摘要
研究了二极管中点钳位(Neutral point clamped,NPC)三电平逆变器的容错拓扑及其控制问题,以保证NPC逆变器在发生器件故障时,仍然能够继续工作。在基本的NPC逆变器中增加一个不对称桥臂,并将其中点用双向可控开关连接到每相负载。为消除输出相电压的低次谐波含量,该桥臂采用SPWM控制方法代替传统的方波控制方法。当检测到NPC逆变器某相器件出现故障时,控制双向可控开关将故障相的负载连接到新加入的不对称桥臂中点。与以前文献提出的容错拓扑相比,在获得相同效果的情况下,提出的拓扑具有使用器件及其驱动电路数量少、电路成本低等优势。仿真和实验结果表明,所提出的NPC逆变器容错拓扑能够在容错控制后保持三相平衡工作,同时不降低原电路的输出功率,电路的可靠性得到很大提高。
A fault-tolerant topology as well as the control technique is proposed for the NPC three-level inverter, whith enables the in- verter to operate normally even under device failures. An additional asymmetrical bridge is added to the basic topology with its neutral point connected to three phase loads by bidirectional switches. The SPWM control method is taken for this additional bridge in place of the traditional square modulation method to eliminate the low harmonics in the phase voltages. When the device fault in one phase of the NPC inverter is detected, the load of this fauhy phase is connected to the neutral point of the asymmetrical bridge through the bidirec- tional switches. Compared to other tolerant topologies proposed before, the topology of this paper has the advantages of fewer switches and their drive circuits, lower costs and so on. The simulation and experimental results show that the NPC inverter can operate in bal- ance of three phases with whole output power and the reliability of the inverter is greatly enhanced.
出处
《控制工程》
CSCD
北大核心
2014年第2期258-262,267,共6页
Control Engineering of China
基金
上海市教育委员会科研创新重点项目(12zz191)
宁波市自然科学基金项目(2012A610007)
