State space representation of current converters in extensive three-phase AC systems

In this paper the approach for the calculation of networks, including current converter bridges presented previously by the authors (1996, 1997) is adapted to extensive 3-phase AC systems. It still utilises the periodicity of all state variables in steady-state operating mode. The entire system consisting of the entire 3-phase network, the current converter and the DC network is represented in complex space phasor components for each switching status. The resulting state space description considers the eigenvalues and switching sequence of the current converter. The respective linear independent circuits are coupled into a linear inhomogeneous boundary value problem which is solved as a whole. Therefore the time functions of all state variables in large and compensated networks are obtained analytically. By further signal processing the harmonic load, power flows, reactive compensation factors and stationary resonance conditions can be calculated.