三相单级式LCL型逆变器光伏并网控制方法研究
Research on PV Grid-Connected Control Methods of Single-Stage Three-Phase Inverter With LCL Filter
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摘要: 可再生能源并网发电的可靠性、稳定性是微电网协调控制分布式发电系统实现能源综合梯级利用及大电网稳定运行的重要保障。针对交流微电网中太阳能光伏并网,采用单级式LCL型光伏并网逆变器拓扑结构并设计滤波器参数;采用有源阻尼消除LCL谐振尖峰,抑制逆变器输出电流的振荡;利用电压前馈控制削减并网公共节点电网电压对并网电流的影响;应用准比例谐振调节器实现电流跟踪控制。仿真结果表明,在光伏能源功率波动情况下,逆变器能实现能量以单位功率因数并网,以及系统快速稳定运行,证明控制方法可行、有效。Abstract: Reliability and stability of renewable energy grid-connected generation is base of micro-grids coordinating control distributed power generation system (DPGS) completing energy source comprehensive cascade use and making up grid power stable operation. Solar photovoltaic grid connected is applied in an AC micro-grid. Appropriate power control methods are designed. The topology of single-stage photovoltaic grid connected inverter with LCL filters and its references are designed. The scheme of active damping by filter capacitor current is applied to suppress the transient resonance of LCL filter.Control method of power grid voltage feed forward is used in protecting the grid connected current from voltage harmonics of the point of common coupling(PCC)of the power grid. Quasi-proportional-resonant (quasi-PR) method is applied in grid-connected current tracking demanded current. The simulation results show that system operation is fast and stable by grid-connected inverter under PV energy fluctuation and the methods are proved effective and feasible.