Novel dual-band controller for regulating DC-bus voltage that contains a large voltage ripple

Autonomous system with DC-AC converter as an interface from the battery source to the inverter load easily suffers from voltage ripples on the DC-bus at the twice load frequency (100 Hz). A fast voltage controller for tightly regulating the DC-bus voltage with the inevitable 100 Hz ripples bears a rapid transient response, however always contaminating battery current with large ripples at 100 Hz, which do harm to the battery life span. In the paper, an average current mode controller with a novel dual-band selector is introduced. This controller has two voltage-loop branches with 5 Hz and 641 Hz bandwidths, for smoothing the battery current in the steady state and regulating the deviating bus voltage in the transients, respectively. Dual-band selector determines how these two voltage-loop branches are switched to each other, aimed at attenuating transients as soon as possible. This control methodology is demonstrated by simulation for an interleaved bi-directional flyback converter that powers the DC-bus from a battery.