The world is interested in applying grid codes to increase the reliability of power systems through a micro-grid (MG). In a common practice, the MG comprises a wind farm, and/or photovoltaic (PV) arrays that are integrated with diesel generators and energy storage devices. Fault ride-through (FRT) capability is an important requirement of grid codes. FRT means that the MG is still connected to the grid during numerous disturbances such as faults. This is required to ensure that there is no loss of power generated due to grid faults. Reactive currents must be injected into the grid to increase the power system stability and restore voltage. To enhance FRT for doubly fed induction generator (DFIG) based WT installation, internal control modifications of rotor-side converters and grid-side converters are applied. The solutions that depend on these modifications are traditional and advanced control techniques. Advanced control techniques are needed due to the non-linear nature and less robustness of traditional ones. External hardware devices are also added to improve the FRT of DFIG which are classified into protection devices, reactive power injection devices, and energy storage devices. A comprehensive review of FRT enhancements of DFIG-based WTs, PV systems, and MGs using hardware and software methods is presented in this effort. A classification of FRT of PV systems is characterized plus various inverter control techniques are indicated. Several FRT methods for hybrid PV-WT are presented, with full comparisons. The overall operation and the schematic diagrams of the DFIG-WT with FRT methods are discussed and highlighted. Many Robust control methods for controlling grid connected AC, DC and hybrid AC/DC MGs in power systems are addressed. A total of 210 reported articles were review, including the most up-to-date papers published in the literature. This review may be used as the basis to improve system reliability for those interested in FRT methods. Various traditional and advanced control techniques to improve the FRT abilities are summarized and discussed, including protection devices, reactive power injection devices, and energy storage. In addition, the classifications of FRT hardware methods for DFIG are presented, including grid code requirements.