This article proposes a new maximum power point tracking (MPPT) controller based on voltage-mode Second-Order Fast Terminal Sliding Mode Control (SO-FTSMC) to obtain better performance in the power extraction from Permanent Magnet Synchronous Generator (PMSG)based Wind Energy Conversion System (WECS). The major objective of the study is the design of SO-FTSMC that can ensure the operation of the system in maximum power reference with higher efficiency, less steady-state error, and voltage fluctuation. Maximum power references are determined by mechanical sensorless MPPT approach. The small-scale WECS configuration incorporates wind turbine, PMSG, uncontrolled rectifier, boost converter, and MPPT controller. SO-FTSMC method has not been performed before as a voltage regulator in such a topology. The proposed controller has been validated for two different wind speed test scenarios in simulation environment, which can be applied effectively to PMSG-based WECS. Moreover, Conventional SMC (C-SMC) is created and then performance of controllers is compared in these wind speed scenarios according to maximum extracted average power, output voltage fluctuation, and voltage error in steady-state, MPPT efficiency, and performance indices. Obtained results indicate that proposed SO-FTSMC-based MPPT controller achieves superior performance.