DC Charging Device Phase Load Balancing
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Solution Overview
Problem
High charging currents for electric vehicles burden the supply network, leading to maximum current carrying capacity and inclination load issues, especially when multiple charging points are connected simultaneously, necessitating load distribution and potential reduction of charging currents to comply with network specifications.
Innovation Solution
A charging infrastructure arrangement that includes a DC charging device with an AC/DC converter, which balances load currents between phase conductors of a three-phase supply system by determining cumulative and local loads, introducing balancing currents to maintain within specified limits, thereby ensuring even loading and preventing peak loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high charging currents are provided for electric vehicles, then charging speed is improved, but the supply network becomes overloaded exceeding maximum current carrying capacity and inclination load limits
Solution Approach 1:
The DC charging device acts as an intermediary between the three-phase supply system and the electric vehicle. It measures the cumulative load of each phase conductor, calculates the inclination load, and introduces balancing currents to compensate for phase imbalances. This mediator function allows high charging currents to be provided while maintaining compliance with supply network limits by actively managing the load distribution across phases.
Solution Approach 2:
The system dynamically changes the charging current parameters based on the measured phase load conditions. The DC charging device adjusts the magnitude and phase of the charging current, and introduces compensating balancing currents to maintain the inclination load within specified limits. This parameter adaptation enables high charging speeds while respecting network constraints.
2Reliability
If multiple AC load units are connected to different phase conductors to distribute load, then maximum current carrying capacity compliance is improved, but device complexity increases
Solution Approach 1:
The DC charging device performs multiple functions: it charges electric vehicles with high currents, measures the cumulative load of each phase conductor, calculates the inclination load, and introduces balancing currents. By consolidating these functions into a single device rather than requiring separate load distribution systems, the solution maintains compliance with current carrying capacity limits while avoiding the complexity of additional dedicated load distribution infrastructure.
3Reliability
If charging current is reduced for individual or all vehicles to comply with maximum current carrying capacity, then supply network compliance is improved, but charging speed decreases
Solution Approach 1:
The DC charging device continuously measures the cumulative load of each phase conductor and uses this feedback to dynamically adjust the charging current. By monitoring the actual load conditions in real-time and introducing balancing currents based on the measured phase imbalances, the system maintains compliance with maximum current carrying capacity limits while providing high charging currents to vehicles, thus avoiding the need to reduce charging speed.
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 effectively balances the load in the three-phase supply system, reducing the actual inclination load and maintaining the maximum current carrying capacity, allowing for faster and higher charging currents without overburdening the external supply network.
Implementation Method 1
a DC charging device (5) with an AC/DC converter (24) connected via connection conductors (16, 17, 18, 19) to the three-phase supply system (7)
Implementation Method 2
introducing a balancing current between the phase conductors (L1, L2, L3) of the three-phase supply system (7) such that the limit values for the maximum inclination load and/or the maximum current carrying capacity are not exceeded in the connection point (6)
Data Source
Figure 1
Figure 2a~3
Figure 4~5
AI summary
The invention relates to a charging infrastructure arrangement for charging electric vehicles comprising a connection point (6) configured for connecting the charging infrastructure arrangement to an external supply network (8), comprising a three-phase supply system (7) with three phase conductors and a neutral conductor leading to the connection point, comprising at least one AC charging point (1-4) connected to at least one phase conductor of the three-phase supply system (7) and the neutral conductor, and comprising a DC charging device (5) with an AC/DC converter connected via connection conductors to the phase conductors and the neutral conductor of the three-phase supply system (7).wherein a maximum current-carrying capacity and/or a maximum unbalanced load are specified for the connection point (6) and wherein the DC charging device (5) is configured to receive information about a cumulative load on each phase conductor of the three-phase supply system (7) by the AC load units and/or a local load on the three-phase supply system (7) by each individual AC load unit, to provide a charging current at a charging point of the DC charging device (5) for an electric vehicle connected to the charging point and to induce a balancing current between the phase conductors and the neutral conductor of the three-phase supply system (7) such that the maximum unbalanced load and/or the maximum current-carrying capacity are not exceeded at the connection point. Furthermore, the invention relates to an unbalanced load balancing unit for a charging infrastructure arrangement and an operating method therefor.