Battery SOC Control for Frequency Regulation
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Solution Overview
Problem
Power systems face challenges in accurately matching rapid changes in energy demand, leading to frequency deviations in AC current, which can cause inefficient and unsafe operation of electronic devices, and existing energy storage technologies struggle to provide fast and efficient frequency regulation.
Innovation Solution
A power management system that includes a battery energy storage system and a charging control unit, which adjusts the State of Charge (SOC) level of the battery to maintain it within a preset range based on system frequency fluctuations, ensuring stable energy transfer and frequency regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power plant changes output to meet rapid load changes, then the power supply can follow load demand, but the frequency regulation becomes difficult to maintain within desired range
Solution Approach 1:
An energy storage device is introduced as an intermediary between the power plant and the load. The device charges when power supply exceeds demand and discharges when demand exceeds supply, mediating the mismatch and maintaining system frequency within the dead band range without requiring the power plant to constantly adjust its output.
Solution Approach 2:
The energy storage device performs preliminary action by charging during periods of excess power supply (when load is smaller than supplied power). This stored energy is then released during periods of high demand, proactively addressing frequency deviations before they affect the power system's stability.
2Speed
If a fast-response power plant is configured to quickly supply energy, then the response speed to frequency changes improves, but the device complexity increases
Solution Approach 1:
Instead of modifying the power plant itself to achieve fast response, the patent uses an energy storage device as a mediator that can rapidly charge and discharge. This approach achieves fast frequency response without the complexity of reconfiguring the power plant, as the storage device handles the rapid power adjustments independently.
3Reliability
If the energy storage device continuously charges and discharges to regulate frequency, then the frequency stability improves, but the SOC level may fall outside the maintaining range
Solution Approach 1:
The control method performs preliminary action by monitoring the SOC level and adjusting the charging/discharging strategy in advance. When the SOC approaches the upper or lower limits, the controller modulates the power flow to prevent the SOC from exiting the maintaining range, while still maintaining frequency stability within the dead band.
Solution Approach 2:
The control strategy dynamically adjusts the energy storage device's operation based on real-time SOC levels and frequency conditions. The controller modulates charging and discharging rates adaptively, ensuring both frequency stability and SOC confinement within the maintaining range through dynamic control parameters.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system stabilizes system frequency by efficiently charging or discharging the battery, maintaining the SOC level within a desired range, thereby improving the stability and efficiency of power distribution.
Implementation Method 1
an energy storage technology such as a battery, a flywheel, a capacitor, or the like may be used to supply energy to an electric power system
Data Source
AI summary
A method for controlling energy storage device includes determining whether the operating frequency of the system falls within a dead band range corresponding to a preset frequency range, determining whether an SOC level indicating the charging amount of the energy storage device falls within a preset maintaining range, in a case where the operating frequency falls within the dead band range, and adjusting the SOC level so that the SOC level falls within the maintaining range in a case where the operating frequency of the system falls within the dead band range and the SOC level is outside the preset maintaining range, wherein the maintaining range represents a range between a preset lower limit and a preset upper limit.