Electromagnetic Compatibility Test for CMS Experiment. Authors C. Rivetta– Fermilab F. Arteche, F. Szoncso, - CERN

EMC Test for CMS experiment – 2 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September 2002 OUTLINE  1.Introduction  2. Common Impedance –LISN. –CDNs.  3.Emission Test –Harmonics. –RF conducted emission test.  4.Immunity Test –RF conducted noise immunity test. –Slow transients - Surge immunity test. –Fast transients - Burst immunity test. –Voltage dips and short voltage interruptions immunity test  5.Conclusions

EMC Test for CMS experiment – 3 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September INTRODUCTION  EMC phenomena are present in CMS –Noise generated by DC-DC converters  Common mode & Differential mode –Transients  Over-voltages –Induced via magnetic fields  Load changes  Switching –Voltage variations –Harmonics  It is important to measure & control them  Goal of these tests –Get the levels of “emission” and “immunity”  Identify possible EMC problems.

EMC Test for CMS experiment – 4 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September INTRODUCTION  Generic, Basic and military Standards & Aerospace rules. –There are a lot of standards  For practical reasons “ we only consider some of them “  Emissions test –RF conducted noise (based EN // MIL-STD-461// IEEE Std 1515)  CM & DM ( high and low frequency) –Harmonics ( based EN )  Special for 400 Hz power supply distribution system (very low)  Immunity test –Immunity to RF conducted noise (based EN ) –Electrical fast transient burst immunity test (based EN ). –Surge immunity test- Over-voltage (based EN ). –Voltage dips, short interruptions and voltage variations immunity test (based EN ).

EMC Test for CMS experiment – 5 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September COMMON IMPEDANCE LISN & CDNs  Two kinds of common impedance –Line Impedance Stabilisation Network (LISN) –Coupling De-coupling Network (CDNs) LISN  Present stable a well defined impedance  Standardise the measurements of test  Values estimated from power cables –HF - Characteristic Impedance (CM & DM )  Different from commercial LISN –Couple EUT - Measuring equipment. –Standardise the measurement to 50 Ohms CDNs –Protect auxiliary equipment –Values specified by the standards

EMC Test for CMS experiment – 6 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September COMMON IMPEDANCE LISN & CDNs Zdm =42 Ohms Zcm =13 Ohms  LISN HCAL Sub-System

EMC Test for CMS experiment – 7 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September EMISION TEST - Harmonics  Effects by pulling the current from power main for only a part of the cycle –Typically rectifiers ( we have 400 Hz power distribution)  Implications –Quality power distribution. –Power supply distribution over-design  Power transformers over-stress  Equipment overheat  Oriented to the 400 Hz PS distribution –AC-Dc converters –Transformers  Limits of harmonics based on international standards & studies. Power supply unit EUT Measurement equipment Zm LISN

EMC Test for CMS experiment – 8 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September EMISION TEST - RF conducted noise  Goal of test control the conducted emission level –Power Supplies & FEE –Frequency Range 9 kHz - 50 MHz  Conducted emissions – Propagation –Common Mode  Group of conductors and ground or other conductors. –Differential Mode  Conductor pairs (Negative-Positive or Phase-Neutral) –Abundant energy exchange between modes CM - DM conversion  System topology as close as possible to final one –Common impedance LISN  Equipment used  Current probes & Spectrum Analyser

EMC Test for CMS experiment – 9 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September EMISION TEST - RF conducted noise  Power Supply  FEE

EMC Test for CMS experiment – 10 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September EMISION TEST - RF conducted noise  Test Results Power Supplies –Input  Results refereed to 50 Ohm to compare them with the standards  We used EN B –Output  There is no standards so we need to generate them –From this values and the values from Immunity test  FEE –Input  Results refereed to 50 Ohm to compare them with the standards EN-55022

EMC Test for CMS experiment – 11 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST- RF conducted noise  Electromagnetic immunity is the ability,of a device equipment or system to perform without degradation in presence of electromagnetic disturbances  Goal of these tests –Immunity level of FEE and PS to conducted disturbances.  Injection of conducted noise to the FEE –Common impedance - LISN  The idea is inject signal and measure pedestal –Identify frequency areas where the pedestal is not valid –This test will define sensible areas of the FEE  Injection via current probes –It is recommended to Voltage & Current

