一种单级高增益电流型光伏并网逆变器

A Single-stage High Gain Current Source Inverter for Grid-connected Photovoltaic System

光伏电池的输出电压范围很大程度上受到诸如温度、太阳辐射等环境因素的影响。由于在并网时光伏阵列较低的输出电压很难满足系统对电压的要求,因此,光伏并网逆变器需要具备较好的升压逆变能力。在传统三态电流型逆变器的基础上,提出了一种新型单级电流型升压逆变器。该逆变器采用了含有2个分别对称的电感和二极管的无源网络,在直流输入电压较低时仍能够实现中间母线电压幅值的较大提升,输出稳定的交流电压。分析了对该逆变器高增益的工作方式,并给出了调制策略的具体方案。通过理论分析和MATLAB仿真验证了该新型逆变器拓扑具有良好的性能。

The output voltage range of photovoltaic(PV)cells is widely influenced by the environment factors,such as temperature,solar radiation,etc.Since the lower output voltage of solar array can hardly meet the requirements for grid-connected operation of the system,the better voltage boosting capacity is necessary for the PV grid-connected inverter.Based on the tranditional tri-state current source inverter,this paper presents a novel single-stage high gain current source inverter(CSI).The topology of the pro-posed inverter is derived from tri-state current source inverter by repl-acing the inductor in dc side with an impedance network consisting of two symmetrical inductors and three diodes separately,obtaining a much high voltage in dc bus and increases the ac output voltage amplitude.Theoretical analysis of operation modes and high voltage gain performance for the proposed inverter is presented,followed by the simulation of the proposed inverter in grid-connected photovoltaic system carried out on MATLAB.