Speaker
Nils Arden
(Max-Planck Institute for Plasma Physics)
Description
Recently an inverter system (called BUSSARD) was assembled to individually feed the 16 in-vessel saddle coils of the fusion experiment ASDEX Upgrade (AUG).The new inverter system consists of 16 inverters, each with an output current of up to 1.3 kA and a bandwidth of up to 500 Hz in arbitrary waveforms. Currently, the system is in operation with 4 inverters feeding four in serial connected coils, each. The full system will be commissioned in 3/2016.
The common DC-link is fed by an existing thyristor current converter, called “Group 0”.The standard operation of this converter is current control mode which remains needed in the future for other applications. But for feeding of BUSSARD’s DC-link, voltage control mode is required. Therefore the control concept of the thyristor rectifier had to be modified. During the development process several control concepts were designed, simulated and tested. For this application the feed forward control was chosen as the best solution with respect to stability.
The Group 0 consists of two independent 2-quadrant thyristor rectifiers (module 0.1 and 0.2). Each module can provide a current of up to 4kA at a voltage of 340V or 600V (star- or delta-circuit configuration) for up to 10 seconds.With the existing output inductances the DC-link voltage oscillates and has strong voltage drops during quick load changes. To avoid this, new inductances, which are well-adapted to the capacitance of the DC-link, were integrated into the output of the modules.For a further optimization of the DC-link voltage level and ripple, some investigations on the real power distribution were done.
All steps required to optimize the converter for BUSSARD’s DC-link supply including results of the first operation campaign are presented in the paper.
Co-authors
Horst Eixenberger
(Max-Planck Institute for Plasma Physics, Garching, Germany)
Markus Teschke
(Max-Planck Institute for Plasma Physics, Garching, Germany)
Michael Rott
(Max-Planck Institute for Plasma Physics, Garching, Germany)
Michael Schandrul
(Max-Planck Institute for Plasma Physics, Garching, Germany)
Nils Arden
(Max-Planck Institute for Plasma Physics, Garching, Germany)
Wolfgang Suttrop
(Max-Planck Institute for Plasma Physics, Garching, Germany)
