光伏并网发电与无功补偿的鲁棒预测控制

Robust Predictive Control Strategy for Photovoltaic Grid-Connected Generation and Reactive Power Compensation

针对分布于电网末梢的单相光伏并网发电系统,提出了一种兼具并网发电和无功补偿功能的鲁棒预测控制方法,使系统在向电网和本地负载提供有功电能的同时也能提供负载所需的无功电能。在分析系统结构基础上,通过构建两相正交电流和利用瞬时无功电流ip-iq算法,检测出单相负载的无功电流的直流分量,通过直流侧电压外环PI控制输出得到有功电流的直流分量,从而获取并网指令电流。考虑到传统无差拍电流控制中的延时和并网滤波电感变化,提出了一种鲁棒预测电流无差拍控制方法,以增强系统的鲁棒性以及降低因控制延时和电感量偏差对并网电流造成的畸变。根据z域内的传递函数对其进行了稳定性分析,确定了控制参数的选取范围。仿真与实验结果证明了提出的控制方法的有效性。

For the single-phase photovoltaic grid-connected generation system installed at the end of the grid, a robust predictive control strategy with the function of active power generation and reactive power compensation is proposed. By this way, the system can provide not only active power to the grid and the local loads, but also the required reactive power to the loads. Based on the analysis of the system structure, two-phase orthogonal currents is constructed, and the dc component of the reactive current of the loads is acquired by the ip--iq algorithm based on the instantaneous reactive power theory, and the DC component of the active current is derived from the output of the PI controller of the outer voltage loop, and thus the grid-connected command current is obtained. Considering the delay and the filtering inductance variation in the conventional deadbeat controller, the robust predictive current deadbeat control is proposed to enhance the system robustness and reduce the current distortion due to the control delay and inductance deviation. In z-domain, the system transfer function is derived, and the system stability is analyzed, and the control parameters are selected. Simulation and experimental results verify the validity of the proposed control strategy.