Adaptive hysteresis band controlled grid connected PV system with active filter function

This paper presents three-phase grid connected photovoltaic (PV) system that not only can inject active power to the grid but also can compensate harmonics and reactive power of nonlinear loads as a shunt active filter. A maximum power point tracking (MPPT) algorithm is used in order to obtain maximum power under different sun irradiance from PV; hence, in the darkness the system is used as an active filter and in the sunlight the system operates as both power conditioner and shunt active filter simultaneously. Control of the presented system is based on instantaneous power theory (p-q theory) and adaptive hysteresis band control (AHBC). Unlike conventional fix band hysteresis control in which instantaneous switching frequency is not constant, by changing hysteresis band in the AHBC method, instantaneous switching frequency will be constant with a little deviation. Simulation results using MATLAB/SIMULINK verifies effectiveness of the system in injecting of maximum power captured by the PV system to the grid and compensating of the harmonic currents and reactive power of the nonlinear load.