Smartbitt SBOL50KTIII-3, Service Manual

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3. Functional Block
As a true online UPS, the product applies a double conversion topology, comprising functional blocks as
shown in Figure 3.1
Figure 3.1 Function block Diagram
The CNTL block controls the action of the UPS system. It detects the voltage and current to control PFC
and inverter, also it supplies the protection for the UPS, When the UPS becomes abnormal, in most case,
the CNTL can provide basic information indicating the status of the UPS.
The COMM block provides the communication interface for receiving and executing command from users
via the panel or other communication protocol, also provides the LCD display task.
The PFC blocks are the input stage of the UPS. The blocks convert AC input power into two stable DC
power stored in the BUS capacitor. In the meantime, PFC (Power Factor Correction) will be executed and
allows input current tracking the input voltage waveform. Therefore, the input power factor will be
corrected to 1 to achieve maximum efficiency and produce lowest power pollution to the utility.
The PFC block in battery mode, also called Booster, is used to convert the low voltage DC power to higher
voltage with stable DC power, stored in the BUS capacitor.
The Inverter block is the output stage of the UPS and used to convert DC power from the BUS capacitor
to sine waveform output power.
When the utility is within the acceptable range, the UPS will provide power directly from the utility input
and the Rectifier and PFC will be executed at the same time. When the utility is outside of the acceptable
range, no matter it’s because of input voltage or input frequency, the UPS will shut down the Rectifier and
PFC functions and turn on the Battery Booster. In case of sudden interruption from input utility, the
controller can detect the interruption in very short time. During the short interval of detecting the
interruption, the output power will be provided by the power stored in the BUS capacitor. In this way, there
is no any interruption on output power.
The charger charges the battery when the utility is normal. The charger converts DC input power to DC
power for recharging the battery. The charger’s output current can be setting form 1A to 4A.
The Input and Output EMI section provides EMI filter function. The input and output EMI filters can prevent
the UPS from being interference by external electronic/magnetic noise which is generated by other
electronic system and prevent other systems from the noise generated inside the UPS system.
Input
Input
Breaker
Input EMI Line SCR PFC
Bat SCR
Battery
Charger
SPS Cntl Comm
INV
Maintenance Bypass
Switch
Output EMI
INV Rly
Byp SCR
Output
Bypass
Maintenance Bypass
Single_Input System Principle
Diagram
OVCD relay