Direct analysis of the steady-state behaviour of power conversion systems

Basically, APoSIS (advanced power system interactive simulator) is simulation software, developed on 32-bit Windows environment, which allows the steady-state analysis of power systems, including static converters, without computing transients. After the insertion of a netlist of the power system, APoSIS can calculate at first the steady-state values of the system state variables at a prefixed initial instant; successively, the program can compute several functions characterizing the steady-state behaviour, such as the mean value and the harmonic coefficients of the most significant variables. In addition, APoSIS can also analyze the stability of the power system and calculates the dynamic evolution produced by a disturbance or a parametric variation. The paper describes the most important computational methods used in APoSIS and it presents also an application to a DC-DC buck converter.