微电网孤岛运行的分层控制策略研究

微电网中的分布式电源自身的不稳定性将导致微电网的运行控制困难,为此提出了分层控制（Hierarchical control）方法。在微电网孤岛运行的控制系统中,分层控制包含2个层次,其控制是通过上层将控制信息发送到下层来实现的。对于低压系统中线路的下垂特性（Droop控制）,提出了基于电压外环、电流内环和功率环等的反馈控制器。通过理论分析,在微电网孤岛运行时,微电网的输出电压幅值和频率显示稳定。利用Matlab/Simulink仿真结果表明,该分层控制策略能稳定地控制微电网的电压和频率,具有很好的稳态性。

Hierarchical Control Strategy for Micro-grid Islanded Operation

The micro-grid technology has many advan- tages. However, the instability of the distributed generations could lead the micro-grid to difficulty in operation, adversely af- fects the power quality of the micro-grid. In order to solve this issue, the hierarchical control method is proposed. In the mi- cro-grid islanded operation control system, the hierarchical con- trol consists of two levels, where the upper level＇s output control signal will be set as the input control signal of the lower level. In addition, the drooping characteristic （Droop control） of the low-voltage circuit in the system is also applied to propose feed- back controllers based on the voltage outer loop, current inner loop and power loop etc. By theoretically analyzing, the voltage amplitude and frequency of the micro-grid are stable in islanding mode. Matlab/Simulink simulation results show that the hierar- chical control strategy could stably control the voltage and fre- quency of the micro-grid with an adequate steady state.