Electromagnetic Compatibility (EMC)

Transcription

1 Elecromagneic Compaibiliy (EMC) General The aim of elecromagneic compaibiliy consideraions is o avoid or minimize he influence of elecromagneic phenomena on a device, equipmen or sysem and on living or iner maer. To achieve his, mehods of measuremen and es, as well as limis and levels of elecromagneic emission and of elecromagneic immuniy are defined in a large number of EMC publicaions. Noe: The European EMC Direcive does no cover he ineracion beween echnical apparaus and he biological environmen. Types of EMC Publicaions EMC publicaions and sandards, developed by he IEC and oher sandardizaion bodies, can be divided ino four general caegories: Generic EMC Sandards, Basic EMC Publicaions, Produc family EMC Sandards and Produc EMC Sandards. These erms are defined in he corresponding chapers below. Produc and Produc Family EMC Sandards ake precedence over Generic EMC Sandards and Produc EMC Sandards ake precedence over Produc Family EMC Sandards. The disincion beween hese four ypes of EMC publicaions is no ye consequenly applied wihin he IEC, CISPR and Cenelec (EN). Generic EMC Sandards Generic EMC Sandards specify requiremens for producs and sysems operaing in residenial or indusrial environmens. They apply o producs for which no dedicaed Produc Family EMC Sandards or Produc EMC Sandards exis. Generic EMC Sandards can be considered o be general Produc Sandards in ha hey specify a limied number of essenial emission and immuniy ess, maximum emission levels as well as minimum immuniy es levels wih assigned performance crieria bu refer o he Basic EMC Sandards for deailed measuremen and es mehods. Table 1: Generic EMC Emission Sandards (only pars relevan o power supplies) IEC /EN : IEC /EN : Elecromagneic compaibiliy Generic sandards Elecromagneic compaibiliy Generic sandards Emission sandard for residenial, commercial and Emission sandard for indusrial environmens ligh-indusrial environmens Por Referenced Frequency range and Referenced Frequency range and required limi basic sandard required limi basic sandard Case CISPR 22/ MHz, class B CISPR 11/ MHz, Group 1, class A (radiaed) EN EN AC mains MHz, class B MHz, Group 1, class A (conduced) IEC / khz EN IEC / khz EN Ediion 5/ /11

2 Table 2: Generic EMC Immuniy Sandards (only pars relevan o power supplies) Referenced Basic Por Requiremens of Generic Sandard Requiremens of Generic Sandard Performance sandard EN (IEC ): IEC /EN : crierion Elecromagneic compaibiliy Elecromagneic compaibiliy Generic sandards Immuniy Generic sandards Immuniy sandard for residenial, commercial sandard for indusrial environmens and ligh-indusrial environmens IEC/EN : Enclosure ±4 kv conac discharge ±4 kv conac discharge B Elecrosaic discharge (case) ±8 kv air discharge ±8 kv air discharge IEC/EN / Enclosure 3 V/m, 10 V/m, A ENV 50204: (case) MHz, AM 80%, 1 khz, MHz, AM 80%, 1 khz, Elecromagneic field 900 MHz, PM 200 Hz MHz, PM 200 Hz 1 IEC/EN : Signal and ±0.5 kv, 5 khz, capaciive clamp ±1 kv, 5 khz, capaciive clamp B Fas ransiens (burs) conrol (only if cables are longer han 3 m) (only if cables are longer han 3 m), ±2 kv, 5 khz, capaciive clamp (only for process conrol and according o EN) DC inpu and ±0.5 kv, 5 khz, direc injecion ±2 kv, 5 khz, direc injecion oupu (only if cables are longer han 10 m) AC inpu and ±1 kv, 5 khz oupu IEC/EN : DC inpu ±0.5 kv line o earh, ±0.5 kv line o earh, Surges (and oupu) ±0.5 kv line o line ±0.5 kv line o line AC inpu ±2 kv line o earh, ±4 kv line o earh, ±1 kv line o line ±2 kv line o line IEC/EN : Signal and 3 V, 10 V, A Common mode conrol lines MHz, AM 80%, 1 khz MHz, AM 80%, 1 khz conduced (only if cables are longer han 3 m) (according o IEC only if cables DC inpu disurbances are longer han 3 m) and oupu AC inpu 3 V, 10 V, and oupu MHz, AM 80%, 1 khz MHz, AM 80%, 1 khz IEC/EN : AC inpu 30%, 10 ms 30%, 0.5 periods B Volage dips 60%, 100 ms 60%, 5 and 50 periods C IEC/EN : >95%, 5000 ms >95%, 250 periods Volage inerrupions MHz is referenced in EN sandards only. Basic EMC Publicaions Basic EMC Publicaions specify he general and fundamenal condiions and rules as well as he measuremen and esing echniques for he verificaion of EMC and serve as reference documens for he produc commiees of he sandardizaion bodies. Basic EMC Publicaions relae o general informaion, o he disurbing phenomena and o measuremen or esing echniques. Basic EMC Publicaions are general sandards or echnical repors and are no dedicaed o specific produc families or producs. They should no include prescribed limis and relaed performances. These are covered by he Generic, Produc Family or Produc Sandards. Ediion 5/ /11

