Experimental design and simulation of a modified PWM with an indirect current control technique applied to a single-phase shunt active power filter

This paper presents an indirect current control technique applied to a single-phase shunt active power filter (SPSAPF) implemented with pulse width modulation (PWM) to compensate harmonics and reactive power of non-linear loads. This method uses a residual signal constructed from the comparison between the supply current and its desired value. The PWM control technique adopted is based on two comparisons of a triangular high frequency carrier signal and the source fundamental active current. This error signal namely +/spl beta/ and its opposite value -/spl beta/ are both used, at the same instant, to generate the gate signals for the semi-conductor devices. The PWM technique eliminates the group of harmonics that are centred on the odd multiples of the switching frequency. It is requires a relatively reduced L/sub c/C/sub c/ input filter. The use of the averaging technique with this modified PWM control has allowed considering that the active filter transfer function may be modeled by a pure gain. This enables us to easily design the two control loops and choose the regulator parameters. This control technique has been implemented on a single phase laboratory prototype using analog devices. Experimental and simulation results show the performance of the control algorithm for SPSAPF. These presented results highlight the performance of the SPSAPF to compensate harmonics and reactive power.