Gain Scheduling Algorithm-Based Control of Renewable Energy Systems for Hybrid Standalone DC Grid

Abstract

In remote locations in India, where the grid is inaccessible, standalone systems can be employed. Due to the abundant availability of solar and wind energy, they are the preferred energy sources in the standalone systems. A battery backup is mandatory as these sources are largely affected by the environmental conditions. Usually, fixed gain proportional-integral controllers are employed to regulate the output voltage of renewable energy and battery systems. Optimal tuning of these controllers is necessary for the desired operation. However, these controllers can be optimally tuned for a specific set of conditions. In order to maintain the voltage regulation in the standalone system over a wide range and under unpredictable atmospheric conditions, the gains must be scheduled dynamically. This paper proposes a hybrid DC local grid where gain scheduled proportional-integral controllers are implemented for the coordinated control of solar, wind, and battery storage under the different operating conditions. The mathematical model of the hybrid DC local grid along with the control system, incorporating proposed GSPI controller for wind, solar, and battery energy systems, is presented in this paper. The performance of the hybrid DC local grid with the proposed GSPI controller is analyzed for the operating conditions experienced in the city of Ahmadabad, Gujarat, India.