Control and Stabilization of DC/DC Buck-Boost Converters Loaded by Constant Power Loads in Vehicular Systems using a Novel Digital Scheme

Power electronics based power systems are being increasingly considered for transportation systems such as land, sea/undersea, air, and space vehicles due to their advantages in efficiency, performance, flexibility, and power density. In order to have superior performance, these multi-converter systems need to be rigorously regulated. Dynamic response of tightly regulated power electronic converters in distributed power electronic systems is similar to the dynamic response of a constant power load (CPL), which acts as negative impedance and destabilizes the DC bus and the system. In order to mitigate the instability problem in multi-converter systems, in this paper, we present a novel digital technique to control DC/DC converters driving CPLs in vehicular systems. The proposed method achieves the output voltage regulation based on generating high and low power pulses instead of conventional pulse width modulation (PWM) techniques. It is simple, straight forward, and easy to implement in specifically designed integrated circuits (IC), digital signal processors (DSP), or field programmable gate arrays (FPGA). Moreover, its dynamic response is fast and robust. Simulation results of applying the proposed method to a DC/DC buck-boost converter confirm the analytical results.