大规模光伏并网发电系统拓扑结构的对比研究

Comparative Analysis on Large-scale Grid-connected PV System Topology

随着新能源技术的迅猛发展,光伏并网发电容量越来越大,并网逆变器作为并网发电的关键设备,其容量和数量也越来越大。由于各并网逆变器产生的谐波会相互叠加影响,甚至通过系统振荡放大,导致电源侧严重谐波污染,因此电力标准要求并网逆变器具有高电压等级、高输出波形质量和高转换效率。目前的主流趋势是通过发电单元的串并联来实现大功率逆变。主要对比分析了在大规模光伏发电系统中使用的或可能使用的拓扑结构,包括逆变器并联方案和逆变器串联方案(多重化、多电平、MMC)以及逆变器串并联方案,指出了各自的优缺点。

With the rapid development of new energy technologies, the capacity of PV grid-connected power generation is increasing, and as a key to grid-connected devices, grid-connected inverters＇ capacity and amount are also growing. As the harmonic produced by each grid-connected inverter will overlay each other, even zoom through the network＇s oscillation, leading grave harmonic pollution on the mains side, electrical standards call for the grid-connected inverter to have high voltage, high quality and high conversion efficiency of output waveform. Currently the mainstream trend is to use series-parallel connection of power generation unit to achieve high power inversion. The topological structures used in large scale PV power systems are compared and analyzed, including inverter parallel schemes and tandem schemes （multiplex, multi-level, MMC） and the inverter series-parallel schemes.