Vehicle DC Charging System Eliminating AC Conversion Losses

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Solution Overview

Problem

Existing mobile electric vehicle charging systems convert direct current to alternating current and back, resulting in low energy transfer rates and significant power wastage, making them inefficient for charging electric vehicles.

Innovation Solution

A vehicle-based direct current charging system that includes a battery, a direct current voltage converter, and a thermal management system, which determines the charging voltage of an electric vehicle and supplies direct current at that voltage, eliminating the need for AC conversion and optimizing energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If existing mobile charging systems convert DC to AC and back to DC, then the system can charge electric vehicles using a battery, but the energy transfer rate is low and significant power is wasted

Engineering Contradiction:

Improvepower wastageVSAvoidenergy transfer rate

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The patent extracts and eliminates the unnecessary AC conversion stage from the charging system. By using a DC-DC converter instead of a DC-AC-inverter-AC-DC converter, the system removes the redundant conversion step that causes energy loss, directly converting DC from the battery to DC for the electric vehicle charging port.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the mechanical/electrical conversion system (DC-AC-DC) with a more efficient direct conversion system (DC-DC). The DC-DC converter replaces the inverter and rectifier components, eliminating the need for mechanical switching and electromagnetic conversion losses associated with AC intermediate conversion.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of time

If existing mobile charging systems use AC conversion, then the system can be simpler in design, but the charging time increases due to low energy transfer rates

Engineering Contradiction:

Improvecharging timeVSAvoidsystem complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent changes the electrical parameters of the charging system by operating entirely in DC mode rather than converting through AC. The DC-DC converter adjusts voltage and current parameters directly without the frequency conversion and phase control required in AC systems, enabling higher power transfer rates and faster charging.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If a DC-DC converter is used instead of AC conversion, then energy transfer efficiency is improved, but the system requires precise voltage matching with the electric vehicle

Engineering Contradiction:

Improveenergy transfer rateVSAvoidvoltage compatibility

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic DC-DC converter system that can adjust its output voltage and current in real-time based on the electric vehicle's charging requirements. The converter dynamically matches the battery voltage to the vehicle's charging port voltage, enabling high-efficiency power transfer while maintaining compatibility with different vehicle types and charging standards.

Inventive Principle:

Principle #15Dynamics

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

The system provides high voltage, Level 3 direct current charging with significant energy savings, delivering 50 kW or more of power while maintaining the battery within a specified temperature range for increased efficiency.

Implementation Method 1

a direct current voltage converter configured to convert direct current received from the battery to a second voltage corresponding to the charging voltage of the electric vehicle

Methodology Applied

Scientific EffectDirect current voltage conversion:

Implementation Method 2

a thermal management system configured to maintain the battery within a selected temperature range

Methodology Applied

Scientific EffectThermal management:

Data Source

PatentUS11485251B2Vehicle-based charging system for electric vehicles

Publication Date: 2022.11.01 MERCEDES-BENZ RES & DEV NORTH AMERICA

AI summary

A vehicle is configured to charge other electric vehicles. The vehicle includes a battery with a number of battery cells, the battery being configured to output direct current at a first voltage. The vehicle also includes a direct current voltage converter configured to convert direct current received from the battery to a second voltage and an electrical connector in electrical communication with the direct current voltage converter, the electrical connector being configured to supply direct current at the second voltage from the direct current voltage converter to an electric vehicle. The vehicle further includes a control system configured to determine a charging voltage of an electric vehicle, and operate the direct current voltage converter to output direct current at a second voltage corresponding to the charging voltage of the electric vehicle, and a thermal management system configured to maintain the battery within a selected temperature range.