光伏并网Z源逆变器无差拍解耦控制策略

A Deadbeat Decoupling Control Strategy of Z-source Photovoltaic Grid-connected Inverter

提出了基于Z源的光伏并网系统无差拍解耦控制方法,避免了传统比例—积分控制性能易受电网电压不平衡及系统非线性的影响。该控制策略将无差拍控制方法与解耦控制方法相结合,并采用双时采样方法,减小了运算及采样时间带来的控制延时,具有动态性能好、精度高、稳定性好的优点。采用改进的空间矢量方法实现了Z源逆变器的桥臂直通,进而实现升压,使系统按单位功率因数运行,并网电流谐波畸变率低。仿真及实验均验证了该控制策略的有效性和可行性。

A deadbeat decoupling control method of Z-source photovoltaic grid-connected inverter is proposed. This method overcomes the disadvantages of conventional PI control method such as sensitivity to the unbalance of the grid system and nolinear characteristic. The proposed control algorithm combines deadbeat and decoupling method. In Order to minimize the error caused by the program executing and sampling time, the dual-timer sampling method is used. This control strategy is good at response speed, high accuracy and stability. A modified space vector pulse width modulation algorithm is used to realize the boost ability of Z-source. The current injected into grid is synchronous with the grid voltage, so a unity power ＇factor is realized. Simulation and experiment results both validate the feasibility of the proposed algorithm.