Transcript Converter Classification ECE 442 Power Electronics 1

Converter Classification
ECE 442 Power Electronics
1
First-Quadrant Converter
• Load Current iL flows
into the load (+)
• Load Voltage is +
• Rectifier
ECE 442 Power Electronics
2
Second-Quadrant Converter
• Load Voltage is +
• Load Current iL flows
out of the load (-)
• Inverter
ECE 442 Power Electronics
3
Second-Quadrant Converter
ECE 442 Power Electronics
4
When the switch is closed
E forces current through L, load voltage vL = 0
di
0L
 Ri  E
dt
i (0)  I
L
L
L
1
E
i  I e  (1  e )
R
0  t  kT
R
 t
L
L
R
 t
L
1
t  t  kT ,
1
ECE 442 Power Electronics
i (t )  I
L
1
5
2
When the switch is opened
di
V L
 Ri  E
dt
i (t )  I
L
S
L
L
1
2
i Ie
L
V E

(1  e )
R
R
 t
L
S
2
0t t
R
 t
L
2
t  (1  k )T
2
ECE 442 Power Electronics
6
V 1  e
I 
R  1  e
V e  e
I 
R  1  e
TR
z 
L
 ( 1k ) z
S
1
z
 kz
S
2
z
z
E
 R
E
 R
ECE 442 Power Electronics
7
First and Second Quadrant Converter
ECE 442 Power Electronics
8
S1 and D4 operate as a first-quadrant converter.
S2 and D4D1 operate as a second-quadrant
converter
ECE 442 Power Electronics
9
Second Quadrant Operation
2
S2 closed
S2 open
ECE 442 Power Electronics
10
Third and Fourth Quadrant Converter
The load voltage is always negative, but the
load current is either positive or negative
ECE 442 Power Electronics
11
Third Quadrant Operation
S3 closed
S3 open
iL, vL are always negative
ECE 442 Power Electronics
12
Fourth Quadrant Operation
S2 closed load current +, load voltage – (zero)
S2 open
load current +, load voltage negative, (-Vs)
ECE 442 Power Electronics
13
Four-Quadrant Converter
Load Current can be positive or negative
Load Voltage can be positive or negative
For fourth quadrant operation, reverse E.
ECE 442 Power Electronics
14
Summary of a four-quadrant converter
ECE 442 Power Electronics
15
Summary of the conducting devices
ECE 442 Power Electronics
16