Study on charge controlled modulation of a current source grid-connected inverter

In this paper, a Charge Controlled Modulation strategy for a current source inverter is studied, which controls the CSI output current integral (charge) to follow a ideal charge track. Charge Controlled modulation is a carrierless scheme switching at a variable frequency. Compared to existing modulation techniques, this Charge Controlled Modulation is not easy affected by dc current ripple, output current can quickly reach to steady state and can not generate high harmonics of fixed frequency. Finally, Charge Controlled Modulation CSI is used in grid connect of wind power and the simulation results show that the inverter can be controlled well.