Open-Winding EV Drive Conversion for Traction and Multi-Mode Charging
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Solution Overview
Problem
Existing 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 (lower and higher voltage), and AC charging, with a compact design that includes a multilevel stator voltage and fault-tolerant operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate traction inverters, on-board chargers, and DCDC converters are used, then each component can perform its specific function reliably, but the system complexity, weight, and cost increase
Solution Approach 1:
The patent combines separate power conversion components (traction inverter, on-board charger, DCDC converter) into a single integrated power conversion system that handles multiple functions through one unified architecture, thereby reducing system complexity, weight, and cost while maintaining reliability through coordinated control of the integrated components
Solution Approach 2:
The integrated power conversion system is designed to perform multiple functions including AC charging, DC charging, and traction motor control through a single system architecture, eliminating the need for separate dedicated components for each function and reducing overall system complexity
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 charging modes and balance batteries is limited
Solution Approach 1:
The patent divides the battery system into multiple battery groups (first and second battery groups) that can be independently managed and connected in different configurations, enabling the system to support multiple charging modes and provide active balancing between groups while maintaining manageable structural complexity
Solution Approach 2:
The patent utilizes the open-winding motor structure to access stator windings at multiple points (both ends and centrally), adding spatial dimensions for connection flexibility that enable multiple charging modes and battery balancing functions without proportionally increasing system complexity
3Device complexity
If an integrated power conversion system is implemented, then complexity, weight, and cost are reduced, but the system must efficiently handle multiple charging modes and functions
Solution Approach 1:
The integrated power conversion system employs dynamic switching between different operational modes (AC charging mode, DC charging mode, traction mode) and configurable battery group connections (series/parallel arrangements) to adapt to various charging requirements and vehicle operating conditions, maintaining versatility through flexible control rather than fixed architecture
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 a compact, efficient, and cost-effective solution that integrates traction, DC charging, and AC charging, with improved electromagnetic interference (EMI) performance and active balancing of 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
an electric motor (EM) with open windings
Implementation Method 3
the inverter/power converter forming a boost direct-current-to-direct-current (DCDC) converter between the DC charger and the battery group
Data Source
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.