An active filtering system arranged to be connected in parallel with an electrical power supply network providing a main power supply current (IMAIN) including a disturbing current, said system comprising: - at least one capacitor to be coupled to a first power supply line of the electrical power supply network, - a controlled current generator comprising an electrical power supply intended to generate a positive determined voltage (+VDC) or a negative determined voltage (-VDC) and connected in series with the capacitor via a first terminal of said current generator, a second terminal of said current generator being intended to be coupled to a second line of the electrical power supply network, - a controlled current generator control device, arranged in order to control the controlled current generator to generate a compensating current (ICAPA) to be applied to the main current to compensate said disturbing current (INOISE) while maintaining a decoupling voltage (VDEC) measured at the connection point between the controlled current generator and said capacitor at a value which is suitable to not saturate the controlled current generator, the current generator further comprising a voltage converter comprising two switches (S1, S2) and an inductance connected at a middle point situated between the two switches, the two switches (S1, S2) being controlled in a complementary manner by the control device so as to apply to said middle point a voltage equal to said positive determined voltage (+VDC) or to said negative determined voltage (-VDC), the control device comprising: - a hysteresis comparator arranged to determine at the output a control (CTRL) to be applied to the switches of the voltage converter based on a control parameter (ICTRL) which is applied at the input, - a filter arranged so as to filter the main current (IMAIN) to obtain a first highfrequency current (IMAINHF), - means for determining a second current (IVAC) from said decoupling voltage (VDEC), said determining means being arranged to apply a dummy impedance to the decoupling voltage (VDEC) to deduce therefrom the second current (IVAC), said dummy impedance being determined in order to eliminate the low-frequency component of the decoupling voltage (VDEC), and - an adder arranged to determine the control parameter (ICTRL) by means of the difference between the first current (IMAINHF) and the second current (IVAC). - at least one capacitor to be coupled to a first power supply line of the electrical power supply network, - a controlled current generator comprising an electrical power supply intended to generate a positive determined voltage (+VDC) or a negative determined voltage (-VDC) and connected in series with the capacitor via a first terminal of said current generator, a second terminal of said current generator being intended to be coupled to a second line of the electrical power supply network, - a controlled current generator control device, arranged in order to control the controlled current generator to generate a compensating current (ICAPA) to be applied to the main current to compensate said disturbing current (INOISE) while maintaining a decoupling voltage (VDEC) measured at the connection point between the controlled current generator and said capacitor at a value which is suitable to not saturate the controlled current generator, the current generator further comprising a voltage converter comprising two switches (S1, S2) and an inductance connected at a middle point situated between the two switches, the two switches (S1, S2) being controlled in a complementary manner by the control device so as to apply to said middle point a voltage equal to said positive determined voltage (+VDC) or to said negative determined voltage (-VDC), - a hysteresis comparator arranged to determine at the output a control (CTRL) to be applied to the switches of the voltage converter based on a control parameter (ICTRL) which is applied at the input, - a filter arranged so as to filter the main current (IMAIN) to obtain a first highfrequency current (IMAINHF), - means for determining a second current (IVAC) from said decoupling voltage (VDEC), said determining means being arranged to apply a dummy impedance to the decoupling voltage (VDEC) to deduce therefrom the second current (IVAC), said dummy impedance being determined in order to eliminate the low-frequency component of the decoupling voltage (VDEC), and - an adder arranged to determine the control parameter (ICTRL) by means of the difference between the first current (IMAINHF) and the second current (IVAC).