Absolute Encoder Phase Compensation Using Edge-Triggered Sampling

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Solution Overview

Problem

The phase deviation detection and compensation method for subdivided signals in absolute encoders is limited by the Analog-to-Digital (AD) sampling ratio, leading to worsened high-frequency detection results and insufficient high-frequency phase compensation accuracy.

Innovation Solution

A method and apparatus that acquire and convert sine and cosine analog signals to digital signals, controlling a sampler to sample based on pulse edge variations to determine and compensate for phase deviations, thereby reducing the required AD sampling ratio and improving high-frequency phase compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the AD sampling ratio is increased to improve high-frequency phase detection accuracy, then the measurement precision improves, but the device complexity and cost increase

Engineering Contradiction:
Improvehigh-frequency phase detection accuracyVSAvoidAD sampling system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an edge detection mechanism as an intermediary between the analog signals and the AD converter. By detecting pulse edges and using these edges to trigger sampling, the system achieves accurate phase detection without requiring a high continuous sampling rate, thus reducing the complexity and cost of the AD sampling system while maintaining measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the AD sampling ratio is increased to improve high-frequency phase compensation accuracy, then the manufacturing precision improves, but the loss of energy increases

Engineering Contradiction:
Improvehigh-frequency phase compensation accuracyVSAvoidenergy consumption of sampling system
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent implements periodic sampling triggered by pulse edges rather than continuous high-frequency sampling. The sampler operates periodically at edge transitions, which reduces the overall energy consumption while still capturing the necessary phase information for accurate high-frequency compensation, thus improving manufacturing precision without excessive energy loss.

Inventive Principle:
Principle #19Periodic action

3Device complexity

If conventional phase deviation detection method is used, then the device complexity is low, but the measurement precision deteriorates at high frequencies

Engineering Contradiction:
Improvedetection system complexityVSAvoidhigh-frequency detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs a dynamic sampling strategy where the sampling timing is adaptively determined by pulse edge detection rather than a fixed sampling rate. This dynamic approach allows the system to maintain low complexity while achieving high measurement precision at high frequencies by concentrating sampling resources at critical moments (edge transitions) where phase information is most significant.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3722756B1Phase deviation compensation method and device
Publication Date: 2023.04.26 ZHUHAI GREE REFRIGERATION TECH CENT OF ENERGY SAVING & ENVIRONMENTAL PROTECTION
  • EP3722756B1 patent drawingFigure 1~2
  • EP3722756B1 patent drawingFigure 3~5
  • EP3722756B1 patent drawing

AI summary

A phase deviation compensation method and device are provided. The method may include: a first sine analog signal and a first cosine analog signal are acquired; the first sine analog signal is converted to a corresponding first sine digital signal, and the first cosine analog signal is converted to a corresponding first cosine digital signal; a sampler is controlled to sample the first sine analog signal and the first cosine analog signal according to variations of pulse edges of the first sine digital signal and the first cosine digital signal, to acquire at least one sine sampled signal and at least one cosine sampled signal; a phase deviation is determined; and phase compensation is performed on the at least one sine sampled signal and the at least one cosine sampled signal according to the phase deviation. The phase deviation compensation method and the phase deviation compensation apparatus solve the problem that a phase deviation detection and compensation method of a subdivided signal of an absolute encoder in the related art is limited by an AD sampling ratio, and accordingly a high-frequency detection result is worsened, and high-frequency phase compensation accuracy is not ensured.