Robust control for rotary type frequency converter using two sets of adjustable speed generators/motors

Japan has two different frequency power systems, 50 Hz system and 60 Hz system. A frequency converter is required for interconnection between them. A power electronics based frequency converter, which is called static type frequency converter, is exploited at the interconnection points. The frequency converter can also be realized by using two sets of adjustable speed generator/motor (ASGM), whose structure is identical to that of an induction machine; rotor windings are excited by an AC voltage, and so called rotary type frequency converter. When applying this type of frequency converter to the interconnection points between two systems, where nonlinearity and disturbance inherently exist, in addition to functioning for interchange power between two systems, it should enhance power system stability by use of an effective and appropriate controller. Robust control for this kind of frequency converter has been studied in this paper and an effective controller is designed against disturbance and uncertainty in the power systems and examined in model power systems by digital simulation.