Dual Stator Permanent Magnet Motor for EV Efficiency
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Solution Overview
Problem
Conventional traction motors in electric vehicles face inefficiencies due to inflexible optimal efficiency regions, leading to reduced maximum driving distance, and existing solutions like WCM, MPCM, and MAM have limitations such as short operating time, jerking, maintenance needs, and insufficient torque density.
Innovation Solution
An electric motor with an annular radial stator, an annular axial stator, and a rotor featuring distributed and concentrated windings, and magnets that interact with magnetic fields to provide two high-efficiency regions at both low and high speeds, allowing for energy-efficient operation with minimal moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional traction motor is used, then the motor operates in a single fixed efficiency region, but the motor cannot provide optimal efficiency across all driving conditions leading to reduced driving distance
Solution Approach 1:
The motor dynamically switches between two stators (radial and axial) based on operating conditions, allowing the efficiency region to adapt continuously rather than being fixed. This dynamic configuration change enables the motor to maintain optimal efficiency across varying speed and torque requirements of different driving conditions.
Solution Approach 2:
The invention changes the fundamental operating parameters by switching between two distinct stator configurations with different magnetic field characteristics. The radial stator provides one set of efficiency characteristics while the axial stator provides another, allowing the system to optimize parameters according to real-time driving conditions.
2Adaptability or versatility
If winding-changing motors are used to improve efficiency, then two high-efficiency regions are achieved, but the operating time at high speed is short due to rapid temperature increase
Solution Approach 1:
The invention replaces the winding-changing mechanism with a stator-switching mechanism. Instead of changing windings which generates excessive heat, the system switches between radially-magnetized and axially-magnetized stators. This substitution maintains high-speed capability while avoiding the thermal limitations of winding changes.
3Adaptability or versatility
If magnet pole-changing motors are used to provide two high-efficiency areas, then efficiency is improved, but jerking occurs due to unstable flux flow when changing magnetizing direction
Solution Approach 1:
The invention segments the stator into two independent configurations (radial and axial) rather than attempting to continuously change magnetizing direction. Each stator provides stable flux flow in its optimized configuration, eliminating the jerking caused by continuous magnetization direction changes while still achieving two distinct high-efficiency regions.
4Adaptability or versatility
If mechanical-assisted motors are used to improve high-speed efficiency, then efficiency is improved, but torque density is insufficient for EV application
Solution Approach 1:
The invention merges the advantages of radial and axial stator configurations into a single integrated system. The radial stator provides high torque density for acceleration and low-speed operation, while the axial stator provides high-speed efficiency. By combining these two configurations in one motor system, both torque density and high-speed efficiency requirements are satisfied simultaneously.
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 solution enables high torque density and efficient energy use across varying driving conditions, extending the motor's operating time and improving driving range by maximizing efficiency in both low and high-speed regions.
Implementation Method 1
Flux from the two or more magnets interacts with one or both of a radial stator magnetic field created by a current flowing through the distributed windings disposed along at least the inner surface of the opening of the radial stator or an axial stator magnetic field created by a current flowing through the concentrated windings disposed along at least the first side of the axial stator
Implementation Method 2
Flux from the two or more magnets interacts with one or both of a radial stator magnetic field created by a current flowing through the distributed windings... or an axial stator magnetic field created by a current flowing through the concentrated windings... The flux interacting with one or both of the radial stator magnetic field or the axial stator magnetic field turns the rotor about the rotor axis
Data Source
AI summary
Various implementations include an electric motor including an annular radial stator, an annular axial stator, and a rotor. The annular radial stator has an opening with an inner surface and distributed windings disposed along at least the inner surface of the opening. The annular axial stator has concentrated windings disposed along at least a first side of the axial stator. The rotor includes two or more magnets. Flux from the two or more magnets interacts with one or both of a magnetic field created by the radial stator windings or axial rotor windings. The rotor is disposed within the radial stator opening and the axes of the axial stator and radial stator are coincident with the rotor axis. The flux interacting with one or both of the radial stator magnetic field or the axial stator magnetic field turns the rotor about the rotor axis.