一种基于逆变器特性的光伏并网功率控制系统

Grid-connected PV Power Control System Based on Inverter's Characteristic

为了能够快速响应电力调度指令,光伏电站需要对并网发电功率进行实时控制。基于这一问题,提出一种根据频率-功率响应特性可调并网逆变器的特性,对其各自输出的最大有功功率进行限制,进而达到对电站总并网功率进行控制的方法。首先,针对频率-功率响应特性可调逆变器,对频率-功率特性参数等于默认值时的各个频率点下的功率样本数据进行变换,生成一组以输出功率上限为输入量,以频率-功率特性参数值为输出量的样本数据。然后,对样本数据利用多项式插值法求出以输出功率上限为自变量的特性参数预测式。最后,在算出特性参数预测值并据其调节逆变器后,根据调节后实际输出功率与目标限定功率之间的误差对特性参数值进行自动调节,最终使各台逆变器的并网输出功率满足要求。

In order to response quickly to power dispatch command, photovoltaic power plant needs to control its grid - connected power in real - time. To solve this problem, proposed a method to limit the ac- tive power of the inverter on line based on the inverte＇s frequency- power response characteristics, so as to adjust the total gird - connected power of the power station. First, for those inverters whose frequency -power response characteristics can be adjusted, transform the inverter＇s frequency- power sample data on the condition that the frequency - power response characteristics is equal to its default value, and obtain a group of sample data whose input data is output power upper limit and output data is the frequency- power response parameter . Then use polynomial interpolation to obtain the prediction formula which make out- put power upper limit as its argument. After obtaining the predicted value of frequency - power response parameter and successfully send it to the inverter, keep adjusting the value according to the actual output power feedback until the inverter＇s output power meets the requirements.