Centralized EV Charging System with Vehicle-Integrated DC-DC Converters

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Solution Overview

Problem

Existing charging systems for motor vehicles are technically complex due to the need for additional DC-DC converters at each charging point for vehicle-specific charging control and inflexible for temporary installations, requiring multiple step-down converters as the number of charging interfaces increases.

Innovation Solution

A centralized AC to DC converter generates a uniform DC voltage distributed to multiple charging interfaces without further conversion, with each vehicle equipped with its own DC-DC converter to adapt the voltage to its energy store, and communication allows for adaptive power management between vehicles and the charging system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional DC-DC converters are installed at each charging point for vehicle-specific charging control, then charging adaptability to different battery voltages is improved, but device complexity increases

Engineering Contradiction:
Improvecharging adaptabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system divides the DC-DC conversion function into two parts: the stationary charging device provides a standardized DC output, and each motor vehicle contains its own DC-DC converter that adapts the voltage to the specific battery requirements. This segmentation eliminates the need for multiple DC-DC converters at charging points while maintaining charging adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of having the charging infrastructure adapt to each vehicle's battery voltage through multiple DC-DC converters, the invention inverts the approach by having each vehicle adapt the standardized DC voltage from the charging infrastructure through its own onboard DC-DC converter.

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If multiple DC-DC converters are deployed to support multiple charging interfaces, then charging control flexibility is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvecharging control flexibilityVSAvoidease of manufacture
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The stationary charging device is designed with a universal DC output that can serve multiple charging interfaces simultaneously. The standardized DC voltage can be distributed to any number of vehicles with different battery configurations, eliminating the need for vehicle-specific conversion infrastructure at each charging point.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If additional converters are added for each charging interface, then vehicle-specific charging capability is improved, but loss of substance increases

Engineering Contradiction:
Improvevehicle-specific charging capabilityVSAvoidmaterial loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The invention merges the DC-DC conversion function into the motor vehicle itself rather than having separate converters at each charging point. This consolidation eliminates redundant conversion equipment and reduces material consumption while maintaining the ability to provide vehicle-specific charging capability.

Inventive Principle:
Principle #5Merging (Combining)

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 approach simplifies the charging system infrastructure, reduces the need for additional converters, and allows for flexible and efficient charging of multiple vehicles with minimal circuitry, enabling easy temporary installations and adaptive power management.

Implementation Method 1

A central converter unit of the charging device is configured to convert an alternating current (AC) voltage from an electrical supply network or power grid into a direct current (DC) voltage. The converter unit can therefore include at least one rectifier.

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP3549812A1Charging system and method for charging the electrical energy storage device of a plurality of motor vehicles and stationary charger and motor vehicle
Publication Date: 2019.10.09 AUDI AG
  • EP3549812A1 patent drawingFigure 1~2
  • EP3549812A1 patent drawingFigure 3~4
  • EP3549812A1 patent drawingFigure 5

AI summary

The invention relates to a charging system (S) for charging a respective electrical energy storage device (12) of several motor vehicles (11), comprising a stationary charging device (10) and the motor vehicles (11), wherein a central converter device (14) is configured to convert an alternating voltage (Uac) into a direct voltage (U).The invention provides that a distribution device (15) is configured to distribute the DC voltage (U) from the converter device (14) to several charging interfaces (16) without a further converter step, and that each of the motor vehicles (11) has a tap device (21) for tapping the DC voltage (U) at one of the charging interfaces (16), wherein the tap device (21) is coupled to the respective energy storage device (12) of the motor vehicle (11) via a vehicle-integrated DC voltage converter (22) and a control device (23) of the motor vehicle (11) is configured to adjust an electric charging current (I1, I2) flowing between the charging interface (16) and the energy storage device (12) and/or a transmitted electric charging power by controlling the DC voltage converter (22).