this Paper presents a model of Wind Energy conversion System (WECS) using Permanent Magnet Synchronous Generator (PMSG).this system is grid connected system and contains two power converters and capacitor bank. This system controlled by PI control for controlling the voltage source inverter (VSI). Particle Swarm Optimization (PSO)code used to calculate the parameters of the controller to minimize the over shoot and settling time of the output power waveform ,the model of the system build by power simulator program (PSIM ) and the PSO code written in Matlab program . The PSIM program has function to connect the two programs together. Finally the results obtained are presented and discussed.