EV Charger Scheduling for Three-Phase Load Balancing
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Solution Overview
Problem
Existing charge control devices cause unbalanced loading of phases in three-phase alternating current systems during vehicle battery charging, leading to inefficiencies and reduced transmission efficiency.
Innovation Solution
A charge control device that includes a processor to acquire scheduled delivery times and battery state of charge, and balances the three-phase alternating current by controlling the charging start and end times of multiple chargers connected to different phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If chargers start charging in the order vehicles are connected without phase balancing control, then charging simplicity is maintained, but phase unbalance occurs leading to reduced transmission efficiency
Solution Approach 1:
The charging control device monitors the current load on each phase in real-time and uses this feedback information to dynamically adjust charging start times and power allocation. This ensures that phase unbalance is detected and corrected through controlled charging scheduling, improving transmission efficiency while maintaining manageable system complexity through automated monitoring and adjustment
Solution Approach 2:
The system performs preliminary assessment of vehicle charging requirements (delivery scheduled time and amount of charge) before actual charging begins. By pre-planning the charging schedule across different phases based on these requirements, the system proactively prevents phase unbalance rather than reacting to it, thereby improving transmission efficiency without requiring complex real-time control adjustments
2Productivity
If multiple vehicles are charged simultaneously on the same phase, then charging speed is improved, but phase unbalance occurs causing load increase on substation
Solution Approach 1:
The system segments the charging load across multiple phases (U-phase, V-phase, W-phase) by distributing vehicle charging assignments to different phases. Instead of concentrating all charging on a single phase for speed, the system divides the charging workload segmentally across three phases, maintaining both charging productivity and phase balance stability through balanced distribution
Solution Approach 2:
The charging allocation system dynamically adjusts which phase receives charging loads based on real-time or predicted phase load conditions. By making the phase assignment dynamic rather than static, the system can optimize for both charging speed (when a phase has capacity) and phase balance stability (by redirecting to underutilized phases), resolving the contradiction between productivity and reliability
3Loss of energy
If charging schedule is optimized for phase balance, then transmission efficiency is improved, but charging control complexity increases
Solution Approach 1:
The charging control device automatically performs phase balance optimization without requiring external intervention or complex manual scheduling. The system serves itself by autonomously monitoring phase loads, assessing vehicle requirements, and making optimal charging schedule decisions, thereby improving transmission efficiency while keeping the control system complexity manageable through self-contained automated logic
Solution Approach 2:
The system optimizes phase balance by changing key charging parameters such as charging start time, end time, and power allocation levels. By adjusting these controllable parameters based on phase load conditions and vehicle requirements, the system achieves improved transmission efficiency through parameter optimization rather than requiring complex structural changes to the charging infrastructure
Data Source
AI summary
A charge control device includes a processor configured to: acquire a delivery scheduled time of a vehicle and an amount of charge of a rechargeable battery when the vehicle including the rechargeable battery is connected to any one of a plurality of chargers of a single phase, each of the plurality of chargers being connected to each phase of the three-phase alternating current; and control the any one of the plurality of chargers such that the three-phase alternating current is balanced according to the delivery scheduled time and the amount of charge.