EET 422 EMC & COMPLIANCE ENGINEERING Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING AC SOURCE FILTER EUT FREQUENCY RESPONSE LOW Frequency High Frequency negligible attenuation at line frequency large attenuation Low Pass High Frequency large attenuation Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

L presents HIGH impedance EMC & COMPLIANCE ENGINEERING LISN COMPARISON OPERATION 150 kHz - 30 MHz from EUT L presents HIGH impedance EUT 1 k W 0.25 mF 2mF L or N G analyser AC SOURCE or 50 W load 50 mH Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING LISN OPERATION: 150 kHz - 30 MHz from EUT LOW impedance path EUT noise to analyser via high pass filter rfi 0. 47mF AC SOURCE EUT 1 kW 0.47 mF Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING INSERTION LOSS (I L) Zload Zsource Vnoise Vn1 Zload Zsource Vnoise FILTER Vn2 Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING SERIES FILTERING Zload Zsource Vnoise FILTER Vn2 Zseries Zseries >> 50 W IMPEDANCE MISMATCH Zsource Zload 50 W Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

PARALLEL (SHUNT) FILTERING Zsource Zload Vnoise Zparallel Vn2 Zparallel << 50 W IMPEDANCE MISMATCH Zsource Zload 50 W Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

INSERTION LOSS MEASUREMENT 50 W Vnoise FILTER Vn2 1:1 differential mode Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

INSERTION LOSS MEASUREMENT 50 W Vnoise FILTER Vn2 common mode Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

INSERTION LOSS MEASUREMENT 50 W Vnoise FILTER Vn2 unsymmetrical mode Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

POWER LINE FILTER TOPOLOGIES Zload or Znoise LOW HIGH HIGH Zac, line LOW Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

POWER LINE FILTER TOPOLOGIES Zload or Znoise LOW HIGH HIGH Zac, line LOW Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING SELF DESIGN or BUY ????? SELF DESIGN ADVANTAGES reduced cost (don't pay filter manufacturers' overheads and profits) better performance for a specific application (design based on known impedances) easier to add to existing PCB Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING SELF DESIGN or BUY ????? BUY ADVANTAGES Power Line Filter design is not an easy exercise! units are enclosed minimising radiated interference and susceptibility safety regulations are inherently covered Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING INSERTION LOSS Irated CX CY L Ileakage 1 A 0.22 mF 2500 pF 18 mH < 0.5 mA 2 A 0.33 mF 10 mH 4A 0.47 mF 4.7 mH 6A 33 nF 2.2 mH < 3.5 mA Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING CM inductor DM inductor L L1 L2 L* CY2 CM capacitor cross coupled DM capacitor CX2 CX2 DM cap CY2 CM capacitor N L1 L2 N* DM inductor CM inductor G LG G* CM inductor Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

TYPICAL POWER LINE FILTER CY1 CX1 M CX2 AC source CY2 EUT N L N * G G* X capacitors connected line – neutral for differential mode (symmetrical) interference Y capacitors connected line-ground neutral-ground common mode (asymmetrical) interference Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

differential mode current COMMON MODE INDUCTOR differential mode current CM common mode current DM Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING COMMON MODE L+M icm M Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING DIFFERENTIAL MODE L-M idm M Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING SECTIONAL WINDING HIGHER LEAKAGE INDUCTANCE BIFILAR WINDING Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING SINGLE LAYER WINDING LOWEST PARASITIC CAPACITANCE INTER-TURN CAPACITANCE HIGHEST RESONANCE FREQUENCIES Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING MULTI-LAYER WINDING HIGHEST PARASITIC CAPACITANCE INTER-TURN + INTER-LAYER CAPACITANCE LOWEST RESONANCE FREQUENCIES Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING RANDOM WINDING PARASITIC CAPACITANCE > SINGLE LAYER HIGHER RESONANCE FREQUENCIES BETTER INTERFERENCE SUPPRESSION Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING COMMON MODE L L L* CY2 CX2 M CX2 CY2 EUT AC source N L N * G G* L L L* CY2 CX2 M CX2 CY2 EUT AC source N L N * G G* Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING COMMON MODE L L L* CY2 CX2 M CX2 CY2 EUT AC source N L N * G G* L L L* CY2 CX2 M CX2 CY2 EUT AC source N L N * G G* Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING COMMON MODE L L L* CY2 CX2 M CX2 CY2 EUT AC source N L N * G G* CX2 L or N G L* G* Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING DIFFERENTIAL MODE L L L* CY1 CX1 M CX2 AC source CY2 EUT N L N * G G* Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING DIFFERENTIAL MODE L L L* CY2 CX2 M CX2 AC source CY2 EUT N L N * G G* Prof R T Kennedy EMC & COMPLIANCE ENGINEERING

EMC & COMPLIANCE ENGINEERING DIFFERENTIAL MODE L L L* CY2 CX2 M CX2 AC source CY2 EUT N L N * G G* CX2 L N L* N* Lleakage Prof R T Kennedy EMC & COMPLIANCE ENGINEERING