An improved control strategy for input-series and output-parallel inverter system at extreme conditions

An improved control strategy for input-series and output-parallel (ISOP) inverter system is proposed in this paper. Compared with the original control strategy, the proposed one has the optimal regulation speed when the input voltages of the constitute modules of the ISOP inverter system are not shared. In the meanwhile, the ISOP inverter system under no-load condition and short circuit current limiting condition are both analyzed with the proposed control strategy. All the theoretical analysis is validated by simulation. A 2 kVA prototype of two-module ISOP inverter is fabricated and tested in the lab and the experimental results verified the proposed control strategy.