Specifications

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CHAPTER 1 INTRODUCTION
1-1 Theory of operation
The main topology of the UPS consists of bypass path, AC-DC converter, DC-AC
inverter, battery charger, DC-DC converter, control circuit and detection circuit.
Moreover, the intelligent power management software is also optional. The function
and efficiency are superior to the traditional UPS.
Figure 1-1 Hardware block diagram of the UPS
The UPS operation is described as below:
When the utility power is applied into the UPS, it was divided into two ways after
going through the breaker and EMI filter. One way is connected to AC-DC converter
which converts the utility AC power into a DC voltage which is called DC-BUS
voltage then divides into two paths. One path goes to charger which converts the
DC-BUS voltage into a proper DC voltage to charge the UPS battery. The other path
goes into DC-AC half bridge inverter. The other way works as a bypass path. The
bypass relay near the output will choose either the bypass path or inverter output. In
general, the UPS will internally do the self-diagnosis. If there is no problem, the
bypass relay will choose the inverter output. This is so called “ON-LINE mode”.
PFC Control
Circuit
AC-DC Double
Booster
Charger DC-DC Converter
Auxiliary Power
Half-bridge DC-AC Inverter
Control Board
EMI
Filter
O/P
BYPASS
RELAY
BYPASS
To Control Board
LED Board
To Auxiliary Power
To Control Board
I/P
AC
To Control Board
Battery Bank
To External Battery Bank
Relay
Breaker
AC
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