AMETEK RS Series - Manual (Page 136)

User Manual AMETEK Programmable Power
RS Series 136
5.7.1 PFC Input Power Converter
The PCF section is located at the bottom of each power module. AC power enters the power
module at the PFC input section. The PFC section using a PWM boost converter to turn the
unregulated three phase 140 V AC into a regulated ± 225 V DC bus. A bank of capacitors is
used to provide ride-through and to support high peak current demands from the amplifier
boards. The PFC PWM circuit drives a set of three high capacity IGBT's. These IGBT's connect
directly to the DC bus bars, which connect the PFC output to the Amplifier boards.
The condition of the PFC section is constantly monitored and reported to the system interface
board. If the DC bus goes out of acceptable operating range, a fault is generated. Furthermore,
in any of the three AC input phases fails, the RS will shut itself down.
5.7.2 Modulator Board
The modulator board is located directly above the PFC board and next to the four-board
Amplifier stack. The modulator board accepts an oscillator output reference signal as input and
drives the four amplifier boards using a high frequency PWM technique. The modulator has the
ability to drive the amplifiers in either parallel or series configuration, thus producing either a high
(300 Vac ./ 400 Vdc) or low (150 Vac / 200 Vdc) output voltage range. Note that some
configurations of the RS Series may be hardwired for single range use.
The modulator contains several feedback loops that control the current sharing and output
regulation of the four power amplifier boards. The Modulator boards connects to one of the
three connectors on the System interface through a 50 pin ribbon cable located at the top front
of each power module.