一种光伏发电系统效率优化策略的研究

Study on New Strategy for Enhancing Efficiency of PV System

研究优化光伏发电,提高发电效率问题,针对目前光伏发电系统效率低,由于发电受到外界光照强度和温度影响,发电功率不稳定,且最大功率点跟踪(MPPT)过程在不同时域分别对快速性和准确性具有不同要求,为了提高稳定性,提出一种带有调整因子的双模模糊控制策略,采用两种模糊控制相结合的组合模型,使PWM信号开关的占空比D总能根据外界条件的变化迅速调节至合适的值,从而在外界条件发生变化时将光伏阵列的输出功率迅速跟踪达到并稳定的最大值,解决了既要快速跟踪又要精确定位的问题,提高了光伏发电系统的效率。通过在MATLAB中建立模型,并进行仿真,结果表明双模模糊控制策略能够根据外部环境的变化,快速、准确地跟踪光伏阵列的最大功率点。适时地改变模糊规则,提高了控制精度,改善了控制效果。

Study the problem for enhancing the efficiency of Photovoltaic（PV） generation systems.Aiming at the low efficiency currently resulted from the instable power generating affected by external light intensity and temperature,and the different requirements of accuracy and rapidity in the process of maximum power point tracking（MPPT） in different time domain,a dual-mode fuzzy control strategy with regulating factor was proposed.It combined rough tuning fuzzy control and precise tuning fuzzy control with regulating factor,then the duty cycle was adjusted continuously to a proper value which made the output power of photovoltaic arrays reach the maximum rapidly and kept it stable,so the conflict between fast tracing and accurate positioning was solved and efficiency of PV system was improved.The simulation model of controller was built in MATLAB environment,and the simulation results show that dual-mode fuzzy control strategy can track maximum power point of photovoltaic arrays accurately and rapidly,and follow the changes in the external environment.Furthermore,fuzzy rules can be modified in real-time by regulating factor,in which it makes the control accuracy and effect both better.