EV Charging Load Balancing via Phase Voltage Feedback

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Solution Overview

Problem

The challenge is to manage the load on a three-phase energy supply network when multiple electric vehicles are charged simultaneously, as uneven distribution can lead to network overload and potential failures, with drivers unable to determine the load on the phase their vehicle is connected to.

Innovation Solution

A system that includes a measuring device to determine charging voltage characteristics, an evaluation device to extract relevant variables, and a communication device to share these with other vehicles, allowing a control device to adjust charging power based on the phase position and magnitude of the charging voltage, thereby balancing the network load without user intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple electric vehicles are charged simultaneously from a three-phase network, then the charging capacity and productivity increase, but the network load becomes unbalanced leading to phase overload and potential network failure

Engineering Contradiction:
Improvecharging capacityVSAvoidnetwork stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system continuously measures the charging voltage at the charging interface to determine characteristic variables including phase position and magnitude. This measurement feedback is communicated to other vehicles in real-time, enabling dynamic adjustment of charging power based on actual network conditions to prevent phase overload while maintaining high charging capacity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The charging power is dynamically adjusted based on real-time phase load conditions. When a phase becomes overloaded, the system automatically reduces charging power for vehicles connected to that phase and redirects power to underloaded phases, creating a dynamic load balancing mechanism that maintains network reliability during simultaneous charging of multiple vehicles

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If single-phase charging stations are evenly distributed across three phases, then the network load is balanced on average, but local asymmetrical load can still occur when multiple vehicles connect to the same phase

Engineering Contradiction:
Improveautomatic load balancingVSAvoidcommunication and control system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Each electric vehicle is equipped with a measuring device that autonomously determines the phase position and magnitude of the charging voltage. The vehicle's control system automatically communicates this information to other vehicles and adjusts its own charging power without external intervention, enabling self-service load balancing that reduces the need for complex centralized control infrastructure

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary measurement of charging voltage characteristics and phase position before charging begins. This advance information is communicated to other vehicles, allowing proactive load distribution decisions to be made before asymmetrical loading occurs, preventing network overload rather than reacting to it

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3041703B1System for charging an electric vehicle, electric vehicle and method
Publication Date: 2020.09.09 ROBERT BOSCH GMBH
  • EP3041703B1 patent drawingFigure 1
  • EP3041703B1 patent drawingFigure 2
  • EP3041703B1 patent drawingFigure 3~4

AI summary

The invention relates to a system for charging an electric vehicle, comprising a measuring device which is designed to measure a charge voltage on a charging interface of the electric vehicle, an evaluation device which is designed to determine first characteristic variables from the measured charge voltage, a communication device which is designed to transfer the first characteristic variables to other electric vehicles and/or to capture, from the other electric vehicles, second characteristic variables relating to charge voltages of the other electric vehicles, a control device which is designed to control, in accordance with the first and/or second characteristic variables, the charge power withdrawn from an energy supply network by the electric vehicle by means of the charging interface. The invention also relates to an electric vehicle and a a method.