NPS2400
User’s Manual
Rev. 3.0
– 17.02.2015
Page 6/38
3 Functional description
A simplified block diagram of the NPS2400 is shown in Figure 3.
Figure 3
NPS2400 simplified block diagram
NPS2400 is a 3-phase input SMPS with 2 power stages, supervised by a microcontroller. The first stage is a power factor
corrector (PFC) module that improves unit efficiency and reduces the harmonic current from the mains. The second stage is a
resonant full bridge converter that provides primary to secondary insulation and high efficiency power conversion.
The product offers additional features that improve the performances and the reliability:
Integrated active ORing diode
: allows connecting several devices in parallel for redundancy (see §4.3.4). When several units
are paralleled for increase of the total output power (up to 8.7kW) this circuit increases the reliability of the system in case of 1
unit failure.
Load share functionality:
allows connecting up to 4 devices in parallel to increase the output power up to 8.7kW. A dedicated
bus allows to equally share the total load current between the paralleled devices.
Remote voltage sensing
: allows regulating the output voltage directly at the load terminals compensating the cables and
connectors voltage drop when long cables are used.
Active surge protection
: this circuit increases the reliability by protecting the device from high voltage transients occasionally
present on the 3 phase mains. On top of that this circuit performs also the function of active inrush current limiter reducing the
inrush current to very low values.
Smart thermal management
:
the fans
’ speed is controlled according to load and internal temperature conditions. This allows
maintaining a safe temperature of the critical parts while maximizing the fans operating life and minimizing the fans noise.
Remote output current measure
: the user can measure remotely the output current delivered by the SMPS. The information is
provided through an opto-
isolated output with 2 industry standard ranges: 0…10V or 4…20mA for 0A to rated output current.
Remote shutdown input
: it allows to remotely switch the SMPS ON or OFF without cutting the 3 phase mains. An opto-isolated
input can be configured as a remote shutdown/enable input
Auxiliary 12V output:
the units provide a regulated 12V/0.1A output completely insulated from the main output. It can be used
to supply light 12V loads, independently on the SMPS output voltage/status.
Battery
charger mode (only on “-24” and “-48” models):
this operating mode allows operating the device as a high
performance battery charger for lead-acid and NiCd/NiMH batteries. 12V, 24V or 48V batteries can be charged up to a capacity
of 1000Ah.
