Background: In this paper, an assessment of active power filter (APF) performance is
presented under direct and indirect current control schemes through on-line compensation theory.
Methods: Conventional Direct Current Control (DCC) measures both load current and filter current
beside source and DC-link voltages, while Indirect Current Control (ICC) measures only source current
beside voltage measurements. Both DCC and ICC control algorithms are implemented using
80C196KC low-cost microcontroller.
Results: The performance parameters of APF are compared under two methods, and it is assigned
that ICC gives a better performance with lower cost due to reduced number of sensors. The DC-link
output voltage is controlled through simple PI-controller, and the PWM switching signals required
by APF power circuit is obtained by hysteresis current controller.
Conclusion: The comparative simulation and experimental results exhibit that performance of APF
due to ICC scheme is superior than DCC one.