Microgrid connected PV-Based Sources

ABSTRACT

Microgrid connected This article studies the control configuration of a microgrid-connected photovoltaic (MCPV) source. In the control of an MCPV, maximum power point (MPP) tracking, droop control, and dc bus voltage regulation are the main required functions. To increase their penetration in the microgrid, MCPV sources have to participate in the microgrid’s frequency regulation. Consequently, MCPVs may be forced to depart from MPP for short periods of time. In this article, a control method is proposed to operate the MCPV in the MPP at all times except when there is a need to stabilize the frequency. The method achieves this objective autonomously without the need to change the control configuration. This method is explained, and its superiority over other controllers to achieve the same objective is investigated. The suggested control configurations are validated through simulation studies and experiments.

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

microgrid connected

(a)

(b)

Fig 1.The hybrid control configuration of the MCPVs: (a) the MPP control configuration and (b) the droop control configuration.

 EXPERIMENTAL RESULTS:

Fig 2.The responses of the dc bus voltage and the reactive  power of the hybrid MCPVs: (a) the dc bus voltage of the  MCPVs and (b) the reactive power of source1, source2, and the hybrid MCPVs.

Fig 3.The frequencies of source1, source2, and the hybrid MCPVs

Fig4.The responses of the dc bus voltage and the reactive power of the universal MCPVs: (a) the dc bus voltage of the MCPV  and (b) the reactive power of source1, source2, and the hybrid MCPV.

 

Fig5.The responses of the power and dp-dv for the universal MCPVs: (a) the power provided by source2 and the universal MCPVs and (b) the value of dp/dv of the universal MCPVs.

Fig6.The frequencies of source1, source2, and the universal MCPVs.

Fig7.The power-voltage characteristics of the simulated PV.

Fig 8.The hybrid MCPV experimental results: (a) the power of source2 and (b) the value of dp/dv of the hybrid MCPVs.

 CONCLUSION

In this article, the control strategies for the MCPVs were investigated. The considered MCPVs comprised the PV source: dc/dc and dc/ac converters. The need for a new control configuration for MCPV sources to participate in the frequency and voltage regulation in addition to the MPPT controller was justified. One way to control the MCPVs was to switch between two controllers, one for MPPT and the other to perform droop control. The combination of the two controllers is called a hybrid controller. The hybrid controller suf In this article, the control strategies for the MCPVs were investigated. The considered MCPVs comprised the PV source: dc/dc and dc/ac converters. The need for a new control configuration for MCPV sources to participate in the frequency and voltage regulation in addition to the MPPT controller was justified. One way to control the MCPVs was to switch between two controllers, one for MPPT and the other to perform droop control. The combination of the two controllers is called a hybrid controller. The hybrid controller suffered from two problems. The first was the need for an external switching signal to switch from one controller to the other, indicating a lack of plug-and-play capability. The second problem was the poor transient in the dynamics whenever there was a change in the controller or the load. A new controller was then proposed that achieved the MPPT, droop control, and dc bus voltage regulation without the need to switch between different configurations. The proposed controller was denoted as the universal controller. In this controller, a dc bus regulator controls the dc bus voltage by adjusting the duty ratio of the dc/dc converter, while both the droop controller and the MPPT controller drive the dc/ ac inverter phase. The controllers were tuned in such a way that, whenever there is a significant change in the load, the droop controller response is dominant to stabilize the frequency of the microgrid. Later, the MPPT moves the operating point to the MPP automatically but smoothly to avoid any disruption in the frequency. The proposed controllers were tested by simulations and experiments, where the validity of the method was verified in terms of stabilizing the frequency, maximizing the power production, regulating the dc bus voltage, and operating autonomously without the need for an external switching decision.

REFERENCES

[1] M. Amin, “Toward self-healing energy infrastructure systems,” IEEE Comput. Appl. Power, vol. 14, no. 1, pp. 20–28, 2001.

[2] G. Venkataramanan and C. Marnay, “A larger role for microgrids,” IEEE Power Energy Mag., vol. 6, no. 3, pp. 78–82, 2008.

[3] M. Prodanovic and T. Green, “High-quality power generation through distributed control of a power park microgrid,” IEEE Trans. Ind. Electron., vol. 53, no. 5, pp. 1471–1482, 2006.

[4] S.-J. Ahn, J.-W. Park, Il-Y. Chung, S.-Il Moon, S.-H. Kang, and S. Nam, “Power-sharing method of multiple distributed generators considering control modes and configurations of a microgrid,” IEEE Trans. Power Delivery, vol. 25, no. 3, pp. 2007–2016, 2010.

[5] F. A. Farret and M. G. Simoes, Integration of Alternative Sources of Energy. Hoboken, NJ: Wiley, 2006.

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