Analysis and control of a buck DC-DC converter operating with constant power load in sea and undersea vehicles

Power electronics based zonal DC power distribution systems are being considered for sea and undersea vehicles. The stability of the DC power electronics based power distribution systems is a significant design consideration because of the potential for negative impedance induced instabilities. In this paper, dynamic properties and control of a buck converter feeding a downstream DC-DC converter are studied. The controller in this system combines an instantaneous current feedback loop using hysteresis with a proportional-integral algorithm to regulate the output voltage of the converter. Based on a large-signal averaged model of the converter, the stability-in-large around the operation point is presented. The complete analysis is carried out considering a buck DC-DC converter operating with a constant power load. Simulations and experimental results are provided to verify the analysis.