The Modulation and Control Strategy of DC-link Current Minimization for Single-Phase Current Source Inverter

DC-link inductance current is usually considered constant and charge-discharge process is ignored in a modulation cycle for traditional single-phase current source inverter (CSI), which cause dc-link inductance current discontinuous or continuous increasing. The dc-side topology of single-phase CSI is improved in this paper. Working mode of dc-link inductance is thoroughly analyzed in modulation process. The least limited value of dc-link inductance current is derived any working condition, and the modulation strategy is designed to maintain dc-link inductance current constant for improved topology. The virtual current and voltage of ac-side is established, the math model of single-phase CSI is derived in two phase rotating reference frame, and closed-loop control strategy of output voltage is designed. Both the simulation and experimental result show the least limited value of dc-link inductance current can suffice demand of ac-side and remain within a certain range, output voltage of CSI can accurately follow the given, which demonstrates the proposed modulation strategy and control method are correct and feasible.