EVSE Power Sharing Controller for Circuit Breaker Load Management
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Solution Overview
Problem
Existing electric vehicle supply equipment (EVSE) installations often face challenges in efficiently sharing power among multiple units, particularly when they share a common circuit breaker, as standard practice dictates that each unit should have a dedicated breaker, which is not always feasible, leading to underutilization of charging capacity.
Innovation Solution
A method and system where two EVSE units share a common circuit breaker by dynamically adjusting the charging current of each unit based on the available capacity, using a controller to limit and restore charge levels, optimize power distribution, and sense ambient conditions to ensure efficient use of power without exceeding the breaker's capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two EVSE units share a common circuit breaker, then the number of charging stations increases and electrical equipment costs are reduced, but the charging capacity of each unit must be limited and power distribution becomes complex
Solution Approach 1:
The system dynamically adjusts the charging current of each EVSE unit based on real-time monitoring of power consumption and breaker capacity. The controller continuously monitors the actual power draw and adjusts current limits to maximize utilization of the shared breaker capacity while preventing overloads, allowing flexible adaptation to changing charging demands.
Solution Approach 2:
The system implements continuous feedback monitoring of power consumption by each EVSE unit and the total load on the shared circuit breaker. The controller receives real-time data on current draw and uses this feedback to adjust charging parameters, ensuring safe operation within breaker capacity while optimizing power distribution among multiple units.
2Reliability
If each EVSE unit is limited to half of the breaker capacity, then safe operation is ensured, but the available charging current is reduced
Solution Approach 1:
Instead of static current limits, the system dynamically adjusts charging current based on real-time breaker utilization. When one EVSE unit is not in use or drawing minimal power, the other unit can access more than half the breaker capacity. The current limit is continuously adapted to the actual state of system utilization, maximizing available power while maintaining safety margins.
Solution Approach 2:
The system changes the operating parameters of EVSE units based on real-time conditions. The current capacity allocation is not fixed but varies dynamically according to the charging state of connected vehicles, ambient temperature, and overall system load, allowing optimal power distribution that adapts to changing conditions rather than relying on conservative static limits.
3Productivity
If continuous monitoring and dynamic adjustment are implemented, then power utilization is optimized, but the control system complexity increases
Solution Approach 1:
The controller performs multiple functions within a single integrated system: it monitors power consumption of each EVSE unit, calculates available breaker capacity, adjusts current limits in real-time, and manages communication between units. This multi-functional approach consolidates what could be multiple separate systems into one unified controller, reducing overall system complexity while maintaining advanced power optimization capabilities.
Data Source
AI summary
A multiple EVSE installation employs a power sharing system for EVSE pairs which share a common circuit breaker. When only one EVSE is connected to an electric vehicle for charging, the connected EVSE is allowed to charge at full capacity. When a second EV connects to the second EVSE of the pair, while the first EVSE is charging, a controller senses the latter event and issues commands to both EVSE units to limit their current so that the rated circuit breaker capacity is not exceeded. The controller continuously monitors the charging of each of the EVSE units and sends commands to adjust the supply of current to each EVSE accordingly.