摘要
多电平逆变器能产生多阶梯、低失真电压波形,特别适合于大功率高电压场合。其中二极管箝位式多电平逆变器(DCMLI)因无需独立的直流电源来维持每级电压而备受关注。但由于该逆变器存在直流侧电容电压的不平衡问题,因而还未能在有功功率变换中得到广泛应用。文中采用空间矢量法研究了负载功率因数对二极管箝位式多电平逆变器(DCMLI)直流侧电容电压不平衡的影响,建立了功率因数与电容电流之间的数学关系。利用DCMLI的电容电流模型计算出了各开关状态下的电容电流大小和方向,并引入不平衡空间矢量的概念,从而揭示了产生DCMLI电容电压不平衡的机理。认为只有舍去不平衡矢量,才能通过选择合适的冗余开关状态使DCMLI电容电压达到平衡。仿真验证了结论的正确性。
Multilevel inverters that provide more than two voltage levels and less distorted waveform offer many benefits for higher power or higher voltage applications. TheDiode-Clamped Multilevel Inverter (DCMLI) does not require a separate dc power source to maintain each voltage level and has been attracting wide industrial interests recently. However, it suffers from problems such as dc bus voltage unbalance and is not widely used in active power transfer. This paper discusses the influence of the load抯 Power Factor(PF) on voltage across each of the dc bus capacitors in DCMLI with the Space Vector method. The mathematic relation between the PF and the capacitors current is presented. In order to know the cause of the voltage unbalance farther, the capacitors current arecalculated qualitative at each of switching states, and the Unbalanced Space Vectors in DCMLI have been found, which should be canceled to maintain the voltage balance across the capacitors, utilizing suitable redundant switching states.Simulation results are given.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2002年第12期111-117,共7页
Proceedings of the CSEE
