Study on Ideal Operation Status of Parallel Inverters

In order to keep a parallel inverter system operating stably, it is important to restrain the circulating current effectively. Based on the theoretical analysis, the limitation of a conventional conclusion about ideal operation status of parallel inverters is studied in detail. And then, the ideal operation status of the parallel inverter system is well investigated in this paper. A new criterion about ideal operation status of parallel inverters is concluded, i.e., there will be no circulating current among parallel inverters only when their output voltages have the same frequency, phase, amplitude and are also uniformly modulated. The concept of "uniform modulation" and the corresponding conclusion are verified by simulation and experimental results.