配电网中分布式并网发电装置的复合控制策略

Composite Control Strategy in Distributed Grid-connected Generation Devices of Distribution Network

针对分布式并网发电中特别是光伏发电设备在夜晚情况下和风力发电设备在无风情况下利用率低,以及有源电力滤波器(APF)成本高、功能单一这一问题,提出了一种分布式并网发电装置的新型复合控制策略,它能在分布式电源最佳功率并网输出的情况下,同时实现电网谐波和无功电流补偿。详细分析了控制系统的结构,并采用改进的谐波及无功检测和并网有功指令电流合成算法及新型复合控制方法,改进算法省去了三相至两相坐标变换及其逆变换,计算量小,检测精度高,而新型复合控制根据自适应滞环比较器中的滞环宽度可随各参数变化而自动调节,重复控制器能保证在周期性负载扰动下稳态精度较高的特点,相应切换控制模式,大大改善了含分布式电源电网的电能质量,提高了电力系统的稳定性,并节省了设备投资。最后,利用Matlab/Simulink仿真验证了该新型复合控制策略的正确性和可行性。

In allusion to low utilization rate of photovoltaic （PV） power generation equipments at night and the wind power generation equipments in the windless situation in distribution network, as well as the high cost and single function of active power filter （APF）, we proposed a new control strategy in distributed grid-connected generating devices, which could make the distributed power work at the best grid-connected power output circumstances, and realize the compensation of grid harmonic and reactive current in real time. Moreover, we analyzed the control struc- ture in detail, and applied an improved harmonic and reactive current detection and grid connected active instruction current synthesis algorithm as well as a new composite control method. The improved algorithm did not require a three- to two-phase coordinate transformation and its inverse transformation, so it needed little computation and had high detection precision; Hysteresis bandwidth of the adaptive hysteresis controller could be automatically adjusted with other parameters, and the repetitive controller could guarantee the steady state accuracy in periodic load dis- turbances, so that the novel composite control could change its controlling mode thus save equipment investment, and improve power quality and system stability. Matlab simulation results test and verify the correctness and feasi bility of this new control strategy.