Power controllable region of a power conversion system for SMES by use of a single natural commutation converter and an ICB energy transfer circuit

Highly efficient current type power conversion system (PCS) is the key component for realizing SMES of the large scale. PCS by use of the inverter-converter bridge (ICB) energy transfer circuit has been proposed to achieve the above requirement, and the experimental studies have been carried out. This PCS can control the power supplying to the utility well when the power factor is small one, however, the system goes out of control in the high power factor operations. In this study, it is theoretically analyzed the reason why the system goes into the unstable states. The experimental results are examined for confirming the theoretical analysis.