Abstract

Aiming at the problem that the filtering effect of inductor capacitance inductor (LCL) filter becomes worse when the Photovoltaic (PV) system works at low power, this paper presents a control strategy to change the switching frequency according to the instantaneous output power of the inverter. By analyzing the design method of each parameter of LCL filter, a single-stage PV grid-connected inverter structure is used to establish the frequency loop based on grid voltage-oriented vector control to determine the optimal switching frequency under the current power state. The design methods of power detector, frequency calculation and frequency hysteresis comparator are analyzed in detail. Finally, the waveforms of grid-connected current before and after frequency conversion are contrasted by MATLAB simulation to verify the feasibility and effectiveness of the inverter control strategy.

中文翻译：

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基于LCL滤波的光伏并网逆变器变频控制

摘要

针对光伏（PV）系统在小功率工作时电感电容电感（LCL）滤波器的滤波效果变差的问题，提出了一种根据逆变器瞬时输出功率改变开关频率的控制策略。 . 通过分析LCL滤波器各参数的设计方法，采用单级光伏并网逆变器结构，建立基于电网电压导向矢量控制的频率环，确定当前功率状态下的最佳开关频率。详细分析了功率检测器、频率计算和频率迟滞比较器的设计方法。最后，