Frequency Control for Renewable Energy Sources in AC Networks
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Solution Overview
Problem
The integration of renewable and conventional energy sources in AC voltage networks faces challenges in coordinating power fluctuations, leading to suboptimal operation of renewable energy sources and increased resource consumption by conventional sources, as renewable sources are typically operated at maximum power only below a predetermined frequency threshold.
Innovation Solution
A method and control device that regulate the operating frequency of energy sources in an AC voltage network by recording power balance and environmental parameters to determine target operating states for maximum power generation, allowing for coordinated operation between renewable and conventional sources without additional communication, and enabling renewable sources to operate as voltage sources for network stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If renewable energy sources are operated as voltage sources to enable network stabilization, then grid stability is improved, but the operating frequency control becomes more complex
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the operating frequency of renewable energy sources based on recorded power balance and environmental parameters. The control device modifies frequency parameters in real-time to maintain grid stability while optimizing power generation, transforming the fixed frequency operation into a variable frequency system that adapts to changing conditions.
Solution Approach 2:
The patent implements feedback control by continuously recording power balance-dependent operating parameters and environmental parameters, comparing them against target values, and adjusting the operating frequency accordingly. This closed-loop feedback mechanism enables the system to maintain stability while automatically adapting to fluctuations in renewable energy generation.
2Productivity
If renewable energy sources operate at maximum power point continuously, then energy production is maximized, but grid frequency stability deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from static maximum power point operation to dynamic operating frequency adjustment. The system continuously adapts the operating frequency based on real-time power balance and environmental conditions, allowing renewable energy sources to contribute to frequency stabilization while maintaining high energy production through optimized operational states.
Solution Approach 2:
The patent changes the operating parameter from fixed maximum power point to variable operating frequency determined by power balance and environmental parameters. This parameter transformation allows the system to balance energy production with grid stability requirements by adjusting frequency rather than maintaining constant maximum power output.
3Reliability
If conventional energy sources compensate for renewable energy fluctuations, then grid frequency stability is maintained, but resource consumption by conventional sources increases
Solution Approach 1:
The patent enables renewable energy sources to self-regulate their operating frequency based on recorded power balance and environmental parameters, reducing the need for conventional energy sources to compensate for fluctuations. By implementing self-service frequency control at the renewable source level, the system minimizes energy consumption by conventional sources while maintaining grid stability.
Solution Approach 2:
The patent uses feedback control at the renewable energy source level to automatically adjust operating frequency in response to power balance and environmental conditions. This local feedback mechanism reduces the burden on conventional energy sources by enabling renewable sources to self-correct frequency deviations, thereby reducing unnecessary conventional source consumption.
4Adaptability or versatility
If operating frequency is used as communication signal between energy sources, then coordination is improved, but system complexity increases
Solution Approach 1:
The patent applies universality by using operating frequency for dual purposes: both power generation control and inter-energy source communication. The frequency signal simultaneously serves as a control parameter for maximizing power output and as a communication medium for coordinating operations between renewable and conventional energy sources, eliminating the need for separate communication infrastructure.
Solution Approach 2:
The patent uses operating frequency as an intermediary signal that mediates coordination between energy sources. Rather than implementing direct communication protocols between diverse energy source controllers, the system uses the universal frequency parameter as an intermediary language that all sources can understand and respond to, simplifying the coordination mechanism.
Data Source
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AI summary
According to the invention, a power balance-dependent operating parameter (X) and a surroundings parameter (PAR) of a first energy source (EQ), preferably a renewable energy source, are detected. A variable target operating parameter (XMPP) for the first energy source (EQ) is ascertained dependent on the detected surroundings parameter (PAR). The target operating parameter (XMPP) can preferably characterize a first energy source (EQ) state in which a maximally possible output would be generated under the current given conditions of the surroundings. The operating frequency (f) is then controlled dependent on the detected power balance-dependent operating parameter (X) and the ascertained target operating parameter (XMPP) such that a deviation of the operating frequency (f) from a specified frequency (fMPP) is coupled to a deviation of the detected power balance-dependent operating parameter (X) from the ascertained target operating parameter (XMPP).