Environmental Engineering Reference
In-Depth Information
Q1:
For the Camry hybrid main traction motor, MG1, parameters listed
above compute the input electrical input power,
P
e
(refer to Example 2 in
Chapter 5) and (6.5).
A1:
P
e
¼
P
pk
/
h
m
¼
111.7 kW.
Q2:
When
U
d
= 600 V
dc
, compute the phase current for the electrical input
power found in Q1.
A2: Hint:
Using (6.5) the maximum phase voltage without pulse dropping yields
U
ph
= 234 V
rms
. The M/G rated phase current for the wye connected stator is
therefore:
I
r
¼
P
e
/(3
U
ph
)
¼
159 A
rms
.
Q3:
For the phase current found in Q2, find the modulation index for this
condition.
A3: Hint:
Using (6.5) for maximum modulation depth within the voltage
synthesis circle of the voltage vector switching hexagram and taking the
condition of
P
pk
at
n
b
, then
m
¼
0.787.
Q4:
For the phase current calculated in Q3 and setting the dc link filter
capacitor ripple current at 60% of this value, given an ESR = |
Z
C
|=
q
ð
ESR
C
þ
X
C
Þ
¼
9
:
496 m
W
at
f
s
= 8 kHz, compute the power dissipation
in the filter capacitor bank if this is a steady-state, cruise, condition.
A4:
I
C
= 0.6
I
r
¼
0.6(159)
¼
95.4 A
rms
. The power dissipation in the dc link
capacitor is therefore,
P
dlink
¼
I
C
2
|
Z
C
| = 95.42(9.496
10
3
)
¼
86.4 W.
Q5:
For the link filter capacitor given and assuming a 20
m
H choke inductor is
placed in the battery power cable, what is the approximate ripple current at
the battery terminals when
f
s
¼
8 kHz switching frequency?
A5:
For this cable, the choke inductance has a reactance,
X
ch
¼
6.283(8,000)
(20
10
6
)
¼
1.00
W
. Therefore, using the formula for current division
among parallel impedances,
I
C
is partitioned among
Z
C
and
X
ch
so that the
battery component,
I
bat
¼
I
C
(
Z
C
/(
Z
C
þ
X
ch
)
¼
0.897 A
rms
.
Q6:
An aluminum electrolytic capacitor rated 10 mF has a time constant of 250
m
s
is charged to 100 V then discharged through a 10 m
W
load resistance,
including cable and switch. The peak discharge current is measured as 2,800 A
with a time to peak current,
t
pk
=8.5
m
s. Compute the equivalent series induc-
tance of this filter capacitor, ESL?
Hint:
The series R-L-C circuit consisting of electrolytic capacitor must be ana-
lysed for the circuit current,
i
(
t
), as follows:
ð
idt
þ
Ri
þ
L
di
1
C
U
c
0
þ
dt
¼
0
ð
6
:
32
Þ
L
::
þ
R
:
þ
1
C
i
¼
0
(6.32) is solved subject to initial conditions
i
(0
+
) = 0 and
di
(0
+
)/
dt
= 0 which
govern the exponential factor coefficient and magnitude of this coefficient,
