EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
EMI EMISSIONS
of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
Rockwell Automation
6400 W. Enterprise Drive
Mequon, WI USA 53092
Figures reprinted from
IEEE Industry Applications Magazine, Vol. 5, No. 6,
November/December 1999, pp. 47-81.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
C
PL ital
g
Di mm
Co
No
or PL
co C
mm
Analog
PLC
Fig. 1. Applications with potential EMI issues.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
line-to-line
voltage
(500V/Div)
Zero
sequence Ilg
(10A/Div)
Fig. 2. 200 hp ASD output waveforms (2 ms/Div).
EMI EMISSIONS of MODERN PWM AC DRIVES
fc
trise
tfall
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
fn = 0.318 / t rise
V dc bus
Drive line-toline voltage
Induced
CM current
CM
voltage
Earth ground
potential
V U-V
τ
t
I lg
t
V 1-2
t
V4
t
Fig. 3. Noise Source: Drive line-to-line voltage, induced CM current, CM
voltage V1-2, and earth ground potential V4.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Drive
U
IMOTOR
V
R01
L01
W
R02
L02
PE
R03
L03
Ill
Ilg
Cll
Clg
Clg-c
Motor
Cll-m
Clg-m
Conduit
Fig. 4. Simplified drive-conduit-motor system showing parasitic cable and
motor components.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Fig. 5. 2 hp ASD phase current showing fundamental sinewave
current, ripple current, and Ilg plus Ill current transients.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
AC Drive
Input Transformer
A
R
B
XO
Ilg
Ilg
PE
C
U
(+)
Vdc
bus
(-)
S
T
Ilg
EARTH
GROUND
Motor Frame
V
Motor Tach
W
C lg-m
Logic
Ilg
Common Mode
Current Path
Ilg
PE
Vng
Potential #1
Potential #2
C lg-c
Ilg
Potential #3
Interface Electronics
0-10V, communication,
4-20 ma,sensor interface,etc
Potential # 4
True Earth Ground (TE)
Fig. 6. Parasitic line-to-ground noise paths in a solidly grounded
ASD system using poor wiring practices.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Vng neutralto-ground
voltage
(100 V/Div)
Ilg CM
current
(2A/Div)
Fig. 7. Measured ASD neutral-to-ground voltage (100 V/Div)
and Ilg (red) CM current (2A/Div) for 30 Hz output
[“0” at offset 4 div; 2 ms/Div]
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Ilg
4 kHz
Vng
Fig. 8. Expanded neutral-to-ground voltage (100 V/Div) and Ilg CM current
(2A/Div) for 30 Hz output [“0” at offset 4 div; 50 µs/Div]
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
+ Bus
IGBT
Conduction
State
- Bus
Vbus / 2
Stator
V /6
Neutral bus
to
Ground - Vbus / 6
Voltage
- Vbus / 2
Fig. 9. Zero sequence voltage generation.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Differential Mode Voltage Spectrum
0
Voltage (dB)
- 50
fc
- 100
1
- 150
π trise
- 200
- 250
1
102
104
106
108
Frequency (Hz)
Fig. 10. Differential mode voltage spectrum of ASD output.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Common Mode Voltage Spectrum
0
fc
Voltage (dB)
- 20
- 40
- 60
- 80
1
- 100
π trise
- 120
102
103
104
105
106
107
108
Frequency (Hz)
Fig. 11. Common mode voltage spectrum of ASD output.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Unshielded Phase Conductor of Drive
C l-g
RECEIV
E
Critical Distance
SEND
i 1-2
Hi
Isignal
Isignal
Lo
Load
Ilg
Isignal
Isignal
i 1-2
Z
Common Mode Voltage V12
i 1-2
Common Mode CurrentIlg
Ground Potential #1
TE Ground Potential #2
Fig. 12. CM current path inducing CM voltage.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Distance (ft)
1000
800
Region Susceptible
to CM Noise
600
400
200
Region where CM
Noise is not an Issue
0
0.01
0.1
1
Drive Output Voltage Risetime CM Noise ( µS )
Fig. 13. Critical interface distance vs. CM voltage risetime.