3 Basic Emission Sandards Elecromagneic emission is he phenomenon by which elecromagneic energy emanaes from a source. Radio Frequency Emission Radio frequency emission, also called radio frequency inerference (RFI) is an elecromagneic disurbance which is generaed by elecrical apparaus and can be received by oher equipmen. In power supplies, he RFI is generaed by he swiching devices. The seeper he volage seps and he higher he swiching frequency, he greaer he high frequency conen of generaed disurbances. These disurbances can couple o oher componens in he power supply, producing noise sources radiaing over a broad frequency specrum. u [dbµv] Fig. 1 Disurbance volage limis (quasi-peak) according o CISPR 11/EN and CISPR 22/EN P [dbpw] f [MHz] 0 f [MHz] Fig. 3 Disurbance power limis (quasi-peak) according o CISPR 14/EN A B Inernaional basic emission sandards are prepared by he CISPR (Comié inernaional spécial des perurbaions radioélecriques Inernaional special commiee on radio inerference) and adoped by naional or mulinaional auhoriies. I is usual o measure disurbances a low frequencies (150 khz up o approx. 30 MHz) as volages beween he supply lines and earh (conduced disurbances) and a higher frequencies (above approx. 30 MHz) as field srengh or power (radiaed disurbances). The graphs below provide an overview of he mos common inernaional sandards for boh conduced and radiaed emissions. u [dbµv/m] Fig. 2 Disurbance field srengh limis (quasi-peak) according o CISPR 11/EN and CISPR 22/EN 55022, normalized o a disance of 10 m A B 1000 f [MHz] CISPR 11/EN 55011: Indusrial, scienific and medical (ISM) radio-frequency equipmen Elecromagneic disurbance characerisics Limis and mehods of measuremen CISPR 14/EN (= VDE 0875, par 14): Limis and mehods of measuremen of radio disurbance characerisics of elecric moor-operaed and hermal appliances for household and similar purposes, elecric ools and similar elecric apparaus This sandard is no direcly applicable o power supplies, bu describes mehods of measuring radiaed elecromagneic power using an absorbing (MDS) clamp. The clamp allows he simple measuremen over a cable of a defined lengh. CISPR 22/EN (= VDE 0878, par 22; corresponds o FCC, par 15): Limis and mehods of measuremen of radio disurbance characerisics of informaion echnology (IT) equipmen MIL-STD-461C: Elecromagneic emission and suscepibiliy requiremens for he conrol of elecromagneic inerference Ediion 5/ /11

