Figure (7) shows speed and torque response of conventional
drive. Drive started up to reference speed of 100 (rad/sec).
Then a load torque is applied at the time 0.5 (sec). Figure
(8) shows the current that feeds the motor. Figure (9) shows
speed and torque shapes for the proposed CSI-fed drive to
compare with conventional drive. In this case, the drive
operates at speed of 100 (rad/sec). Nominal torque is
applied at the same time. Figure (10) shows inverter output
current, active filter current and motor current shapes
respectively. Figure (11) shows FFT and THD diagram of
the inverter output current phase-a and figure (12) shows
FFT and THD diagram of the motor current phase-a. The
motor efficiency should be studied under different
conditions to have a general feasibility of comparison.
Therefore, the motor efficiency results are presented at low
speeds.