Development of the medium-voltage DC power management systems is an important objective for future submarines and surface combatants. In such a system, DC/DC converters are usually used to supply constant current/power for electrical energy devices. However, constant current loads inherit the negative incremental impedance characteristics, resulting in deteriorated response of the system against load disturbances, and therefore, the system should be suitably controlled. To solve this problem, this research proposes a voltage-controlled quadratic buck converter based on a sliding-mode (SM) control approach which guarantees the system stability and delivers the required energy for constant output current to be supplied. The proposed voltage-mode control is capable of stabilizing the DC power system in different operation modes and over the significant variations in the input voltage and load. The asymptotic stability of the switching surface and existence of SM operation are proved in this paper. The proposed control solution is confirmed by means of simulations through PSIM program, and experimental evidences are provided to validate the expected features for the voltage stability of a quadratic buck converter with constant loads.
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