4 Harmonic Curren Emission Elecrical and elecronic equipmen injec harmonic currens ino heir AC supply sysem. In order o ensure elecromagneic compaibiliy, maximum harmonic disurbance levels have been defined in he corresponding sandards. cos j For undisored, sinusoidal waveforms cos j is he displacemen facor of he load curren compared o he mains volage (fig. cos j). Harmonic Disorion For nonlinear loads (for example recifier) he load curren will no be sinusoidal anymore (fig. Harmonic disorion). I I Fig. 6 Harmonic disorion Fig. 4 cos j j = w 0 For his special case j is also equal o he phase difference beween rue power and he apparen power. Apparen power: S = rms I rms True power: P = rms I rms cos j = S cos j Reacive power: Q = rms I rms sin j Apparen power is he vecor sum of he rue and reacive power (fig. AC-power componens). Q Reacive Power Apparen Power True Power Fig. 5 AC-power componens S P Since rue power only akes place a he fundamenal frequency (frequency of mains volage), he analysis of he curren ino fundamenal and harmonic currens has o be calculaed (Fourier analysis): I () = I 0 sin (ω 0 + j 0 ) + I 1 sin (ω 0 + j i ) I n sin (ω n + j n ) I 0 : ampliude of fundamenal I i : i = 1...n ampliude of i h harmonic ω 0 = 2 π f 0 f 0 = 50/60 Hz frequency of fundamenal ω i = i ω 0 i = 1...n frequency of i h harmonic j 0 phase shif of fundamenal j i i = 1...n phase shif of i h harmonic Based on his decomposiion he Disorion Facor can be calculaed: Conens of harmonics K = rms-value Σ Ii 2 i = 1 K = Σ Ii 2 i = 0 Power Facor For single phase sysems he power facor is defined as he raio of he rue power delivered o he load o he apparen power. Power facor is he generalized case of cos j, since he waveforms do no have o be sinusoidal. For he special case where he waveforms are sinusoidal, he power facor is equal o cos j. True power P PF = = Apparen power S In pracice he mains volage can be assumed o be sinusoidal. So he power facor only depends on he disorion of he load curren: The more he waveform is disored, he lower he power facor. A perfec power facor would be equal o 1, whereas he wors case power facor is 0. I 0 cos j 0 PF = I rms I 0 : Fundamenal of load curren cos j 0 : Displacemen facor of fundamenal of load curren I rms : rms-value of load curren Ediion 5/ /11

5 IEC/EN : Limis for harmonic curren emissions (equipmen inpu curren 16 A per phase) This sandard deals wih he limiaion of harmonic currens injeced ino he public supply sysems wih nominal volages of 220 V (line o neural) or more. I is applicable o equipmen having an inpu curren up o and including 16 A per phase. The sandard defines 4 classes of equipmen wih differen harmonic curren limis: Class Descripion Limis ni Harmonic order Maximum permissible harmonic curren A Balanced hree-phase equipmen A and all oher equipmen, excep hose included in one of he following classes B Porable ools Limis of class A, muliplied by 1.5 C Lighing equipmen 2 2 % of inpu curren a he 5 10 fundamenal frequency (odd only) l %; l = circui power facor D Equipmen having an inpu curren ma/w wih a "special wave shape" (as defined in he sandard) and an acive inpu power above W up o 600 W (odd only) Power-One power supplies which don' supply porable ools or lighning equipmen are deemed o be class A if hey provide an acive power facor correcion circui or have an acive inpu power above 600 W, oherwise hey are class D. The lower acive power limi for class D equipmen will be reduced from 75 W o 50 W. Basic Immuniy (Suscepibiliy) Sandards Elecromagneic immuniy is he abiliy of a device, equipmen or sysem o perform wihou degradaion in he presence of elecromagneic disurbances. Elecromagneic suscepibiliy is he inabiliy o perform wihou degradaion, i.e. suscepibiliy is he lack of immuniy. The aim of basic immuniy sandards is o provide es procedures and es levels o verify elecromagneic immuniy. Boh conduced and radiaed phenomena are considered. The resuls of ess are classified in erms of he loss of funcion or degradaion of performance of he equipmen under es as follows: Performance Crieria A Normal performance wihin limis specified by he manufacurer. Power-One specifies normal performance as he oupu volage of a power supply no deviaing by more han 3% from he value prior o he es. B Temporary loss of funcion or degradaion of performance which ceases afer he disurbance ceases. Power-One specifies degradaion of performance as a volage deviaion of more han 3% from he value before he es. C Temporary loss of funcion or degradaion of performance, he correcion of which requires operaor inervenion or sysem rese. In case of Power-One power supplies, operaor inervenion can mean urning he uni off and on by removal and re-applicaion of he inpu supply or by means of he inhibi inpu. D Loss of funcion or degradaion of performance which is no recoverable, due o damage of hardware or sofware or loss of daa. Ediion 5/ /11

