advanced inrush current mitigation ‎techniques for microprocessor-less high ‎power ac/dc/dc synch-buck ‎converters: a start-up perspective

This paper investigates the starting current of an ac/dc/dc converter, consisting of a ‎three-phase diode bridge rectifier and a synchronous buck converter. the use of ‎microprocessors in such converters increases the total cost and also reduces reliability due ‎to emi phenomena. for this reason, by removing the microprocessor, a start-up plan ‎including a limiting starting resistor and then soft starting the switching module is proposed ‎in this paper. by modeling the system under different operating modes, a solution is ‎presented to minimize the circuit startup period, which includes minimizing the bypass time ‎of the startup resistor and reducing the switching soft startup period as possible. the ‎proposed method has been implemented on a 15-kw converter feeding from a three-phase ‎‎380 v power grid and provides up to 300 vdc/50 adc to supply an electroplating pool. the ‎results show that the sequential startup procedure, including using a 50 ohm/1500 w resistor ‎for 3 seconds, and then bypassing it, then starting soft switching after half a second and ‎during 1.5 s, can move this circuit to a steady state in 5 seconds, keeping current in all parts ‎below half rated current.‎