光伏系统中一种改进MPPT算法的研究

针对传统扰动观察法存在功率振荡和误判的问题,提出了一种功率预测与自适应变步长相结合的扰动观察法。自适应变步长能够按照P-U特性曲线的斜率自动改变步长,进而解决传统扰动法跟踪速度与跟踪精度不能兼顾和稳定后功率波形振荡较大的问题。当光照强度发生剧烈变化时,功率预测法能够根据P-U输出特性曲线进行预测,进而达到消除误判的问题。在MATLAB/Simulink中搭建光伏系统MPPT仿真模型,并对改进扰动法和传统扰动法进行仿真对比,结果表明,改进的扰动法能够克服传统扰动法存在功率振荡和误判问题,可以使光伏系统快速、准确地实现最大功率点跟踪控制,并使之稳定运行在最大功率点处。

Research on an Improved Maximum Power Point Tracking Method in Photovoltaic System

Aiming at the problems of power oscillation and misjudgment in traditional disturbance observation method, a disturbance observation method combining power prediction with adaptive variable step size is proposed. Adaptive variable step size can automatically change the step size according to the slope of P-U characteristic curve, thus solving the problem that the traditional perturbation method can not take into account the tracking speed and tracking accuracy, and the power waveform oscillates greatly after stabilization. When the illumination intensity changes sharply, the power prediction method can predict according to the P-U output characteristic curve, and then eliminate the problem of misjudgment. MPPT simulation model of photovoltaic system was built in MATLAB/Simulink, and simulation comparison was made between improved disturbance method and traditional disturbance method. The results show that the improved disturbance method can overcome the problem of power oscillation and misjudgment existing in the traditional disturbance method, and can enable the photovoltaic system to realize the tracking control of the maximum power point quickly and accurately, and make it run steadily at the maximum power point.