Voltage Ripple Mitigation in DC Microgrid with Constant Power Loads

With the evolving renewable energy source technologies and their integrations, the DC microgrids are going to play significant role in near future. When these DC microgrids are operational, the load on the system needs to be shared among different sources. For the sharing of the load, droop control methods are well accomplished by the industry and academia. In these droop methods, one has to make judicious choice between the voltage regulation and load sharing. Though near zero voltage regulation can be achieved by virtual droop compensation methods, they suffer from high ripple content in the dc bus voltage based on nature and variation in load. With increase in percentage of the constant power loads in the DC microgrid, the system will experience increased ripples in voltage and is prone to voltage instability. To overcome this limitation, a nonlinear control integrated virtual droop mechanism is proposed in this paper. The proposed droop control mechanism is evaluated for different kinds of loads, including constant power loads, at different operating conditions. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.