Comparative Study on Interharmonics Mitigation for Grid-connected PV Systems

Interharmonic is a significant power quality issue in photovoltaic (PV) systems. Single-stage inverters (SSI) are commonly employed in interharmonic mitigation studies, which have demonstrated that interharmonics can be mitigated by phase shifting the maximum power point tracking (MPPT) perturbations of PV cells. But the two-stage inverter (TSI) is more effective than other inverters in regulating the voltage and frequency on the dc bus, as it does not necessitate the implementation of intricate control techniques. This paper adopts a phase-shifted MPPT (PS-MPPT) method for mitigating interharmonics applicable to TSI and SSI and demonstrates the effectiveness of this method. Furthermore, the interharmonics suppression effect of the adopted method is compared on TSI and SSI. The PS-MPPT method was found to be effective in suppressing interharmonics on both inverters, with the TSI exhibiting a lower interharmonics than the SSI. The results were verified by simulations.