When the frequency drops, the voltage is completely proportionally reduced, then because the AC impedance becomes smaller and the DC resistance remains unchanged, the torque generated at low speed will tend to decrease. Therefore, given V/f at low frequency, it is necessary to increase the output voltage to obtain a certain starting torque. This compensation is called enhanced starting. It can be realized by various methods, such as automatic method, selection of V/f mode, or adjustment of potentiometer.