Modular Bidirectional DC Wallbox for Parallel EV Charging
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Solution Overview
Problem
Current bidirectional charging systems are complex and expensive, limiting their adoption in private environments, and existing standards prohibit parallel charging of multiple electric vehicles, necessitating separate charging infrastructure for each vehicle.
Innovation Solution
A modular, wall-mounted bidirectional DC charging station with electrical isolation and a modular expansion design, allowing for simultaneous standard-compliant charging of multiple electric vehicles, featuring a rectifier with power factor correction, DC/DC converters with adjustable output voltages, and the ability to distribute charging power flexibly between vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a customer owns several electric vehicles and wishes to connect them at the same time to his charging infrastructure, then the charging capacity must be increased, but purchasing a further DC wallbox and having it installed in his garage is required, which increases installation complexity and cost
Solution Approach 1:
The charging system is divided into modular units with independent AC inputs that can be connected in parallel. Each module can serve one or more vehicles independently, allowing incremental expansion from 1 to N vehicles without requiring complete system replacement or complex multi-phase configurations.
Solution Approach 2:
The charging module is designed to be universally applicable for charging multiple electric vehicles simultaneously through parallel AC connections. The same basic module configuration serves both single-vehicle and multi-vehicle charging needs, eliminating the need for different infrastructure types.
2Adaptability or versatility
If private DC charging systems are used, then charging flexibility is improved, but the systems are very complex and expensive
Solution Approach 1:
The complex DC charging function is segmented into separate modular units, each handling AC input, rectification, and DC output independently. This modular approach simplifies the overall system architecture while maintaining DC charging flexibility, as each module operates autonomously without requiring complex coordination between multiple high-voltage DC systems.
Solution Approach 2:
The system introduces an intermediary AC bus connection between independent charging modules. This AC intermediary allows multiple modules to communicate and coordinate power distribution without requiring direct complex DC-DC coupling, thereby simplifying control while maintaining charging flexibility.
3Productivity
If parallel charging of several vehicles at the charging station is implemented, then charging efficiency is improved, but standard DIN EN 61851-23 prohibits this configuration
Solution Approach 1:
The charging station is segmented into independent charging modules, each with its own AC input and control system. This segmentation allows each module to independently charge one or more vehicles in parallel while maintaining individual compliance with charging standards, thereby achieving overall standard-compliant parallel charging capability.
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
Enables cost-effective expansion of charging capacity without additional infrastructure, allowing for simultaneous charging of vehicles with different voltages and bidirectional energy transfer, reducing installation costs and enhancing flexibility in power distribution.
Implementation Method 1
a rectifier (AC/DC converter) with a power factor correction filter (PFC) configured to rectify a three-phase AC voltage
Implementation Method 2
an alternating voltage bus system (AC bus) having a primary side and a secondary side electrically isolated therefrom
Data Source
AI summary
A bidirectional DC charging station is provided for wall mounting (DC wallbox) for a private sphere, to which a plurality of electric vehicles can be connected in parallel. A method for operating the DC wallbox is also provided.