Maximum solar energy tracker from solar photovoltaic system using fuzzy logic controller
In solar PV system, the output DC voltage is variable with insolation, temperature, etc. The basic I-V characteristics of solar cell is non-linear from maximum (short circuit) to minimum (open circuit) with varying load. The maximum power transfer takes place at a particular voltage (Vm) called as Maximum Power point Tracker (MPPT). The MPPT is time varying with insolation, temperature and load, etc. To get the maximum output from SPV the system always operates at MPPT for maximum efficiency and economic operation of integrated SPV system. Generally, the maximum power point is within voltage range of 13V to 15V. The DC to DC converter (chopper) is used for this purpose. Here, the converter is modeled as a non-linear system. The Chopper output voltage is a function of input voltage (Vi) and duty ratio (delta). The Fuzzy Logic Controller (FLC) is used to operate the SPV at Vm voltage, though insolation, temperature and load are changed with respect to time, by controlling the duty ratio. Firstly, from previous knowledge base of the system FLC determines the voltage of MPPT considering the instantaneous temperature, insolation and load. Then the FLC operate the system at that voltage. The error and rate of change of error in output voltage for a certain value of input voltage are input to FLC. Then FLC determines the new duty ratio to minimize the error in output voltage (Vm). Here, the new duty ratio is non-linear function of error and rate of change of error in output voltage. The switch is ON for one or two duty cycles. After that again measure the parameters (Vm, dVm/dt) to determine the new duty ratio by using the Fuzzy Logic and the switch will be ON according to new duty ratio. This process will continue until the error in output voltage (Vm) is zero. The Fuzzy Logic Controller Base maximum solar energy tracker has fast response and is more accurate than feed forward control system with conventional controllers.
- Research Organization:
- S.S.G.M.College of Engineering, Buldana (IN)
- OSTI ID:
- 20000177
- Country of Publication:
- United States
- Language:
- English
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