EV Charger Junction Box Switching for V2G and Backup Power
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Solution Overview
Problem
Existing charging systems for electric vehicles lack efficient control mechanisms to manage power supply and charging operations based on power failure conditions and the operation mode of external on-board chargers, leading to suboptimal power distribution between the system power supply, external loads, and on-board chargers.
Innovation Solution
A charger system with a junction box and a controller that selectively connects terminals to the system power supply, external load, and external on-board charger, allowing for adaptive power routing based on power failure status and operation mode, utilizing a switch unit and communication device to manage connections and operation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional unidirectional charger is used, then the charging function is simple and reliable, but the system cannot supply power to external loads or perform V2G/V2H operations
Solution Approach 1:
The on-board charger is designed to perform multiple functions: it can charge the vehicle battery from the power supply network, supply power to external loads (V2H), and return power to the grid (V2G). The switch unit enables the charger to dynamically reconfigure its operation mode based on system conditions, allowing a single device to replace multiple specialized charging devices.
2Reliability
If the on-board charger operates in V2G mode, then the system can stabilize power quality and generate profits, but the control mechanism becomes complex and requires coordination with grid conditions
Solution Approach 1:
The switch unit dynamically reconfigures the electrical connections based on real-time system conditions. When operating in V2G mode, the switch unit connects the on-board charger to both the power supply network and the grid, enabling bidirectional power flow. The controller continuously monitors system state and adjusts the switch configuration accordingly, allowing the system to adapt to changing grid conditions and maintain power quality stability.
Solution Approach 2:
The control mechanism incorporates feedback from the power supply network and grid status to regulate the on-board charger's operation. The controller receives information about system conditions and adjusts the charging/discharging rate and switch configuration to maintain power quality and optimize profit generation from V2G operations.
3Reliability
If the on-board charger operates in V2H mode, then the battery can serve as backup power source during power failure, but the system requires sophisticated control to manage power distribution between multiple loads
Solution Approach 1:
The switch unit segments the power distribution paths into distinct configurable connections. During V2H operation, the switch unit can isolate the vehicle battery from the power supply network and connect it directly to external loads, creating an independent backup power system. This segmentation allows the battery to serve as a standalone power source during grid failures while simplifying the control logic by dividing the system into separate operational zones.
Solution Approach 2:
The switch unit acts as an intermediary device that manages power flow between the on-board charger, power supply network, vehicle battery, and external loads. It mediates the complex power distribution requirements by providing configurable connection paths, allowing the system to seamlessly transition between grid-powered operation and battery backup mode while managing multiple external loads.
4Productivity
If the switch unit dynamically reconfigures connections based on power failure and operation mode, then power distribution efficiency is optimized, but the system complexity and control requirements increase
Solution Approach 1:
The switch unit is designed to dynamically reconfigure electrical connections based on real-time system conditions such as power failure detection and desired operation mode. The controller automatically adjusts the switch configuration to optimize power distribution efficiency, enabling the system to adapt its topology for charging, V2H, or V2G operations without manual intervention.
Data Source
AI summary
Disclosed are a charging system including a junction box having a first terminal connected to a system power supply, a second terminal connected to an external load, a third terminal connected to an external on-board charger, and a switch unit configured to selectively connect at least two of the first to third terminals, and a controller configured to control a connection state of the switch unit on the basis of whether power failure occurs in the system power supply and an operation mode of the external on-board charger, and a charger for the charging system.