With the gradual exhaustion of conventional energy and increased environmental pollution,the research ondistributed generation systems has become an important issue.Therefore,establishing model ofdistributed generation systems the primary problem.In this paper, introduceing a reverse modeling theory based on emulation,which is system identification for building model,inverter model identification equations based on least squares method is presented. In matlab,system identification based on the theory of least squaresmethod is established.The transfer function is calculated by identifying on grid inverter power output response.Finally, a simplified model which is established by the transfer function is compared with the original model to verifiy the feasibility of system identification.
