Enhancing the Stability of Cascaded Pulsed Load Power Supply Through Virtual Impedance Optimization and I 2 Average Current Control

ABSTRACT This paper investigated a cascaded pulsed load power supply (PLPS) with optimized control schemes for pulsed power loads (PPLs). The first stage of the PLPS is a phase‐shifted full‐bridge converter (PSFB) to provide the average power for PPL. A buck converter is selected for the second stage to facilitate the pulsed load current. The cascaded PLPSs usually select a buck converter at the second stage, while the second‐stage buck converter's input impedance acts as a negative resistor that leads the cascaded system to instability. Therefore, a series virtual impedance (SVI) based optimization is utilized to improve the system stability, and an output current feedforward path is added to the control loop of the fast response‐stage to raise the load tracking speed. Moreover, to reduce the system input current fluctuations and overcome the PSFB converter's slow response and bandwidth limitation, an I 2 average current control is used. An experimental‐based analysis is performed to confirm the validity of the control scheme. The results on the prototype of cascaded PLPS with 784 W peak and 117.6 W average powers, 100 V input voltage, 28 A output pulsed current, and a pulse repeating frequency (PRF) of 100–300 Hz validated that the proposed optimization scheme outperforms other leading available schemes.