中文摘要：

为提高三相并网逆变器的功率等级，提出一种由耦合电抗器组成的新型并联型三相并网逆变器，通过对耦合电抗器去耦得出并联型逆变器的等效电路，并分别在三相静止坐标系和同步旋转坐标系下建立平均模型，阐明耦合电抗器抑制零序环流的根本机理，即耦合电抗器可以增大零序环流阻抗。根据所得平均模型设计电流解耦控制策略，抑制了零序环流，解决了零序环流引起的不均流、波形畸变问题，提高了系统的可靠性和效率。最后，对一组1．5MW并联型三相并网逆变器进行了仿真验证。结果证明了上述分析及控制策略的正确性。

英文摘要：

To increase the power rating of three-phase grid-connected inverters, a topology of parallel three-phase grid-connected inverters composed of interphase inductors is proposed. The equivalent circuit was derived by decoupling the interphase inductors. Besides, the average-value models were obtained in the three-phase stationary coordinates and the synchronous rotating coordinates respectively. The funda- mental mechanism of zero-sequence circulating current suppression with interphase inductors is that the interphase inductors can increase the impedance of zero-sequence circulating current. Then the control strategy of the system was designed according to the average-value model in the synchronous rotating coor- dinates. The zero-sequence circulating currents were suppressed well and the discrepancy and distortion of currents were overcome. Therefore, the reliability and efficiency of the system were improved. Finally, the parallel three-phase grid-connected inverters with the power rating of 1.5 MW were simulated, which verified the validity of the above analysis and control strategy.