EV Charging Control for Phase Current Balance
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Solution Overview
Problem
Electric vehicles charging at single-phase currents exceeding 20 amperes can cause unbalanced loads in electricity grids, violating maximum permissible limits set by energy supply companies and distribution network operators, leading to potential overload and instability.
Innovation Solution
Monitoring phase currents and adjusting charging power to maintain unbalanced loads below the specified threshold by communicating power specifications to electric vehicles, allowing for higher individual charging currents while preventing overload through continuous monitoring and power adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If electric vehicles charge at high single-phase currents exceeding 20 amperes, then individual charging power is improved, but unbalanced load exceeds maximum permissible limits
Solution Approach 1:
The system dynamically adjusts the charging current of electric vehicles based on real-time monitoring of phase currents. The control unit continuously monitors the unbalanced load and communicates power specifications to electric vehicles, allowing the charging current to vary between 0 and 20 amperes per phase depending on grid conditions, thus resolving the contradiction between high charging power and unbalanced load compliance
Solution Approach 2:
The system implements a feedback mechanism where phase currents are continuously monitored at the balance point, the unbalanced load is calculated, and power specifications are communicated back to electric vehicles. This closed-loop control ensures that individual charging currents are adjusted to maintain unbalanced load below the 20-ampere threshold while maximizing charging power within available headroom
2Reliability
If maximum unbalanced load threshold is strictly limited to 20 amperes, then grid stability is improved, but total charging capacity is reduced
Solution Approach 1:
The system changes the operational parameters by allowing individual phase currents to exceed 20 amperes temporarily when headroom is available, while maintaining the unbalanced load threshold compliance. The control unit calculates available headroom based on the difference between maximum permissible unbalanced load and actual unbalanced load, and adjusts charging currents accordingly to maximize total charging capacity while ensuring grid stability
Data Source
AI summary
A method for charging electric consumers at an electricity grid with multiple phases may include measuring a phase current of each of the multiple phases of the electricity grid at a balance point. The method may also include determining to which of the multiple phases each electric consumer of the electric consumers is connected for charging via the balance point. Additionally, the method may include holding an unbalanced load of the multiple phases below an unbalanced load threshold value via communicating a power specification to each electric consumer connected for charging.