Fleet Charging Controller Predicts Demand to Store Energy
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Solution Overview
Problem
Battery-electric vehicles (BEVs) face limitations in range and charging time compared to internal combustion engine vehicles, and there is insufficient public infrastructure for recharging, discouraging widespread adoption.
Innovation Solution
A fleet charging system with a controller that predicts charge demand and time intervals for both fleet and non-fleet vehicles, allowing fleet vehicles to store excess energy for sale to non-fleet vehicles, and throttle charging rates to minimize energy differences, while providing incentives for reservation requests and optimizing energy usage based on tiered electric rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fleet vehicles are charged to full capacity for their own use, then fleet vehicle operational reliability is improved, but energy availability for nonfleet vehicles decreases
Solution Approach 1:
The system performs preliminary charging of fleet vehicles beyond their immediate operational needs when electricity costs are low, storing excess energy in advance for future nonfleet vehicle charging demands. This advance preparation allows the system to meet both fleet reliability requirements and public charging demands without conflict.
Solution Approach 2:
The charging strategy dynamically adjusts the charge level of fleet vehicles based on predicted nonfleet charging demands and electricity price variations. The system optimizes the balance between fleet vehicle charge levels and energy reserved for public use, adapting to changing conditions in real-time to maximize overall system efficiency and revenue.
2Loss of energy
If charging rates for nonfleet vehicles are throttled to match energy stored, then energy cost efficiency is improved, but charging service quality deteriorates
Solution Approach 1:
The system changes the parameter of charging rate dynamically based on the balance between energy stored in fleet vehicles and energy demanded by nonfleet vehicles. When stored energy exceeds demand, the system throttles charging rates to optimize cost efficiency; when stored energy is insufficient, charging rates are increased to meet demand, thus adapting the service quality to current system conditions.
Solution Approach 2:
The system continuously monitors the difference between energy stored in fleet vehicles and actual energy delivered to nonfleet vehicles, using this feedback to adjust charging rates. This closed-loop control ensures that throttling is applied only when it is cost-effective and does not compromise service quality when energy availability is sufficient.
3Reliability
If fleet vehicles are charged during high electricity cost periods, then fleet vehicle charging reliability is improved, but overall energy cost increases
Solution Approach 1:
The system charges fleet vehicles during periods of low electricity cost in advance of when they are needed, performing the charging action beforehand when it is more economical. This preliminary charging during off-peak hours ensures fleet vehicles are ready for operation while minimizing energy costs, avoiding the need to charge during expensive peak periods.
Solution Approach 2:
The system implements periodic charging cycles that alternate between low-cost and high-cost periods, charging fleet vehicles during economical off-peak hours and reducing or eliminating charging during expensive peak hours. This periodic strategy maintains fleet reliability while optimizing the timing of energy consumption to minimize overall costs.
Data Source
AI summary
A fleet charging system includes a plurality of chargers. A controller is programmed to predict charge demand for fleet and nonfleet vehicles over a predetermined time interval. The controller generates a charge strategy for the predetermined time interval that minimizes a total energy cost and includes storing energy in the fleet vehicles for sale to the nonfleet vehicles. The controller charges and discharges the fleet and nonfleet vehicles according to the charge strategy.