ferrotec Temescal CV-12SLX User Manual page 51

Section 4: Theory of Operation 4.2 HVPS Theory of Operation
4.2.4 PCB Functionality
Inverter Board
From the load side of circuit breaker CB1, the three AC line phases are fed to the Inverter board,
which converts the 50/60Hz AC line power into high-frequency power. Part of that conversion
process involves rectifying the AC input voltage through a three-phase bridge rectifier and
employing a "DC link" choke (L1) to smooth the current. This inductor improves the power
factor of the power module as seen by the AC power grid. High-speed IGBTs on the Inverter
board switch the rectified bus voltage through HV transformer T1 at 25 kHz, thereby converting
the intermediate DC power once again into AC power. Other functions performed by the Inverter
board are rail capacitor charging, temperature sensing, and monitoring auxiliary power and rail
voltage.
HV Rectifier Board
The HV Rectifier board converts the high-frequency, high-voltage output of HV transformer T1
into DC high-voltage power. The Rectifier board also scales the output voltage and current for
feedback to the Regulator board's control circuits.
HV Output Board
The HV Output board provides secondary-tuning capacitance, HV rectification, and voltage and
current feedback to the Regulator board. High frequency AC voltage driven on the primary of
the HV transformer by the Inverter is transformed by a fixed ratio (15:225) and connected to
the input of the HV Output board at J1 and J2.
Regulator Board
The Regulator board performs virtually all logic, control, and analog processing functions.
However, its primary function is output voltage control. The board performs this function by
comparing the output feedback to the references provided and then feeding the Inverter board's
IGBT gate drives to properly actuate them. DC output voltage is delivered from the Regulator
board to the external load through the custom high-voltage "cablewell" connector J1 on the
unit's rear panel. A mating connector and cable for J1 are provided with each power supply.
Interface Board
The Interface board is mounted to the upper left-hand corner of the rear panel. Three D-
subminiature connectors on the Interface board connect the remote I/O signals to the Regulator
board. J1, a 14-pin D-sub connector (labeled J5 on rear panel), provides the interface to the
filament power supply. J2, a 37-pin D-sub connector (labeled J3 on rear panel), provides
diagnostic signals to the user's system. Appendix B provides a pinout table for these signals. J3,
a 24-pin D-sub connector (labeled J4 on rear panel), serves as the active control interface for
user-supplied I/O signals.
0101-8292-0, Rev. C 4-3 CV-12SLX User Manual