Powerware 9330 - Manual (Page 87)

6--13 Powerware 9330 (10 kVA--40 kVA) Installation and Operation
164201300 REV. G 061502
6.3.2 Boost Converter and Neutral Regulator
A Boost Converter converts the raw DC IN to a regulated DC Link of approximately
400 volts DC. It is operated in current mode and controlled using a variable
frequency modulation technique at approximately 18---20 kHz. An artificial neutral is
generated by the Neutral Regulator (Buck/Boost configuration in current mode
control), which balances the center point to 1/2 the DC Link (+/--- 200 Volts).
6.3.3 Inverter and Filter
The Inverter is a traditional (current mode controlled) hard---switched IGBT
3---phase topology. The IGBTs are modulated by a variable frequency,
current---mode control technique at approximately 18---20 kHz. An output filter filters
out the high frequency switching components (line to neutral).
6.3.4 Battery and Battery Charger
The Battery is comprised of a string of 144 cells, made up of twenty---four 12 volt
Battery blocks. The Battery Charger is configured as a simple Buck or Boost
current mode controlled converter (mode auto selected based on I out), powered
by the raw DC IN, which regulates the battery charge voltage/current. The unit
utilizes Advanced Battery Management (ABM) technology, which essentially
isolates the Battery from the electrical environment, except for periodic charging or
reserve mode operation, extending its life.
6.3.5 Bypass
The Bypass has a continuously rated SCR switch in the Bypass circuit and a
contactor in the Inverter leg. In normal mode, the Contactor connects the Inverter
to the output. A backfeed contactor is also provided.
6.3.6 Maintenance Bypass
A user accessible shrouded 4---wire Mechanical Maintenance Bypass switch is
provided.
6.3.7 External Batteries
External Batteries connect in parallel to the Internal Battery via an internal breaker.
The internal charger charges the Batteries in parallel or in conjunction with an
optional external charger