-7-
2.2
Basic Principles
When commercial power is normal, (3kVA) UP
S input, through PFC,
increases the voltage to ±370V stabilized DC voltage, which supplies DC/AC
inverter and transmits stable 220VAC, while at the same time completing the
charging of the battery. When commercial power is abnormal, the battery
increases the voltage through DC/DC to ± 390V DC voltage and supplies
DC/AC inverter.
UPS principle lock diagram is shown in Fig. 2-4. DC/AC inverter adopts
half-bridge structure, while DC/DC voltage increase adopts push-pull or
BOOST circuit. PFC is active power-factor correction circuit controlled by
UC3854, while CHARGER is complete isolation type charger.
