Improvement FRT Capability of DFIG Wind Energy based on Three Level Converter A Novel Hybrid-HHOPSO Algorithm Based Optimal Compensators of Four-Layer Cascaded Control for a New Structurally Modified AC Microgrid Optimal PI Based Secondary Control for Autonomous Micro-Grid via Particle Swarm Optimization Technique Improving Power quality by Fed DFIG Converter with Various Switching Techniques Optimal design of proportional‐resonant controller and its harmonic compensators for grid‐integrated renewable energy sources based three‐phase voltage source inverters Optimal design of controllers and harmonic compensators for three-level cascaded control in stationary reference frame for grid-supporting inverters-based AC microgrid