Integrated Charging Unit and Drive Converter for High-Power EV Traction

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Solution Overview

Problem

Conventional traction networks for motor vehicles are limited by low AC charging power and lack of vehicle-controlled DC charging current, requiring separate components and infrastructure for higher charging powers, which restricts efficient battery charging.

Innovation Solution

A traction network integrating a charging unit and drive converter with power electronic components like IGBTs and diodes, allowing for multi-phase charging, regulated DC charging, and galvanic isolation, enabling high power density and flexible charging capabilities through shared power semiconductors and converter topologies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If separate components are used for AC charging unit and DC connection, then infrastructure compatibility is maintained, but charging power is limited to 22kW or 44kW

Engineering Contradiction:
Improvecharging powerVSAvoidcomponent integration
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent combines the AC charging unit and DC charging unit into a single integrated charging device that shares power electronic components (IGBTs, diodes, capacitors) with the drive converter. This merging allows the system to achieve higher charging powers (up to 300kW) while reducing overall system complexity through component sharing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The drive converter is designed with universal power electronic components that can serve multiple functions: driving the electric machine, AC charging, and DC fast charging. The IGBTs and diodes are configured to handle both motor operation and charging operations, allowing a single component set to perform multiple roles in the traction network.

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

2Ease of operation

If conventional AC charging units are used, then infrastructure compatibility is ensured, but vehicle control over charging current is lost

Engineering Contradiction:
Improvevehicle control capabilityVSAvoidcontrol system integration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The integrated charging device enables the vehicle to independently control its own charging process. The vehicle's energy management system can directly regulate the charging current and voltage through the shared power electronic components, eliminating the need for external off-board current control and giving the vehicle full autonomy over charging parameters.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The integrated control system incorporates feedback mechanisms that allow the vehicle to monitor charging parameters and adjust power flow in real-time. The control unit receives feedback from sensors monitoring battery state, current, and voltage, enabling precise vehicle-controlled charging current regulation throughout the charging process.

Inventive Principle:
Principle #23Feedback

3Power

If power semiconductors are dedicated solely to drive converter, then driving performance is optimized, but charging power density is reduced

Engineering Contradiction:
Improvepower densityVSAvoidcomponent utilization
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The power semiconductors (IGBTs and diodes) are designed with universal capability to handle both driving and charging operations. The same semiconductor switches and rectifier diodes that drive the motor during vehicle operation are configured to perform power conversion during AC and DC charging, maximizing component utilization and achieving high power density without requiring separate dedicated charging components.

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

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 integrated approach enables high-power charging up to 300kW, supports both AC and DC fast charging, and allows vehicle-controlled power management, reducing infrastructure requirements and enhancing charging efficiency for long-range electric vehicles.

Implementation Method 1

A galvanic isolation of the charging unit from the traction battery can be achieved, for example, via a series resonant circuit, which includes, for example, a transformer

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3238978A1Combined multilevel converter and acdc power charging unit
Publication Date: 2017.11.01 VOLKSWAGEN AG
  • EP3238978A1 patent drawingFigure 1
  • EP3238978A1 patent drawingFigure 2
  • EP3238978A1 patent drawingFigure 3

AI summary

Traction network for a motor vehicle, comprising a charging unit (2) for charging a traction battery (3), and a drive inverter (1) that couples both an electric machine (4) and the charging unit (2) to the traction battery (3).