Maximum Power Tracking Using the Temperature Based Method with Digital OCC Modulation
OCC, MPPT, PV systems, Digital Controllers.
Photovoltaic systems have stood out among the different types of renewable sources by directly converting sunlight into electricity, low maintenance, good performance in electricity production and do not produce greenhouse gases. Due to some climatic changes of temperature, radiation and shading on the panel, the production of electricity is compromised and this causes a decrease in the generation efficiency of the photovoltaic panels. Due to this, they need a tracking system that makes the panel operate at the maximum power point. These tracking systems are the so-called Maximum Power Point Tracker – MPPT. The main objective of this work is to build a photovoltaic generation system controlled by a DSP TMS320F28335 and switched converter boost type, so that the system traces the maximum panel power, maximizing your efficiency. In this work a control strategy is implemented based on the panel temperature measurement to provide the reference voltage equivalent to the maximum power point under outside conditions of international testing standards and simulating shading effects of photovoltaic cells and temperature and load variations. According to the temperature read by the sensor LM35, the DSP TMS320F28335 will adjust the reference voltage of the PI controller resulting in a duty-cycle value of the Boost converter. The switch of the boost converter will be done using the control technique One Cycle Control – OCC rather than the widely used Pulse Width Modulation – PWM. The OCC switching technique provides some advantages over PWM as a quick response to the reference change, null error in steady state and rejection of input disturbances. Simulations and experimental results show that this scheme presents some advantages over the conventional Constant Voltage method and other more sophisticated methods like Hill Climbing, besides OCC provide some advantages over PWM.