Power Sharing Relay for EVSE Load Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing EVSE installations in older homes and multi-unit dwellings often lack sufficient electrical power capacity to charge newer electric vehicles efficiently, as they typically require 220V AC at 30 to 50 amps, which is not feasible with 100 amp service panels, and sharing the same breaker with household utilities violates electrical codes due to concurrent power usage concerns.
Innovation Solution
A power sharing device with a microprocessor-controlled relay system that senses utility current, allowing full power charging to EVSE when utility current is below a threshold, reducing power to EVSE when exceeding the threshold, and restoring full power after a delay, ensuring compliance with electrical codes and efficient power allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If EVSE is connected to share the same breaker with household utility, then power capacity for EV charging is improved, but electrical code compliance deteriorates due to concurrent power usage concerns
Solution Approach 1:
The system dynamically switches the breaker connection between household utility and EVSE based on power availability. The microprocessor monitors utility power consumption and actuates the relay to connect EVSE to the breaker only when sufficient power is available, creating a dynamic, adaptive solution that maintains code compliance while enabling power sharing capability.
Solution Approach 2:
The microprocessor continuously monitors the utility's power consumption and uses this feedback to control the relay switching. When utility power drops below a threshold, the system automatically switches the breaker to supply EVSE, and vice versa, creating a closed-loop feedback system that manages power allocation in real-time.
2Reliability
If automatic switching between utility and EVSE is implemented, then electrical code compliance is improved, but device complexity increases
Solution Approach 1:
The microprocessor performs multiple functions: monitoring utility power consumption, determining power availability, controlling the relay switching, and managing the time delay logic. By consolidating these functions into a single multi-functional device, the system achieves code compliance without proportionally increasing overall system complexity.
Solution Approach 2:
The relay acts as an intermediary switching device that physically connects or disconnects the EVSE from the breaker based on microprocessor commands. This intermediary component simplifies the control architecture by providing a clear on/off switching mechanism rather than requiring complex power modulation circuitry.
3Adaptability or versatility
If power is reduced to EVSE when utility current exceeds threshold, then power allocation fairness is improved, but charging speed deteriorates
Solution Approach 1:
The microprocessor continuously monitors utility power consumption in real-time and periodically switches the breaker connection based on whether power thresholds are met. This periodic monitoring and switching enables fair power allocation when utility needs arise, while restoring full charging speed when utility power is available.
Solution Approach 2:
The system implements a time delay after utility power drops below the threshold before switching to EVSE power supply. This preliminary waiting period ensures that transient utility load variations don't cause unnecessary switching, while still enabling timely response when genuine power availability changes occur.
Data Source
AI summary
A power share module is employed to sense the power usage of an electric utility at a residence and to selectively provide power to an EVSE for charging an electric vehicle. If the power drawn by the utility such as an electric dryer or a range is above a certain threshold, power is not supplied to the EVSE. When power is less than the threshold, the power sharing module allows power to be supplied to the EVSE.