10
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Unshielded Phase Conductor of Drive
Cl-s
SEND
Hi
Isignal
Isignal
Cl-s
RECEIVE
Isignal
Isignal
Load
I lg
Lo
Z
Ground Potential #1
I lg
TE Ground Potential #2
Fig. 14. CM current capacitively coupled to signals.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
I lg
Unshielded Phase Conductor of Drive
C l-s
ilg
RECEIVE
ilg
Isignal
Hi
Lo
120 Vac
Interface
Power
Leads
Critical Distance
Load
SEND
Isignal
ilg
CS-Lo
CS-Hi
ilg
Shield
Ground
Z
I lg
Ground Potential #1
TE Ground Potential #2
Fig. 15. CM current capacitively coupled to interface power.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Unshielded Phase Conductor of Drive
I lg
C l-g
Critical Distance
SEND
RECEIVE
i1-2
Hi
Load
Isignal
Isignal
Lo
Noisy
Shield i1-2
Ground
CS-Lo
i1-2
CS-Hi
Z
Common Mode Voltage V1-2
i 1-2
Common Mode Current I lg
Ground Potential #1
TE Ground Potential #2
Fig. 16. Noise coupling: Noisy shield ground.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Unshielded Phase Conductor of Drive
C l-g
SEND
i1-2
Hi
Critical Distance
RECEIVE
i1-2
Isignal
Load
I lg
Isignal
Lo
i1-2
CS-Lo
i1-2
Shield
Ground
CS-Hi
Z
Common Mode Voltage V1-2
i1-2
Common Mode Current I lg
Ground Potential #1
TE Ground Potential #2
Fig. 17. Noise coupling: Noisy source ground.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Drive
Cable
Motor
U
V
C lg
Cll
Cmg
W
PE
Loop Antenna Area
Common Mode Current
Ilg
Ground Potential #1
Ground Potential #2
Fig. 18. Radiated emissions loop area.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
XO
Ungrounded System
Earth Ground Potential
XO
Rng
High Resistance
Grounded System
Earth Ground Potential
XO
Solidly
Grounded System
Earth Ground Potential
Fig. 19. Neutral grounding philosophy influences system EMI.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Cold
Water
Pipe
Grounding
Electrode
Grounding
Conductor
Ground Bus
Triangular Configuration Spacing Not Less Than 10 Feet
Fig. 20. Suggested grounding practice for steel frame buildings [18].
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
ASD-1
ASD- 2
Logic
Logic
PE
ASD- 3
ASD- 4
Logic
Logic
PE
PE
V1
TE
V2 PE Safety V4
Ground
V1-2
I1-2
I3-4
PE
TE
V3
V5
V3-4
V0
TE “Clean” Logic Ground
Cabinet
Remote
electronics
V6
Common Mode Voltage V60
Common Mode Noise CurrentI6-0
Remote Ground Potential #6
Fig. 21. CM current and CM voltage paths in safety PE and signal
TE grounds.
