Sensorless Control Techniques for the Flyback-Type Solar Tile Microinverter
Date
2019-04-29
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Abstract
Typically, while operating a photovoltaic (PV) microinverter, the current must be measured to perform maximum power point tracking (MPPT). The current measurement is required as it is used to calculate the power generated by the PV module. This dissertation studies the operation of a flyback-type PV microinverter without the use of current measurement and explores associated current estimation methods. Four methods of estimating the current are tested and compared. Two are already present in the literature; they are based on integrating the flyback transformer's primary-side sawtooth current waveform over a half-grid cycle. The other two are novel methods using the voltage ripple over the capacitor present at the direct current (DC) input of the microinverter to calculate the input current. One novel method also includes an estimate for the magnetizing inductance of the flyback transformer in the control loop, providing adaptability to a varying inductance. Each current estimation technique is derived mathematically, simulated, and implemented experimentally. A solar microinverter is designed and built to carry out practical tests on an experimental setup. The current estimation methods are compared by studying their effects on MPPT performance.
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Keywords
Renewable, Photovoltaic, Microinverter, Flyback, Sensorless, Control system
Citation
Falconar, N. (2019). Sensorless Control Techniques for the Flyback-Type Solar Tile Microinverter (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.