In order to improve the maximum output power of PV system, the two stage single-phase grid connected PV system is studied. The Boost circuit of the system to put forward a new variable step incremental conductance method to achieve maximum power point tracking based on improved traditional incremental conductance method (MPPT), the inverter adopts P-Q control mode to realize the fast tracking of grid voltage, voltage outer loop electric double loop loop control, the inverter stable output of reactive power and active power. By setting up the MPPT model based on Boost circuit in Simulink, simulation of variable step size in maximum power tracking method and control strategy of grid connected inverter, the system not only can effectively improve the tracking speed and accuracy, fluctuations in the maximum power of the suppression system and can better meet the requirements of photovoltaic power generation, gridconnected inverter.%文章对两级单相光伏并网发电系统进行研究,系统前级使用新型变步长电导增量法,来实现最大功率点跟踪;后级逆变器采用P-Q控制方式,实现快速电网电压跟踪;使用电压外环,电流内环的双环控制,使逆变器输出稳定的无功和有功功率.在Simulink中搭建仿真模型,结果验证系统不仅能够有效提高跟踪速度和精度,而且可以较好的抑制系统在最大功率处的波动,满足光伏发电对并网逆变器的要求.
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