engineering Contradiction:
Improvedecoding accuracyVSAvoidsignal processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary measurement of the amplitude ratio and phase difference between sine and cosine signals during an initialization or calibration phase. These pre-measured parameters are then used to generate optimized reference signals, avoiding the need for continuous iterative optimization during normal operation and reducing real-time processing time

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies iterative optimization only partially - specifically for generating the initial set of optimized reference signals based on measured transformer characteristics. Once the reference signals are generated with the correct amplitude ratio and phase difference, the system uses these fixed optimized signals for subsequent decoding operations, balancing accuracy improvement with processing efficiency

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4650721A1Method, system and device for decoding rotary transformer, and storage medium
Publication Date: 2025.11.19 FORTIOR TECHNOLOGY (SHANGHAI) CO LTD
  • EP4650721A1 patent drawingFigure 1
  • EP4650721A1 patent drawingFigure 2
  • EP4650721A1 patent drawingFigure 3

AI summary

Disclosed are a method, a system and a device for decoding a rotary transformer, and a storage medium. The method includes: (S10), generating a first sine reference signal and a first cosine reference signal; (S20), obtaining a first difference signal by subtracting the first sine reference signal from a real-time sine signal, and obtaining a second difference signal by subtracting the first cosine reference signal from a real-time cosine signal; (S30), inputting the first difference signal and the second difference signal into a preset error model to obtain an overall error; (S40), when the overall error is greater than a preset error threshold, regenerating the first sine reference signal and the first cosine reference signal in cycles; or (S50), when the overall error is not greater than the preset error threshold, determining an angle output by the rotary transformer as a decoding result.