Decentralized Microgrid Energy Storage Control via Power Sharing
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Solution Overview
Problem
In microgrids with multiple energy storages, existing control systems face challenges in efficiently sharing power to correct frequency and voltage deviations, leading to potential stability issues and power imbalances due to limited charging and discharging rates and the risk of tripping from high discharge rates.
Innovation Solution
A decentralized control mechanism where each energy storage's control unit calculates and shares its capability parameters with others to determine a power sharing ratio, allowing for coordinated power injection without a central control unit, using processor circuitry to transmit and receive capability information and calculate power sharing ratios for stabilizing the microgrid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple energy storages are added to a microgrid to improve stability and power injection capability, then the system's ability to correct frequency and voltage deviations is improved, but the complexity of coordinating power sharing among storages increases and control challenges arise
Solution Approach 1:
The patent divides the microgrid control into autonomous control units, each managing a specific energy storage device. Each control unit independently calculates its own power sharing ratio based on local measurements and communicated capability parameters, eliminating the need for complex centralized coordination while maintaining system-wide stability.
Solution Approach 2:
The patent implements a feedback mechanism where control units exchange capability parameters (such as available power, energy state of charge) with each other. Each unit continuously adjusts its power injection based on observed microgrid deviations and updated capability information from peer units, enabling dynamic and adaptive power sharing.
2Speed
If energy storages operate with high discharge rates to quickly correct deviations, then the response speed and power quality improvement are enhanced, but the risk of tripping and power imbalance increases
Solution Approach 1:
The patent applies partial action by having each energy storage device contribute only its calculated share of the total required power correction. The power sharing ratio ensures that no single storage unit is overloaded beyond its capability, distributing the corrective action partially across multiple units to avoid tripping while maintaining adequate response speed.
Solution Approach 2:
The patent dynamically adjusts the power injection parameters of each storage unit based on real-time capability parameters (state of charge, available power) and observed grid deviations. This adaptive parameter adjustment allows the system to respond quickly when capabilities permit while automatically reducing individual contributions when storage limits are approached, preventing tripping.
3Ease of operation
If a centralized control system is used to coordinate multiple energy storages, then power sharing can be managed, but the system requires more infrastructure and communication overhead
Solution Approach 1:
The patent enables each energy storage control unit to autonomously determine its own power sharing ratio by calculating based on locally observed deviations and capability parameters received from peer units. This self-service approach eliminates the need for a centralized control entity, reducing infrastructure complexity while maintaining coordinated power sharing.
Solution Approach 2:
The patent combines the functions of centralized monitoring, capability assessment, and power dispatch into the distributed control units themselves. Each unit performs multiple functions (local measurement, capability communication, power sharing calculation, and control signal generation) that would traditionally be separated in a centralized architecture, simplifying the overall system structure.
Data Source
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AI summary
The present disclosure relates to a method performed by a first control unit (21) for controlling a first energy storage (2) in a microgrid. The method comprises calculating a first storage capability parameter for the first energy storage. The method also comprises transmitting capability information about the first storage capability parameter to at least a second control unit configured for controlling a second energy storage in the microgrid. The method also comprises receiving capability information about a second storage capability parameter for the second energy storage from the second control unit. Further, the method comprises calculating a first power sharing ratio for the first energy storage, based on the first and second storage capabilities. Subsequently, the method comprises sending control signals comprising information based on the calculated first power sharing ratio, for controlling said first energy storage to inject an amount of power (P) into the microgrid in accordance with the first power sharing ratio for correcting an observed deviation ( Δf; ΔΥ) in the microgrid.