Mechanik und Mechatronik
> Zum Inhalt

LTS-Flywheel als 12h-Energiespeicher

LTS-Flywheel Overview

Flywheels are a sustainable solution for decentralized energy storage. They offer longer life cycles (over 25 years), no requirement for maintenance, and usage of harmless, easily available materials, compared with other storage technologies, as for example accumulators. Flywheels, available up to now, are designed for short term energy storage in the region of minutes.

The technological challenge within this research project is the development of fundamentals for a technology leap - Long Term Storage flywheel. Aim is a significant increase in storage time (12 hours at 80% load efficiency). Additionally, high reliability and low system costs are defined as project aims. This LTS-flywheel shall allow decentralized storage of electrical energy, for instance produced in in-house photovoltaic systems. Therefore, it is an essential contribution for developing the technological basis for the building of the future, especially the positive energy house.

For realizing the research aims, the project comprises the following focuses:

  • Exploratory focus on a full parametric simulation model
    Development of a full parametric simulation model for optimizing a flywheel regarding to a freely definable performance function: Definition of all required optimization parameters, determination of all interdependences, modeling of all flywheel components as MATLAB-Simulink simulation models, optimized regarding to minimal computing time.

  • Exploratory focus on bearings
    Development of fundamentals of a magnetic bearing system with significantly increased energy efficiency compared with present magnetic bearing systems, and high reliability - cascaded hybrid magnetic bearing system with high reliability for radial and axial stabilization. This means permanent magnetic bearings for the application of static bearing forces, highly efficient active magnetic bearings (AMBs) for minimum energy consumption during normal operation with fully-adaptive control. Further, an additional add-on high performance AMB system for start-up, interception of large external forces (e.g. earthquake) or emergency operation, as well as a redundant high performance AMB system in case of a power supply collapse or a malfunction within the regular highly efficient/high performance AMB-system.

  • Exploratory focus on the rotor
    Development of fundamentals for an optimum rotor design with respect to high energy storage capacity, small necessary control inputs concerning the bearing, integration of all required bearing and motor/generator components and optimum utilization of material properties (density, young’s modulus, tensile strength, internal damping) with respect to rotor configuration (eigenfrequencies, material combinations, winding and lamination technology, costs of materials and manufacturing, balancing, et cetera).

  • Exemplary optimization for 12h-energy storage for photovoltaic systems and experimental validation of the research results
    Exemplary optimization of the whole system as LTS-flywheel with 12h-storage time for photovoltaic systems using MATLAB-Simulink and PSpice co-simulation. Validation of the research results, using a test arrangement based on the optimization results. Investigation of total power losses dependent on diverse operational states (rotary speed, load momentum, behavior in case of component faults or sudden high bearing forces, power supply collapse).

The results of the proposed research project will serve as a basis for a cooperative technology development with an industry partner, or a company founding, respectively.

Contact: Dr. Alexander Schulz

SEE-Flywheel-Ausfallsichere Magnetlager für Flywheels hoher Speicherleistung und Energietransfer-Rate

SEE-Flywheel Overview

Flywheels represent an ecologically and economically sustainable technology for decentralized energy storage. Compared to other storage technologies such as e.g. accumulators, they offer longer life cycles (more than 25 years) without performance degradation over time and usage and need no systematic maintenance. Furthermore, they are made of environment-friendly, easily available materials.

Flywheels store electrical energy in the form of kinetic energy using a motor to accelerate a flywheel mass. The stored kinetic energy can be rapidly re-transformed to electrical energy by a built in generator. For high storage capacity high revolution speeds and great rotating masses or rather high moments of inertia, are needed. To achieve low bearing losses a combination of permanent magnetic bearings and active magnetic bearings (hybrid magnetic bearings) are state of the art, as they permit a contact-free and therefore minimum friction bearing of the rotor. This enormous advantage bears one major disadvantage: in case of malfunction or failure of an important component of the bearing system, which comprises sensors, controller, power amplifiers, electromagnets, the rotor crashes into its emergency bearing. The stored kinetic energy leads to uncontrollable whirl-movements of the rotor, which usually have disastrous consequences. This results in complex and expensive service and repair work, like disassembly and balancing, overhauling or replacement of the rotor and replacement of the emergency bearing. In a worst case, if the emergency bearing fails, a total loss of the storage system results.

Within this research project a fail-safe magnetic bearing, tailored to meet the requirements of flywheels with high storage performance and energy-transfer-rate, shall be developed. Additionally, this concept should allow for an augmentation of overall efficiency.

In order to reach the goals the following research goals are set:

  • Development of a special hybrid magnetic bearings to support the heavy-weight, high-speed rotor,
  • tailored design of the motor/generator and its control, including segmentation of stator windings for adaptive current feed in order to minimize the resulting bearing forces,
  • backup rotor support by using the motor/generator stator windings as additional backup bearing,

power supply of the backup active magnetic bearing systems using kinetic energy stored in the flywheel.

 Contact: Prof. Johann Wassermann

Optimum Shape Flywheel - Kostenreduktion durch neue Konstruktionsansätze, Rotorbauformen und Fertigungsverfahren

Exampled of Optimum Shape (FEM Result)

High-efficiency Flywheels represent an ecologically and economically sustainable technology for decentralized storage of electrical energy. In comparison to other storage technologies, as e.g. accumulators, Flywheels offer a much longer lifetime. They require minimal systematic maintenance and are made of environmentally friendly materials. The few currently available Flywheels have suboptimal material utilization due to their complex structure and there-fore high capital cost.

As part of OptimumShapeFlywheel research project, innovative approaches to optimal de-sign and the optimum material composition of the central component of any high-efficiency Flywheel, the rotor, and suitable manufacturing techniques will be developed within a co-operation between the Technical University of Vienna and FWT Wickel-technik GmbH.

This, on the one hand significantly reduces investment costs and on the other hand improves the overall efficiency, making high-efficiency Flywheels economically viable for a wide range of applications.

Following research areas are planned for this purpose

  • Finite element-based modeling for strength analysis of composite materials
    Preparation of complex models for the calculation of the OptimumShapeFlywheel geometry. Implementation of the most suitable failure criterion for composite Flywheels. Experimental acquisition of all required material parameters and selecting the best approach.

  • Innovative flywheel design with integrated shaft
    A completely new flywheel geometry for the best material utilization.

  • Manufacturing process for optimal composite topology
    Production of complex composite structures, optimization, secure integration of all components.

  • Verification of all research results
    Static test setup for the secure verification of the FE calculations. OptimumShapeFly-wheel measuring-setup for total verification of all models, the interaction of all components and the overall efficiency benefit.

The OptimumShapeFlywheel technology is thus an essential contribution to the transition to sustainable energy supply with a high proportion of renewable energy. The findings will lead to a large step towards mass production.

Contact: Dr. Alexander Schulz