Open-Winding EV Drive Inverter for Traction and Charging Integration
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Solution Overview
Problem
Current electric vehicle (EV) systems lack an integrated power conversion system that efficiently enables traction, DC charging, and AC charging with an open-winding drive system, leading to increased complexity, weight, and cost.
Innovation Solution
An integrated power conversion system for EVs utilizing an electric motor with open windings, two inverters/power converters, and two battery groups, allowing for traction, DC charging, and AC charging in a compact package, with fault-tolerant and efficient power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate traction inverters, on-board chargers, and DCDC converters are used, then each component can be optimized for its specific function, but the overall system complexity, weight, and cost increase
Solution Approach 1:
The patent combines the traction inverter, on-board charger, and DCDC converter functions into a single integrated power conversion system. The first and second inverters share a common motor (the electric vehicle), and both battery groups are integrated into the same system architecture. This merging eliminates the need for separate standalone components, thereby reducing system complexity, weight, and cost while maintaining all required functions.
Solution Approach 2:
The integrated power conversion system is designed to perform multiple functions simultaneously: it can operate as a traction inverter to drive the motor, as an on-board charger to receive AC power, and as a DCDC converter to manage power between battery groups. The system's modular inverter architecture with open-winding motors enables it to adapt to different operational modes, providing universal functionality across all power conversion needs.
2Device complexity
If a single battery group is used with open-winding motors, then the system structure is simpler, but the ability to enable all traction, DC charging, and AC charging functionalities is limited
Solution Approach 1:
The patent divides the battery system into two separate battery groups (first and second battery groups), each connected to its own inverter. This segmentation allows independent management and charging of each battery group, enabling the system to handle different charging scenarios (DC charging of one or both groups, AC charging) while maintaining a relatively simple overall structure through the modular architecture.
Solution Approach 2:
The dual battery group configuration, combined with the open-winding motor architecture, enables the system to perform multiple charging functions: DC charging can be applied to either or both battery groups independently, AC charging can charge both groups simultaneously or sequentially, and the system can balance power between groups. This multi-functional capability is achieved while keeping the system structure manageable through the integrated inverter design.
3Adaptability or versatility
If multiple battery groups are used, then all traction, DC charging, and AC charging functionalities are enabled, but the system complexity increases
Solution Approach 1:
The patent merges the control and power conversion functions for two battery groups into an integrated system where the first and second inverters share common components and control architecture. The open-winding motor structure allows both inverters to connect to the same motor terminals, reducing the need for separate complete inverter modules. This merging approach enables dual battery group management while controlling overall system complexity.
4Device complexity
If an integrated power conversion system is used, then complexity, weight, and cost are reduced, but the need for open-winding motors with accessible terminals is required
Solution Approach 1:
The open-winding motor design provides universal accessibility to all stator winding terminals, allowing multiple inverters to connect to the same motor without requiring additional windings or complex connection structures. This universal access capability simplifies the overall system integration while the motor itself remains a standard electromagnetic device that can be manufactured using conventional techniques, thus balancing manufacturability with integration benefits.
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 reduces complexity, weight, and cost while providing efficient power conversion and balancing across battery groups, enhancing EV range and functionality.
Implementation Method 1
Each power converter can have any topology that enables conversion from DC voltage on the battery side to AC voltage on the EM side
Implementation Method 2
The stator windings are accessible on both ends of the EM and centrally, and the EM has terminals equal to 2-times the number of phases
Data Source
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AI summary
An integrated power conversion system for an electric vehicle including: an electric motor utilizing open stator windings; a direct-current-to-alternating-current (DCAC) inverter/power converter electrically coupled to an end of the open stator windings; and a battery group electrically coupled to the inverter/power converter; where the integrated power conversion system is adapted to be selectively operated in all of a traction mode, a lower voltage direct-current (DC) charging mode, a higher voltage DC charging mode, and an alternating current (AC) charging mode. The integrated power conversion system may also include: another DCAC inverter/power converter electrically coupled to another end of the open stator windings opposite the inverter/power converter; and another battery group electrically coupled to the other inverter/power converter, where the other battery group is isolated from the battery group. The DCAC inverters/power converters may be 2-level or multilevel.