Environmental Engineering Reference
In-Depth Information
three voltage ratings that must be considered when selecting the dc operating
voltage [10]:
The dc voltage according to the cosmic radiation level threshold for failure and
the long term leakage current stability.
●
The repetitive overshoot voltage spikes during turn-OFF due to circuit and
parasitic inductance that must not exceed the component,
V
DRM
(GTO and
IGCT) or
V
CES
(for IGBTs).
●
The maximum voltage at which the device can switch rated, or other specified,
current and remain within its safe operating area (SOA).
●
Table 2.2 excerpted from Reference 10 summarizes the dc operating voltage
levels for the typical 3-level power inverter used in many of the high power
applications discussed in this chapter.
Table 2.2 Semiconductor block voltage rating for stated ac line voltages and dc
link voltage
Nominal line
voltage (V
rms
)
Nominal dc link voltage
for cosmic ray rating (V
dc
)
Preferred repetitive blocking
voltage rating (V
DRM
,V
CES
)
2,300
1,900
3,300
3,300 V
dc
2,000
3,300
3,300
2,700
4,500
4,160
3,400
5,500
6,000
4,900
8,000
6,600
5,400
8,500
6,900
5,600
9,000
7,200
5,900
9,500
The traction motors are frameless, 4-pole, cage rotor, 3-phase induction
machines manufactured with laminated stator and rotor cores. The windings are
Class 200 insulated in the stator and vacuum-pressure impregnated with silicone
resin. The cage rotor is made from solid copper bar and end rings for extremely
rugged construction. Each of the traction motors is rated 13 kNm peak and 8.8 kNm
continuous (at 520 kN tractive effort).
The locomotive drive is important to this chapter on hybrid architectures
because it illustrates three important facts:
1.
Power electronics processing elements may be interconnected for high voltage
capability (e.g. 3 kV). Today, matrix converters are being applied.
2.
Induction traction motors can be connected in parallel to share the total tractive
load. For the locomotive case, each driven axle (i.e. bogie) has one induction
motor and a truck unit (2-3 axles) has traction motors ganged together.
