【摘要】 随着分布式发电系统的不断发展,并网逆变器作为系统能量交换接口,地位越来越重要。在非理想电网条件下(电网含谐波及电网电压不平衡),并网逆变器采用传统并网控制方法难以输出高质量的并网电流。针对上述问题,本文以三相LCL并网逆变器为例,研究了一种基于电网电压前馈的控制策略。在传统PI控制的基础上,将电网电压前馈信号叠加到并网逆变器的调制波中,从而消除电网电压谐波和不平衡分量对并网电流的影响。论文首先推导出三相LCL并网逆变器在dq坐标系下控制数学模型,在此基础上分析了电网电压对并网电流质量的影响,并给出了基于电网电压前馈的三相LCL并网逆变器控制方法,最后搭建三相LCL并网逆变器实验平台,实验验证了电网电压前馈控制的并网电流谐波和不平衡抑制能力。更多还原

【Abstract】 With the continuous development of Distribution Generation(DG) system, the position of grid-connected inverter is very important which is the system energy exchange interface. Under the non-ideal grid conditions, the grid-connected inverter with conventional grid-connected control methods fails to inject high quality current into the utility grid. Thus, the feedforward control scheme of grid voltage based on the three phase LCL-type grid-connected inverter is proposed in this paper. On the basis of conventional PI control, the grid voltage feedforward signal is added to the inverter modulation wave, to suppress the impact of the harmonics and unbalanced component in the grid voltage on the injected current. Firstly, the mathematical model of the three phase LCL-type gridconnected inverter with the d-q coordinate system is deduced in this paper. Based on the model, the effect of grid voltage on grid-connected current is derived. The current control method for three-phase LCL-type grid-connected inverters with grid voltage feedforward is depicted. Then the prototype is built to evaluate the current control method with grid voltage feedforward.更多还原