Modified Passivity-Based Control Technique of Three-Phase Multilevel Inverters for Uninterruptible Power Supply Applications

A modified passivity-based control technique for three-phase multilevel uninterruptible power supply (UPS) inverters is suggested in this paper. The suggested control technique is according to energy shaping and damping injection that is accomplished in order to regulate the energy flow of the UPS inverter to a preferred level and also guarantee global asymptotic stability. It has been proven that the classical passivity-based controller causes a globally stability in company with steady-state errors of the output voltage, which happen because of the nonattendance of voltage loops in the control inputs. Thus, this control scheme is developed via adding output voltage loops. The considered loops remove the steady-state error of the output voltage without eradicating the system stability. The steady-state and transient operation of the three-phase three-level UPS inverter with the suggested control technique has been confirmed through the simulation results in the presence of resistive and diode bridge rectifier loads.