ABB RER620 Technical Manual page 444

Section 9
Other functions
438
The UPD provides six high current drive channels of a proximally 60 amps max, and 250
Vdc maximum. The architecture of the six channels is that of a half bridge driver. When
placed in service the six are grouped to form three full bridge drivers, so that each channel
will provide its load with either positive or negative current flow. The UPD may drive its
load via constant on or PWM method. The constant on mode does not apply to the highside
driver, only the lowside.
Control of the UPD is through a parallel bus. The parallel bus is decoded by a CPLD
located on the UPD. The CPLD supplies the decoded commands to a TI DSP via an SPI
bus. The DSP controls the bridge drives. Data also flows in reverse, from the DSP, to the
CPLD, to the parallel bus. The DSP is the master of the SPI bus and the CPLD the slave.
The UPD has an electrically isolated portion to protect the RER620 from electrical
disturbances that may be received by the wiring connecting the UPD to the pole top High
Voltage Cabinet. This isolated portion of the UPD is powered from two external voltage
sources. One is a 250 Vdc source, and the other a 60 Vdc source. There is a switch mode
power supply that converts the 60 Vdc to 15 Vdc and 4.2 Vdc.
The UPD is equipped with a two-wire, non-isolated, RS485 communication channel. The
primary purpose for this communication channel is to provide a pass through connection
between the RER620 CPU board and the UPS.
The UPD is equipped with six, non-isolated binary inputs that are designed for reading
switches located in the High Voltage Cabinet.
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RER620
Technical Manual