Phase and Frequency Determination Using Positive Sequence Components

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Solution Overview

Problem

Existing methods for determining the phase and frequency of electric quantities associated with electrical devices, such as generators and power grids, face inaccuracies due to higher harmonic components, which can affect the efficiency of vector control and require costly hardware like encoders.

Innovation Solution

A method that extracts the fundamental component of an electric quantity using Fourier analysis or electronic filters, calculates the positive sequence component, and determines the phase and frequency using a Phase Lock Loop, potentially omitting the need for encoders and allowing for precise determination across a wide range of frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an encoder is used to determine rotor position and rotor speed, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improverotor position and rotor speed measurement precisionVSAvoidhardware sensor complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical encoder (hardware sensor) with a software-based estimator that calculates rotor position and speed using measured electrical quantities and a machine model, thereby eliminating the need for physical sensors while maintaining measurement capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a virtual model (electrical machine model) that replicates the behavior of the physical system, allowing the estimator to derive rotor position and speed information from electrical measurements without direct mechanical sensing

Inventive Principle:

Principle #26Copying

2Device complexity

If an estimator is used to determine rotor position and rotor speed, then device complexity is reduced, but measurement precision deteriorates due to higher harmonic components

Engineering Contradiction:

Improvesoftware-based estimation simplicityVSAvoidrotor position and rotor speed estimation precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the estimation process into distinct functional blocks: a fundamental component extractor that isolates the fundamental frequency from harmonic distortions, and a positive sequence component calculator that processes the extracted fundamental, thereby improving estimation precision through structured signal processing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate processing stages (fundamental component extraction and positive sequence calculation) between the raw electrical measurements and the final rotor position/speed estimation, acting as mediators that filter out harmful harmonic components before the main estimation calculation

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If measured electrical quantities with higher harmonic components are used directly in estimation, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:

Improvedirect use of measured electrical quantitiesVSAvoidphase and frequency determination precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent extracts only the useful fundamental component from the measured electrical quantities, separating it from the harmful higher harmonic components, thereby improving precision by eliminating the distorted portions of the signal while retaining the essential information needed for accurate phase and frequency determination

Inventive Principle:

Principle #2Taking out (Extraction)

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 accuracy and robustness of phase and frequency determination, improving vector control and reducing costs by eliminating the need for additional hardware, while enabling efficient control of electrical machines and power grids.

Implementation Method 1

The determined phase and frequency may be determined by means of a Phase Lock Loop

Methodology Applied

Scientific EffectPhase Lock Loop:

Data Source

PatentEP2623997B1Determining a phase and a frequency of an electric quantity of an operating electrical device

Publication Date: 2018.01.03 SIEMENS AG

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Figure 3~4

AI summary

A method and an apparatus for determining a phase (θ) and a frequency (ω) of an electric quantity being associated with an operation of an electrical device are described. The method comprises extracting a fundamental component (Vα1, Vβ1) of the electric quantity, calculating a positive sequence component (V+α1, V+β1) of the electric quantity based on the extracted fundamental component (Vα1, Vβ1), and determining the phase and the frequency of the electric quantity based on the calculated positive sequence component (V+α1, V+β1).