多模式下风电直流微网功率协调控制策略研究

Research on power coordinated control strategy of wind turbine-based DC micro-grid under various modes

直流微电网系统的功率平衡是电网安全稳定运行的重要保证。综合考虑微网的运行方式和换流站功率裕量,将含有全功率笼型异步风电机组、储能蓄电池、交直流负载的直流微电网系统分为5种运行模式,即并网运行模式、限流运行模式、短时故障运行模式、孤岛减载运行模式和孤岛降功率运行模式。针对以上5种运行模式,提出一种基于多变量的功率协调控制策略。该策略根据并网变流器电流、蓄电池荷电状态以及直流电压的变化量自动协调各端换流站的工作方式,保证各工况下微网内部的功率平衡和直流母线电压的稳定。最后,在MATLAB/Simulink仿真平台中进行了仿真实验,验证所提出功率协调控制方法的有效性和可行性。

The power balance of DC micro-grid system is an important guarantee for the safe and stable operation of power grid. According to the working operation of DC micro-grid and capacity of the converter stations,we divide the DC micro-grid system with full power cage asynchronous wind turbines,energy storage battery,AC/DC load into five modes,namely grid-connected operation,current-limited operation,short-time failure operation,islanded load-off operation and islanded power-down operation. The proposed power coordinated control strategy can automatically coordinate the working operation of each converter station according to the DC voltage variation,the state of charge of battery and the current of grid connected converter. Then,the active power within DC micro-grid under any working condition can be balanced to maintain the voltage stability of DC bus. Finally,the simulation experiments are carried out in the MATLAB/Simulink simulation platform to verify the effectiveness and feasibility of the proposed power coordinated control method.