Modelling and Comparative Evaluation of Control Techniques Applied to a PWM Three-Phase Four-Wire Shunt Active Power Filter

Current harmonics, which are injected in the utility by nonlinear loads, cause major problems that tend to deteriorate the power quality at the mains. To reduce such harmonics, active power filters (APF) are commonly employed. In this paper, two multiple-loops control schemes for a shunt three-phase four-wire APF are considered. The APF is used to compensate the current distortion and the reactive power created by a typical 60 kW industrial load. The first control scheme is based on the use of hysteresis current controllers for the current wave shaping, whereas the second one employs linear PI regulators designed on the basis of a small-signal averaged model of the converter. Both control schemes are designed to ensure voltage regulation at the DC side of the filter, and current wave shaping at the AC side. The control systems are implemented numerically using Matlab/Simulink tool. The performance of the both control approaches are finally evaluated and compared through the obtained simulation results