An Enhanced State Observer for DC-Link Voltage Control of Three-Phase AC/DC Converters

To regulate the dc-link voltage of three-phase ac/dc converters, an enhanced state observer-based controller is presented in this letter. The proposed controller, contrary to the traditional ones, does not require the dc-link current measurement and offers a “plug and play” capability, a rather high disturbance rejection ability and robustness against the dc-link capacitance parameter variation. The design procedure of the suggested controller is discussed, and its effectiveness is verified using experimental results.