6 IEC/EN : Elecrosaic discharge (ESD) immuniy es Saic elecriciy discharges may be presen in environmens wih low relaive humidiy, using low-conduciviy (arificial fibre) carpes, vinyl garmens, ec. This sandard specifies requiremens and ess for he immuniy of elecrical or elecronic equipmen which are subjec o elecrosaic discharge. The ess are based on a human body model wih a capaciance of 150 pf and a discharge resisance of 330 Ω. The discharge shall eiher be applied in direc conac or over a shor air disance o pars of he device under es which can be ouched by persons during normal use. Fig. 7 Elecrosaic discharge pulse Conac discharge Air discharge Tes level Tes volage kv Peak curren A Tes level Tes volage kv Peak curren A x special x special IEC/EN : Radiaed, radio-frequency, elecromagneic field immuniy es Mos elecronic equipmen is affeced by elecromagneic radiaion which is generaed by hand-held radio ransceivers, fixed-saion radio and elevision ransmiers and various indusrial elecromagneic sources. The radiaed immuniy es is applicable o all producs, where radio frequency fields are presen. The es is performed by applying an elecromagneic far field of defined srengh while varying he frequency in he range MHz. The able gives he field srengh of he unmodulaed signal. For esing, his signal is 80% ampliude modulaed wih a 1 khz sinewave. Tes level Tes field srengh V/m x special ENV 50204: Radiaed elecromagneic field from digial radio elephones Immuniy es The radiaed immuniy es is applicable o all producs, where radio frequency fields from digial radio elephones are presen. The es is performed by applying an elecromagneic far field of defined srengh wih a fixed frequency. Two differen spo frequencies are defined: 900 ±5 MHz and 1890 ±10 MHz. The able gives he field srengh of he unmodu-laed signal. For esing, his signal is pulse modulaed wih a duy cycle of 50% a a repeiion frequency of 200 Hz. This es is subjec o be implemened in IEC/EN Tes level Tes field srengh V/m x special Ediion 5/ /11

7 IEC/EN : Elecrical fas ransien/burs immuniy es The fas ransiens es is applicable o producs which are conneced o AC or DC power sysems or have cables in close proximiy o such sources. I is inended o demonsrae immuniy o ransien disurbances such as hose originaing from swiching ransiens (inerrupion of inducive loads, relay conac bounce, ec.). The waveform of a single ransien is characerized by a rise ime of 5 ns, a ime o half-value of 50 ns and a maximum energy of 4 mj a 2 kv ino a 50 Ω load. The impedance of he ransien source is 50 Ω. The repeiion frequency of he ransiens is a funcion of he es level. Burs duraion is 15 ms and burs period 300 ms. Coupling is performed via a coupling/decoupling nework wih coupling capaciors of 33 nf for power supply pors and via a capaciive coupling clamp wih a capaciance of pf for signal, daa and conrol pors. 15 ms 300 ms Fig. 8 Elecrical fas ransiens/burss Tes level On AC and DC power supply pors On signal, daa and conrol pors Open-circui peak volage kv Repeiion frequency khz Open-circui peak volage kv Repeiion frequency khz x special special special special IEC/EN : Surge immuniy es Surges are mainly generaed by swiching ransiens or by lighning srokes injecing high currens producing volages or inducing high volages/currens via elecromagneic fields. Swiching ransiens can be generaed by power sysem swiching, load changes, shor circuis or arcing fauls o he earhing sysem of he insallaion. The surge immuniy es is applicable o producs, which are conneced o mains supplies or oher neworks leaving he building. I is inended o demonsrae immuniy o surge volages caused by swiching and lighning effecs. I is no inended o es he capabiliy of he insulaion o wihsand high-volage sress. The sandard specifies wo differen open-circui surge waveforms: One wih a rise ime of 1.2 µs and a ime o halfvalue of 50 µs, and he oher wih a rise ime of 10 µs and a ime o half-value of 700 µs. The source impedance for he 1.2/50 µs surge, is 2 Ω for line o line coupling and 12 Ω for line o earh coupling. The 10/700 µs surge impedance is 42 Ω. Coupling for boh waveforms is performed via a coupling/decoupling nework wih coupling capaciors of 0.1, 0.5, 9 or 18 µf, or wih arresors, depending on he kind of lines o be esed. Tes level Open circui es volage kv x special Fig. 9 Surge Ediion 5/ /11

