L23: Electromagnetic compatibility L23: 21-MAY-2019 Lund University / LTH / IEA / AR / EIEN25 / 2019-05-21 2 Outlook • Electromagnetic energy – Emission and propagation – Interference and disturbance • Electromagnetic compatibility – Power electronics – Electric drives • Remedies and Regulations – Conducted emission limits
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L23: Electromagnetic compatibilityEMC).pdfElectromagnetic compatibility • Electromagnetic compatibility (EMC) is the branch of electrical engineering concerned with the unintentional
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L23: Electromagnetic compatibility
L23: 21-MAY-2019
Lund University / LTH / IEA / AR / EIEN25 / 2019-05-21 2
Outlook
• Electromagnetic energy– Emission and propagation
– Interference and disturbance
• Electromagnetic compatibility – Power electronics
– Electric drives
• Remedies and Regulations– Conducted emission limits
Lund University / LTH / IEA / AR / EIEN25 / 2019-05-21 3
Electromagnetic compatibility
• Electromagnetic compatibility (EMC) is the branch of electrical engineering concerned with the unintentional generation, propagation and reception of electromagnetic energy which may cause unwanted effects such as electromagnetic interference (EMI)
– Coupling – identify propagation mechanisms between transmitter and receiver
– Susceptibility – (receiver as victim) lack of immunity to electromagnetic disturbances
Lund University / LTH / IEA / AR / EIEN25 / 2019-05-21 4
EMC is an equipment
characteristic or property
EMI is a phenomenon
Electromagnetic interference
• Electromagnetic interference (EMI) is en external disturbance that affects an electrical circuit by the coupling mechanisms
1. Radiative
2. Conductive
3. Electric Capacitive
4. Magnetic Inductive
transmitterreceiver
1
2
3
4
Lund University / LTH / IEA / AR / EIEN25 / 2019-05-21 5
Conducted emission
• Electromagnetic energy propagation via a direct electric contact, capacitive and inductive paths in a power distribution network (cables, transmission line, frames, …)
ZdiffUdiffVcom
Vcom ZcomZcom
Idiff
Idiff
Icom
Icom
Coupled less than
a wavelength apart
compared to wave
propagation
Lund University / LTH / IEA / AR / EIEN25 / 2019-05-21 6
Types of interference
• Continuous wave from DC to daylight– Audio frequency from low to 20 kHz
– Radio frequency 20kHz to 30MHz for conducted EMI
– Broadband noise
• Pulse or transient interference– Switched & pulsed supplies (repetitive)
– Power line surges & pulses
– Electrostatic discharge, lightning
– Geomagnetically induced currents
Lund University / LTH / IEA / AR / EIEN25 / 2019-05-21 7
– HF bearing currents: non circulating discharge and circulating
Lund University / LTH / IEA / AR / EIEN25 / 2019-05-21 13
Insulation system response
• Electrical machine as a load– RC for electric insulation
system (EIS) & RL for windings
– Ringing at voltage switching– Voltage distribution
determined by distributed capacitances – local inception E field and discharges
• Leakage current measurement
– Ground, differential across winding, zero sequence, ..
–10
-110
010
110
210
310
410
5-0.05
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
indu
ctan
ce,
L [H
]
10-1
100
101
102
103
104
105
100
101
102
103
104
105
resi
stan
ce,
R [
Ohm
]
frequency, f [Hz]
HMOU12
HMRU12
HKRU12
HKRU-VW
FEO 1mA
FEO 1A
FER 1mA
FER 1A
A B C D
+
– +
+’
–
–’
RMF & LMF CMF1 CMF2
ZCM(f)
ZDM(f)f
Z(f)
fR1 fR2 fR3 fR4 fR5
Lund University / LTH / IEA / AR / EIEN25 / 2019-05-21 14
d=2μm E=4.9kV/mm
d=12μm E=3.8kV/mm
d=7μmE=4.3kV/mm
d=4μm E=4.6kV/mm
B:32
A:17 A:32
B:17
43
Electric field intensity E, [kV/mm]
1
Insulation fatigue and failure
• Variable speed drive insulation system safety requirements – electric field distribution over the imperfect insulation system at possible thermal load conditions