The paper deals with MATLAB/Simulink models of single-phase active filters used for reducing the harmonic level and electromagnetic interference and to get compliance with the power quality standards. Four cases are modeled and studied in order to design and tune the best configuration for the active filter. Two of them are determined by the configuration of the load, which consists of a single-phase rectifier which feeds a resistive load, having a capacitive dc filter as a first setup and an inductive dc filter as the second setup. The single-phase active filtering system is based on a single-phase Voltage Source IGBT inverter with dc-link capacitor and a complete current control system that uses two different pulse-width modulation techniques. The two switching techniques, triangular carrier and hysteresis, determine the third and the fourth cases. The power quality and the existing standards are discussed, including the disturbances in a power system for a single-phase rectifier. The harmonics, how they are generated, and what problems they may introduce in the power system, are presented. The reference current for the power active filter is generated by the means of a resonant sinusoidal signal integrator filter implemented with a transfer function block. All simulations performed in MATLAB/Simulink validate the theoretical considerations but not all of them reveal a good agreement with the existing standards. The sinusoidal signal integrator integral coefficient it’s tuned in order to obtain a good compromise between grid THD current and transient response to load change. The results are interpreted and centralized so they can be useful in possible hardware implementation.