Carriers synchronizing method of hybrid frequency parallel inverter and system thereof

A carriers synchronizing method of a hybrid frequency parallel inverter is proposed. A low-frequency ripple simulating step is performed to drive a high-frequency controlling unit to simulate a low-frequency ripple. An equidistant grid sampling step is performed to drive the high-frequency controlling unit to sample a sample ripple to generate a sample group and sample the low-frequency ripple to generate a plurality of low-frequency reference groups. An actual shifting angle searching step is performed to drive the high-frequency controlling unit to compare the sample group with the low-frequency reference groups to search an actual shifting angle from the reference shifting angles. A high-frequency carrier adjusting step is performed to drive a proportional integral controller to calculate the actual shifting angle to generate a sync reference, and then a period counter adjusts a starting point of the high-frequency carrier according to the sync reference.