Design and implementation of a DC line-interactive uninterruptible power supply (UPS) with load leveling

A Digital Control System for UPS Systems With Smart-Grid Capability

“…In the normal mode, the UPS is used as an interface to provide high-quality power for the load by amplifying/attenuating and filtering the line voltage. In the event of power failure, the UPS enters backup mode, the utility grid is disconnected from the load and the energy stored in batteries is made available to the load by the UPS [14][15][16][17].…”

“…• [14][15][16][17][18]. Consequently, the UPS provides protection for sensitive equipment as they prevent them from instant shut-off or being exposed to the distorted grid voltage.…”

“…17 shows the performance of PWM with bipolar modulation. According to this figure, the output voltage of the bidirectional AC/DC converter either fluctuates between zero and +V dc or between zero and −V dc for the positive half cycles and the negative half cycles, respectively.…”

UPS design without inverter to power ISP servers

“…Also, the battery current and voltage control is done using a PI controller.In order to reduce the current and voltage harmonics, the method of isolating the input current from the output with the help of interface transformers [8] or the use of active lters can also be suitable solutions [9] to adjust the load voltage, we can replace DC line interactive UPS with AC UPS. Let us popularize three phases [4] In reference [6], the topology for the data center is presented using a scalable module, which seeks to improve e ciency and reduce costs. AC-DC converter and DC-DC converter are formed, the rst part converts AC input voltage to DC voltage and the second part converts DC voltage to several DC voltage outputs at different levels such as 3.3v, 5v, 12v, -12v convertsContinuous UPSs, if the loads under their power supply are AC powered, it is necessary to place an intermediary between the batteries and the load called an inverter (DC to AC converter), which requires its own control circuits in reference [14].…”