Active Filter Control for Wind Inverter Harmonic Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wind power installations face challenges in filtering out harmonics from the electrical alternating current generated by inverters, leading to non-compliance with electrical supply grid requirements, particularly in countries with stringent standards like Brazil, due to limitations in operating range and signal transit times of both passive and active filters.
Innovation Solution
A method involving an active filter controlled directly by the inverter's activation signals, eliminating the need for continuous measurement and reconfiguration, which minimizes harmonics by synchronizing the control signals with the inverter's switching actions, allowing for efficient filtering without time delays and initial setup for each location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive filters are used to filter harmonics, then the structure is simple, but the operating range is restricted and filtering effectiveness is insufficient
Solution Approach 1:
The patent applies dynamics by making the filter characteristics adjustable through switching elements (transistors, thyristors, or triacs) that can change the filter's impedance and resonant frequency in real-time. This allows the filter to adapt to different operating conditions and harmonic spectra, resolving the contradiction between simple structure and restricted operating range.
Solution Approach 2:
The patent changes physical parameters of the filter by varying the switching frequency and duty cycle of the active elements, which dynamically adjusts the filter's impedance characteristics and resonant frequency. This enables the filter to maintain effectiveness across a wide operating range while keeping the physical structure relatively simple.
2Adaptability or versatility
If active filters with continuous measurement and control are used, then adaptability is improved, but signal transit time increases and response speed decreases
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing optimal switching patterns and filter parameters in memory before they are needed. When harmonic filtering is required, the system retrieves pre-computed control signals from memory rather than calculating them in real-time, significantly reducing signal transit time while maintaining adaptability.
Solution Approach 2:
The patent uses copying by storing pre-computed control patterns and filter parameters in memory that can be quickly retrieved and applied. This allows the system to replicate proven filtering strategies without undergoing complex real-time calculations, reducing response time while maintaining filtering effectiveness.
3Manufacturing precision
If active filters are re-configured for each location, then filtering precision is improved, but device complexity and setup time increase
Solution Approach 1:
The patent applies universality by designing a single filter architecture that can operate effectively across multiple locations and applications. The microprocessor-based control system with pre-stored patterns and adaptive algorithms allows the same hardware to be deployed universally while maintaining high filtering precision through software-based customization rather than hardware reconfiguration.
Solution Approach 2:
The patent implements self-service by enabling the filter to automatically adapt to different locations and harmonic conditions through its microprocessor control system. The device performs self-diagnosis, retrieves appropriate control patterns from memory, and adjusts its operation autonomously without requiring manual reconfiguration, thereby maintaining precision while reducing complexity.
Data Source
AI summary
A wind power installation and a method for feeding a filtered alternating current into an electrical supply grid by the wind power installation are provided. The wind power installation includes at least one inverter having an inverter output for providing an inverter current. The at least one inverter is coupled at its inverter output to an active filter. The active filter filters the inverter current provided at the inverter output and provides the filtered alternating current for feeding into the electrical supply grid. The method includes providing the inverter current at the inverter output by switching at least one switch of the inverter, sensing the switching, and controlling the active filter based on the sensed switching to filter the inverter current provided at the inverter output and produce the filtered alternating current.