【摘要】 微电网存在两种运行模式,即并网运行模式和孤岛运行模式,两种运行模式的平滑切换是微电网安全稳定运行的重要保障。文中主要从两个方面考虑微电网运行模式的平滑切换,一方面是系统级微电网整体控制策略,采用主从控制和对等控制相结合的综合控制方法,另一方面是局部微电源控制策略,提出一种下垂系数随微网频率和电压动态变化的改进下垂控制,同时为实现微电网孤岛运行模式向并网运行模式的平滑切换设计了预同步控制器。最后通过MATLAB仿真表明,该方法不仅可以实现切换过程中电压和频率的稳定,而且还能减少微电源控制方式的切换次数,在一定程度上减小了控制方式切换失败的可能性,从而提高了微电网运行的可靠性。更多还原

【Abstract】 There are two operating modes in micro-grid,that is grid-connected operation mode and islanded operation mode,The smooth switching between two modes is an important measure to ensure the secure and reliable operation of micro-grid. In this paper,considering micro-grid operating modes of smooth switching from two sides,on the one hand,it is a system-level micro-grid overall control strategy,which uses an integrated control method from the combination of using the main control and peer control,on the other hand,it is a local micro-power control strategy,which proposes an improved coefficient droop control,and the droop coefficient can dynamically change with frequency and voltage,At the same time,the pre-synchronous controller is designed to achieve the smooth switch from micro-grid islanded operation mode to grid-connected operation mode. Finally,MATLAB simulations show that this method can not only realize the voltage and frequency stability during the process of switching,but also to reduce the switching number of the micro-power supply control mode,to some extent,it reduces the possibility of failure of the control mode switching,thus improving the reliability of the micro-grid operation.更多还原