Three-Phase Voltage Detection for Stable Harmonic Tracking
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Solution Overview
Problem
Existing methods for measuring and compensating harmonics in three-phase electrical supply networks, particularly in systems with frequency converters, are computationally intensive and may exceed the processing capacity of microcontrollers, leading to instability and inefficiency in harmonic detection and compensation.
Innovation Solution
A method using a state observer, preferably a Kalman filter, to measure three-phase electrical voltage in polar coordinates, track voltage vectors, and calculate compensation currents to reduce harmonics, employing pre-calculated observer matrices based on detected mains frequency to stabilize the observation and reduce computational effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods for measuring and compensating harmonics are used, then measurement precision and harmonic detection accuracy are improved, but computational load increases beyond microcontroller capacity
Solution Approach 1:
The patent segments the harmonic detection and compensation process into distinct functional modules: voltage measurement, harmonic analysis, compensation current calculation, and active filter control. This segmentation allows each module to be optimized independently and processed sequentially, reducing the computational burden on the microcontroller while maintaining detection accuracy.
Solution Approach 2:
The system performs preliminary measurements and calculations during idle periods or between control cycles. Voltage and current waveforms are measured and stored, then harmonic analysis is performed on the accumulated data rather than in real-time continuous processing. This preliminary action approach reduces peak computational requirements while preserving measurement precision.
2Object-generated harmful factors
If existing harmonic compensation methods are implemented, then harmonic reduction effectiveness is improved, but system stability deteriorates due to processing delays
Solution Approach 1:
The patent implements periodic harmonic analysis and compensation at optimized intervals rather than continuous processing. The system performs harmonic detection and calculates compensation currents at specific sampling rates that balance harmonic reduction effectiveness with system stability. This periodic action prevents processing delays from causing instability while maintaining adequate harmonic control.
Solution Approach 2:
The system continuously monitors the effect of compensation currents on grid harmonics and uses this feedback to adjust subsequent compensation actions. The microcontroller measures the actual harmonic reduction achieved, compares it with target values, and modifies the compensation current accordingly. This feedback loop ensures system stability while maintaining effective harmonic reduction.
3Measurement precision
If complex harmonic analysis algorithms are used, then detection precision is improved, but processing speed decreases below required thresholds
Solution Approach 1:
The patent replaces complex continuous mathematical computations with discrete, simplified algorithms suitable for microcontroller implementation. Instead of using heavy continuous-time harmonic analysis methods, the system employs discrete Fourier transform variants or simplified phasor-based calculations that achieve adequate measurement precision with significantly reduced processing requirements, enabling faster execution within microcontroller capabilities.
Data Source
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AI summary
The invention relates to a method for detecting the electrical voltage in an electrical, three-phase supply network in terms of magnitude and phase for a fundamental oscillation and at least one harmonic oscillation, comprising the following steps: measuring an electrical, three-phase voltage of the supply network; transforming the measured voltage value into polar coordinates with a revolving voltage indicator for the fundamental oscillation as a measured reference indicator; and monitoring values respectively of at least one voltage indicator for the fundamental oscillation and of at least one voltage indicator for at least one harmonic oscillation to be detected, using a state monitor; as well as updating the monitored values according to the measured reference indicator.