VPP Relay Control for Demand Response Charging Continuity
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Solution Overview
Problem
The existing virtual power plant (VPP) systems face challenges in managing the number of relay switchings between vehicles and the power network, leading to increased relay degradation and reduced participation in demand response requests, especially for V1G vehicles that can only charge externally.
Innovation Solution
A power management system that includes a server communicating with vehicles to manage relay switchings by maintaining the relay in a connected state until charge processes are completed, setting minimum continuation times, and adjusting values based on charge power and last charge time to minimize relay on times and prevent excessive switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the relay is switched frequently to handle demand response requests, then the responsiveness to DR requests is improved, but the relay degradation accelerates and lifespan decreases
Solution Approach 1:
The system performs preliminary actions by maintaining the relay in a connected state in advance before charge processes are completed. The server instructs the vehicle to keep the relay connected during charge suspension periods, so that when charging resumes, the relay is already in the correct state, avoiding additional switching operations and reducing relay degradation while maintaining DR responsiveness
2Reliability
If the relay is maintained in connected state during charge suspension, then the number of relay switchings is reduced, but the charge process efficiency may be affected
Solution Approach 1:
The system dynamically adjusts the relay control strategy based on charge process status. The server monitors charge suspension and resumption events, and dynamically instructs the vehicle to maintain or switch the relay state accordingly. This dynamic approach allows the relay to remain connected during suspension (reducing switching) while still enabling efficient charging when power is available
3Reliability
If the relay switching threshold is set low, then relay degradation is suppressed, but the ability to handle demand response requests is reduced
Solution Approach 1:
The server implements feedback control by monitoring the charge process status, charge suspension events, and relay switching history. Based on this feedback, the server intelligently determines when to instruct the vehicle to maintain the relay in connected state versus when to allow switching, optimizing both relay lifespan and DR request handling capability through adaptive decision-making
Data Source
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AI summary
A power management system (1) manages power transmitted between a VPP connected to a power network installed in a predetermined area and the power network. The VPP includes vehicles each including a power storage device that is chargeable by receiving power from the power network. A server of the power management system acquires the state of a relay for each of the vehicles. When number of on times that the relay is brought from a disconnected state to a connected state is more than a first value in a case that the power storage device is charged in a target vehicle in accordance with a request for an increase in amount of power demanded in the power network, the server instructs the target vehicle to maintain the relay in the connected state until a charge process executed in accordance with the request is completed.