Decentralized Microgrid Frequency Control via Local Load Estimation
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Solution Overview
Problem
Microgrids face operational challenges due to unreliable communication between local controllers and central controllers, which hampers the coordination of distributed energy resources, leading to instability in power supply and frequency control.
Innovation Solution
A decentralized control method where each local controller measures frequency and estimates power load based on type and size of plants, allowing renewable and generator plants to adjust power supply independently to match demand, without relying on central communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a central controller is used to coordinate distributed energy resources, then power supply stability is improved, but communication reliability deteriorates due to vulnerable communication links
Solution Approach 1:
The patent divides the centralized control function into distributed control units at each energy resource node. Each controller independently makes control decisions based on local measurements and simple peer-to-peer communication, eliminating the single point of failure in centralized architecture while maintaining coordination capabilities through decentralized consensus mechanisms.
Solution Approach 2:
Each energy resource node performs self-control and self-coordination through local intelligence. The distributed controllers autonomously adjust power output based on grid conditions detected locally, reducing dependency on central communication infrastructure and enabling the system to maintain stability even when communication links are compromised.
2Adaptability or versatility
If renewable energy resources are integrated into the microgrid, then energy autonomy is improved, but frequency control stability deteriorates due to intermittent power generation
Solution Approach 1:
The patent implements distributed feedback control where each controller continuously monitors local frequency and power output, and automatically adjusts renewable energy generation to maintain frequency within acceptable ranges. The feedback loop operates autonomously at each node, compensating for intermittent power generation without requiring centralized coordination.
Solution Approach 2:
The control system dynamically adapts to varying renewable energy generation conditions by allowing each distributed controller to adjust its control parameters based on real-time grid state. This dynamic response enables the system to maintain frequency stability despite the intermittent and variable nature of renewable energy sources.
3Adaptability or versatility
If generator sets are used to provide flexible power generation, then adaptability to peak consumption is improved, but energy efficiency deteriorates due to high fuel consumption
Solution Approach 1:
The patent combines multiple distributed energy resources including renewable generators, conventional generator sets, and energy storage systems into a coordinated network. This merging allows the system to leverage the flexibility of generator sets while compensating for their fuel consumption through renewable sources and storage, achieving both adaptability and energy efficiency.
Solution Approach 2:
Each distributed energy resource node is designed to perform multiple functions - renewable generators provide base power, generator sets provide peak shaving capability, and storage systems provide frequency regulation and energy time-shifting. This multi-functionality allows the system to meet varying demand conditions while optimizing overall fuel consumption by coordinating resource utilization.
Data Source
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AI summary
The invention relates to a method for controlling a microgrid having at least one renewable plant of distributed renewable energy resources and at least one generator plant of distributed non-renewable energy resources, wherein each plant has a local controller. The method includes providing type and power size of each plant to each local controller. At each local controller, measuring the frequency and estimating the total power load demanded based on the measured frequency. The local renewable controller decreasing the frequency at which power is supplied when the supplied power falls below the estimated power load and increasing the frequency when the supplied power exceeds the estimated power load. And the local generator controller: increasing power supply in response to detecting a decrease in frequency, and decreasing power supply in response to detecting an increase in frequency.