Motor-Generator With Static Magnetic Transference
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Solution Overview
Problem
Conventional electric machines face challenges in generating power at low speeds without increasing machine size, cooling efficiency, copper usage, heat generation, and start-up torque in wind turbines, as well as limitations in converting between synchronous and asynchronous modes.
Innovation Solution
The proposed motor/generator design features a static central axial permanent magnet or electromagnets with a unidirectional magnetic flux flow, reducing copper usage, increasing voltage per turn, enhancing cooling through ventilation, eliminating cogging torque, and allowing conversion between synchronous and asynchronous operations by using a combination of permanent and electromagnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional alternators with static electromagnetic excitation and multiple air gaps are used, then the machine structure is established, but the voltage per turn is low and power generation at low speeds is insufficient
Solution Approach 1:
The patent divides the magnetic circuit into multiple independent air gaps (first air gap between rotor and stator, second air gap between stator and keeper) with separate magnetic flux paths. This segmentation allows each air gap to contribute independently to the total magnetic flux, increasing the overall flux per turn and enabling higher voltage generation at low speeds without increasing machine size.
Solution Approach 2:
The patent introduces a third dimension to the magnetic flux path by adding the keeper component that collects and redirects magnetic flux. The magnetic flux flows through multiple spatial dimensions (rotor→stator→keeper→rotor), creating additional flux paths that increase the total flux linkage and voltage per turn beyond what conventional two-air-gap designs achieve.
2Power
If more copper is used in field coils, then the magnetic flux can be increased, but the ohmic losses and heat generation increase
Solution Approach 1:
The patent employs permanent magnets mounted on the rotor that generate magnetic flux without requiring external excitation current. This self-service approach eliminates copper losses in field coils while maintaining strong magnetic flux, as the permanent magnets continuously produce the necessary magnetic field through their inherent magnetic properties rather than through resistive heating of windings.
Solution Approach 2:
The patent replaces the electromagnetic excitation system (field coils requiring electrical current) with a magnetic system based on permanent magnets. This substitution eliminates the need for copper windings in the field circuit, removing the source of ohmic losses and heat generation while maintaining or enhancing the magnetic flux production.
3Temperature
If conventional cooling systems are used, then heat dissipation is provided, but the cooling efficiency at low speeds is insufficient
Solution Approach 1:
The patent extracts the cooling function from the rotational motion-dependent system and implements it through dedicated cooling channels and ventilation openings in the stator and keeper. This separation allows the cooling system to operate independently of rotor speed, providing effective heat dissipation even when the rotor rotates slowly, as the cooling paths are structurally provided rather than dynamically generated.
4Loss of substance
If permanent magnets are used in the rotor, then copper usage is reduced, but cogging torque is generated in wind turbine applications
Solution Approach 1:
The patent extracts the cogging torque problem by introducing the keeper component that acts as a magnetic flux collector and redistributor. The keeper absorbs and redistributes the magnetic flux from the permanent magnets, smoothing out the flux density variations that cause cogging torque while allowing the permanent magnets to continue providing copper-free excitation.
Solution Approach 2:
The patent introduces the keeper as an intermediary component between the permanent magnets and the stator. This intermediary redistributes the magnetic flux, acting as a buffer that reduces the direct interaction between the permanent magnets and stator teeth, thereby minimizing cogging torque while maintaining the benefits of permanent magnet excitation.
5Power
If synchronous mode operation is maintained, then voltage regulation is achieved, but conversion to asynchronous mode is limited
Solution Approach 1:
The patent implements a dynamic control system that can adjust the excitation of field coils in real-time. By dynamically controlling the field coil excitation while permanent magnets provide base flux, the system can adapt its magnetic characteristics to operate in synchronous mode for voltage regulation or transition to asynchronous mode for different operational requirements, providing versatility without sacrificing control 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
This design achieves higher voltage per turn, reduced ohmic losses, lower copper content, efficient cooling, and simplified regulation, enabling efficient power generation at low speeds and easy conversion between synchronous and asynchronous modes, while minimizing heat and cost.
Implementation Method 1
a machine in which the magnetic flux flow enters the rotor by transference through a passive air gap from a static source of magnetic flux
Implementation Method 2
The motor/generator that is claimed pertains to the field of electric machines of magnetic rotating field. It is a machine able to transform mechanical power, i.e. a moving mechanical force, into electric energy, and vice-versa
Implementation Method 3
enhancing cooling through ventilation
Implementation Method 4
a machine in which the magnetic flux flow enters the rotor by transference through a passive air gap from a static source of magnetic flux
Data Source
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AI summary
The invention relates to an electrical power motor-generator excited by magnetic transference, and which further comprises a stator (1) and a rotor (2) with an external core (3) stationary relative to the stator and rotor, said external core (3) comprising: an outer axial part, or axial armature (6) joined to the stator (1), an inner part that communicates through an air gap (4) with the rotor (2), a third part, disk (8), that joins the other two parts, where the rotor does not have any excitation coils, and hence no rings or collector brushes. The outer core (3) has an axial permanent magnet (12) and permanent magnets (10) on the outer axial part (6) thereof, and electromagnets (11) in the other two parts or on the disk (8). The rotor does not have brushes to create a magnetic field, which is created by the magnets and coils of the outer core (3), the magnetic flow transmitting the induction flow to the rotating rotor, through an air gap, thus dispensing with rings and collector brushes.