Ground
Potential #0
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
For PLC grounding
recommendation
refer to Publication
1770-4.1
PLC
TE-ZERO VOLT
BUS
Building
ground grid
or
structure steel
Motor
Logic
PE
TE
Logic
PE
Motor
PE
GROUND
Possible bond
to nearest
Building ground
Fig. 22. Drive cabinet grounding with system grounding needs.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
AC Drive
Input Transformer
A
R
B
XO
Ilg
I lg
PE
C
Ilg
Common Mode
EARTH GROUND
Potential 4
Conduit
U
(+)
S
Ilg
V
Vdc
bus
T
(-)
I lg
W
s
t
r
a
p
PE
Current Path
Potential #1
Motor
C lg-m
Motor PE
GND wire
PE
Ilg
Motor Frame
Accidental
Contact of
conduit
Potential #2
I lg
Potential #3
Fig. 23. Good wiring solution: Conduit with PE wire reduces radiated noise
but may not contain CM noise current.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Input Transformer
AC Drive
A
R
B
XO
Ilg
I lg
PE
Shielded Cable / Armor
with PVC Jacket
Motor Frame
C
Ilg
S
V
Motor
Vdc
bus
T
(-)
I lg
W
PVC
C lg-m
PE
I lg
PE
Common Mode Current Path
EARTH GROUND
Potential 4
U
(+)
Ilg
Potential #1
Additional
Motor PE
GND wire
Potential #2
Potential #3
Fig. 24. Better wiring solution: Shielded output with insulated jacket
controls EMI noise path.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Transformer
Cabinet Frame
Cable / Armor
& PVC Jacket
AC Drive
A
Cable / Armor
& PVC Jacket
Motor Frame
R U
Ilg
XO
B
S
I lg
C
PVC
PVC
PE
PE
EARTH GROUND
Potential 4
C lg-m
T W
PE
HRG or
SOLID GND
Motor
V
I lg
Ilg Common Mode
Current Path
Potential #1
Additional
Motor PE
GND wire
Potential #2
Potential #3
Fig. 25. Best wiring solution: Shielded input/output with insulated
jacket completely avoids ground noise problems in system.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
UVW
ASD Output
Conduit / Armor
bond to cabinet
Cabinet Back Plane
PE
ASD - 1
A
RST
PE
ASD - 2
A
B
PLC or
Electronics
ASD Input
Conduit / Armor
Bond to cabinet
Transient Common
Mode Current on Armor
PE
PE
ASD - 3
ASD - 4
PE
PE
PE Copper Bus
B
Transient Common
Mode Current on PE Wire
Optional PE to
Building Structure
B
Fig. 26. Proper cabinet layout with drives and controls.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
U VW
B
RST
A
PE
A
ASD Output
Conduit / Armor
bond to cabinet
Cabinet Back Plane
AB
PLC or
Electronics
ASD - 1
PE
ASD Input
Conduit / Armor
Bond to cabinet
ASD - 2
A
Transient Common
Mode Current on Armor
PE
PE
ASD - 3
ASD - 4
AB
PE
B
Transient Common
Mode Current on PE Wire
PE
PE Copper Bus
B
Wire To System PE
of Building Structure
B
Fig. 27. Improper cabinet layout with drives
and controls.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Inverter
output
Voltage
Vu-v
70 nS
Ipeak
Common
Mode
Ilg Current
Ilg Current
With
Common
Mode
Chokes
6 MHz Oscillation
Slower 1.5 us to 5 us risetime
Lower 200 kHz to 63 kHz Oscillation
Lower 1/3 Ipeak
Fig. 28. IGBT risetime developed Ilg current; with and without CM choke.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
A
AC Drive
R
B
XO
S
Common Mode
Choke
U
Vdc bus
(+)
I lg
V
W
T
C
Common Mode
Bus Capacitors
PE
PE
Ilg
Ilg Common Mode Current Path
EARTH GROUND
Potential 4
Potential #1
Motor
C lg-m
(-)
PE
Motor Frame
Motor PE
GND wire
C lg-c
Potential #2
Fig. 29. Attenuation of CM noise using CM choke and high
frequency bypass capacitors.
I
lg
Potential #3
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
SEND
RECEIVE
Hi
Load
Isignal
Isignal
Lo
Z
Common Mode
Choke on
Interface Leads
Ground Potential #1
Shield
Ground Potential #2
Fig. 30. CM core solution for power and signal leads.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
W
PVC
Outer
Sheath
B
Filler
R
Red, White,
and Black
Conductors
G
Single
Ground
Conductor
TRAY CABLE
Armor
Cable
W
G
Filler
R
Red, White,
and Black
Conductors
PVC
Inner &
Outer
Sheath
G
B
Three
Ground
Conductors
G
ARMOR CABLE
Armor
Cable
W
Red, White,
and Black
Conductors
R
Stranded
Neutral
B
G
Single
Ground
Conductor
INTERLOCKED
ARMOR CABLE
R
W
TRAY
B
PVC
Outer
Sheath
W
R
Red, White,
and Black
Conductors
B
Filler
EUROPEAN UTILITY
R
W
B
TRAY
Fig. 31. Different methods of cable construction.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Radiated Voltage
with No Shield
Radiated Voltage
with Braided Shield
Fig. 32. Shielding effectiveness of tray cable vs. shielded cable for ASD
@ 10 kHz, 700 ft of cable ( 400 mV/Div, 10 µs/Div).
