Low-Voltage Microgrid Control for Proportional DER Power Sharing
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Solution Overview
Problem
Existing technologies for single-controllable low-voltage microgrids (MGs) lack efficient methods for sharing active and reactive power proportionally among distributed energy resources (DERs), compensating for current unbalance at the point of common coupling (PCC), and balancing battery bank charging status without requiring detailed knowledge of the electrical grid's parameters or topology.
Innovation Solution
The modified Power-Based Control (PBC) process (MPBC) enables proportional sharing of active and reactive power among DERs, compensates for unbalance at the PCC, and balances battery bank charging status by using a centralized controller that communicates with DERs and tertiary controllers, allowing for arbitrary inverter connections and operation without prior knowledge of the grid's parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional control methods are used for power sharing among DERs, then detailed knowledge of grid parameters and topology is required, but this increases system complexity and difficulty of implementation
Solution Approach 1:
The patent introduces a centralized controller as an intermediary that receives power measurement data from DERs and calculates reference active and reactive powers. This mediator eliminates the need for each DER to have complex local control algorithms requiring detailed grid parameter knowledge, while still achieving accurate proportional power sharing through centralized coordination.
2Adaptability or versatility
If proportional power sharing is implemented among DERs with different battery technologies, then compatibility across different battery types is achieved, but coordination complexity increases
Solution Approach 1:
The patent segments the control function by separating measurement (performed locally at each DER), communication (data exchange with centralized controller), and calculation (reference power determination at centralized controller). This segmentation allows different battery technologies to operate independently with their own characteristics while achieving coordinated proportional power sharing through the standardized control framework.
3Quantity of substance
If battery banks are utilized for energy time shift service, then full capacity energy supply is achieved, but unbalance compensation at PCC becomes more challenging
Solution Approach 1:
The patent implements feedback mechanisms where the centralized controller continuously receives measurement data from DERs including power injections and battery state of charge information. Based on this feedback, the controller dynamically adjusts reference active and reactive powers to maintain proportional sharing while compensating for unbalance at the PCC, even when battery banks are actively charging or discharging.
Data Source
AI summary
This technology refers to a control process for single-controllable low-voltage microgrids (Mgs) (SCM) having centralized communication. The process is based on the “Power-Based Control” (PBC) technique by adapting it to the context of SCMs through a modified PBC process (MPBC). The technology includes a process that provides the following technical effects: (1) sharing of active power and reactive power proportionately to the capacity of distributed energy resources (DERs or DGs) in the MG, for example, rendering the use of batteries based on different technologies (lead-acid, ion-lithium, etc.) compatible; (2) compensation for the current unbalance at the point of common coupling (PAC); (3) allows exploration of battery banks by balancing the charging status of storage elements; (4) allows implementation of the control process without knowing the electrical grid's parameters and topology; (5) is able to deal with the arbitrary connection of inverters into the MG, in addition to other advantages. The technology is applied in the technical field of equipment and infrastructure for the development of MGs.