Dual Rotor Synchronous Machine Electromagnetic Independence
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Solution Overview
Problem
Existing double rotor electric machines face challenges in achieving electromagnetic independence between the two rotors, leading to torque transmission issues and the need for power supply brushes and coolant systems.
Innovation Solution
A synchronous electric machine design with two rotors, where the stator has two independent windings and a specific arrangement of teeth and magnetic poles, allowing the rotors to be electromagnetically independent by configuring the stator windings to produce zero net torque on one rotor while generating torque on the other, and utilizing a non-magnetic stator frame for coolant circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single stator winding is supplied with composite alternating current to drive both rotors, then the structure is simplified, but electromagnetic independence between the two rotors cannot be achieved and torque transmission interference occurs
Solution Approach 1:
The single stator winding is segmented into two independent windings: a first stator winding for driving the first rotor and a second stator winding for driving the second rotor. This segmentation allows each rotor to be electromagnetically independent while maintaining separate control over their respective operations, eliminating torque transmission interference between the rotors.
Solution Approach 2:
Different regions of the stator are assigned different winding configurations optimized for specific rotors. The first stator winding is configured with teeth and coils optimized for the first rotor's magnetic poles, while the second stator winding is configured for the second rotor, allowing each rotor to operate independently without electromagnetic interference.
2Use of energy by moving object
If power supply brushes are used to supply power to the rotating rotor winding, then the rotor can be powered, but the structure becomes more complex and reliability decreases due to brush wear
Solution Approach 1:
The mechanical brush-and-commutator system is replaced with a stationary stator winding that generates rotating magnetic fields to induce currents in the rotor windings. This substitution eliminates the need for sliding contacts, reducing mechanical complexity and improving reliability by eliminating brush wear and maintenance requirements.
3Temperature
If the first rotor winding is integrated into the shaft of the rotating rotor for coolant circulation, then cooling is achieved, but the structure becomes more complex and maintenance difficulty increases
Solution Approach 1:
The coolant circulation system is extracted from the rotating rotor shaft and relocated to the stationary stator structure. The stator frame is designed with coolant channels that provide cooling without requiring integration into the rotating components, simplifying the rotor structure and eliminating the complexity of maintaining rotating coolant systems.
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 design achieves electromagnetic independence between the rotors, reducing torque interference and eliminating the need for power supply brushes and coolant integration, with the rotors being independent in both motor and generator modes, and enabling efficient operation as a continuously variable transmission.
Implementation Method 1
The first rotor winding and the second rotor winding are supplied with alternating currents which generate a first rotating magnetic field and a second rotating magnetic field, respectively
Implementation Method 2
The interaction between the rotating magnetic fields and the permanent magnets produces electromagnetic torque on the rotors
Implementation Method 3
a non-magnetic stator frame for coolant circulation
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Synchronous electric machine comprising: - a stator (12) including a plurality of teeth (18) arranged at equal angular intervals and having first and second active surfaces (20, 22), - a first stator winding (24) having a series of first coils (28) wound on said teeth (18), - a second stator winding (26) having a series of second coils (30) wound on said teeth (18), - a first rotor (14) having a series of first permanent magnets (32) arranged at equal angular intervals with alternate polarities and facing said first active surfaces (20), - a second rotor (16) having a series of second permanent magnets (34) arranged at equal angular intervals with alternate polarities and facing said second active surfaces (22), wherein the first and the second rotors (14, 16) are supported in rotation, independently of each other, around a common axis (A), wherein the first coils (28) and the second coils (30) of each stator winding (24, 26) are arranged in pairs, with the two coils (28i', 28i"; 30i', 30i") of each pair offset from each other by a predetermined angle, wherein, during operation as a motor, the two first coils (28i', 28i") of each pair produce concordant torque contributions on the first rotor (14) and discordant torque contributions on the second rotor (16) and the two second coils (30i', 30i") of each pair produce concordant torque contributions on the second rotor (16) and discordant torque contributions on the first rotor (14).