Islanded Virtual Synchronous Micro-Grid Frequency Adjustment
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Solution Overview
Problem
Existing micro-grid systems face challenges in achieving rapid and stable frequency adjustment and power proportion equalization in islanded virtual synchronous micro-grids due to high communication complexity and potential delays.
Innovation Solution
A method and system utilizing a differential delay algorithm to cyclically adjust inverter frequencies, where each cycle determines a reference inverter with the highest active output and sends its local output factor as the maximum output factor to other inverters, allowing for active power adjustments to achieve rated frequencies and power proportion equalization, reducing communication pressure and ensuring stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If diffusive information comparison over the whole system or adjacent units is used for frequency adjustment, then comprehensive system information is obtained, but the response speed is slow and communication complexity increases
Solution Approach 1:
The patent segments the frequency adjustment process into cyclic iterations, where each inverter independently determines its output factor relative to others without requiring global information exchange. This segmentation allows parallel processing and reduces communication overhead while maintaining system-wide coordination.
Solution Approach 2:
The patent implements preliminary action by having inverters pre-determine their local output factors based on their active power outputs before frequency adjustment begins. This preliminary determination eliminates the need for real-time information comparison during the adjustment process, thereby reducing communication complexity and improving response speed.
2Productivity
If cyclic frequency adjustment with differential delay algorithm is implemented, then response speed increases and communication pressure decreases, but system complexity increases
Solution Approach 1:
The patent applies self-service by enabling each inverter to autonomously determine its own output factor and participate in frequency adjustment without requiring complex centralized control. The differential delay algorithm allows inverters to self-coordinate based on their local measurements, improving efficiency while the modular nature of the algorithm keeps implementation complexity manageable.
3Reliability
If multiple data types are transmitted through communication path for coordination, then comprehensive control information is available, but communication pressure increases and system becomes more vulnerable to delays and failures
Solution Approach 1:
The patent extracts only the essential information needed for frequency adjustment by having each inverter transmit only its local output factor to others. This extraction of minimal necessary data reduces communication burden and vulnerability to delays while maintaining sufficient information for reliable coordination, as the differential delay algorithm can function with this limited data exchange.
Data Source
AI summary
The present invention provides a method, a system and a storage medium for frequency adjustment of an islanded virtual synchronous micro-grid. The method includes: performing frequency adjustment on inverters in the micro-grid in a cyclic manner until the respective inverters reach rated frequencies; where each cycle includes: determining, in a differential delay manner, an inverter with a highest active output in the micro-grid as a reference unit, and sending a local output factor of the reference unit as a maximum output factor of a current cycle to other inverters; determining, for each inverter in the micro-grid, an active power adjustment amount of the inverter according to the maximum output factor, a preset rated frequency, a local output factor and an actual angular frequency of the inverter; and performing frequency adjustment on the inverter according to the active power adjustment amount.