Adaptive Switching Frequency Boundary in Hybrid DCM and BCM Method for Flyback Micro-Inverter

Abstract:
Flyback inverters are widely adopted in the field of PV microinverters due to the advantages of fewer devices, simple control, and input/output isolation. Currently, flyback microinverters are mostly optimized for performance with hybrid DCM and BCM modulation control strategies. However, the fixed switching frequency boundary in this scheme cannot maximize the BCM operating range in the mid-power stage. To solve this problem, an adaptive variable switching frequency boundary scheme is proposed in this paper, so that the boundary value changes with the power change, effectively extending the BCM operating range, thus improving the system power density and system efficiency.