面向直流微电网的升压型光伏发电系统研究

摘要

Aiming at the boost type of PV generation system for DC micro grid , a deep research has been done mainly from several aspects , such as the engineering model of PV cells , the MPPT ( maximum power point tracking ) control technology and the performance simulation and digital realization of the system .According to the uni-modality of P-U curve, a MPPT implementation plan based on the combination of impedance transformation of boost converter and in -cremental conductance technique has been determined , and the principle of achieving MPPT by incremental conduct-ance technique has been analyzed in details .In this paper , an improved variable step incremental conductance meth-od is proposed through researching on the MPPT control strategy of traditional fixed step incremental conductance . These two methods have been verified by simulation , and the experiments have been conducted .The corresponding experimental results prove that the improved variable step incremental conductance method , and solves the problem that the tracking speed and steady state accuracy can not be regulated at the same time , which is existing in the tradi-tional fixed step incremental conductance method .%针对面向直流微电网的升压型光伏发电系统，主要从光伏电池的工程模型、最大功率点跟踪控制技术以及升压型光伏发电系统的性能仿真与数字化实现等方面开展了深入的研究。根据P-U曲线的单峰性，确定了利用升压型变换器的阻抗变换作用和电导增量法相结合的最大功率点跟踪实现方案，并详细分析了电导增量法实现最大功率点跟踪的原理。通过研究传统的固定步长电导增量法最大功率点跟踪控制策略，提出了一种改进的变步长电导增量法，并这两种方法进行了仿真验证，并进行了实验研究。相应的实验结果证明了所设计的改进的的变步长电导增量法，解决了传统的固定步长电导增量法所存在的跟踪速度与稳态精度无法同时调节的问题。