Determination of optimal supplying parameters for power losses minimization in an induction motor

The minimizing of total losses in a squirrel-cage induction motor can be achieved by flux control. For every load exists an optimal value of voltage for the scalar control, and optimal values of stator current components for the vector control, which reduces the losses. These optimal supplying parameters can be determined by using an analytical method, which was worked out by author. The application of this method requires knowledge of core and mechanical losses, magnetization characteristic, resistances and reactances of motor windings. The investigation of proposed method was made for a small motor with rated data: PN = 1.1 kW and nN = 1415 rev/min. For this motor two steering characteristics Uopt = ∫(Ts) were prepared; first through laboratory measurements and second using the analytical method. The both characteristics made for five selected frequencies 50, 40, 30, 20, 10 Hz are compared in Fig. 3. The comparison shows the close agreement of both characteristics. In addition two characteristics of stator current components for 50 Hz and 30 Hz are presented in Fig. 1 and Fig. 2.These results proved usefulness of the proposed analytical method for calculation of optimal supply parameters