The filter compensates for unwanted harmonic waves on an electricity distribution network. It includes an energy source (19,20)a waveform bridge network (21) connected between the energy source and a control unit (22) which controls the waveform bridge for harmonic compensation. The state of the energy source (19,20) is independent of the waveform bridge control effected by the control unit (22) and the control unit (22) injects harmonic components independent of the state of the energy source.
