Xtreme Power Conversion P91 - 4 Working Principle of the Major Functional Block; 4.1 Switch Power Supply

Xtreme Power Conversion Corporaon
P91, TX91, TX91L, TXVR Service Manual
Page 8
Uninterrupble Power Supply
The Recer and 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 meanme, PFC (Power Factor Correcon) 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 eciency and produce lowest power polluon to the ulity.
The PFC block in baery 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 ulity is within the acceptable range, the UPS will provide power directly from the ulity input and
the Recer and PFC will be executed at the same me. When the ulity is outside of the acceptable range, no
maer it’s because of input voltage or input frequency, the UPS will shut down the Recer and PFC funcons
and turn on the Baery Booster. In case of sudden interrupon from input ulity, the controller can detect the
interrupon in very short me. During the short interval of detecng the interrupon, the output power will be
provided by the power stored in the BUS capacitor. In this way,
there is no any interrupon on output power.
The charger charges the baery when the UPS system is working. Yo u can set the current to be
1A/2A/3A/4A by LCD or command. And you can choose a dierent voltage corresponding to dierent baery
pieces by changing the jumper on the CNTL board, either LCD or command.
The Input EMI secon provides EMI lter funcon. The input EMI lters can prevent the UPS from being
interference by external electronic/magnec noise which is generated by other electronic system and prevent
other systems from the noise generated inside the UPS system.
The SPS generates DC power supply needed by operaon of the circuit of the UPS itself. The Bypass provides
a path that ulity can power the output directly when the Inverter is not executed. The Maintenance Bypass
provides another path that ulity can power the output directly when UPS is in maintenance status.
4. Working Principle of the Major Funconal Block
4.1 Switch Power Supply
The Switch Power Supply (SPS) supplies DC power for UPS operaon. The input source of the SPS is the
grid when the grid voltage is higher than 110V . Or the input source of the SPS is the baery.
Figure 4.1 Basic circuit of power supply