Integrated power management strategy of parallel inverters for distributed generation system

Abstract

This paper proposes a power management strategy for parallel inverters based dg system. PV, Fuel cells are considered as the two DG units for this system. Generally Inverter based micro grids plays a key role in accommodating the growth of electricity needs due to this, controlling of inverter is essential, basic droop control methods are conventionally used to control the parallel inverters, predominantly for the low voltage distribution network opposite droop method is the best choice, but this method is also not effective for nonlinear loads, to compensate nonlinear loads also in a effective way virtual impedance is usually implemented as the time derivative of the inverter output current, yet this makes the system highly sensitive to the output current noise and to non linear loads with high slew rate. In order to avoid this a second order general integrator scheme is proposed to implement the virtual output impedance, which is less sensitive to output current noise, reduces the total harmonic distortion and to achieve more accuracy in power sharing and stability. Different linear and nonlinear loads are also connected to verify how the parallel inverters are working with two DC sources connected in islanding mode. Matlab/Simulink is used to validate the proposed control.