What exactly is 1.x and 2.0 power scalar V/f control in VFDs?
It is about efficient operation of your pump/fan. Affinity law says load torque is proportional to square of speed for fan or pump load. If you analyse a induction motor with equivalent circuit you will find that it is slip which determines efficiency. There is a slip value band from 0.05 to 0.15 where your machine operate with highest efficiency. Your motor is designed to operate at maximum efficiency at rated operating point. Most of the time V/f relation is derived from rated operating point. But then in lower speed operating region slip goes beyond 0.05 and efficiency performance degrade. Parabolic V/f relation can tackle that problem. It can ensure high efficiency even in low speed operation maintaining the slip band.
Hope this helps you.