DC-link voltage stabilization for reduced dc-link capacitor inverter

A PMW inverter with reduced dc-link capacitor has a problem that the dc-link voltage is less stable compared to the conventional inverter because of the lack of energy storage capability. The proposed dc-link voltage stabilization algorithm using active damping gives a solution to this problem. To achieve load/source independent stabilization, the source state estimator which estimates both source voltage and current is also proposed. The proposed methods are evaluated by experimental results. While the inverter with a small DC link capacitor tripped due to dc-link overvoltage fault at step load change, the fluctuation of dc-link voltage of the inverter is suppressed under the tolerance range with the proposed method at the same step load change.