An Interharmonics Mitigation Control Scheme for Discontinuous Conduction Mode Flyback Microinverters

When large-scale photovoltaic (PV) systems are connected to the grid, the influence of interharmonics cannot be ignored. This paper proposes a modified MPPT method to reduce the amplitude of harmonic components in the duty cycle, thereby greatly mitigating the interharmonics in the grid-connected current. The modified MPPT method and sinusoidal pulse width modulation (SPWM) method are integrated as a dedicated analog control scheme, which features in simple structure and low cost, making it suitable for discontinuous conduction mode (DCM) flyback microinverters.