基于改进锁相环的单相光伏并网逆变器研制

摘要

This paper presents an improved Software Phase-locked-loop(SPLL) algorithm for a single phase photovoltaic grid-connected inverter which arrays synchronizing a sinusoidal current output with a voltage grid. Through a phase delay , two orthogonal voltage in stationary coordinate system are generated, virtual d, q coordinate transformation is employed, the phase and frequency of grid voltage is obtained and the computing speed of PLL is improved.For achieving zero steady state error of current inner loop, quasi-proportion resonant (PR) controller is applied, voltage outer loop employs proportion integeral(PI) controller. Finally, simulation analysis based on Matlab and construction of single-phase grid-connected inverter confirm the theory feasibility of the method.%介绍了一种应用于单相光伏并网逆变器的改进型软件锁相环算法,可使逆变器输出电流与电网电压同步.将电网电压通过相位延迟,得到静止坐标系下2个正交电压,采用虚拟d,q坐标变换,经过一系列处理后,得到电网电压的相位及频率,提高了锁相速度,消除了谐波干扰,快速锁定任意频率和幅值电网电压的相位和频率.利用准比例谐振(PR)控制器对电流内环进行跟踪,实现了无静差调节,外环采用PI调节器.最后,通过Matlab仿真及样机实验分别验证了基于改进软件锁相环的单相并网逆变器的可行性.