Three-Phase Signal Phase Detection Using Section-Based Linear Interpolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional synchronous motor controllers face challenges in accurate real-time phase detection, requiring complex calculations and high computing capacity, leading to poor detection accuracy and inability to perform instantaneous phase detection.
Innovation Solution
A phase detection method that determines the section of magnitude correlation between R-phase, S-phase, and T-phase signals and calculates normalized amplitude values, then converts these to vector phases by adding specific angles, allowing for accurate real-time phase detection with a simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three-phase to two-phase conversion with arctan transform is performed to detect phase in real time, then instantaneous phase detection is achieved, but processing becomes complicated and large computing capacity is required
Solution Approach 1:
The patent divides the phase detection process into six discrete sections based on the relative magnitude relationships between R-phase, S-phase, and T-phase signals. Each section corresponds to a specific 60-degree phase range, allowing the use of simple linear calculations instead of complex arctan transforms. This segmentation enables real-time phase detection with minimal computing resources while maintaining high accuracy (error less than 1.1 degrees).
Solution Approach 2:
The patent changes the detection parameter from continuous arctan calculation to discrete section-based linear interpolation. By detecting which of the six sections the current signal magnitudes fall into and applying corresponding linear formulas, the system achieves the same phase detection function with dramatically reduced computational complexity and no requirement for high computing capacity.
2Ease of operation
If phase detection is performed only at zero-crossing points, then detection timing is simplified, but detection accuracy deteriorates and instantaneous phase cannot be detected
Solution Approach 1:
The patent performs preliminary classification of the signal magnitudes into six sections based on their relative relationships. This preliminary action enables the system to determine the current phase range before performing the actual phase calculation, allowing accurate instantaneous phase detection at any timing rather than being restricted to zero-crossing points only.
3Measurement precision
If section determination based on signal magnitude correlation is performed, then accurate real-time phase detection is achieved, but calculation complexity increases
Solution Approach 1:
The patent segments the entire 360-degree phase cycle into six 60-degree sections, each characterized by a specific magnitude correlation pattern among R-phase, S-phase, and T-phase signals. This segmentation allows the use of simple comparison operations and linear calculations within each section, dramatically reducing computing power requirements while maintaining high detection accuracy.
Solution Approach 2:
The patent changes the calculation approach from continuous complex arithmetic to discrete linear interpolation based on section identification. By determining which section the signals belong to and applying the corresponding linear formula, the system achieves accurate phase detection with minimal computational power, suitable for real-time control applications.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
It is determined (S101, S102) which of six continuous sections having different magnitude correlation of signal amplitude of each phase of an input three-phase signal a section is. Predetermined subtraction is performed between respective phases in the section, to obtain (S103) a normalized amplitude value normalized in the section, using the subtraction result. The normalized amplitude value is converted to a vector phase for one cycle based on a predetermined phase and output (S104) corresponding to the determined section.