Hybridization Controller for Grid Frequency Response and Battery SOC
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Solution Overview
Problem
Existing power generation systems struggle to maintain frequency stability in electrical power distribution networks due to the need for robust predictions of grid fluctuations, especially with increasing renewable energy sources, and the wear on electromechanical components from frequent actuator adjustments.
Innovation Solution
A hybrid control system using a controllable power generation unit and energy storage unit, managed by a hybridization controller, which incorporates a state-of-charge monitoring and time derivative of power production to adjust power output, avoiding direct filtering of frequency deviation signals, and utilizing fuzzy logic for setpoint management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a battery storage system is used to provide FCR service with dynamic optimization of charge thresholds, then frequency control performance is improved, but the complexity of prediction systems increases and becomes difficult to maintain with renewable energy integration
Solution Approach 1:
The patent extracts the prediction function from the control system by using a hybrid approach where the power generation unit handles long-term prediction and planning, while the energy storage unit handles immediate frequency regulation responses. This separation removes the burden of complex long-term predictions from the battery control system.
Solution Approach 2:
The control system is segmented into two independent control loops: one for the power generation unit (handling setpoint adjustments and long-term planning) and one for the energy storage unit (handling immediate frequency responses). This segmentation allows each component to operate independently with simpler control logic.
2Reliability
If a power generation unit responds rapidly to frequency deviations, then frequency stability is improved, but wear on electromechanical components increases due to frequent actuator adjustments
Solution Approach 1:
The energy storage unit acts as an intermediary between the grid frequency deviations and the power generation unit actuators. It absorbs the high-frequency variations and transmits only smoothed, long-term trends to the power generation unit, protecting the electromechanical components from frequent adjustments.
Solution Approach 2:
The system performs preliminary frequency regulation using the energy storage unit before any adjustments are needed from the power generation unit actuators. This preliminary action prevents the need for frequent actuator movements by handling immediate frequency deviations with the storage system.
3Speed
If the energy storage unit handles all frequency regulation, then response time is improved, but the power generation unit cannot optimize its operation and maintenance needs increase
Solution Approach 1:
The system dynamically allocates frequency regulation tasks between the energy storage unit and power generation unit based on real-time conditions. The energy storage unit handles immediate responses, while the power generation unit optimizes its operation by focusing on long-term setpoint adjustments and maintenance scheduling.
Solution Approach 2:
The hybrid controller implements feedback mechanisms that monitor both the energy storage unit state of charge and the power generation unit operational status. This feedback allows the system to optimize the division of labor, ensuring the power generation unit can perform maintenance and optimizations while the storage unit handles frequency regulation.
Data Source
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AI summary
To control the hybridization of an electrical production group comprising an electrical power production unit (1) and an energy storage unit (2), a hybridization controller (34) includes an inference controller (343) which receives as input a first signal (ESS_SOC) representing the state of charge of the storage unit, a second signal (PESS) representing the power stored or delivered by the storage unit and a third input signal representing the time derivative of the power (PHPP_FCR) produced by the production unit, and produces as output a signal (F_HPPn) setting the power produced by the production unit as its contribution to the primary frequency control of the electrical network (3).The hybridization controller (34) is configured to control the power (PESS) stored or delivered by the energy storage unit (2) from the difference (342) between the expected primary frequency control power (PFCR) from the generating group as its contribution to the primary frequency control of the electrical grid (3) and the power (PHPP_FCR) produced for this purpose by the electrical power generating unit (1).