Model‐based control of four‐leg inverter for UPS applications considering the effect of neutral line inductor

A control approach for three-phase four-leg LC-filtered voltage source inverters (VSIs) is proposed an uninterruptible power supply (UPS) application. filter inductor in the fourth (neutral) leg of VSI considered to enhance output quality when feeding different types loads such a system. The based on modelling UPS system dq0 synchronous frame. First, switching functions inverter under study are extracted from achieved model. Afterward, developed by introducing virtual time constant, which simultaneously affects system's damping ratio, and undamped natural frequency functions. It offers flexibility improving dynamic steady-state responses as desired. While final constant decreases transient response overshoot, resulting leads alleviation error voltage. performance evaluated via SIMULINK-based real-time simulation results.