Voltage regulation and stabilization of DC/DC buck converter under constant power loading

The low and medium voltage renewable energy based dc distribution systems are catching increased attention world-wide due to their inherent benefits over ac systems. Higher efficiency, simple control, more suitable for integration of the sources producing dc power, are some of the main benefits of the dc systems. However, these systems are prone to serious stability issues caused by the constant power load (CPL) nature of the point-of-load converters (POLs). This paper deals with the stabilization and voltage regulation of dc/dc buck converter feeding a combination of the constant voltage resistive load (CVL) and CPL in a dc micro-grid application. A sliding mode controller is proposed which ensures supply of constant power demanded by the CPL and tight voltage regulation (error less than 0.1 V) of the output voltage. The effectiveness of the controller is validated through simulation results under different operating conditions. It is shown that the controller is robust to the large changes in supply voltage and the load.