A reduced-rating hybrid filter to suppress neutral current harmonics in three-phase four-wire systems

This letter proposes a reduced-rating hybrid filter to suppress neutral current harmonics in three-phase four-wire systems. Under unbalanced loading, the proposed filter eliminates only harmonics in the neutral current while it does not affect the fundamental. The VA rating of the inverter is significantly reduced compared to the conventional one since only fundamental current due to unbalanced loading could flow through the inverter switch.