混合直流供电微电网系统的直流自适应调频方法OA北大核心CSTPCD

Frequency fluctuations will inevitably occur when the microgrid with hybrid DC power supply of line commut-ated converter(abbr.LCC)-voltage source converter(abbr.VSC)is disturbed.In order to keep the frequency within the specified range under the different kinds of disturbances,a DC frequency regulation method with self-adapt disturbance changes was proposed in the LCC-VSC supplying microgrid system.Firstly,the critical droop coefficient required to pull the system frequency into the specified range after disturbance was theoretically deduced,and based on this,a primary frequency regulation method of variable droop coefficient with self-adapt disturbance changes was proposed to rapidly control the dis-turbed system frequency within the specified range by means of the rapidity of DC reaction.Secondly,as the primary fre-quency regulation is still a differential regulation,the second-ary frequency regulation strategy of variable reference power was proposed.Finally,a simulation model was established on the PSCAD/EMTDC platform.The results show that when the load changes within 12.5%and the light changes within 10%,the primary frequency regulation can restore the frequency de-viation to within 0.2 Hz,and when the load changes within 15%,the secondary frequency regulation can achieve zero-er-ror frequency regulation,which verifies the effectiveness of the proposed strategy.