Magnetically Geared Generator Eliminates Mechanical Gearboxes
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Solution Overview
Problem
Conventional electrical generators in ship propulsion and wind energy systems require mechanical gearboxes to achieve the necessary rotational frequency for efficient energy conversion, leading to heavy, noisy, and inefficient systems due to the need for high rotational torque and constant output frequency despite variable input speeds.
Innovation Solution
A magnetically geared generator system that combines a magnetic gear unit with a frequency converter, utilizing a rectifier and inverter unit to adjust the rotational input frequency into a constant electrical output frequency without mechanical gearing, using inner and outer winding units with different pole pairs and a rotating magnetic flux modulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a mechanical gearbox is used to increase rotational frequency, then the electrical output frequency requirement is met, but the system weight increases significantly
Solution Approach 1:
The patent replaces the mechanical gearbox with a magnetic gear system consisting of a primary rotor with permanent magnets, a secondary rotor with wound windings, and a stator with wound windings. The magnetic interaction between these components provides the gear ratio function without mechanical contact, eliminating the need for heavy mechanical gears while achieving the required speed multiplication.
Solution Approach 2:
The patent uses variable frequency control of the stator windings to dynamically adjust the magnetic field frequency, which in turn controls the rotational speed of the secondary rotor. This allows the system to maintain optimal operating conditions across varying input speeds without requiring a fixed-ratio mechanical gearbox.
2Speed
If a mechanical gearbox is used to increase rotational frequency, then the electrical output frequency requirement is met, but the system noise increases
Solution Approach 1:
The patent eliminates mechanical gear teeth, bearings, and lubrication systems that generate noise by replacing them with a magnetic field-based speed multiplication mechanism. The magnetic interaction between rotors and stator produces minimal acoustic noise compared to mechanical gear engagement.
3Speed
If a mechanical gearbox is used to increase rotational frequency, then the electrical output frequency requirement is met, but the mechanical efficiency decreases
Solution Approach 1:
The patent replaces mechanical power transmission through gear teeth and bearings with electromagnetic power transmission. The magnetic coupling between the primary rotor, secondary rotor, and stator minimizes energy losses associated with mechanical friction, tooth engagement, and bearing resistance.
4Adaptability or versatility
If the mechanical rotational input frequency is varied, then the adaptability to different operating conditions is improved, but the electrical output frequency becomes variable
Solution Approach 1:
The patent employs a frequency converter that monitors the rotational speed of the primary rotor and dynamically adjusts the frequency of the stator windings accordingly. This feedback control ensures that the secondary rotor maintains a constant electrical output frequency regardless of variations in the mechanical input frequency from the wind turbine.
Solution Approach 2:
The system uses variable frequency control of the stator windings to decouple the input mechanical frequency from the output electrical frequency. By adjusting the electrical parameters of the stator field in real-time, the system maintains stable output frequency while accommodating variable wind conditions.
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 solution eliminates the need for mechanical gearboxes, reducing weight, noise, and increasing efficiency by maintaining a constant electrical output frequency regardless of variable mechanical input speeds, while allowing for the transformation of low rotational frequencies into high-frequency electrical output.
Implementation Method 1
A magnetically geared generator includes a magnetic gear unit combined with a frequency converter (303) comprising a rectifier unit (304) and a converter unit (305)
Implementation Method 2
utilizing a rectifier and inverter unit to adjust the rotational input frequency into a constant electrical output frequency without mechanical gearing
Data Source
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AI summary
The present invention provides a magnetically geared generator including an inner winding unit having a first number of pole pairs, an outer winding unit arranged coaxially around the inner winding unit and having a second number of pole pairs, and a rotatable magnetic flux modulator arranged coaxially between the inner winding unit and the outer winding unit. The inner winding unit, the outer winding unit and the rotatable magnetic flux modulator are adapted to convert rotational input energy provided at the rotatable magnetic flux modulator into electrical output energy provided as an alternating output current at one of the inner winding unit and the outer winding unit, and to control an output frequency of the alternating output current by communicating output energy as an alternating feedback current to the other one of the inner winding unit and the outer winding unit and by adjusting a feedback frequency of the alternating feedback current.