Design considerations of local controller for ITER coil power supply with high availability and reliability

Abstract

Abstract The local controller of an AC/DC converter for ITER coil power supply comprises a conventional system, an interlock system, and a safety system, which exhibit high reliability and availability through optimized designs for each system feature. The conventional system is made of three controllers according to each function, such as an interface controller (INTFC), an alpha controller (ALPC), and an analog-to-digital converting controller (ADC). They are configured with a 1 kHz UDP for real-time communication and 10 Hz TCP for transient recorder and with the digital fault recorder function to help facilitate data analysis and to easily troubleshoot problems in the fault event to improve the availability. Further, it is designed for accurate diagnosis by delivering time-stamped data to the parent system using the precision time protocol following the specification of IEEE 1588-2008 v2. The interlock system comprises a slow/fast local interlock controller (S-LIC/F-LIC). The S-LIC is configured with a redundant power supply and redundant Profinet communications for system availability, as well as a highly reliable programmable logic controller (PLC) for system reliability. The F-LIC is designed with an analog circuit board for protection and is evaluated for reliability. The safety system comprises highly reliable PLCs with a redundant power supply to monitor the safety-relevant signals and to transmit them to the parent system for occupational safety. In this study, the local controller of an AC/DC converter is introduced with designs applied to each system to satisfy the requirement and improve its reliability and availability.