| Title |
A High-Efficiency Control Method for a Flyback Converter-Based Unfolding Inverter in Residential Photovoltaic Power Generation Systems |
| Authors |
Pyeong-Kang Kim ; Ui-Chang Mun ; Seung-Ho Song |
| DOI |
https://doi.org/10.5207/JIEIE.2026.40.4.293 |
| Keywords |
Flyback inverter; Grid connected inverter; Microinverter; Photovoltaic inverter |
| Abstract |
This paper proposes a high-efficiency control and design method for a flyback converter-based unfolding inverter for residential photovoltaic power generation systems. Residential photovoltaic power generation systems require miniaturization and high-efficiency operation of inverters due to limited installation space and frequent low-power operation conditions. Under low-power conditions, switching losses and the reactive power effect of the filter capacitor cause degradation in efficiency and power factor. To address these problem, this paper proposes a method that considers low-voltage input and low-power operating conditions. For high-efficiency operation, a two-phase interleaved structure and BCM operation are applied to reduce input current and peak current stress. In the low-current region, the operating mode is changed to DCM to limit the switching frequency. The grid-side filter was designed based on a 50 W operating point to ensure the target power factor. When the PV output power is low, burst-mode operation is applied to operate the inverter intermittently. To verify the proposed method, a 500-W flyback-converter-based unfolding inverter was modeled in PSIM. The simulation results show that the maximum switching frequency was reduced from 1.6 MHz to 60 kHz, and switching loss was reduced by 80%. In addition, a power factor of 0.99 was achieved by applying the burst mode operation. These results verify the validity of the proposed control method. |