Double Stator Rotary Machine Torque Balance

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Solution Overview

Problem

The double stator-type rotary machine experiences inefficiency due to a significant difference in torque applied by the outer and inner stators, leading to degraded motor performance when high power output is required.

Innovation Solution

Incorporating permanent magnets on both sides of the rotor, allowing the outer stator to function as a switched reluctance motor and the inner stator as a permanent magnet motor, thereby balancing the torque applied to the rotor and enhancing motor efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a double stator structure is employed to improve the performance of a switched reluctance rotary machine, then the power output capability is improved, but a large difference occurs between the torque applied from the outer stator and the torque applied from the inner stator, degrading motor efficiency

Engineering Contradiction:
Improvepower output capabilityVSAvoidmotor efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by introducing permanent magnets to the inner stator, fundamentally altering the operational characteristics of the inner stator from switched reluctance mode to permanent magnet mode. This parameter change in the inner stator's magnetic field generation method enables it to produce higher torque density, thereby balancing the torque contribution between the outer and inner stators and improving overall motor efficiency while maintaining high power output capability

Inventive Principle:
Principle #35Parameter changes

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 increases motor efficiency by reducing the torque difference between the outer and inner stators, allowing for more effective power transmission and improved performance.

Implementation Method 1

permanent magnets are provided in a double stator-type rotary machine

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the inner side of the rotor can be operated as a permanent magnet (PM) motor

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 3

a torque is applied to the rotor from both of the stators

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP3208918B1Double stator-type rotary machine
Publication Date: 2020.11.25 IHI CORP
  • EP3208918B1 patent drawingFigure 1
  • EP3208918B1 patent drawingFigure 2
  • EP3208918B1 patent drawingFigure 3

AI summary

This double stator-type rotary machine is provided with: an annular rotor (2); an outer stator (3) that is disposed on the outer side of the rotor; and an inner stator (4) that is disposed on the inner side of the rotor (2). The rotor (2) is provided with permanent magnets (2d) that are arranged on the inner stator (4) side.