DEVELOPMENT OF PV-ECS SYSTEM WITH INTELIGENT FUNCTION

作为一种进一步利用可再生能源的手段，自主光伏发电系统的发展是可望的，其日发电模式完全独立于可用太阳辐射模式。为了实现这一类型的环保型光伏系统，必须在光伏系统中加入某种储能装置，而我们使用的是带有电子电路元件的超级电容器作为储能装置，本研究开发了一种具有智能功能的并网光伏系统。所开发的光伏系统的主要特点是能够利用提前一天的天气预报实现负载均衡功能。研究结果总结如下：(1)使用双向逆变器，新系统的能效和控制能力比以前开发的光伏-ECS系统有很大提高。(2)对于束流辐射，使用Hotell方程，对于漫射辐射，使用Lie和Jordan方程，以理论能量为基准值，并与各种天气条件下的实测值进行比较，确定了晴天、阴天、雨天等不同天气条件下的能量因子。(4)为了实现负载均衡功能，提出了一种基于天气预报的PV-ECS系统日运行优化算法，并通过各种实验结果验证了该算法的有效性

As a means for further utilization of the renewable energy, the development of autonomous photovoltaic system of which daily generation pattern is totally independent from the available solar radiation pattern is expected. To realize this type of an environment friendly PV system, some kind of energy storage device must be added to PV system, and we use a super capacitor with electronic circuit elements, called ECS (Energy Capacitor System), as a power storage device and developed a grid-connected PV-ECS system with intelligent function in this study. Main feature of the developed PV system is in its ability to realize a load leveling function using a day-ahead weather forecast.The study results are summarized as follows :(1).Using the bi-directional inverter, the new system's energy efficiency and control ability are improved greatly compared with those previously developed PV-ECS system.(2).Using the Hotell's equation for the beam radiation and the Lie and Jordan equation for the diffused radiation, we developed a reliable and practical estimation algorithm for available solar energy at the system site.(3).A day-ahead available solar energy for a sunny day is calculated Setting tins theoretical energy as a base value and comparing with the actually measured value for various weather conditions, energy factors for various weather conditions of fair, cloudy and rain are determined.(4).To realize the load leveling function, we developed an optimization algorithm for the daily PV-ECS system operation using weather forecast based available solar energy and confirmed its usefulness through the various experiment results