Eaton 93PR - Figure 2-9: Path of Current through the UPS in Double Conversion Mode

Eaton 93PR 60-1200 kW UPS
Installation and Operation Manual
17
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Figure 2-9: Path of current through the UPS in Double Conversion Mode
Three-phase AC input power is converted to DC using a multilevel converter with IGBT devices
to produce a regulated DC voltage to the inverter. The UPS status indicated on the display is “Unit
Online” and the UPM status is “Active”.
The battery converter derives its input from the regulated DC output of the rectier and provides
regulated charge current to the battery. The battery is always connected to the UPS and ready to
support the inverter should the utility input become unavailable.
The inverter produces a three-phase AC output to the critical load. The inverter derives regulated
DC from the rectier and uses multilevel converter technology with IGBT devices and pulse-width
modulation (PWM) to produce a regulated and ltered AC output.
If the utility AC power is interrupted or is out of specication, the UPS automatically switches to
Battery Mode to support the critical load without interruption. When utility power returns, the UPS
returns to Double Conversion Mode automatically.
If the UPS su󰀨ers inverter overload exceed the allowance timer, the UPS seamlessly switches to
Bypass Mode and continues supplying the load through the static bypass. The UPS automatically
returns to Double Conversion Mode when the abnormal condition, such as an extended time
overload, is cleared and system operation is restored within specied limits.
If a UPM power module within the UPS su󰀨ers an internal failure, the remaining UPMs will
continue support the load in double conversion. The UPS is automatically internally redundant
when the UPS supporting power less than N-1 UPM rated power. However, if there is no
redundancy between the UPMs due to high load level, the UPS switches automatically to Bypass