In this paper, a new energy control system is planned for actively controlled hybrid dc microgrid to reduce the adverse impact of pulsed power loads. The proposed energy control is an adaptive current-voltage control (ACVC) scheme based on the moving average calculation method and an adaptive proportional compensator.
Unlike conventional energy control methods, the proposed ACVC approach has the advantage of controlling both voltage and current of the system while keeping the output current of the power converter at a almost constant value. For this study, a laboratory scale hybrid dc microgrid is grown to check the work of the ACVC method and to compare its work with the other conventional energy control methods.
Using experimental test results, it is shown that the proposed plan highly improves the dynamic work of the hybrid dc microgrid. Although the ACVC method causes slightly more bus voltage variation, it efficiency eliminates the high current and power pulsation of the power converters.
The experimental test results for different pulse duty ratios display a significant growth achieved by the grow ACVC system in enhancing the system ability, reducing the ac grid voltage drop and the frequency variation.
- Hybrid dc microgrid
- Energy control system
- Pulse load
- Active hybrid power source
Fig. 1. Schematic diagram of the hybrid dc microgrid under study
EXPECTED SIMULATION RESULTS:
Fig. 2: Experimental test results of ACVC and CACC technique during constant pulse load operation.
Fig. 3: Experimental test results of CACC method and ACVC technique when pulse load frequency changes from 0.1-Hz to 0.2-Hz and its duty ratio increased from 20% to 40%.
Fig. 4: Variation of the normalized average dc bus voltage and the kv in the proposed ACVC technique when pulse load frequency changes from 0.1-Hz to 0.2-Hz and its duty ratio increased from 20% to 40%.
Fig. 5: Experimental test results of CACC method and ACVC technique when pulse load changed from 2-kW to 3-kW.
Fig. 6: Hybrid DC microgrid performance comparison when ACVC, LBVC and IPC methods are utilized.
In this paper, a new energy control plan was grown to reduce the adverse impact of pulsed power loads. The proposed energy control was an adaptive current-voltage control (ACVC) plan based on the moving average current and voltage calculation and a proportional voltage compensator. The work of the grown ACVC method was experimentally decide and it was compared to the other common energy control methods.
The test results showed that the ACVC plan has a similar work with the continuous average current control (CACC) method during a constant pulsed power load operation. However, the transient response of the ACVC method during pulse load variation was efficiency improved and it prevented any steady state voltage error or dangerous over voltage.
Also, the work of the grown ACVC method was compared with the limit-based voltage control (LBVC) and instantaneous power control (IPC) methods for different pulse rates and duty ratios. The comparative analysis showed that although the maximum dc bus voltage variation in the case of ACVC plan was higher than the IPC and LBVC methods, the planned ACVC method required smaller power capacity of the converter and energy resources.
Moreover, the growth ACVC method efficiency eliminated the power pulsation of the slack bus generator and density fluctuation of the interconnected AC grid while the ac bus voltage drop was well reduced. Additionally, the efficiency analysis for different pulse duty ratios showed that the growth ACVC method considerably enhanced the efficiency of the system since the maximum current of the converter was reduced and the converter was operating at a almost constant value.
 M. E. Baran and N. R. Mahajan, “DC Distribution for industrial systems: opportunities and challenges,” IEEE Trans. on industrial applications, vol. 39, no. 6, pp. 1596-1601, November/December 2003.
 M. Farhadi, A. Mohamed and O. Mohammed, “Connectivity and Bidirectional Energy Transfer in DC Microgrid Featuring Different Voltage Characteristics,” Green Technologies Conference, 2013 IEEE, vol., no., pp.244-249, 4-5 April 2013.
 D. Salomonsson, L.Soder, A. Sannino, “An Adaptive Control System for a Dc Microgrid for Data Centers,” Industry Applications Conference, 2007. 42nd IAS Annual Meeting. Conference Record of the 2007 IEEE, vol., no., pp.2414,2421, 23-27 Sept. 2007.
 M. Falahi, B K.L. utler-Purry and M. Ehsani, “Reactive Power Coordination of Shipboard Power Systems in Presence of Pulsed Loads,” Power Systems, IEEE Transactions on, vol.28, no.4, pp.3675-3682, Nov. 2013.
 M. Farhadi, and O. Mohammed, “Realtime operation and harmonic analysis of isolated and non-isolated hybrid DC microgrid,” Industry Applications Society Annual Meeting, 2013 IEEE , vol., no., pp.1,6, 6-11 Oct. 2013.