Rockwell Automation SA3100 AC Power Modules - Manual (Page 16)

2-2 SA3100 Power Modules
Pre-charge Assembly
• The pre-charge assembly for common bus and diode rectified stand-alone Power
Modules consists of a pre-charge resistor or resistors, SCR/diode, and a printed
circuit board assembly. The SCR/diode is used to bypass the pre-charge resistor(s)
after bus voltage reaches a programmable threshold value.
DC-to-DC Converters
• The DC-to-DC converters provide 24 VDC for use by the gate drivers as well as the
+5, +15, and -15 VDC necessary for the PMI Regulator and other circuits.
Gate Driver Board
• The gate driver board receives gate firing signals from the AC power control
circuitry on the PMI Regulator and converts these signals into the appropriate
voltage and current levels to turn the IGBTs in the inverter power bridge on and off.
Feedback indicating the status of the gate drivers and IGBTs is then sent back to
the PMI Regulator.
Inverter Power Bridge
• The function of the Inverter power bridge is to convert the Power Module’s internal
DC bus voltage to three-phase AC power with controllable amplitude and
frequency. The inverter power bridge contains six state-of-the-art semiconductor
IGBTs. These are switched on and off by the gate drivers to provide modulated
phase voltages (U, V, W) to the motor.
Snubber
• The resistors, diodes, and capacitors of the snubber circuitry control the voltage
overshoot and undershoot produced when the IGBTs are switched on and off.
PMI Regulator
• The PMI Regulator consists of a large main motherboard and a Resolver & Drive
I/O board mounted above the motherboard. The motherboard contains the PMI
Regulator’s processor, AC power control circuitry, and a Flex I/O interface.
Fiber-optic and meter ports are provided along the lower edge of the motherboard.
An LED status indicator board displays drive status and errors. The PMI Regulator
is described in instruction manual S-3057.
Resolver & Drive I/O Board
• The Resolver & Drive I/O board provides position feedback used for speed
regulation. This board also provides an analog input connection that can be used
for an analog tachometer or other user input device and digital I/O connections for
standard drive-related signals, such as motor thermal overload. See instruction
manual S-3057 for further information.
Fiber-Optics Communications Ports
• Fiber-optic cabling is used for communication between the Universal Drive
Controller (UDC) module in the AutoMax rack and the PMI Regulator because it is
immune to electromagnetic interference (EMI) and eliminates ground loops. For
more information on fiber-optic cabling refer to the Distributed Power System
Fiber-optic cabling instruction manual (S-3009).