A new space-vector-based control method for UPS systems powering nonlinear and unbalanced loads

In this paper, a new real-time space-vector-based control strategy is presented for three-phase uninterruptible power supply systems powering nonlinear and unbalanced loads. The proposed control strategy generates the inverter reference and gating signals in closed loop and guarantees high-quality output voltages at the load terminals. The approach, which is implemented on a digital signal processor, adapts to a wide variation of nonlinear and unbalanced load conditions without specific knowledge of the output filter (L-C) component values. Analysis and experimental results on a 10-kVA prototype are presented. The results show that the output voltage is restored at heavy nonlinear and unbalanced load.