Grouped-Tooth Electric Motor for High-RPM Torque Output
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Solution Overview
Problem
Existing electric motors face challenges in efficiently achieving high rotational speeds and torque output, particularly at high RPMs, due to limitations in electromagnetic field interactions and timing constraints related to coil charging and discharging cycles.
Innovation Solution
The use of non-uniform angular spacing of rotor teeth and coordinated torque pulses, along with a flowing wavefront of EMF magnitude on stator teeth, allows for increased rotational speed and torque output without mechanical gearing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a switched reluctance motor with a large number of poles (e.g., 24 stator teeth) is used, then torque output is improved, but rotational speed decreases
Solution Approach 1:
The stator teeth are divided into multiple groups (first group, second group, third group) that can be independently controlled. This segmentation allows different groups to be activated at different times, creating a coordinated torque pulse sequence that enables both high torque and high speed operation by reducing the effective number of poles involved in each switching cycle.
Solution Approach 2:
The motor employs periodic switching of coil windings in a specific sequence across different stator tooth groups. By activating groups in a coordinated periodic pattern (first group, then second group, then third group), the system generates flowing wavefronts of electromagnetic force that maintain torque while enabling higher rotational speeds than traditional simultaneous activation methods.
2Productivity
If high rotational speed is achieved, then productivity is improved, but torque output at high RPMs deteriorates
Solution Approach 1:
The controller pre-coils selected coil windings before activation and maintains a predetermined timing relationship between coil charging and discharging cycles. This preliminary action ensures that electromagnetic force is already building when rotor teeth need engagement, maintaining torque effectiveness even at high rotational speeds where timing margins are reduced.
Solution Approach 2:
The system dynamically adjusts switching parameters including the sequence of group activation, coil charging/discharging timing, and current magnitude. By changing these parameters in response to operating conditions, the motor maintains optimal torque production across a wide speed range, particularly preserving torque at high RPMs where traditional motors fail.
3Speed
If coordinated torque pulses with non-uniform angular spacing are used, then rotational speed is improved, but device complexity increases
Solution Approach 1:
The control system manages complexity by segmenting the 24 stator teeth into three manageable groups of eight teeth each. This segmentation simplifies the control logic compared to individually managing all 24 teeth, while still enabling the coordinated torque pulse sequence needed for high-speed operation. Each group can be controlled as a unit with predetermined timing relationships.
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 configuration enables electric motors to operate at higher RPMs and maintain power density, overcoming timing constraints and achieving desired rotational speeds efficiently.
Implementation Method 1
Transmitting a current pulse through the coil winding may generate an electromagnetic force to apply a torque to a rotor tooth
Implementation Method 2
an electromagnetic force generated on a stator tooth may interact with a rotor tooth to provide a torque to cause rotation of a rotor
Data Source
Figure 1A~1B
Figure 2A~2E
Figure 3A
AI summary
An electric motor may comprise a rotor and a stator comprising rotor and stator teeth, respectively. A non-uniform angular spacing or grouping of rotor teeth may facilitate desired rotational speeds of the rotor.