Load-Adaptive EVSE Control for Panel Capacity-Limited Charging
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Solution Overview
Problem
Current electrical installations for residences and commercial locations face challenges in efficiently integrating local electric vehicle supply equipment (EVSE) due to inadequate capacity in existing systems, leading to longer installation times, higher costs, and reduced EV charging efficiency, as they are not designed to account for EVSE loads.
Innovation Solution
The implementation of a Load Adaptive EVSE system that uses current transformers to measure real-time power levels and adjust the EVSE load based on the premises' current capacity, ensuring safe and efficient energy distribution by dynamically adjusting the pilot signal to maintain or increase charging capacity as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a local EVSE is installed as an add-on by connecting to the main panel box via a new conduit, then EVSE functionality is added to the premises, but installation complexity and labor time increase significantly
Solution Approach 1:
The patent introduces a new intermediary device - a load management controller that sits between the EVSE and the main panel box. This controller includes a current transformer for monitoring panel load and a communication interface for coordinating with the EVSE, thereby simplifying the physical connection requirements while maintaining safety and functionality.
Solution Approach 2:
The patent segments the EVSE installation into two independent parts: the power delivery component (EVSE) and the load management component (controller with current transformer). This segmentation allows the EVSE to be installed independently without requiring direct integration into the main panel box, reducing installation complexity.
2Power
If the EVSE is sized to draw 50 Amperes or more, then charging capacity is sufficient for EV needs, but service upgrade requirements increase costs and installation time
Solution Approach 1:
The patent implements dynamic load management where the EVSE charging rate is continuously adjusted based on real-time monitoring of the main panel box load. The current transformer measures the existing panel load, and the controller dynamically modulates the EVSE output to ensure the combined load never exceeds panel capacity, eliminating the need for service upgrades.
Solution Approach 2:
The system employs feedback control by continuously monitoring the main panel box current through the current transformer and using this information to adjust the EVSE charging rate. This closed-loop control ensures optimal charging capacity is delivered without overloading the panel, avoiding service upgrade requirements.
3Device complexity
If the EVSE load is reduced due to inadequate current capacity in existing panel boxes, then installation complexity is reduced, but charging duration increases
Solution Approach 1:
The patent makes the EVSE charging rate dynamic rather than static. The system continuously monitors panel box capacity and adjusts the charging rate in real-time, allowing the EVSE to operate at higher rates when panel capacity is available and automatically reducing rates when other loads are active, thereby optimizing charging duration without requiring panel upgrades.
4Reliability
If complete replacement of old systems is performed to locate available spare parts, then system reliability is improved, but installation costs and time increase
Solution Approach 1:
The patent introduces a standalone load management controller as an intermediary device that connects to the main panel box through a simple current transformer and communication interface, rather than requiring integration into the existing panel infrastructure. This approach allows the system to work with existing panel capacity without needing to locate or replace old components.
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
This solution reduces installation complexity and costs, allows for faster EV charging, and enhances energy utilization by automatically adapting to changing load conditions, thereby improving the efficiency and convenience of EVSE integration.
Implementation Method 1
interconnecting a current transformer (CT) at the main service entry point for the meter being served so as to capture the real time power level of the meter
Data Source
AI summary
An adaptive electric vehicle supply equipment (EVSE) unit provides intelligent control to vary the EVSE load placed upon the local electric connection based upon real time load measurements of both the overall premises load and the specific capacities and requirements of the EVSE. The EVSE unit includes a current power transformer at the main service entry point to capture real time power level at the meter. Additional real time current measurements are available within unit to measure the real time output power on the AC legs going to a vehicle. The unit is configured to a controller module which measure and controls the pilot signal output based on a comparison of the power level at the meter with the power level at the EVSE unit against the desired or required power output to the vehicle.