MPPT based on a novel load segmentations structure for PV applications

Abstract

The main disadvantage of photovoltaic (PV) systems is the mismatch between load and generation profiles. To overcome this disadvantage, it is either connected to battery bank or connected to the utility grid via inverters. While the battery choice is expensive and produces contaminating elements, the grid-connected mode is the most common choice. However, the inverters represent high percentage of the system cost that affect its potential to be a competitive economic replacement for other conventional energy sources. In addition, interfacing different users to the grid using inverters increase the total harmonics distortion (THD) and reduce the power quality of the grid. Moreover, exporting surplus energy generated from PV during off-peak periods with lower tariff reduces the economic effectiveness of PV systems. This paper proposes a segmented structure of the electric thermal loads with control algorithm that can achieve the MPPT objectives with no need for inverters. Moreover, with the right selection of PV size, it is possible to be locally consumed each generated kWh of energy without the need to export any to the main grid with low tariff. The segments of the electric thermal load that satisfy the MPP condition are connected to the PV while the rest segments are connected to main grid via set of electromagnetic relays. A simulation of the proposed structure and control algorithm was performed. The results shows that accurate MPPT was achieved according to the number of load segments. To increase the accuracy, the number of load segments should be increased.

Keywords

• MPPT
• Load segments
• PV
• Control algorithm
• DC/DC Converter