Abstract:
In order to analyze the influences of parallel driving mode on the operation stability and circulating current characteristics of motor-generator pair(MGP), based on the vector control strategy of MGP driven by parallel inverters, firstly, the mechanism of circulating current was studied, and the similarity of current control of MGP and circulating current control of inverters in principle was compared and analyzed according to the equivalent circuit of the parallel drive system in this paper. The results reveal that the current regulation coefficient of MGP can effectively restrain the circulating current of the inverters. Then the stability of current loop and circulating current loop was analyzed and the parameters were optimized according to the experimental parameters, in addition, the influence of the number of parallel inverters
N on the stability of the circulating current loop was analyzed under the parameters. The results show that the increase of the number will reduce the amplitude margin of the control system and slow down the speed of response. Finally, the stability of current control was verified on the experimental platform of 5 kW MGP system driven by double inverters in parallel operation. The proposed control strategy has a good performance on the grid connected operation of MGP, the response speed of the system is fast, and also the circulating current between the inverters is relatively small.