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DC LINK STATE
Power is provided to the inverters and motors via the
DC link.
The DC link has two associated states:
powered and unpowered. The following defines the
conditions necessary to establish each state as well
as the transitional conditions between the two states:
Powering the Link
The PSC software will attempt to power the DC link
(i.e., command the system configuration defined be-
low) if all of the following conditions are true:
1. Event restrictions do not prohibit power on the DC
link.
2. The system is in Test state and any initiated
testing is complete.
3. The engine is running.
4. The Gate Drive Power Converters have been
enabled.
5. Neither inverter is requesting that a low voltage
test be run.
In attempting to power the DC link, the PSC software
will establish the necessary system configuration as
follows:
1. GF closed and GFR picked up,
2. AFSE enabled,
3. Alternator field reference is commanded such that
the desired DC link voltage or three-phase volt-
age is maintained,
4. RP contactors open,
5. Chopper turn-on voltage is set above 600 volts.
NOTE: Before the AFSE is allowed to output firing
pulses, the RP contactors will be commanded open
and GF contactor will be verified to be closed. The
AFSE will not output firing pulses if it is disabled, if GFR
is dropped out, or if the alternator reference signal is
0.
E02014 3/01
De-Powering the Link
The PSC software will attempt to de-power the DC link
(i.e., command the system configuration defined be-
low) if the system is in Test or Ready state, and any of
the following conditions are true:
To accomplish this, the PSC software will establish the
necessary system configuration as follows:
CONTROL FUNCTIONS
Engine Control
This software function generates the engine speed
command. The engine electronic fuel control is re-
sponsible for maintaining that speed.
The desired engine speed is determined according to
the system state:
Propel State:
The engine speed is commanded such that the engine
supplies only as much horsepower as is required to
achieve the desired torque.
All Other States:
The engine speed is a direct function of the accel
pedal. Additional constraints on the engine speed
command are:
Electrical Propulsion System Components
1. Event restrictions prohibit power on the DC link,
2. The system is preparing to transition to
Startup/Shutdown state for the purpose of shut-
down (i.e., all the non-link-related conditions for
Startup/Shutdown state have been satisfied),
3. The system is preparing to transition to Rest state
(i.e., all the non-link-related conditions for Rest
state have been satisfied),
4. The engine is being shut off.
1. Alternator field reference set to zero,
2. AFSE disabled,
3. GF open and GFR dropped out,
4. Chopper turn on voltage set below approximately
600 volts,
5. Close RP2 or RP3, alternating each time to pro-
vide even wear.
E2-33
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Table of Contents
Troubleshooting
