Online Load Sensitivity Identification in Low-Voltage Microgrids Based on Power Electronic Transformer

Online load sensitivity identification is a novel load modeling method. Based on the research on the online load sensitivity identification method for low-voltage microgrid containing power electronic transformer (PET) and its application, firstly, in allusion to the PET based low-voltage microgrid a mathematical model of AC/DC/AC type of PET was established and a basic method to implement the online load sensitivity identification by PET was given, besides, the influence of switching-in distributed generation on identification results was analyzed in depth. Secondly, on this basis, a flexible load control strategy for microgrid, which was based on PET voltage/frequency coordinated control, was proposed. Simulation results show that by use of online identification the parameters of load model can be obtained in real-time, and in terms of the obtained load model it is possible to track flexible load shedding instructions by PET system to implement flexible control and management of microgrid to provide technical support for flexible load control of microgrid.