Microgrid Power Switching with Master-Slave Synchronization
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Solution Overview
Problem
Existing microgrid systems face instability when switching from isolated to grid-connected operations due to unsynchronized electric power, as they do not effectively manage the synchronization of power between the microgrid and the external power network.
Innovation Solution
A server manages power grids by determining a master and slave among power adjustment resources to achieve synchronization through master-slave control, prioritizing resources close to the connection point to minimize power grid instability during switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the microgrid switches from isolated operation to grid-connected operation without master-slave control synchronization, then the switching speed is fast, but electric power instability occurs due to desynchronization with the external power network
Solution Approach 1:
The system performs master-slave control synchronization before the actual grid-connection switching occurs. The master power adjustment resource pre-adjusts the microgrid's electric power parameters (frequency, voltage, phase) to match the external power network, ensuring synchronization is achieved in advance before connection, thus preventing instability while maintaining efficient switching.
2Area of stationary object
If a power adjustment resource distant from the grid-connection point is selected as master, then the coverage area is larger, but electric power synchronization accuracy deteriorates due to high inductance of the electric wire
Solution Approach 1:
The system selects the master power adjustment resource based on its proximity to the grid-connection point, prioritizing local resources with shorter electric wire connections. This ensures low inductance and high synchronization accuracy at the critical connection point, while the master resource still manages to coordinate broader power adjustment across the microgrid through control signals.
3Measurement precision
If master-slave control is implemented with synchronization before grid connection, then electric power synchronization accuracy is improved, but the control complexity increases
Solution Approach 1:
The system introduces a server as an intermediary that centrally manages the master-slave control logic. The server receives electric power information from all power adjustment resources, determines the master resource based on proximity to the grid-connection point, coordinates the synchronization process, and manages the switching control. This centralized intermediary simplifies the overall control architecture while achieving high synchronization accuracy.
Data Source
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AI summary
A first switching unit switches a first power grid (MG) from an isolated operation to a grid-connected operation. In switching the first power grid from the isolated operation to the grid-connected operation, the first switching unit determines a master and a slave among a plurality of power adjustment resources (500) (S31) and allows the first power grid to be connected to the second power grid (S37) after master-slave control by means of the master and the slave (S34) such that electric power of the first power grid is in synchronization with electric power of the second power grid. The first switching unit preferentially selects as the master, a power adjustment resource close to a point of connection between the first power grid and the second power grid from among the plurality of power adjustment resources (S31).