dsPIC Mıcrocontroller Based Implementation of a Flyback Photovoltaıc Mıcroınverter Using Dırect Digital Synthesis

Abstract

In this paper, the design and implementation of a dsPIC microcontroller-based photovoltaic (PV) microinverter using direct digital synthesis technique has been presented. The flyback PV microinverter is controlled via a low-cost dsPICmicrocontroller circuit, with the duty cycle variation of the power switch generated directly from the AC grid voltage, or from a reference sinusoidal waveform at power frequency in the case of standalone applications. The proposed scheme has the inherent voltage phase detection and control properties via the Direct Digital Synthesis technique adopted. Furthermore, the maximum power pointtracking algorithm, and the anti-islanding protection feature required in gridconnected PV systems are easily implemented by the microcontroller, without the use of any extra hardware. The experimental results are obtained on a 150 W, 220-V 50 Hz prototype system verify the validity of the compact and low-cost dsPIC based flyback microinverter.