STATE-SPACE CALCULATION OF 6-PULSE CURREN T CONVERTER BRIDGES IN STEADY-STATE

The method of approach presented here for the calculation of 6-pulse c urrent converter bridges is applicable for higher order current conver ters as well as for modern FACTS (Flexible A.C. Transmission Systems) equipment. It utilizes the periodicity of the complex space phasor sta te variables of the 3-phase a.c. system and the d.c. state variables i n steady-state operation. The entire system is transferred into two li near independent space phasor component networks for each switching st atus and is represented in state space with regard to its eigenvalues and the periodic 'strokes' of the current converter. The analytic solu tion of the resulting linear inhomogeneous boundary value problem lead s to the time functions of the state variables after the retransformat ion into original (R, S, T) coordinates. The result represents a compl ete system description.