Power electronics systems are nonlinear variable structure systems. They involve passive components such as resistors, capacitors, and inductors, semiconductor switches such as thyristors and MOSFETs, and circuits for control.The analysis and design of such systems presents significant challenges. Fortunately, increased availability of powerful computer and simulation programs makes the analysisdesign process much easier.PSIM® is an electronic circuit simulation software package, designed specifically for use in power electronics and motor drive simulations but can be used to simulate any electronic circuit. With fast simulation speed and user friendly interface, PSIM provides a powerful simulation environment to meed the user simulation and development needs.