Thermal Design of High-Power DC Reactor for ITER Poloidal Field Converter

This paper presents an alternative computationally efficient approach to the thermal design of high-power DC reactor which is applied to ITER poloidal field converter module. The proposed approach takes full advantages of the property of time-saving from heat transfer theory and high accuracy from 3-D finite-element analysis, focusing on the predictions of the temperature rise and pressure loss of circulating water. Thermal measurements from two prototypes test show a good agreement with the predictions, which proves the high efficiency and accuracy of the proposed approach in the design of hundred-kilowatt-class thermal power DC reactor.     

On the Current Sharing Control of ITER Poloidal Field Converter

Current sharing control is used to assure the stability of unbalanced current between two paralleled bridges when International Thermonuclear Experimental Reactor poloidal field converter operates in parallel mode. This paper, based on the equivalent model of current sharing circuitry, describes the dynamic behavior of current sharing control by means of frequency and time domain methods. A control strategy is proposed and simulations are performed to verify the effectiveness of the proposed strategy in current sharing control.     

On the Circulating Current Control of ITER Poloidal Field Converter

The dynamic behavior of circulating current control of International Thermonuclear Experimental Reactor poloidal field converter is the subject of this investigation. Four quadrants operation with circulating current has proved to be a reasonable way to perform smooth transition at the zero crossover of load current. In this paper, a control method, specially for circulating current control, on the basis of equivalent circuit, is proposed. With simulations it is verified that the circulating current can be controlled in such a way that it never become zero, and load current can change polarity without any discontinuity and dead zone, even if in the case that the total reference voltage of converter changes rapidly.     

Analysis of Internal and External Bypass Circuit Design for ITER Poloidal Field Converter System

This paper describes the bypass circuit design applied to International Thermonuclear Experimental Reactor (ITER) poloidal field converter system. In the baseline design, an internal bypass scheme was designed for purposes of quench protection and reactive power reduction by bypass operation. However, due to the potential risks that exist in case of fault protection, internal bypass scheme is abandoned finally and external bypass scheme is proposed to replace the internal bypass design. In this paper, the weakness of internal bypass design has been reviewed and the reliability of external bypass design at different sites is analyzed. Simulations based on SIMULINK are performed to confirm the reasonability and availability of external bypass proposals.     

The Research of High-Performance Integrator for ITER Poloidal Field Converter Measurement System

Rogowski coil is used to measure the current of the thyristor in ITER poloidal field converter, the output of the Rogowski coil is the differential of current over time, so the result should be synchronized with input signal by using the integrator. In the process of measuring, the integral drift is caused by the input offset current, input offset voltage and the input bias current, which produces errors which will be larger after a long time, so something should be taken to decrease the errors. Then a real-time way of compensation was proposed in this paper based on the foregoing analysis. According to the method, the high-performance integrator was designed and tested to fulfill the demand of decreasing the errors by simulation analysis and experimental test.     

A Timed-Token Based Network for the ITER Poloidal Field Converter Control System

The control system for poloidal field (PF) in ITER is running in a cluster of distributed controller nodes connected by a soft real-time network. The non-functional performance of network communication, such as latency and jitter, plays an important role in the control system. We analyze the essential of network communication for PF converter control system with stringent real-time requirement and identify the feasibility of the conventional time division method at the request of current data size. However, in order to meet the increased demand for communication data size, we present the design of a timed-token based method and its network scheduler. A test scenario involving a cluster of local control cubicles has been set up to verify the method. The test result shows the timed-token method is more competent to the conventional method and more qualify to the networked control system of PF converter. Meanwhile, in other network with similar architecture, implementation of the timed-token method can guarantee real-time performance as well.     

Primary Design and Analysis of Feeder for ITER Poloidal Field

An electromagnetic （EM） analytic model for the PF feeder, applied to ITER and needed to convey the cryogenic supply and electrical power to the PF magnets, was ...