Dual Reluctance Motor Assembly for Low-Loss EV Torque Delivery
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Solution Overview
Problem
Existing electric motors in hybrid and electric vehicles, particularly those using rare earth permanent magnets, face high costs, sustainability issues, magnetic flux generation, inefficiencies, cogging, and demagnetization risks, along with increased losses and noise due to rotor design.
Innovation Solution
A dual reluctance motor system comprising a first and second reluctance motor with rotors drivingly connected, allowing independent or combined torque generation, reducing magnetic flux and losses, and incorporating a controller for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If permanent magnet motors are used, then torque density is improved, but cost increases significantly due to rare earth magnets
Solution Approach 1:
The patent extracts and removes the permanent magnets from the motor system, replacing them with an active electromagnetic field generation system. This eliminates the need for expensive rare earth magnets while maintaining torque generation capability through controlled electromagnetic interactions between stator and rotor windings.
Solution Approach 2:
The patent replaces the passive magnetic field system (permanent magnets) with an active electromagnetic system where fields are generated dynamically through controlled current in windings. This substitution allows torque control without relying on expensive permanent magnet materials.
2Power
If permanent magnet motors operate at high speeds, then power output is improved, but magnetic flux generation causes safety and reliability issues
Solution Approach 1:
The patent implements control systems that monitor and regulate electromagnetic field generation in real-time. By using feedback control, the system can manage magnetic flux levels dynamically, preventing excessive flux generation at high speeds while maintaining power output, thus improving reliability and safety.
Solution Approach 2:
The patent transitions from a static magnetic field system (permanent magnets) to a dynamic electromagnetic field system where field strength and distribution can be actively adjusted based on operating conditions. This dynamic control allows the system to optimize performance at different speeds while preventing harmful magnetic flux effects.
3Force
If permanent magnet motors are used, then torque generation is improved, but cogging torque and noise increase
Solution Approach 1:
The patent replaces the permanent magnet-based torque generation system with an electromagnetic system that uses controlled current in stator and rotor windings. This substitution eliminates cogging torque by removing the permanent magnetic fields that interact with rotor slots, thereby reducing noise and vibration while maintaining torque generation capability.
4Power
If rotor windings are added to increase torque, then power output is improved, but copper losses increase
Solution Approach 1:
The patent optimizes the electrical parameters of the rotor windings, including resistance, inductance, and current density, to minimize copper losses. By carefully selecting winding configurations, conductor materials, and operating current levels, the system achieves high power output while keeping resistive losses minimal.
Solution Approach 2:
The patent applies different winding configurations and material properties to different regions of the rotor to optimize local current distribution and minimize losses. By tailoring the electrical characteristics locally, the system reduces overall copper losses while maintaining the required power output capability.
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 dual reluctance motor system enhances efficiency, reduces costs, and improves safety by minimizing torque ripple and acoustic noise, while maintaining high performance across varying torque and speed ranges.
Implementation Method 1
each of the first and second motors is operable to generate torque
Implementation Method 2
the second motor being a reluctance motor
Data Source
AI summary
Electrical sub-assembly and associated method of operation There is provided an electrical sub-assembly having first and second motors, the second motor being a reluctance motor. Each of the first and second motors has a respective rotor drivingly connected to the other and is independently operable to generate torque either alone or in combination with one another. The torque generated by each of the first and second motors may be transmittable to a drivetrain of a vehicle. As such, the electrical sub-assembly may have particular application in a hybrid or electric vehicle.