Design and development of MPPT algorithm for high efficient DC-DC converter for solar energy system connected to grid

Abstract

Because of combustion of fossil fuels global warming caused by environmental problems, the raising prices of crude oils and natural gases. They promote continuous effort to improve energy system and its efficiency. There is a need to search for abundant and clean energy sources due to the depleted and increasing prices of oil. Solar energy acts as an alternative renewable energy source. Photovoltaic cells are used as renewable energy system. Photovoltaic (PV) cells can be used to generate dc voltages and given to DC-DC converter. DC-DC converter used is Buck boost type of converter. The converter output is given to battery to inverter and load. Buck boost converter gives constant output which will controlled by PWM controller and feedback control system. Feedback control system has compensation network with different types and parameters. Designing of converter gives constant output. A maximum power point tracking (MPPT) algorithm technique is needed to track the peak power to maximize the produced energy. The maximum power point in the power voltage graph is identified by an algorithm called as incremental conductance method. This algorithm will identify the suitable duty cycle ratio in which buck boost converter should operate to maximum point. The MPPT algorithm is vital in increasing the efficiency of the system. This output is given to battery though the H bridge inverter circuit. The ac output voltage is directly fed to low voltage grid though the PLL circuit. The control of PWM for converter, inverter, MPPT algorithm and PLL is controlled by using MICROCHIP dsPIC30F4011 DSP processor. The total experimentation is carried out and results of converter, inverter, grid control and MPPT characteristics are analyzed.