Dual EV Drive Converter Layout for Torque-Free Three-Phase Charging
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Solution Overview
Problem
Existing EV architectures require separate charging and traction systems, leading to high capital and operational expenses, inflexibility, and inefficiencies, especially when charging from a three-phase grid, which can cause mechanical stress and noise.
Innovation Solution
An arrangement for electric power conversion and dual electric drive using two power converters with open-end stator windings and power switches to integrate charging and traction functions, allowing for single-phase or three-phase charging without torque production, utilizing existing power electronics, and enabling bidirectional power flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate charging and traction systems are used, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines charging and traction functions into a single integrated system using two power converters that share common DC link capacitors and control circuitry. The first power converter handles charging operations while the second power converter handles traction motor control, but both converters share the same DC energy storage capacitors and control unit, reducing overall system complexity and cost while maintaining reliability through functional separation during different operating modes.
2Device complexity
If charging and traction functions are fully integrated, then device complexity is reduced, but adaptability deteriorates
Solution Approach 1:
The patent segments the power conversion system into two distinct power converters (first for charging, second for traction) that can operate independently or in coordination. Each converter maintains its own control logic and switching circuits, allowing the system to adapt to different operational requirements (charging mode, traction mode, or combined mode) while sharing common DC link components. This segmentation provides operational flexibility without requiring a completely separate charging system.
3Productivity
If three-phase charging is performed with additional converters, then charging capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing two power converters universal by enabling them to perform both charging and traction functions depending on operational mode. The first power converter can handle three-phase charging input and convert it to DC for the battery, while the second power converter drives the traction motors. Both converters share the same DC link capacitors and control unit, allowing three-phase charging capability without requiring additional dedicated charging converters.
4Power
If charging from three-phase grid is performed, then charging power is improved, but harmful factors increase due to torque production
Solution Approach 1:
The patent dynamically switches between different operational modes using a control unit that monitors system state. During charging operations, the first power converter is activated to handle three-phase grid input and charge the battery through the shared DC link capacitors, while the second power converter is deactivated or used only for traction. This dynamic mode switching ensures that charging power is delivered without producing harmful mechanical torque, noise, or vibration, as the charging and traction functions are temporally separated through intelligent control.
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 integration reduces system size and cost, enhances power density, efficiency, and reliability, while providing customizable operation for various EV requirements, including single-phase and three-phase charging, and bidirectional power flow.
Implementation Method 1
The first power switch is configured to selectively disconnect one of the second ends of the stator windings of the first electric motor from all other of its second ends to establish at most two distinct electric potentials; The second power switch is configured to selectively disconnect one of the second ends of the stator windings of the second electric motor from all other of its second ends to establish at most two further distinct electric potentials.
Implementation Method 2
first and second power converters respectively comprising three legs; A power converter as used herein may refer to a device that is capable of converting electric energy from one form to another, such as converting between alternating current (AC) and direct current (DC) and/or vice versa, changing a voltage or frequency
Implementation Method 3
first and second electric motors respectively including three open-end stator windings respectively having first and second ends; The first ends of the stator windings of the first electric motor are connected to respective legs of the three legs of the first power converter
Data Source
AI summary
The technology of this application relates to an arrangement for electric power conversion and dual electric drive, a system comprising the arrangement, a method of operating the arrangement, and a computer program for carrying out the method, which enable charging of dual-drive electric vehicles (EV) from a three-phase power grid without producing any torque, while making use of all the power electronics already existing for the traction system and the motor inductances. As such, space is saved and power density, efficiency and reliability are increased.