A novel low-voltage ride-through capable energy management scheme for a grid-connected hybrid photovoltaic-fuel cell power source

A novel low-voltage ride-through capable energy management control system is proposed for a grid-connected hybrid photovoltaic-fuel cell power source. The scheme is designed to enable the hybrid power source to follow a power demand from the grid operator. Additionally, the system is able to ride through both symmetrical and asymmetrical voltage sags while providing active and reactive power support to the grid. The injected active power is kept constant during asymmetrical voltage sags without requiring a phase locked loop or positive-negative sequence extraction, thus lowering the computational complexity and design requirements of the control system. Several test cases are simulated using the SimPowerSystems toolbox of MATLAB/Simulink computing environment to demonstrate effectiveness of the proposed strategy both under normal and voltage sag conditions. Results of the control algorithm's digital implementation on a low-cost microcontroller are also presented.