单相单级光伏LCL并网逆变系统控制策略  

Control Strategy of Single-Phase Single-Stage LCL Grid-Connected Photovoltaic Inverter System

作　　者：江渝[1] 姜琦[1] 黄敏[1] 梁波[1] 

机构地区：[1]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆市沙坪坝区400044

出　　处：《电网技术》2015年第2期312-319,共8页Power System Technology

摘　　要：在传统的光伏LCL并网逆变系统中,直流侧电压只有大于其最小需求电压时,逆变器才能有效控制并网电流,而最小需求电压随电网电压的增加而增加。为此需在单级逆变系统中串联多块光伏电池以提高其直流侧电压,但这提高了光伏并网发电系统的应用门槛。对此提出一种新型的LCL并网逆变系统及其控制方法,该逆变系统对并网电流有较强的控制能力,对逆变器直流侧电压没有要求,且电网电压对其控制能力也没有影响。与传统LCL电路相比,新型LCL电路同样具有较好的滤波效果。在控制系统中利用基波分量提取环节增加系统阻尼,提高系统稳定性;根据光伏电池的直流电压、电流和2次脉动电压、电流判断光伏的最大功率点;通过控制并网电流使光伏电池工作在最大功率状态。仿真结果验证了所提系统结构及其控制方法的正确性。In order to control the grid current completely, the DC voltage of the inverter meets the voltage requirement for the traditional LCL grid-connected inverter system. And the required voltage increases with the grid voltage increasing. The lower output voltage for each cell results in the fact that in the traditional single-stage PV series-connection for meeting system cells are often in the DC voltage requirement, which is disadvantage for the further application of PV system. In this paper, a new LCL grid-connected PV inverter system and its corresponding control strategy is proposed. The proposed LCL inverter is able to control the gird current effectively and abandon DC voltage requirement. Furthermore, the gird voltage has no influence on the control of proposed inverter. The proposed LCL has a strong high-frequency attenuation capability just like the traditional LCL circuit. In addition, a method is introduced to suppress the resonance and improve the stability of system, which extracts the fundamental component of grid current. And the real maximum power point of PV cell is judged according to the DC component and second harmonic of the PV voltage and current. The maximum power tracking of PV is achieved by controlling the grid current. Then the proposed system with the corresponding control strategy is verified by the simulation.

关 键 词：单相单级 并网 光伏逆变器 最大功率点跟踪 

分 类 号：TM46[电气工程—电器]