This paper presents the hardware implementation of a new control method of three-phase active power filters based on improved harmonic isolation. The harmonic isolator is based on high selectivity filters and the current control technique consists in a modulated hysteresis current controller. This active filter is intended for harmonic compensation of a diode rectifier feeding a RL load. The study of the active filter control is divided in two parts. The first part deals with the harmonic isolator which generates the harmonic reference currents and is implemented into a DSPACE DS1104 prototyping card. The second part focuses on the generation of the switching pattern of the IGBTs of the inverter by the modulated hysteresis current controller, implemented into an analogue card. The use of high selectivity filters instead of classical extraction filters allows extracting directly the voltage and current fundamental components in the alpha-beta axis at high performances. The effectiveness of the new proposed method is verified by computer simulation and by experimental study.