Grid Stability Support via Virtual Synchronous Machine and Energy Buffer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern wind turbine generators and renewable energy systems struggle to provide adequate grid stability during severe frequency disturbances without incurring significant costs and power losses, as they require additional hardware to effectively respond to grid faults.
Innovation Solution
A system comprising a power generator with a main converter coupled to the grid, an energy buffer with a secondary converter, a grid stability monitor, and a controller that operates the main converter as a virtual synchronous machine when stability is high and switches to the energy buffer for support during instability, minimizing power losses by only activating the secondary converter when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional hardware is added to enable wind turbine generators to provide grid-stabilizing response during severe frequency disturbances, then the ability to support grid stability is improved, but the cost and power losses increase significantly
Solution Approach 1:
The system dynamically switches between two operational modes based on grid stability conditions: during normal operation, the main converter operates as a virtual synchronous machine providing continuous stability support, while during severe disturbances, the energy buffer is activated to provide additional rapid response. This dynamic activation only when needed minimizes power losses while maintaining reliability.
Solution Approach 2:
The energy buffer is pre-charged during normal operation to be ready for rapid deployment during severe frequency disturbances. This preliminary preparation ensures that when grid instability occurs, the buffer can immediately provide the required stabilizing response without delay, improving reliability without requiring continuous operation that would increase power losses.
2Reliability
If additional hardware is added to enable wind turbine generators to provide grid-stabilizing response during severe frequency disturbances, then the ability to support grid stability is improved, but the cost increases significantly
Solution Approach 1:
The energy buffer serves multiple functions: it provides rapid response during severe frequency disturbances, maintains operational readiness through periodic charging, and can support other grid stability functions. This multi-functionality justifies the added hardware cost by providing comprehensive grid support capabilities across different operating conditions.
Solution Approach 2:
The system uses dynamic control to activate the energy buffer only when severe disturbances are detected, rather than operating continuously. This selective activation reduces the effective utilization cost of the additional hardware while maintaining the capability to provide grid stability support when needed.
3Reliability
If the secondary converter is continuously operated to maintain energy buffer readiness, then the ability to respond to grid disturbances is improved, but power losses increase
Solution Approach 1:
Instead of continuous operation, the secondary converter is activated periodically to recharge the energy buffer when state-of-charge thresholds are reached. This periodic maintenance operation keeps the buffer ready for rapid response while minimizing the time the converter is active, thereby reducing power losses associated with continuous operation.
Solution Approach 2:
The system dynamically determines when the secondary converter needs to operate based on the energy buffer's state-of-charge levels and grid conditions. This dynamic control ensures the buffer is ready for disturbances while avoiding unnecessary operation that would increase power losses, optimizing the balance between reliability and energy efficiency.
Data Source
AI summary
A system for supplying electric power to a grid and for supporting the grid is provided. The system includes (a) a power generator including a main converter, (b) an energy buffer including an energy storage and a secondary converter, (c) a grid stability monitor-configured to provide a grid stability, and (d) a controller configured to control the main converter and the secondary converter in dependency on the grid stability indication such that when the stability level is at least equal to a predetermined threshold value, the main converter is controlled to operate as a virtual synchronous machine and the secondary converter is controlled to operate to maintain a predetermined amount of energy in the energy storage, and when the stability level is below the predetermined threshold value, the secondary converter is operated to provide a predetermined response in order to support the grid stability.