Brushless Synchronous Machine Rotor Excitation via Induction
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Solution Overview
Problem
Synchronous electric machines face challenges with high costs and complexity due to the use of rare earth magnets and mechanical brushes, which lead to increased manufacturing costs and maintenance requirements, while also posing environmental concerns and reliability issues.
Innovation Solution
A synchronous electric machine design without brushes or magnets, utilizing a rotor with a specific configuration and a stator with a winding and toothing arrangement, and an excitation coil for magnetic induction, which simplifies the structure, reduces costs, and enhances reliability by eliminating mechanical interactions and heat-related losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If permanent magnets are used in synchronous machines, then torque density and rotor loss performance are improved, but manufacturing cost increases and manufacturing complexity increases
Solution Approach 1:
The patent extracts and removes the permanent magnets from the synchronous machine structure, replacing them with an excitation coil system. This eliminates the need for rare earth magnets while maintaining the magnetic field generation capability through electromagnetic induction, thereby reducing manufacturing costs and complexity associated with magnet procurement and installation.
Solution Approach 2:
The patent replaces the permanent magnet-based magnetic field generation with an electromagnetic induction system using excitation coils. This substitution transitions from a static magnetic field source to a dynamically controllable electromagnetic field, eliminating the need for expensive permanent magnets while maintaining torque density performance.
2Power
If permanent magnets are used in synchronous machines, then torque density and rotor loss performance are improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the permanent magnets from the synchronous machine structure, replacing them with an excitation coil system. This eliminates the need for rare earth magnets while maintaining the magnetic field generation capability through electromagnetic induction, thereby reducing manufacturing costs and complexity associated with magnet procurement and installation.
Solution Approach 2:
The patent replaces the permanent magnet-based magnetic field generation with an electromagnetic induction system using excitation coils. This substitution transitions from a static magnetic field source to a dynamically controllable electromagnetic field, eliminating the need for expensive permanent magnets while maintaining torque density performance.
3Ease of operation
If brush systems are used for rotor excitation, then electrical connection is achieved, but maintenance requirements increase and reliability decreases
Solution Approach 1:
The patent replaces the mechanical brush-and-commutator system with a contactless electromagnetic induction system. The excitation coil generates a magnetic field that induces current in the rotor windings without requiring physical contact, thereby eliminating wear, sparks, and maintenance associated with brush systems while improving reliability.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the stator excitation coil and the rotor windings. This magnetic field serves as the medium for transferring energy and generating excitation current without requiring direct electrical contact, thereby eliminating the need for brushes and improving system reliability.
4Reliability
If multi-stage generators with rotating transformers are used, then brushless operation is achieved, but device complexity increases significantly
Solution Approach 1:
The patent extracts and removes the complex multi-stage generator structure including rotating transformers and rotating rectifier bridges. Instead, it employs a simplified single-stage design where the excitation coil directly generates the magnetic field for rotor excitation, maintaining brushless operation while dramatically reducing structural complexity.
Solution Approach 2:
The patent inverts the conventional multi-stage approach by using a single-stage electromagnetic induction system. Rather than generating AC power at the rotor and then rectifying it through multiple stages, the excitation coil directly creates the magnetic field needed for rotor excitation, simplifying the overall architecture while achieving brushless operation.
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 a compact, reliable, and cost-effective synchronous electric machine that can operate as both a motor and generator, with reduced maintenance needs, lower dependence on rare earth materials, and improved service life of components, while maintaining high torque density and efficiency.
Implementation Method 1
a rotor excitation coil, fixed with respect to the stator, supplied with a direct electric current , arranged around the intermediate part of the rotor and configured to generate a magnetic flux in the rotor by magnetic induction
Data Source
Figure 1a~3b
Figure 4a~7
Figure 8~10
AI summary
The invention relates to a brushless and magnet-free synchronous electrical machine, characterized in that it comprises a stator (20) comprising a ring (22), a winding (28) and a tooth system (24) comprising teeth (26) extending parallel to the axis of rotation from the ring (22), said winding being wound around the tooth system (24), a rotor (10), comprising a first portion (12a) extending in p preferred directions (18a), a second portion (12b) extending in p preferred directions (18b) shifted by p with respect to the preferred directions of the first portion (18a), and an intermediate portion (14) linking the first portion (12a) to the second portion (12b), and a coil (40) for exciting the rotor, fixed with respect to the stator, supplied with a DC electric current, positioned around the intermediate portion (14) of the rotor and configured so as to generate an electric flux in the rotor (10) through magnetic induction.