System harmonics compensation using PWM voltage source inverter-based active filters

This paper deals with the design and hardware implementation of two types of single-phase filter. The first type is the active shunt filter for compensating harmonic currents generated by nonlinear loads. The second type is the active series filter for eliminating harmonics inherent in the voltage source. The topology of the filter is based on a single-phase voltage source inverter (VSI) with four IGBT semiconductor switches. Simple time-domain extraction techniques are used to determine the harmonic components present in the load current or source voltage. The pulse-width-modulated (PWM) technique is then used to generate the required gate drive signals to the full-bridge VSI. A low-pass filter is also incorporated in the output of the inverter to provide a sufficient attenuation of the high switching ripples caused by the VSI.