Brushless Electric Rotating Machine With Soft Magnetic Rotor
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Solution Overview
Problem
Existing electric rotating machines for hybrid electric vehicles face issues with current loss and drag loss due to magnetic attractive forces in unloaded states, particularly when using permanent magnets, and suffer from reliability and cost concerns with brush-based electromagnet configurations, as well as heat generation and vibration issues in induction machines and switched reluctance motors.
Innovation Solution
A brushless electric rotating machine design where field poles are generated in the stator by supplying current to a winding, with rotors made of soft magnetic material, satisfying the relational expression |M±N|=K, allowing for magnetic modulation and torque generation without the need for permanent magnets or additional coils, thereby reducing current loss and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If permanent magnets are used to generate magnetic field, then magnetic torque is produced, but extra armature current is required causing current loss and drag loss
Solution Approach 1:
The invention extracts the permanent magnets from the rotor structure and replaces them with soft magnetic members. The magnetic field is now generated by electromagnets in the stator rather than permanent magnets in the rotor, eliminating the need for reverse armature current and the associated current loss and drag loss.
Solution Approach 2:
The invention substitutes the permanent magnet-based magnetic field generation system with an electromagnet-based system. By using electromagnets in the stator controlled by three-phase AC power, the system replaces the passive permanent magnets with an active, controllable electromagnetic field generation mechanism.
2Adaptability or versatility
If brush and slip ring configuration is used to supply current, then variable magnetic field is created, but reliability is impaired and components increase
Solution Approach 1:
The invention removes the brush and slip ring components from the system entirely. By placing the electromagnets in the stationary stator rather than the rotating rotor, current can be supplied directly without mechanical contact components, eliminating reliability issues associated with brushes and slip rings.
Solution Approach 2:
The invention inverts the traditional motor structure by placing the electromagnets in the stator instead of the rotor. This reversal allows the magnetic field to be generated in the stationary part of the machine, eliminating the need for sliding contacts and improving reliability.
3Adaptability or versatility
If induction machine or switched reluctance motor is used without brush, then variable magnetic field is generated, but heat generation damages bearing and causes noise and vibration
Solution Approach 1:
The invention extracts the current supply function from the rotor and relocates it to the stator. By placing electromagnets in the stationary stator, the rotor no longer requires current supply and thus generates no heat, eliminating thermal damage to bearings and reducing noise and vibration.
Solution Approach 2:
The invention substitutes the rotor-based current supply system with a stator-based electromagnet system. This replacement eliminates the heat generation problem in the rotor that occurs in induction machines and switched reluctance motors, as all electromagnetic heating now occurs in the stationary stator.
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 solution enables improved performance with reduced current loss and drag, enhanced endurance against centrifugal force, and a simpler, more reliable brushless structure that prevents heat generation, while maintaining efficiency as a generator and motor.
Implementation Method 1
the armature coil, which generates an armature rotation magnetic field
Implementation Method 2
the rotors have K (K being a natural number) soft magnetic members including a plurality of protrusions on a side facing the stator
Implementation Method 3
a new second rotation magnetic field is generated in the stator, from an armature rotation magnetic field of M pairs of poles and a static field magnetic field of N pairs of poles. The rotors serving as modulators are rotated by the second rotation magnetic field
Data Source
AI summary
In an electric rotating machine, a stator has an armature coil wound around an armature core segments with M pairs of poles, and N pairs of field sources (field coil and field magnetic field), a rotor has K soft magnetic members including a plurality of protrusions on a side facing the stator, and the armature coil, the field sources, and the soft magnetic members satisfy a relational expression of |M±N|=K. With this configuration, rotors are rotated based on the magnetic modulation principle, so that field poles can have alternating electromagnetic action on the armature coil, and the performance of the electric rotating machine can be improved with a brushless structure.