A Communication-Free Carrier Synchronization Method for Parallel Inverters

Parallel inverters have become popular in high power applications for the merit of larger capacity. However, for parallel inverters, the problem is the carrier asynchronization due to the manufacture. The carrier asynchronization will cause the harmonics of the output current varying with carrier phase differences. A communication-free carrier synchronization method still needs to be investigated. Hence, this paper proposes a communication-free carrier synchronization (CF-CS) method for parallel inverters. Firstly, the impact of the carrier phase difference on the synthesized output current of parallel inverters is analyzed based on the Double Fourier analysis. Next, a communication-free carrier synchronization method is proposed to achieve the carrier synchronization. Finally, the proposed CF-CS method is verified and compared with the exiting method by software simulation and experimental results.