Recently, there was a great focus on integrating renewable energy sources (RESs) into ‎electrical power systems (hybrid systems) due to their many environmental and economic ‎advantages. The output of most of these RESs is DC; some power electronic devices, ‎including inverters, must be used to integrate these RESs into the electrical grid. Any ‎maloperation, faults, or improper control in these power electronic devices will enormously ‎affect these hybrid systems’ performance. This paper aims to mitigate the misfire and fire-‎through faults that occur at the switching of the inverter that connects three renewable ‎sources: PV, wind, and the fuel cell to the grid. This mitigation of such inverter faults (misfire ‎and fire-through) is performed through optimal tuning of the PI controller driving a dynamic ‎voltage restorer (DVR) connected at the system’s AC side. The optimization technique used is ‎particle swarm optimization (PSO). While mitigating these two inverter faults using the PI-‎PSO controller for the DVR, improved system performance through voltages, currents, and ‎powers waveforms is achieved. Besides, the three renewable sources were kept in continuous ‎operation without disconnection from the system during these faults.‎