Current control of magnetically coupled superconducting coils for nuclear fusion experimental system using H/spl infin/ control scheme

Precise current control within 0.01% accuracy of superconducting coils composing the Large Helical Device (LHD), which is a nuclear fusion experimental system under construction in Japan, is needed under the condition with strong mutual coupling between coils and some disturbances such as plasma, vacuum vessel etc. Application of the H/spl infin/ control scheme with a two-degree-of-freedom controller was studied. Good control results were obtained from the experimental model system with two superconducting coils. Simulation results with the LHD's circuit parameters show the possibility of successful control results.