8 IEC/EN : Immuniy o conduced disurbances, induced by radio-frequency fields The source of conduced disurbances is basically an elecromagneic field, emamaing from RF ransmiers, ha may ac on he whole lengh of cables conneced o insalled equipmen. The in-going and ou-going leads behave as passive anenna neworks if hey are several wavelenghs long. The conduced immuniy es is applicable o producs operaing in environmens where radio frequency fields are presen and which are conneced o mains supplies or oher neworks (signal or conrol lines). This es is a supplemen o IEC/EN which defines es mehods for immuniy o radiaed elecromagneic energy. The es is performed by applying a volage of a defined value o he por o be esed while varying he frequency in he range 150 khz...80 MHz. The signal is 80% ampliude modulaed wih a 1 khz sinewave. The able gives he field srengh of he unmodulaed signal. The impedance of he es generaor is 50 Ω. The waveform is coupled o each of he n lines of he por o be esed (common mode) via a coupling/decoupling device wih an impedance of n 100 Ω per line or via an injecion clamp. Tes level Open circui es volage (rms) V db (µv) x special special IEC/EN : Power frequency magneic field immuniy es The power frequency magneic field is mainly generaed by power frequency currens in conducors. In general his es is limied o producs which are suscepible o magneic fields (e.g. hall effec devices, CRTs and special producs o be insalled in high magneic field environmens). I has no relevance o power supplies. The es is performed by applying a 50 or 60 Hz magneic field of a defined srengh o he equipmen o be esed. Coninuous Shor duraion (1...3 s) Tes level Magneic field Tes level Magneic field srengh A/m (rms) srengh A/m (rms) no defined no defined no defined x special x special H ET Fig. 11 Tesing wih power frequency magneic field Fig. 10 Tesing of immuniy o conduced disurbances wih injecion clamp Ediion 5/ /11

9 IEC/EN : Pulse magneic field immuniy es Pulse magneic fields are generaed by lighning srokes on buildings and meal srucures including aerial mass, earh conducors and earh neworks and by iniial faul ransiens in low volage, medium volage and high volage sysems. This es is mainly applicable o producs o be insalled in elecrical power plans (e.g. eleconrol cenres in close proximiy o swichgear). I is no relevan for disribuion nework equipmen. The es is performed by applying 6.4/16 µs magneic field pulses of defined srengh o he equipmen o be esed. IEC/EN : Damped oscillaory magneic field immuniy es The damped oscillaory magneic field is generaed by he swiching of high volage bus-bars by isolaors. This es is mainly applicable o producs o be insalled in high volage subsaions. The es is performed by applying damped oscillaory magneic field (sinusoid waves) of defined srengh o he equipmen o be esed. Waveform specificaion "Low frequency" "High frequency" Tes level Pulse magneic field srengh A/m (peak) 1 no defined 2 no defined Oscillaion frequency 0.1 MHz 1 MHz Decay rae 50% of he peak value afer 3 o 6 cycles Repeiion rae 40 Hz 400 Hz Tes duraion 2 s 2 s x special Tes level Damped oscillaory magneic field srengh A/m (peak) H no defined 2 no defined x special Fig. 12 Tesing wih pulse magneic field H H Fig. 13 Tesing wih damped oscillaory magneic field Ediion 5/ /11

