Sensorless current balancing and MPPT control for photovoltaic AC module type interleaved flyback inverter

In this paper, a sensorless current balancing and MPPT control for photovoltaic AC module type interleaved flyback inverter is proposed. A conventional interleaved flyback inverter for photovoltaic(PV) AC module systems performs the current balancing control through comparison of phase currents each, and a maximum power point tracking(MPPT) using numerical values calculated through a input current and voltage. As was stated above, the conventional current balancing and MPPT control method are in need of one voltage sensor, three current sensor and peripheral circuits for each sensor. Because the sensors and peripheral circuits increase the size, volume and cost of PV AC module systems, the conventional control method is not suited for the PV AC module systems of small output power such as 300W. To overcome this problem, a proposed method performs the current balancing and MPPT control through only each phase current sensor. In order to verify these, theoretical analysis, simulation and experiment are performed.