Implementation and simulation of modified PWM with two current control techniques applied to single-phase shunt hybrid power filter

Filter and source current control strategies are applied to a single-phase shunt hybrid power filter (SPSHPF). These techniques are implemented with a modified pulse width modulation (M-PWM) in order to compensate for the harmonics and reactive power required by nonlinear loads and the high-frequency harmonics generated by the switching process. Contrarily to the existing methods, the proposed source current control eliminates switching spikes in the supply current and appears to be more suitable than the filter current control method. Furthermore, the M-PWM technique ensures the elimination of all groups of harmonics that are centred on the odd multiples of the switching frequency. It requires a relatively reduced size input passive filter. In addition, it attenuates the harmonics that are located around twice the switching frequency four times less than the S-PWM. The measured power losses of the M-PWM hybrid filter are also one-fourth compared to that of the standard PWM control. Experimental results obtained on a 1 kVA developed laboratory prototype system and through simulations validate the effectiveness of the SPSHPF adopting the source current control with the modified PWM technique.