Effect of Increasing Rated Torque of PMSG with Variable Wind Speed on Per Phase Output Voltage for Off-Grid Wind Energy Conversion System

To utilize the renewable energy resources, wind energy conversion systems (WECS) are a popular choice. In WECS, generators such as, Squirrel Cage Induction Generator (SCIG), Permanent Magnet Synchronous Generator (PMSG), Wound Field Synchronous Generator (WFSG), and Doubly Fed Induction Generator (DFIG), are used. Recently PMSG is gaining popularity over conventional generators, due to benefits such as no gearbox, high power density, and high precision and easy to control. Since, these generators are located very near to the load; power quality (PQ) disturbance, due to non-linear loads, mostly affects them. Thus, analysis of wind generator performance with harmonics injected by non-linear loads becomes necessary. This effect of harmonics injected by nonlinear loads has been analyzed for PMSG in off-grid mode. The analysis has been performed for different ratings of the PMSG operating with variable wind speed using Matlab/Simulink. Further, the effects of variation of ratings of PMSG on the total harmonic distortion (THD) of generator voltage and current with variation of wind speed has been analyzed. The results show that higher rating generators are more affected by harmonics in offgrid mode.