EMI EMISSIONS of MODERN PWM AC DRIVES
Cable Common Mode impedance [ Ohms]
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
1000
Source wire with Separate &
Isolated PE Return ground wire
Conduit with
PE ground wire
100
10
Tray Cable with Foil Shield & PE ground wire
Braided Cu Shield, Foil, Drain & PE ground wire
1
105
106
107
108
Frequency [ Hz]
Fig. 33. CM surge impedance vs. frequency comparison for isolated PE wire,
conduit with PE wire, tray cable with foil and PE wire, and braided shield cable
with PE wire.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
CM current of 3 output phases
Current in Braided Shield & Foil
Current in Insulated PE wire
Net Ground Current outside of Cable
All traces: 2 Amps / Div
10 microseconds / Div
Fig. 34. Shielded cable reduces magnitude and frequency of CM
current into ground.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Main Plant Xfmr. LISN
Drive EMI Filter
A
AC Drive
R
XO
B
U
S
V
Lf
HRG
Unit
W
T
C
Cf
PE
PE
Potential #1
I lg
Motor
C lg-m
Motor PE
GND wire
C lg-c
Ilg
EARTH GROUND
Potential 4
Motor Frame
Potential #2
I lg
Potential #3
Fig. 35. EMI filters with shielded output cable and proper bonding at
drive contain EMI radiated and conducted noise.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Main Plant Xfmr.
Drive Isolation Xfmr.
AC Drive
A
A
XO
B
XO
Ilg
HRG
Unit
EARTH GROUND
Potential 4
C
to other
plant loads
U
B
V
S
I lg
C
R
I lg
Ilg
Motor
W
T
C lg-m
PE
PE
Motor PE
GND wire
C lg-c
Ilg
Potential #1
Motor Frame
Potential #2
Fig. 36. Drive isolation transformer contains CM noise current
out of main distribution grid.
Ilg
Potential #3
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
200 ft
Analog
Out
+10 V
V
S
2k
PE
Ground
Lead
(PE)
Shield
Drive
Side
Shield
Load
Side
Fig. 37. Single ended ASD interface test circuit.
TE
Potential 2
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
No Shield
0V
Shield connected
to drive only
0V
Shield connected
to both sides
0V
Shield connected
to load side only
0V
10 V / Div. 500 µs / Div.
Fig. 38. CM noise demonstration: Noisy shield ground.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Shield Open
0V
Shield connected
to drive only
Shield connected
to both sides
0V
0V
Shield connected
to load side only
0V
10 V / Div. 500 µs / Div.
Fig. 39. CM noise demonstration: Noisy shield ground and CM core solution.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
ASD with
shielded
tray cable
2 Volts / Div
ASD with
standard
tray cable
2 Volts / Div
Fig. 40. Noise demonstration: Effect of CM noise on tachometer signal
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
“0” State Sampling
A
w_phase to + bus
0
500 V / Div
v_phase to + bus
0
500 V / Div
u_phase to + bus
0
B
u_phase Current
0
0
100
200
500 V / Div
300
400
5 Amp / Div
500
Time (microsecond)
Fig. 41. Drive voltage and phase current, 2 kHz, 300 ft,
# 12 AWG, 50 nS risetime.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
“0” State Sampling
u_phase to + bus
0
500 V / div
v_phase to + bus
0
500 V / div
w_phase to + bus
500 V / div
0
u_phase current
0
0
40
80
120
160
200
5 Amp / div
300 - 400 kHz
Time (microseconds)
Fig. 42. Drive voltage and phase current, 8 kHz, 300 ft,
# 12 AWG, 50 nS risetime.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Low Pass Filter
I
II
III
C
Current Feedback
Device
R
+5V
R
+12 V
+12 V
R
Ribbon Cable
C
Rburden
R
Op Amp
Comparator
R
Ribbon Cable
-12 V
C
R
-12 V
Ground
Impedance
Power Board
Ribbon
Cable
Control Board
Fig. 43. Motor phase current detection circuitry.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
7.5 MHz
32 Apk
u_phase Current
20 Amp / Div
Fig. CI
0
0
0
0
400
800
1200
1600
Current Sensor
Output
16.8 Amp / Div
Filtered Current
Sensor Output
16.8 Amp / Div
Fig. CII
Fig. CIII
2000
Time (nanoseconds)
Fig. 44. Motor phase current signals at current sensor circuitry testpoints.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
160
140
Impedance (dB)
120
100
80
60
40
20
0
10
102
103
104
105
106
Frequency (Hz)
Fig. 45. System impedance as a function of cable length.
