Three-phase uninterruptable power supply based on high performance Z-source inverter

This paper presents a three-phase uninterruptable power supply (UPS) based on the high performance Z-source inverter (ZSI). The proposed control strategy is based on two loops. The first loop is dedicated to regulate the dc voltage of the Z-network capacitor and limiting the peak value of the dc link voltage by controlling the shoot-through duty cycle. The second loop employs the instantaneous voltage control technique to maintain the sinusoidal shape of the output voltage. Coordination between the two control loops is achieved by utilizing the simple boost control method to generate the PWM signals for the ZSI switches. Simulations of the proposed UPS system are conducted to evaluate the dynamic performance of the proposed control strategy.