tailieunhanh - Clean Energy Systems and Experiences Part 2

Tham khảo tài liệu 'clean energy systems and experiences part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 8 Clean Energy Systems and Experiences Output power which depends on the load is not only constant for certain specific conditions but also is bounded so that the boost converter must be controlled in order to regulate the output voltage and makes sure to maintain the required output voltage at the load. All this is made by using a sliding mode controller in order to introduce a good dynamic response to the system Sira-Ramirez Rios-Bolivar 1994 . The sliding surface considered allows avoiding the use of current sensors Vazquez et al. 2003 . In spite of weather conditions output power must be maintained so that the system takes in consideration the battery set in order to supply the required energy which allows feed the load properly. Auxiliary switches are turned on and off depending on the availability of the renewable source in order to be able to do this a modified MPPT algorithm which is performed with a microcontroller is considered. Modified MPPT not only defines the maximum power point MPP for the renewable source but also established when the energy must be taken either from the two voltage sources or just from a single one. Algorithm determines when the renewable source delivers the possible maximum power in order to optimise its use and the battery set provides the complement. Sometimes when the required load power is lower than the maximum and the demanded energy can be obtained from the renewable source the maximum point is not tracked. The system is turned off for safety purposes when energy is not enough to maintain the system operation because the battery set is discharged. a Modified MPPT algorithm Figure 2 shows the renewable source behaviour for certain weather conditions the output power may be different depending on the load. The figure illustrates three points where each point represents a specific load power. If load requires power between points A and B then the photovoltaic wind system is able to provide the total load power this leads that