Abstract
Module parallel three-level T-type inverters (3LT2Is) can increase power rating and efficiency of systems. However, the topology of transformerless inverters with common dc-link would cause the zero-sequence circulating current (ZSCC) problem. Previous papers have proven that the ZSCC can be suppressed by adjusting the time of the zero-sequence component. However, the performance would be deteriorated without considering the disturbance caused by differences in currents. An averaged model of ZSCC was analyzed in detailed. A small vector feed-forward control method with the PI controller was proposed to reject disturbance in zero-axis current systems. Moreover, a double sampling method was employed to expand the bandwidth of the zero-axis current system. Therefore, the ZSCC can be suppressed satisfactorily when output currents are different by applying the proposed scheme. The effectiveness of the proposed method is verified by the experimental results.
Original language | English |
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Journal | Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering |
Volume | 37 |
Issue number | 14 |
Pages (from-to) | 4165-4174 |
Number of pages | 10 |
ISSN | 0258-8013 |
DOIs | |
Publication status | Published - 20 Jul 2017 |
Externally published | Yes |
Keywords
- Double sampling method
- Small vectors feed-forward control
- Three-level T-type inverter (3LTI)
- Zero-sequence circulating current (ZSCC)