A novel four-leg three-phase inverter control strategy to reduce the data center thermal losses: Elimination of neutral current

In this paper a novel control strategy is proposed for a three-phase-four-leg UPS-inverter for data center application. The control strategy takes care of the unbalanced three-phase loading of the data center server without the manifestation of the neutral current. Thus, the power distribution unit (PDU) transformer can be eliminated from the power architecture while feeding the total data center load from a standard three-phase-three-wire utility supply. The proposed control strategy adjusts the inverter output voltages in such a way that even in the presence of unbalanced loading of the servers, the neutral current is maintained at zero in the steady-state. The proposed methodology is thus capable of reducing the thermal losses due to PDU as well as neutral wire improving the power usage efficiency (PUE) of the date center.