Development of Modified Hysteresis Current Controller Switching Scheme for Multifunctional Grid-tied Photovoltaic Inverters

This paper proposes a modified hysteresis current controller (MHCC) switching scheme for grid tied PV system to eliminate switching frequency problems along with shoot-through effect. This grid PV system performs multifunctional operation where it feeds the active power to the local grid during day time and acts as an shunt active power filter (SAPF) to mitigate reactive power, current harmonics and switching frequency problems. The PV system connected to the local grid through voltage source inverter (VSI), but, it has distinct disadvantages shoot-through effect where two power electronic switches of VSI leg will be shorted due to slow turn off time of power electronic switches. To eliminate this effect, an interleaved inverter is proposed for PV grid tied system. This interleaved inverter developed by the power switches like MOSFET/IGBTs. The switching frequency is the major concern for the development of this Grid-tied Photovoltaic shunt active power filter. The conventional hysteresis current controller (CHCC) has higher switching frequency with the higher hysteresis bands. This may limit the use of power switches in the application of Grid-tied Photovoltaic active power filtering. The MHCC switching scheme gives lower switching frequency with the lower bands which enhance the harmonic compensation capability of Grid-tied Photovoltaic shunt. A MATLAB/Simulink software is used for developing proposed PV system. A rigorous tests have been conducted to verify the proposed PV interleaved inverter system with MHCC technique.