Control System Design and Fault-Ride-through Performance Analysis of Grid-Connected Microturbine Generation System

In recent years, microturbines as one the distributed generation sources have widly used. This paper investigates the control structure of the microturbine and analyzes its performance in grid-connected mode. In this way, first, the mechanical model of the microturbine is presented. Then, the electrical structure of the microturbine, consisting  of permanent magnet synchronous generator (PMSG) and power electronics converters (PECs), is introduced. The PECs placed between the PMSG and DC-link are known as the generator-side converter and includes a three-phase diode rectifier and a buck converter. Also, a three-phase voltage source inverter (VSI) is employed between the DC-link and grid as the grid-side converter. As the paper novelty, two control approaches for the generator- and grid-side converters are defined, and then control structures of the converters are presented. Simulation results of the study system in the Simulink/MATLAB environment show that the in the first control approach the DC link voltage reaches a value 3.5 times the nominal value during the fault, while the peak value of the DC link voltage with the esecond control approach is 1.2 times the nominal value during the fault. Hence, the second control approach, in which the generator-side converter controls the DC bus voltage and the grid-side converter regulates the injected active and reactive powers, is better in terms of fault-ride-through performance.