基于电网电压定向的光伏并网逆变器系统研究

针对传统的光伏并网系统逆变控制策略存在控制复杂、谐波含量多的问题,提出了一种基于电网电压定向的光伏并网逆变器直接电流控制方法,给出了以TMS320F2812为主控制器的三相光伏并网逆变器系统的硬件及软件设计。该逆变器直接电流控制方法采用过零检测电路测量电网电压的过零点时刻,得出过零点时刻的电网电压的旋转角度,从而得到逆变器输出电压的幅值和相位;采用SVPWM技术控制IPM的开断,使逆变器输出上述幅值和相位的电压,从而实现单位功率因数并网发电功能。实验结果表明,该逆变器直接电流控制方法简单,逆变器输出电流与电网电压基本保持相同的频率和相位,并网发电功率因数接近于1。

Research of Grid-connected Photovoltaic Inverter System Based on Grid Voltage Orientation

In view of problems of complex control and multi-harmonic of traditional inverter control strategy of grid-connected photovoltaic system,the paper proposed a direct current control method of grid-connected photovoltaic inverter system based on grid voltage orientation and gave design of hardware and software of three-phase grid-connected photovoltaic inverter system taking TMS320F2812 as main controller.The direct current control method uses zero cross detection circuit to measure zero cross time of grid voltage to gain rotation angle of grid voltage at zero cross time,so as to get amplitude and phase of output voltage of inverter,and uses SVPWM to control on-off of IPM to make inverter output voltage with above amplitude and phase,so as to realize grid-connected generation function with unity power factor.The experiment result showed that the direct current control method is simple,output current of inverter keeps same frequency and phase with grid voltage,and grid-connected power factor is close to 1.