Michael Rott, Claus-Peter Käsemann, Oliver Seibold-Benjak, ASDEX Upgrade Team
{"title":"Replacement and enhancement of power electronics at the flywheel machine EZ2","authors":"Michael Rott, Claus-Peter Käsemann, Oliver Seibold-Benjak, ASDEX Upgrade Team","doi":"10.1016/j.fusengdes.2025.115054","DOIUrl":null,"url":null,"abstract":"<div><div>The flywheel generator “Energiezentrale 2″ (EZ2), consisting of motor, flywheel, generator and auxiliary generator, aged 50 years, supplies ASDEX Upgrades copper Toroidal Field coils with DC current of up to 80 kA. Since there is no redundancy for this machine, a high availability has to be ensured. Therefore, during the 2023/24 experimental brake the inverter was replaced, that supplies the rotor of the 5.7 MVA doubly fed induction drive motor that accelerates the 223 t flywheel of EZ2. For starting the machine, a liquid rheostat is connected to the rotor. This resistor is also used for braking the machine. The inverter of 2 MVA is able to control the speed of the machine in the operating range between 1275 and 1650 rpm.</div><div>In addition, the rectifier has been replaced that supplies the excitation of the high current pulse power synchronous generator. By this excitation the voltage at the stator clamps is controlled that ramps up the DC current in the toroidal field coils of ASDEX Upgrade by the help of diode rectifiers. The main objectives of the excitation controller are a fast rise and a constant DC current to get a useful toroidal field during a plasma pulse. Also auxiliary rectifiers have been replaced, as two 400 A rectifiers heating the slip rings of the synchronous machine in order to reduce high abrasion, a rectifier for compensation of the remanence field of the machine resulting in a high idling current and the excitation inverter feeding the auxiliary generator that supplies DC emergency oil pumps.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":"216 ","pages":""},"PeriodicalIF":1.9000,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Fusion Engineering and Design","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0920379625002522","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"NUCLEAR SCIENCE & TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The flywheel generator “Energiezentrale 2″ (EZ2), consisting of motor, flywheel, generator and auxiliary generator, aged 50 years, supplies ASDEX Upgrades copper Toroidal Field coils with DC current of up to 80 kA. Since there is no redundancy for this machine, a high availability has to be ensured. Therefore, during the 2023/24 experimental brake the inverter was replaced, that supplies the rotor of the 5.7 MVA doubly fed induction drive motor that accelerates the 223 t flywheel of EZ2. For starting the machine, a liquid rheostat is connected to the rotor. This resistor is also used for braking the machine. The inverter of 2 MVA is able to control the speed of the machine in the operating range between 1275 and 1650 rpm.
In addition, the rectifier has been replaced that supplies the excitation of the high current pulse power synchronous generator. By this excitation the voltage at the stator clamps is controlled that ramps up the DC current in the toroidal field coils of ASDEX Upgrade by the help of diode rectifiers. The main objectives of the excitation controller are a fast rise and a constant DC current to get a useful toroidal field during a plasma pulse. Also auxiliary rectifiers have been replaced, as two 400 A rectifiers heating the slip rings of the synchronous machine in order to reduce high abrasion, a rectifier for compensation of the remanence field of the machine resulting in a high idling current and the excitation inverter feeding the auxiliary generator that supplies DC emergency oil pumps.
期刊介绍:
The journal accepts papers about experiments (both plasma and technology), theory, models, methods, and designs in areas relating to technology, engineering, and applied science aspects of magnetic and inertial fusion energy. Specific areas of interest include: MFE and IFE design studies for experiments and reactors; fusion nuclear technologies and materials, including blankets and shields; analysis of reactor plasmas; plasma heating, fuelling, and vacuum systems; drivers, targets, and special technologies for IFE, controls and diagnostics; fuel cycle analysis and tritium reprocessing and handling; operations and remote maintenance of reactors; safety, decommissioning, and waste management; economic and environmental analysis of components and systems.