Seamless Switching of AC-DC Microgrid Based on Multi-Control Complexity
In the hybrid AC-DC microgrid under peer-to-peer control,the grid-connected inverters will switch different control modes with the change of operating status.When different control modes are switched,there will be transient changes in voltage,frequency,current and other power levels,resulting in the microgrid unable to run smoothly.In order to realize seamless switching between islands and grid-connected modes,a soft switching composite control strategy based on sag control and PQ control is designed in this paper,and the current inner loop of the two control modes is coupled to form a dual-mode combined controller based on current tracking,so that the reference current of the input current inner loop controller can track the state before the switching time and maintain the correct initial The initial value and the compensated pre-synchronization control strategy for frequency,phase and amplitude are designed to make the microgrid island/grid-connected mode switch smoothly.Through PQ control,the active switching power P and reactive switching power Q are 0,and the switching power of the large grid side and the micro grid is 0,and the grid-connected/island mode is switched.Finally,the effectiveness and feasibility of the control strategy are verified in MATLAB/Simulink.
dc microgriddroop controland seamless switching off the network