Improving Load‐Transient Response of a Cascaded Pulsed Load Power Supply Through a Robust Nonlinear Dual‐Loop and I 2 Average Current Control

ABSTRACT This article studies a DC‐DC cascaded topology of pulsed load power supply (PLPS) system with the first stage of phase‐shifted full bridge (PSFB) and the second stage of buck converter. Despite DC‐DC converters' notable nonlinear characteristics, most studies on PLPSs propose linear controllers to address them. This study proposes a simplified V 2 control technique for the fast‐stage converter to address the system's nonlinear characteristics and enhance its transient response. The input impedance of the fast‐stage buck converter in the cascaded system is adjusted to maintain the system in a stable region and avoid the possible impedance‐based instability issue. Additionally, a lead compensator is designed and incorporated into its control loop to improve the phase margin to prevent the impact of buck input impedance behavior as negative resistance on the stability for lower frequencies. Furthermore, an I 2 average current control is employed to reduce input‐current fluctuations and compensate for the PSFB's weak response. The PLPS system is experimentally verified for a peak power of 784 W and a pulsed load frequency from 150 to 300 Hz. The results of this article are compared to those of relevant papers and validate its dominance over other control methods.