A New Adaptive Power Sharing and Control Strategy of Hybrid DG Units in Grid-Connected AC Microgrid

Abstract

This paper describes a new control, power management, and power sharing strategy of hybrid energy sources (HESs) system in a grid-connected microgrid. The whole structure of HES system contains photovoltaic (PV), super-capacitor (SC), fuel cell (FC), and battery units. This system provides both active and reactive power to support a three-phase ac load. In this paper, to keep the balance of power between generation and consumption, a direct power control scheme (DPCS) based on nonlinear sliding mode control (SMC) is proposed. The proposed control method directly determines the required voltage of interface inverter that can be able to omit the instantaneous errors of reactive and active powers without considering any phase angle tracking of microgrid voltage or synchronization transformations. Additionally, extra current control loops are not involved to enhance the transient operation and to simplify the design of system. Performance and effectiveness of the proposed control strategy for the HES system is verified using simulation studies in Matlab/Simulink environment under fault scenarios. Also, the results are compared with a proportionalintegral (PI) control method.

Keywords

• sliding mode control
• power sharing
• robust control
• hybrid energy sources system
• microgrid