Control and analysis of the low voltage DC grid

In this paper, the control effects of the droop current sharing control and output voltage trimming used in the low voltage DC grid are investigated. Firstly, the parallel DC/DC converters system with droop current sharing control is investigated. The desired loop gain profile of the stand alone DC/DC converter is affected at paralleled operation due to impedance interaction. It leads to reduce available bandwidth and thus might deteriorate the regulated performance of the output voltage. After analyzing the frequency response of the droop current sharing loop, a simple droop voltage controller uses to compensate the deficiency. As a result, the output voltage to voltage trimming transfer function can be approximated to the first order system. Furthermore, the derived steady state model of the voltage trimming control could use to explain the output current committed capability to specified DC/DC converter powered by different energy sources. As a result, the reliability and energy bill reduction can both achieve. Some simulations and experimental results will provide.