Control and Optimization of Pulsation Power Buffer for High Peak-to-Average Power Ratio Pulsed Power Loads

In pulsed power applications, depending on the peak to average power ratio, energy buffering is required to support the instantaneous energy balance between the constant input and the pulsed output. Also, depending on the Pulse Repetition Frequency (PRF) of the load, the necessary energy storage requirement for a stable DC bus can become huge when done conventionally with a DC-link capacitor. This paper presents a Pulsation Power Buffer (PPB), to reduce the energy storage capacitance requirement and thus improve power density and performance of the pulsed power converter. This is done by adding an auxiliary circuit with separate capacitors whose average and ripple voltage can be controlled independent of the main DC-link. A new control approach based on a hierarchical control scheme with gain scheduling and structure variable controllers is proposed for the PPB. Simulation results are presented for 1 MW peak power, 0.5 Hz PRF, and 200 ms pulse width pulsed power load showing excellent dynamic performance and reduction of buffer capacitance by more than 400 times with PPB circuit and the novel controller.