For the circulating current induced by the three-phase converter modules in parallel system which share DC bus and AC filter inductor

a control strategy based on the reconstruction of pulse width modulation wave to inhibit the circulating current is proposed. With this strategy

the master-slave control sends the information in the form of parameters and synchronous signal to the subordinate controller via broadcast communication. Good synchronization pulse width modulation signal is reconstructed by decoding the carrier synchronization signal and pulse width modulation wave parameters on the slave controller under the sampling clock cycle constraints. The consistent pulse width modulated signal is reconstructed by each subordinate controller to achieve the purpose of reducing circulating current. And the effect of communication delay in system stability is studied by analyzing the transfer function of the system. The communication delay time of critical stability is determined. A parallel converter experimental system is built. Experiment results verify that the proposed control strategy can reduce the circulating current.