Modelling and simulation of a non-linear circuit

137 leaves : ill. ; 30 cm.PolyU Library Call No.: [THS] LG51 .H577M EIE 2001 LeiDevice Represented of Averaged Fourier Transforms (DRAFT) has been proved to be fruitful in generating SPICE macromodels for series, parallel and series-parallel resonant converters. However, The macromodels are inaccurate when state variables are not sinusoidal and the more accurate version of the models lead to convergence problems in a simulator. In this thesis, a novel macromodel and a new SPICE simulation program are presented. An algorithm of the new macromodel is extended from the averaged Fourier transforms. The algorithm uses actual solutions of state variables. A SPICE macromodel for a resonant converter is generated by the algorithm. The simulated results of the new macromodel are much more accurate than those given by the previous macromodels. A new nonlinear dependent source is proposed to enhance SPICE. The new source can solve equations of the form f (x)=0 with no convergence problems. The implementation of the new source is presented. A macromodel for a resonant converter is taken as an example to demonstrate the application of the new source. In addition, a new SPICE simulation program is written based on SPICE3 using object-oriented programming paradigms. The internal structure of the new SPICE simulation program is outlined. The object-oriented programming paradigms provide a set of features to simplify the internal structure of the new SPICE. When comparing with SPICE3, the new SPICE has many advantages for further development and maintenance.Department of Electronic and Information EngineeringM.Phil., Dept. of Electronic and Information Engineering, The Hong Kong Polytechnic University, 200