10 IEC/EN : Volage dips, shor inerrupions and volage variaions immuniy ess Volage dips and shor inerrupions are caused by fauls in he nework or in insallaions or by a sudden large change of load. Volage variaions are caused by he coninuously varying loads conneced o he nework. These ess are applicable o equipmen conneced o AC mains wih raed inpu currens no exceeding 16 A per phase. Preferred es levels and duraion for volage dips and shor inerrupions Tes level in % of raed volage for he Corresponding volage change in % of Duraion in number of periods. Any equipmen under es raed volage for he equipmen under es duraion may apply o any es level , 1, 5, 10, 25, 50, x (special) The es for immuniy o volage variaions is opional. I specifies a defined ransiion beween he lower and upper volage of he nominal volage range and he changed volage. Timing of shor-erm supply volage variaions The es for immuniy o volage dips and shor inerrupions is performed by an abrup change of he supply volage of he equipmen under es a any phase angle on he mains volage a he lower and a he upper volage of he nominal volage range. For power supplies, immuniy o hese phenomenon can normally be derived from he specificaions of inpu volage range and hold-up ime. Tes level in % of raed volage Time for decreasing Time a reduced Time for increasing for he equipmen under es he volage in s volage in s he volage in s 40 2 ±20% 1 ±20% 2 ±20% 0 2 ±20% 1 ±20% 2 ±20% 40 x (special) x (special) x (special) 0 x (special) x (special) x (special) rms % nom (Periods) 40% nom Fig. 14 Volage dips 0% nom s Fig. 15 Volage variaions Ediion 5/ /11

11 IEC/EN : Oscillaory waves immuniy es This sandard specifies ess o simulae wo phenomena: The ring wave (non-repeiive) appears a he erminals of equipmen as a consequence of swiching in power and conrol lines, as well as a consequence of lighning. The ring wave es is applicable o equipmen conneced o AC mains in cerain counries (e.g. he mains nework in he SA). This es has exised for a long ime under he designaion ANSI/IEEE C The damped oscillaory wave (repeiive) appears a he erminals of equipmen as a consequence of swiching wih resriking of he arc. The damped oscillaory wave es is applicable o equipmen used in high volage subsaions (saic relays). This es, bu wih a frequency of 1 MHz only, has exised for a long ime under IEC 255-4, appendix E5: High frequency disurbance es, also known as ANSI/IEEE C.37.90a-1989, and has been ransferred o IEC : Elecrical disurbance ess for measuring relays and proecion equipmen 1 MHz burs disurbance ess. By inclusion in IEC he frequency range was exended. Coupling is performed via a coupling/decoupling nework wih coupling capaciors of 0.5, 3 or 10 µf, depending on he oupu impedance of he es generaor. Wave specificaion Ring wave Damped oscillaory wave Open circui peak volage 250 o 4000 V 250 o 2500 V Oscillaion frequency 100 khz 100 khz and 1 MHz Decay rae 60% of he preceding peak value 50% of he peak value beween he hird and sixh periods Repeiion rae 1 o 60 per minue 40 Hz for 100 khz and 400 Hz for 1 MHz Oupu impedance 12 Ω, 30 Ω and 200 Ω 200 Ω Coupling mode Common mode and differenial mode Common mode and differenial mode Tes duraion per por and coupling mode 5 posiive and 5 negaive ransiens 2 s Tes Ring wave volage kv (peak) Damped oscillaory wave volage kv (peak) level Common mode Differenial mode Common mode Differenial mode x special special special special Fig. 16 Damped oscillaory wave Produc Family EMC Sandards A produc family is a group of similar producs for which he same sandards can be applied. Produc Family EMC Sandards define specific elecromagneic (EM) requiremens and es procedures dedicaed o paricular produc families. They also give precise performance crieria aking ino accoun he purpose of he equipmen where possible. They apply he Basic Sandards and coordinae wih he Generic Sandards o he exen pracicable. Applicable Produc Family EMC Sandards ake precedence over Generic Sandards. Produc EMC Sandards Produc EMC Sandards relae o a paricular ype of produc for which produc specific requiremens should be considered. Applicable Produc EMC Sandards ake precedence over Generic Sandards and Produc Family EMC Sandards. Ediion 5/ /11