Micro Gas Turbine/Renewable Hybrid Power System for Distributed Generation: Effects of Ambient Conditions on Control Strategy

Hybrid power systems are becoming popular for remote areas due to lower operating cost and green gas emission. Most of these systems are used in remote or harsh environments, so the effect of ambient conditions on system operation is an important factor that should not be ignored. In this paper, the system referred is a domestic hybrid power system including a renewable energy conversion device (Photovoltaic, PV), a traditional energy conversion device (Micro Gas Turbine, MGT) and an electrochemical energy storage unit (batteries). A numerical model, which considers the effect of ambient conditions on the whole system, has been developed. Model Predictive Control (MPC) strategy has been applied to the analysis of power management. The control strategy includes the objective of minimizing system costs, while considering real operational constraints of the plants. Performances attainable with the MPC strategy have been evaluated in comparison with a standard Rule Based Control logic (RBC), by means of costs and efficiency parameters of the system. The effects of ambient conditions on system operation based on MPC-based strategy are evaluated. The simulation has been carried out for the summer and winter periods in four places with different climate in China. Results show that a lower cost of primary fossil energy is found by using the MPC strategy. This is mainly due to the increased use of renewable energy sources by considering the future load. An obvious effect of ambient conditions on control process is observed. A significant improvement for the whole year in efficiency of the system, especially in high latitude cold regions with larger temperature difference from the design condition, is achieved by considering the ambient conditions. The highest reduction of fuel consumption reaches to 4% during the winter. As a result, the effect of the ambient conditions in some areas must be taken into account for control system design.