Methods for performing predistortion calibration on wireless communications circuitry are provided. In an embodiment of the invention, an IC can be tested on an undiced wafer by coupling a wireless transmitter of the IC to a wireless receiver of the IC. At least one blade is pivotally fixed to the frame, and is positionable to engage the surface. A zero torque commutation method is employed to control the brushless DC motor to the commanded position only when a time-rate change in the commanded position is less than a first threshold, a difference between the commanded position and actual position is less than a second threshold, and, the monitored energy used is less than a third threshold. This arrangement simplifies the structure and increases the stability, reliability, and service lifetime of vertical axis wind turbines by making on-site assembly easy and cutting the on-site workload and cost, without undermining the wind resistance capability and safety prompting wider application of vertical axis wind turbines.