TY - JOUR
T1 - Investigation of Nonlinear Droop Control in DC Power Distribution Systems
T2 - Load Sharing, Voltage Regulation, Efficiency, and Stability
AU - Chen, Fang
AU - Burgos, Rolando
AU - Boroyevich, Dushan
AU - Vasquez, Juan C.
AU - Guerrero, Josep M.
PY - 2019/10/1
Y1 - 2019/10/1
N2 - Linear droop faces the design tradeoff between voltage regulation and load sharing due to cable resistances and sensing errors. Using a larger droop resistance improves load sharing, but requires a wider droop voltage range. In the nonlinear droop, droop resistance is a function of the converter's output current, and its value increases when the output current increases. As a result, the impacts from sensors and cables are reduced. In this paper, the design of nonlinear droop in dc power distribution systems is studied with special emphasis on load sharing, voltage regulation, system efficiency, and stability. After discussing the piecewise linear and nonlinear droop control, a generic polynomial expression is presented to unify different droop equations. The impact of droop on dc system efficiency is analyzed by evaluating cable and power converter losses. The converter's output impedance using nonlinear droop is modeled to analyze the system stability with constant power loads. The selection and design guidelines of nonlinear droop are summarized, considering both the static performance and interaction with load systems. The analysis is verified in 400-V multi-source dc systems. The nonlinear droop is fully distributed as it only needs local information.
AB - Linear droop faces the design tradeoff between voltage regulation and load sharing due to cable resistances and sensing errors. Using a larger droop resistance improves load sharing, but requires a wider droop voltage range. In the nonlinear droop, droop resistance is a function of the converter's output current, and its value increases when the output current increases. As a result, the impacts from sensors and cables are reduced. In this paper, the design of nonlinear droop in dc power distribution systems is studied with special emphasis on load sharing, voltage regulation, system efficiency, and stability. After discussing the piecewise linear and nonlinear droop control, a generic polynomial expression is presented to unify different droop equations. The impact of droop on dc system efficiency is analyzed by evaluating cable and power converter losses. The converter's output impedance using nonlinear droop is modeled to analyze the system stability with constant power loads. The selection and design guidelines of nonlinear droop are summarized, considering both the static performance and interaction with load systems. The analysis is verified in 400-V multi-source dc systems. The nonlinear droop is fully distributed as it only needs local information.
KW - Constant power load (CPL)
KW - current sharing
KW - dc microgrids
KW - droop
KW - efficiency
KW - nonlinear
KW - stability
KW - voltage regulation
UR - http://www.scopus.com/inward/record.url?scp=85068727018&partnerID=8YFLogxK
U2 - 10.1109/TPEL.2019.2893686
DO - 10.1109/TPEL.2019.2893686
M3 - Journal article
AN - SCOPUS:85068727018
SN - 0885-8993
VL - 34
SP - 9407
EP - 9421
JO - IEEE Transactions on Power Electronics
JF - IEEE Transactions on Power Electronics
IS - 10
M1 - 8616804
ER -