Digital control scheme of single-phase uninterruptible power supply

This paper presents the digital control scheme of a single phase uninterruptible power supply (UPS). In order to obtain fast response in the current control, the authors propose the digital control scheme based on the instantaneous values. The inverter of the UPS is connected to the load in parallel to reduce the loss of the UPS. The controller is constructed by a DSP. The control schemes in all of the operations of the UPS are described. All operations of the UPS using the proposed control scheme have been verified by experiments.