Evaluation of input low frequency current ripple performance in front-end converter with single phase inverter load

Due to non-linear time-varying characteristic of a single phase DC/AC inverter, its front-end DC/DC converter tends to draw an AC ripple current at twice the output frequency, which may cause interaction issues (e.g. stability problem and input ripple current limit in distributed generation systems such as nor-grid-connected wind power system). A novel method is proposed for analyzing the behavior of low frequency input current ripple. This method is based on back current gain A_i(s)(input current to output current) model of the DC/DC converter. The theoretic model with different control schemes is verified in Saber environment. It is shown that the average current mode control strategy is more effective compared with voltage mode control and open loop control schemes. Design principles are presented based on A_i(s) as guide lines. Simulation and experimental results with open loop, single voltage loop, and average current mode control are provided for verification.