A Low Harmonic Control Method of Bi-Directional Three- Phase Z- Sources

Three-phase Z-source inverters offer a voltage boosting solution of single-stage topology. They can also operate bidirectionally as rectifiers, hence have excellent potential for applications in the area of transportation electrification like Vehicle-to-Grid (V2G) chargers. In this paper, three new modulation schemes for three-phase Z-source converters are presented and analyzed. The best performed one is further extended to a closed-loop PI control technique. Although the voltage conversion ratio is adjustable, the output voltage. Total Harmonics Distortion (THD) is less than 3% between the voltage ratio range of 0.5 to 2.5. The effectiveness of the developed method has been completely verified in MATLAB/Simulink simulations and RT- LAB Hardware-In-Loop (HIL) experiments according to the real-time simulator OPAL-RT OP4510. The proposed one is compared with conventional control techniques operates better with lower harmonics, adjustable voltage gains, and less complex control algorithm. Index Terms—Z-source converter, Bi-directional converter, shoot-through states, voltage harmonics, closed-loop control. Key Words: Z-source inverter, power electronics, vehicle-to-grid (V2G), renewable energy, three-phase inverter, low harmonic control, power conversion efficiency, bidirectional operation.