Magnetically Coupled Flywheel Energy Storage System
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Solution Overview
Problem
Flywheel energy storage systems face challenges in minimizing energy loss due to frictional forces during the store phase, requiring intermittent current supply to maintain rotational kinetic energy, and lack of efficient mechanisms for balancing and stabilizing the flywheel shaft.
Innovation Solution
A magnetically coupled flywheel energy storage system with a vacuum enclosure, open-frame motor/generator unit, and active magnetic balancing system, utilizing magnetic coupling to reduce mechanical friction and axial forces, and an active magnetic balancing system to stabilize the flywheel shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the flywheel is mechanically coupled to the motor/generator shaft, then torque transmission is direct and efficient, but frictional forces increase energy loss during the store phase
Solution Approach 1:
The patent replaces the mechanical coupling between the flywheel and motor/generator with a magnetic coupling system. Magnets are positioned on the flywheel and corresponding magnets on the motor/generator rotor create magnetic attraction forces that transmit torque without physical contact. This eliminates mechanical friction between the flywheel and motor/generator components, significantly reducing energy loss during the store phase while maintaining efficient torque transmission.
2Use of energy by moving object
If the flywheel rotates at high speed to store more energy, then rotational kinetic energy increases, but frictional forces and mechanical stress increase
Solution Approach 1:
By substituting mechanical contact with magnetic coupling, the system enables high-speed rotation of the flywheel without the frictional losses that would otherwise increase with speed. The magnetic attraction force maintains torque transmission effectiveness across a range of rotational speeds, allowing the flywheel to operate at optimal high speeds for maximum energy storage while minimizing frictional energy loss.
3Reliability
If mechanical bearings are used to support the flywheel shaft, then the shaft is supported structurally, but friction and wear occur
Solution Approach 1:
The patent replaces traditional mechanical bearings with magnetic bearing technology. Electromagnets positioned around the flywheel shaft create magnetic fields that levitate and support the shaft, eliminating physical contact between the shaft and bearing surfaces. This provides stable structural support for the rotating shaft while completely eliminating friction and wear associated with mechanical bearings, thereby reducing energy loss and improving reliability.
4Productivity
If the motor/generator unit is always connected to the flywheel, then torque can be continuously applied, but electromagnetic drag increases energy loss during the store phase
Solution Approach 1:
The patent implements a dynamic control system that adjusts the magnetic coupling strength between the flywheel and motor/generator based on operational requirements. During the store phase, when the flywheel needs to rotate freely to minimize losses, the magnetic coupling is weakened or temporarily disengaged. During charge and discharge phases, the magnetic coupling is strengthened to enable effective torque transmission. This dynamic adjustment allows continuous operational capability while minimizing electromagnetic drag losses during the store phase.
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 system minimizes energy loss by reducing mechanical friction and stabilizes the flywheel shaft, enhancing the efficiency and reliability of energy storage and retrieval, while allowing for cost-effective and flexible operation with shared motor/generator units.
Implementation Method 1
a rotor, the rotor being fixed to the shaft in a cantilevered manner within the enclosure so as to rotate within the stator and magnetically couple to the stator
Implementation Method 2
the flywheel being enclosed within a vacuum enclosure that is evacuable to form a vacuum
Data Source
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AI summary
A stabilization system for a rotating load, such as a flywheel, includes a mechanical bearing to continuously support a shaft of the rotating load so as to hold the shaft at a substantially fixed axis of rotation. A magnetic stabilization assembly includes a plurality of electromagnets arranged around the shaft. Control circuitry for controls a resultant magnetic field generated by the electromagnets such that the magnetic field acts on a ferromagnetic element of the shaft to reduce imbalance forces acting on the shaft.