Toward the completion of the Power Supply system for Resistive Wall Modes control in JT-60SA

The Power Supply system for Resistive Wall Modes (RWM) control in the JT-60SA experiment is an Italian in-kind contribution to JT-60SA within the Broader Approach Agreement. A very efficient control of RWM is necessary to access plasma currents with high βN values (3-5) sustained for a hundred seconds, as foreseen in the JT-60SA research plan. The development of the whole RWM control system (coils, power supplies and control) went through several steps of optimization; the final coil configuration is made of three toroidal rings of six coils placed on the plasma side of the a stabilizing plate, inside the vacuum vessel; the coils are individually fed by dedicated power amplifiers, controlled in real time. A key aspect highlighted by the physics studies was the need of a very fast reaction of the control system to prevent an excessive growth of the plasma instabilities and to limit the power required for their control. The main requirements for the power amplifiers were a peak current of 300 A, output voltage of 240 V, bandwidth of 3 kHz and a latency shorter than 50 μs.The satisfaction of so fast dynamics was addressed via an R&D program which led to an innovative design solution adopting hybrid Silicon-Silicon Carbide (Si-SiC) semiconductor for the power amplifiers and to the development of a new sophisticated inverter on-board control. The schedule of the procurement was finalized in 2015 and was articulated in a relatively longer phase, for the detailed design, prototype development and testing, with respect to the manufacturing due to the high level of innovation. The delivery to Japan is expected in September 2018. An overview of the main phases of the development and realization of this advanced system, the first in fusion experiments adopting SiC semiconductors, will be presented.30th edition of the Symposium on Fusion Technology (SOFT 2018

Development of Supervisory Control System for Magnet Power Supplies in JT-60SA

Magnet power supply (PS) system of JT-60SA is being implemented within the Broader Approach Agreement aiming to achieve first plasma in 2020. The system consists of several components such as DC power supply, switching network unit, quench protection circuit and motor-generator. All the componentshave their own internal controller (LCC) for stand-alone operation so the individual commissioning are in progress and almost completed. The next step scheduled is a combination test with all components in which supervisory control system manage LCCs remotely. The supervisory system covers the following roles: 1) machine status monitoring; 2) discharge sequence management; 3) real-time reference waveforms management; 4) data acquisition; 5) machine protection; 6) human safety. The supervisory system consists of several subsystems; PS supervising computer (PS-SC), PS programmable logic controller (PS-PLC), PS internal protectionsystem(PS-IPS) and PS safety interlock system (PS-SIS). PS-SC covers the primary roles in 1) – 4) which is built on CompactPCIs with real-time OS INtime. PS-SC and LCCs are linked through a Reflective Memory (RM) network to share common data in real-time (4 kHz). PS-SC is also linked to the upstream JT-60SA supervisory control system (SCSDAS) via another RM network as an interface for the power supply internal control systems. During discharge sequence, PS-SC also manages motor-generator speed, AC circuit breakers OPEN/CLOSE status with a controller PS-PLC and magnets current according to request from SCSDAS. PS-IPS covers the function of 5) which is implemented on FPGA. PS-IPS is connected to LCCs via fiber optical and hard-wired signals. In case of emergency events such as magnet quench and earth quake, PS-IPS commands to shut down the magnets currents immediately. PS-SIS plays the role in 6) such as status and permission of fence OPEN/CLOSE and grounding switch for maintenance. In this presentation, overview and development of the supervisory system are described.30th edition of the Symposium on Fusion Technology (SOFT 2018

Development of Supervisory Control System for Magnet Power Supplies in JT-60SA

Supervisory control system for superconducting magnet power supplies in JT-60SA is designed and developed. This system is in charge of many kinds of control; discharge sequence control, real-time magnet current control, data acquisition, machine protection and human safety. In the design, communication interface has to be optimized according to all requirements. The most important feature is real-time control with 4 kHz which is required for equilibrium control of plasma. In order to satisfy this requirement, reflective memory (RFM) network is applied for high speed data sharing with multiple controllers. This paper describes the architecture of the control system and the operation of the power supply system under the supervision