A single phase inverter-zigzag transformer hybrid filter to suppress neutral harmonic currents in three-phase four-wire systems

This paper proposes a new hybrid filter to suppress neutral harmonic currents in three-phase four-wire systems. The compensation characteristics illustrate that the proposed scheme works well not only with harmonic voltage-source loads but also with harmonic current-source loads. 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. The experimental results on a prototype validate the proposed control approach.