EMC Test for CMS experiment – 12 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST - RF conducted noise  Three different set-ups –DM configuration  9 kHz / 14 kHz up to 100 MHz –CM at HF configuration  10 kHz up to 100 MHz –CM at LF configuration  (A few hertz up to 10 kHz)  The value of the amplitude of the signal depends on the sensitivity of the FEE.  This test is complementary of Conducted emission TEST Current DM measurement LISN Voltage DM measurement LISN Current CM measurement Injection of CM current Voltage DM measurement Voltage CM measurement

EMC Test for CMS experiment – 13 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST - RF conducted noise - Example µA  CM ICM I1 12 V

EMC Test for CMS experiment – 14 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST - RF conducted noise - Example  I1  CM 0.41mA IDMICM

EMC Test for CMS experiment – 15 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST - Surge immunity Test  The goal of test - Determinate the equipment susceptibility to damage by over-voltage generated by –Load changes /Short Circuits /Faults to earth  Common Impedance LISN & CDNs to protect auxiliary equipment  Coupling network will be used to inject the transient  9 µf & 10 Ohms or 18 µf - Depends on the Test  Pulse Characteristic –Voltage O.Circuit 1.2/50 µs. –Current S.Circuit 8/20 µs  A Zenner / Trans-absorb protect EUT from this emission

EMC Test for CMS experiment – 16 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST - Surge immunity Test  The amplitude of the signal –Standards  Electrical environment –5 Different Class  0.5, 1kV, 2 kV, 4 kV –For CMS values  Counting Room - Detector –Class 3 or 4 - (1kV-4 kV)  Balconies - Detector –Not clear  Test simulation for 3 different amplitudes –1 kV, 500 V, 100 V –Line - Line Trans-absorb Filter CDNs FEE

EMC Test for CMS experiment – 17 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST - Surge immunity Test  It is difficult to find a device to dissipate this power and clamp the voltage within maximum values valid for the FEE.  Level selection –High level  Increase cost or could not have any technical solution –Low level  Increase risk of failure by over-voltage  Final selection based on: –Preliminary studies –Reliability. –Cost –Risk 83 V 45 V 15 V 17 kW 4.5 kW 0.3 kW

EMC Test for CMS experiment – 18 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST - Burst immunity Test  The goal of test –Fix the susceptibility to damage by over-voltage generated by switching transients.  Common Impedance LISN & CDNs to protect auxiliary equipment.  Coupling network will be used to inject the fast transient - 33 nf.  Pulse Characteristic –Double exponential 5ns/50 ns. –Burst duration ~ 15 ms / 300 ms (1 minute).  Spectra content of signal HF. –Layout very important. –Coupling of burst depends strongly from parasitic capacitance.

EMC Test for CMS experiment – 19 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST - Burst immunity Test  Class is not defined yet. –Not very important  A simple Capacitor protects to FEE from this emission  Test simulation –3 different RF capacitors  5nf, 500nf, 1000nf –Line - Ground –Amplitude  Class KV. 14 V 9 V 8.5 V

EMC Test for CMS experiment – 20 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September IMMUNITY TEST - Voltage dips immunity Test  Noise source –Faults in the networks –Sudden large change of load  Test on FEE –Short interruptions & Voltage variations  Test on Power Supplies –Short interruptions & Voltage variations –Voltage dips  Common impedance LISN  Test level –Standards  Voltage dips –( %) V nominal - Voltage variations – (0 -40 % ) V nominal. - –For us under study

EMC Test for CMS experiment – 21 / 21 8 th Workshop on Electronics for LHC Experiments COLMAR - France, 9-13 September CONCLUSIONS  EMC phenomena is present in CMS –It is important to measure and control them  EMC tests are based on standards and aerospace industry.  EMC test will be focus on conducted noise –Immunity and emissions test –Only a few test will be considered due to practical reasons  Test levels has not fixed yet –It has a big influence in the elections of filters & protections –It will depend on  Technical studies  Reliability  Cost  Risk