Three-Phase AC Phase Sequence Detection via Clarke Transform
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Solution Overview
Problem
Existing three-phase AC phase sequence detection methods are complex, requiring feedback circuits and parameter adjustments, making them difficult to implement and prone to errors, especially in electrical drive devices where incorrect sequence can lead to device failure and safety hazards.
Innovation Solution
A method and apparatus for detecting three-phase AC phase sequence that involves real-time sampling, Clarke coordinate conversion, arc tangent calculation, and determining the sequence based on a periodic function's increasing or decreasing nature within a minimum positive period, eliminating the need for feedback circuits and parameter adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If angular frequency information extraction method is used to detect phase sequence, then measurement precision is improved, but device complexity increases due to feedback circuits and parameter adjustments
Solution Approach 1:
The patent extracts only the essential information needed for phase sequence detection by using instantaneous voltage values directly, rather than extracting angular frequency information which requires complex feedback circuits. The method takes out the core detection function and implements it through simple coordinate transformation and arc tangent calculation, eliminating unnecessary feedback mechanisms while maintaining detection precision.
Solution Approach 2:
The patent replaces the mechanical feedback circuit system with a digital calculation system. Instead of using physical feedback circuits and analog parameter adjustments to extract angular frequency information, the invention uses digital coordinate transformation (Clarke transformation) and arc tangent calculations to determine phase sequence, substituting complex mechanical/electrical systems with simpler computational methods.
2Measurement precision
If feedback circuits and parameter adjustments are used for angular frequency extraction, then phase sequence detection precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent makes the detection system self-service by using the instantaneous voltage values themselves to determine phase sequence through coordinate transformation. The system automatically processes the voltage signals through Clarke transformation and arc tangent calculation without requiring external feedback circuits or manual parameter adjustments, making the operation simpler while maintaining precision.
3Measurement precision
If complex feedback circuits are used for angular frequency extraction, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent extracts the essential detection function and implements it through simple digital calculations rather than complex feedback circuits. By taking out only the necessary computational steps (coordinate transformation and arc tangent calculation), the system becomes much easier to manufacture while maintaining detection precision.
Solution Approach 2:
The patent replaces complex mechanical feedback circuits with digital computational methods, making the system easier to manufacture. The substitution of physical feedback mechanisms with algorithm-based detection simplifies the manufacturing process while preserving measurement precision.
Data Source
AI summary
The disclosure provides a three-phase AC phase sequence detecting method, including the steps of: 1) sampling instant values of three-phase AC electrical signal in real-time; 2) converting said instant values into electrical signal components in a two-phase still coordinate system in manner of coordinate conversion; 3) performing an arc tangent calculation on the electrical signal components to obtain a output signal value; 4) executing step 1) to step 3) one or more times, to obtain one or more output signal values; 5) the output signal values obtained from step 3) and the one or more output signal values obtained from step 4) composing a periodic function, if the periodic function is an increasing function within one minimum positive period, the three-phase AC phase sequence is determined to be positive sequence; otherwise, negative sequence. Three-phase AC phase detecting a detecting apparatus using the above detecting method is also provided.