similar machines may not be equal even if they come from
the same manufacturer. Moreover, the rotor resistance
changes with loading and temperature. The equivalent rotor
resistance also changes with the frequency of the rotor
currents and slip due to the deep-rotor-bar effect, which
depends on the rotor design [5], [6]. In a load sharing
system composed of several machines, such variations in the
value of rotor resistance results into different torque-speed
characteristics for the machines and hence different values
of developed electromagnetic torque. In other words, the
load will not be equally shared among the motors and/or the
symmetry might gradually deteriorate due to changes in
loading, temperature, etc. This issue is further discussed in
the next section and a new and improved V/F control
scheme is proposed to ensure a symmetric load sharing
among the motors despite.