Optimal control of three-phase PWM inverter for UPS systems

This work presents a new digital control strategy of a three-phase PWM inverter for uninterruptible power supplies (UPS) systems. To achieve a fast transient response, a good voltage regulation, nearly zero steady state inverter output voltage error, and low total harmonic distortion (THD), the proposed control method consists of two discrete-time feedback controllers: a discrete-time optimal + sliding-mode voltage controller in outer loop and a discrete-time optimal current controller in inner loop. To prove the effectiveness of the proposed technique, various simulation results using Matlab/Simulink are shown under both linear and nonlinear loads.