This paper presents the effects of enhancing control systems' work conditions on active power filter performance in improving power quality. We will convert the changeable inputs of the controllers into static ones. The high harmonics' amplitude will
be the set-values of the controllers, so the active filter reduces them into zero and then THD will be in its permitted limits.
This paper presents a three phase shunt Active Power Filter (APF) for power quality
improvements in terms of harmonics compensation. The compensation process is based on
measure non-liner load currents and Active Filter currents, and then extract t
he references
from measured currents. Measured currents are then transferred from abc frame to d-q
reference frame. A Synchronous Proportional Integral controller (Synchronous PI
controller) is used. The control signals then drive the Pulse Width Modulation (PWM)
routine, where its output controls the Voltage Source Inverter (VSI) switching devices. The
performance of the Active Filter and the Synchronous PI controller is validated though the
simulink results in MATLAB environment.
Induction motors are the most widely used electrical motors due to their reliability,
low cost and robustness. However, induction motors do not inherently have the capability
of variable speed operation. Due to this reason, earlier dc motors were a
pplied in most of
the electrical drives. But the recent developments in speed control methods of the induction
motor have led to their large scale use in almost all electrical drives.
Out of the several methods of speed control of an induction such as pole changing,
frequency variation, variable rotor resistance, variable stator voltage, constant V/f control,
slip recovery method etc, the closed loop constant V/f speed control method is most widely
used. In this method, the V/f ratio is kept constant which in turn maintains the magnetizing
flux constant so that the maximum torque remains unchanged. Thus, the motor is
completely utilized in this method.