107
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
I
B
I
S
X
P
I
I
Push - Pull
C
S
RB
V
C
B
Fig. 46. Closed loop Hall effect current sensor.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
+15
R8 C1
R1
Bx
+IC
-IC
+
VH
-
R2
R3
R4
+15
R7
+15
Ip
Is
Bx
+15
+
-
C2
R5
R6
Magnetic
rb
-15
-15
-15
Control
-15
Magnetic
Fig. 47. Closed loop Hall effect current sensor schematic.
C3
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
20
15
Experimental
10
System ID
Gain ( dB )
5
0
-5
-10
-15
-20
nd
2
Order Model
-25
0.01
0.1
1
Frequency ( MHz )
10
6.3 MHz
Fig. 48. Current sensor transfer function – magnitude.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Emitter
Gate
CM
COX
Gate
Oxide
N+
Conduction
Parasitic
Thyristor
Source
Lateral Voltage Latch-up
Base
BJT
Emitter
Drain
MOSFET
CDS
Collector
CCE
COX
Gate
CGD
P
RB
N-
CBE
N+
P+
Collector
Fig. 49. High frequency IGBT model.
Only on PT devices
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
U
U
V
V
W
W
Fig. 50. IGBT failure demonstrating melted emitter regions.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
M1
M1
M1
M1
M1
M1
M1
M1
M1
M1
Fig. 51. Complex FEA motor model [50].
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Vt
C HF
L LF
R ZO
R LF
Fig. 52. Simple differential mode resonant tank motor model.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
1 hp Motor Impedance & Curvefit
Impedance (Ohms)
100000
10000
Motor A
Motor B
Curvefit
1000
100
10
10
100
1000
10000
100000
1000000
Frequency (Hz)
Fig. 53. Differential impedance for 1 hp motors.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
3/4 hp Motor Model Verification
1300
Simulation
Experimental
1100
Voltage
900
700
500
300
100
-100
75
80
85
90
95
100
105
110
115
120
Time (microsecond)
Fig. 54. Simulation and experimental results for a 3/4 hp motor
with 500 ft (150m) of #12 AWG cable.
EMI EMISSIONS of MODERN PWM AC DRIVES
Quasipeak-Detector
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Trace A:
No filter
120
A
dB (microV)
100
B
C
Class A
80
Trace C:
Standard
filter /
shielded
cable
60
Class B
Trace D:
Special filter
/ shielded
cable
40
D
20
10 kHz
100 kHz
1 MHz
Trace B:
Standard
filter
10 MHz
Frequency (Hz)
Fig. 55. Conducted EMI emissions vs. Frequency of ASD.
30 MHz
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
LISN
AC Main
Phase A
L2
L1
C3
C2
R5
R3
C1
Drive
Under
Test
R1
Instrument
R4
Fig. 56. Single phase schematic of LISN.
R2
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
X
2 Line
2 Load
L1
L1'
L2
L2'
L3
L3'
L CM
Y 2Line
Y1Line
LOAD
LINE
X
L Phase
Y 2Load
Y1Load
PE
PE
Fig. 57. Standard three phase EMI filter schematic.
EMI EMISSIONS of MODERN PWM AC DRIVES
Gary L. Skibinski, Russel J. Kerkman, and Dave Schlegel
IEEE Industry Applications Magazine, November/December 1999, pp. 47-81.
Field Intensity [dBmicroV/m]
100
80
60
40
20
30
100
300
Frequency [MHz]
Fig. 58. Typical radiated emissions with filter.
1000