滑模控制在两级级联光伏发电系统中的应用

Application of sliding-mode control in two-stage cascade photovoltaic power generation system

在光伏发电系统的应用中存在太阳能的间歇性导致电网不稳定的难题。为解决该问题,提出一种两级级联分布式光伏发电系统,该系统有两个独立控制的太阳能电源,每个光伏电池板包含一组两级级联升压转换器,由两个独立的滑模控制器分别控制。首先,采用极值搜索控制(ESC)算法实现最大功率点跟踪(MPPT)控制策略以最大限度地改善可再生能源的能量收集;然后,根据每个太阳能电源的可用发电量和蓄电池的充电状态,提出四种监控策略由监控中心选择;最后,通过数字化仿真来演示监视控制器的精确操作和每一种运行条件下MPPT算法的功能。仿真结果显示了该方法的可操作性和实用性。

In order to solve the problem that the intermittent solar makes the power grid unstable in the application of photo- voltaic power generation system, a two-stage cascade distributed photovohaic power generation system is proposed. The system has two solar power supplies controlled independently. Each photovohaic panel contains a set of two-stage cascaded boost converter controlled by two independent sliding-mode controllers respectively. The extremum seeking control （ESC） algorithm is used to realize the maximum power point tracking （MPPT） control strategy to improve the energy harvesting of the renewable energy sources to the utmost extent. According to charging state of storage battery and available generated energy, four monitoring strategies are proposed for monitoring center selection. The accurate operation of the monitoring controller and functions of MPPT algorithm under each operating condition were demonstrated by means of digital simulation. The simulation results show that the method is feasible and practical.