并网光伏电站汇流箱组串电流的节能控制

Energy Saving Control of the Set-of-String Current of the Junction Box of the Grid Connected Photovoltaic Power Station

并网光伏电站汇流箱组串电流节能控制过程中,采样和计算存在一定的误差,传统的节能控制过程,汇流箱输出电压不准确,实际输出汇流箱组串电流无法准确跟踪指令电流的变化,不能有效实现节能控制。提出一适用于并网光伏电站汇流箱组串电流节能控制方法,将并网光伏电站汇流箱组串指令电流转换成指令电压,并将其当成SPWM的调制波。在输出指令电压中加入一个前馈电压,使得并网光伏电站汇流箱电感两端的电压差含有一个基波分量,依据并网光伏电站汇流箱组串电流控制结果获得隐含层全部节点的正定矩阵,通过cholesky对隐含层的输出矩阵进行分解,基于分解结果获取并网光伏电站汇流箱组串电流节能控制效果最优解。仿真实验结果表明,所提方法在组串电流控制精度和节能方面均具有较好的工作性能。

There are some errors between the sampling and calculation in the energy saving control of the set-of-string current of the junction box for the grid-connected photovoltaic power station. In the traditional energy saving control process,the output voltage of the junction box is inaccurate, the actual output set-of-string current of the junction box cannot accurately track the instruction current change, therefore cannot effectively achieve energy-saving control. This paper presents a method suitable for the energy saving control of the set-of-string current of the junction box for the the grid-connected photovoltaic power station, in which the instruction current is changed to the instruction voltage which is used as an SPWM modulation wave. A feed-forward voltage is added to the ins-truction voltage output, and the voltage difference between the two sides of the inducer of the junction box is made to contain a fundamental component, and according to the control result of the set-of-string current of the junction box, the positive definite matrix of all the nodes in the hidden layer are acquired and decomposition is made for the output matrix of the hidden layer by cholesky decomposition. Based on the decomposition result the optimal solution of the energy saving effect of the setof-string current of the junction box for the grid-connected photovoltaic power station can be obtained. The simulation results show that the proposed method has good performance in the set-of-string current control precision and energy saving.