M. Rott

Conceptual design of the power supply system for the in-vessel saddle coils for MHD control in ASDEX Upgrade

Abstract In the frame of an ASDEX Upgrade enhancement, a system of active in-vessel coils (of two types, dubbed “A” and “B”) and conducting wall for MagnetoHydroDynamic (MHD) stabilization is being designed and implemented. The conceptual design of the power supply (PS) system has been worked out and extensive analyses have been performed to verify that the identified basic modules, based on a cascade topology with two IGBT (Isolated Gate Bipolar Transistor) H-bridges in series for the A units and one H-bridge for the B ones, were able to fulfil all the requirements, well within semiconductors safety operating limits. The paper summarizes the work which led to the definition of the PS requirements, describes the topologies of the selected basic units and of the overall scheme, discusses the design choices and reports the results of the numerical simulations carried out to check the overall performance.

Power inverter design for magnetic perturbation coils in nuclear fusion experiments

An economical, broad-band switched power inverter for supplying electrical current to magnetic perturbation coils in magnetic confinement nuclear fusion devices is designed and tested. The unit uses commercial IGBT blocks for a load current up to 1.3 kA at a DC-link voltage up to 500 V. Current is controlled by means of an embedded PC with real-time patched Linux operating system and commercial I/O boards. H-bridge and neutral point clamped (NPC) topologies are compared, both with standard and phase-shifted pulse width modulation (PWM). DC to 500 Hz bandwidth is demonstrated with good step response at full output current, making the system suitable for the supply of 16 in-vessel saddle coils of the ASDEX Upgrade tokamak. With multi-level topology and phase-shifted PWM the inverter design can also cover a planned additional coil set with DC to 3kHz bandwidth.

BUSSARD — The high current high bandwidth multiple-phases inverter for ASDEX upgrade

The generated magnetic field of 16 coils for the control of magneto-hydrodynamic instabilities (1.3 kA each, 500 Hz bandwidth) installed into the nuclear fusion experiment ASDEX Upgrade have to be freely adjustable in space and time. Therefore, a 16-phases, fast-switching IGBT-based inverter system, dubbed BUSSARD, was designed and implemented.

Pulsed power supply system of the ASDEX upgrade Tokamak research facility

The Max Planck Institute for Plasma Physics (IPP) researches the basic principles for a power plant which - similar to the sun - will produce energy by fusion of light atomic nuclei. The operation of the ASDEX Upgrade (AUG) Tokamak relies on three large flywheel generators. These generators feed the pulsed power supply system for the magnetic confinement (high current) and additional heating (high voltage) of the plasma. 17 high current thyristor converters supply the copper magnet coils that induce the plasma current and provide positioning, shaping and ohmic heating of the plasma. For the heating and current drive of the plasma by neutral beam injection and electron and ion cyclotron resonance frequencies, 28 high voltage modules are available. This article gives an overview of the AUG 580 MVA pulsed power supply system. It presents the challenges to integrate new technologies into an up to 40 year old, grown system and reports on the performance achieved during AUG plasma experiments.