A microcontroller based SHE inverter for maximum power point operation

MPP (Maximum Power Point) integrated inverters are essential to reduce cost and improve efficiency of PV system. It removes the need of two separate power electronic devices: dc/dc converter for MPP; and dc/ac inverter for grid connectivity or driving ac loads. To popularize roof top PV power, micro inverters are commonly used and the system cost can be further reduced if maximum power point tracking is integrated into the inverter. The paper focuses on a new breed of MPP integrated inverter that will produce high quality power with reduced THD while operating the inverter at a point to extract maximum power from the PV panel. The work will be centered on new research results that employ microcontroller based selective harmonic elimination with digital control of the fundamental amplitude. This has been implemented by the authors to eliminate harmonics up to 7^th followed by low-pass filtering. The fundamental amplitude will be controlled digitally with a feedback from the load voltage to arrive at the MPP. No such approach has been investigated in the current literature. The current work in this area employs a one cycle controller in conjunction with the H-ridge to adjust the output current supplied to the grid as a function of PV voltage to extract the maximum power.