Double-Stator Double-Rotor Motor Magnetic Circuit Design
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Solution Overview
Problem
Conventional split-core/double-rotor type motors have inefficient magnetic circuits due to long magnetic paths, leading to increased magnetoresistance and loss of magnetomotive force, which affects motor efficiency and torque output.
Innovation Solution
A double-stator/double-rotor type motor design is implemented, where a nonmagnetic material separates dual magnetic circuits for inner and outer rotors, and a double stator is placed between them to form independent magnetic circuits, reducing the magnetic path length and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional split-core/double-rotor type motor uses a single stator core for both inner and outer rotors, then the motor structure is simplified, but the magnetic path length increases causing increased magnetoresistance and loss of magnetomotive force
Solution Approach 1:
The patent divides the single stator core into two separate stator cores (inner stator core and outer stator core), each dedicated to serving one rotor. This segmentation creates independent magnetic circuits for the inner and outer rotors, shortening the magnetic path length for each circuit and reducing magnetoresistance, thereby resolving the contradiction between structural simplicity and energy loss.
Solution Approach 2:
The patent introduces a nonmagnetic material as an intermediary substance placed between the inner and outer stator cores. This nonmagnetic material acts as a magnetic circuit separator, preventing magnetic flux leakage between the two magnetic circuits and ensuring that each stator core maintains its independent magnetic path, thus reducing overall magnetoresistance and magnetomotive force loss.
2Ease of manufacture
If a conventional split-core/double-rotor type motor uses a single stator core, then manufacturing is easier, but leakage flux increases reducing motor efficiency
Solution Approach 1:
By segmenting the stator core into two separate cores, the patent eliminates the leakage flux problem that occurs in single-stator designs. Each stator core independently serves its corresponding rotor, creating isolated magnetic circuits that prevent flux leakage. This segmentation maintains manufacturing feasibility while significantly improving motor efficiency and reliability.
Solution Approach 2:
The nonmagnetic material serves as an intermediary barrier between the inner and outer stator cores, physically and magnetically isolating the two magnetic circuits. This intermediary substance prevents magnetic flux from leaking between circuits, thereby maintaining high motor efficiency without complicating the manufacturing process.
3Loss of energy
If dual magnetic circuits are separated for inner and outer rotors, then magnetoresistance is reduced and efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent implements segmentation by creating two separate stator cores, each dedicated to one rotor. This segmentation naturally forms two independent magnetic circuits with shorter path lengths, reducing magnetoresistance and improving efficiency. The modular segmented structure makes the complexity manageable through standardized design units.
Solution Approach 2:
The nonmagnetic material acts as a simple intermediary component that enables dual magnetic circuit separation without requiring complex shielding or isolation mechanisms. This straightforward intermediary approach achieves magnetic circuit separation with minimal added complexity, balancing the trade-off between reduced magnetoresistance and increased device complexity.
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 design reduces magnetoresistance, minimizes leakage flux, and promotes motor efficiency while enabling high torque and low-speed operation in laundry mode and low torque and high-speed operation in dehydration mode, suitable for washing machines.
Implementation Method 1
a nonmagnetic material is provided between inner and outer stators so as to form dual magnetic circuits that are respectively separated for an inner rotor and an outer rotor
Implementation Method 2
a main path of a magnetic flux forms a magnetic circuit starting from a permanent magnet of a rotor and proceeding toward a stator via an air gap
Implementation Method 3
a rotor formed of a cylindrical permanent magnet
Implementation Method 4
coils are wound on a number of protrusions formed on the inner circumferential portion thereof in order to form an electronic magnet structure
Data Source
AI summary
Provided are a double-stator/double-rotor type motor, and a direct drive apparatus for a washing machine using the double-stator/double-rotor type motor, in which a nonmagnetic material is provided between inner and outer stators so as to form dual magnetic circuits that are respectively separated for an inner rotor and an outer rotor, and a double stator is disposed between an inner rotor and an outer rotor so as to separably form a magnetic circuit with a shortened magnetic.