Experimental comparison of conventional and mppt charge controllers used in photovoltaic systems

Solar energy, an infinite source of energy, is converted into electrical energy using photovoltaic (PV) panels. Radiation and temperature are significant factors affecting the power generated by PV panels. Increased radiation boosts panel current and voltage, while increased temperature decreases voltage and slightly increases current. Although the efficiency of PV panels is low, various factors further reduce their efficiency. Particularly, shading, dust and dirt accumulation, and reflection caused by decreased radiation and temperature lead to reduced power output from the panel. Each PV panel has a maximum power output under certain conditions. Maximum power cannot be drawn from the panel at every load value. Therefore, various Maximum Power Point Tracking (MPPT) methods have been developed to ensure that photovoltaic systems operate at or around the maximum power point to maximize power transfer to the load. These methods determine the duty cycles of DC-DC converters to operate the PV system at its maximum power point. In this thesis, a PV panel feeding an ohmic load through a boost DC-DC converter is modeled in the Matlab Simulink environment. Two model simulations were prepared using the Perturb and Observe (P&O) and Incremental Conductance (INC) algorithms as MPPT algorithms. The current, voltage, and power values produced by the PV panel and the current, voltage, and power values of the converter in both models have been examined. In this thesis, an experimental setup was established to compare the performances of an MPPT charge controller using the MPPT algorithm and a PWM (Pulse Width Modulation) charge controller. Two experimental setups were prepared for the study. In the first experimental setup, a 100W PV panel was used to charge a 24 Ah gel battery using a 30A PWM charge controller. In the second setup, all elements were the same, but a 30A MPPT charge controller was used. The batteries were continuously discharged with a 50Ω, 1000W rheostat and used at 20-25% charge levels. Measurements were taken simultaneously from both experimental setups under the same temperature, radiation, wind, humidity, and other environmental conditions, and these measurements were compared with each other. The experimental results showed that the system using the MPPT charge controller had higher power and efficiency at all hours of the day compared to the system using the PWM charge controller. Moreover, it was observed that the efficiency and power of the system with the MPPT charge controller increased even more during hours of higher radiation compared to the other system.