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Published on 18 Dec 2020 by Rebecca Charles

Exxelia onboard Solar Orbiter

Solar Orbiter, a European Space Agency mission, was launched on an Atlas V rocket 411 (AV-087) from Space Launch Complex 41 at Cape Canaveral Air Force Station at 11:03 p.m. EST on Sunday, Feb. 9 2020. The satellite reached its first working orbit around the Sun, called “halo orbit” and is ready to begin its first scientific observation campaign. The campaign will last six months, during which time the 55 payloads will be turned on one by one and tested before being used to perform scientific observations. Solar Orbiter is a highly complex scientific laboratory. Deploying such a mission is a one-of-a-kind achievement! The mission will take years and is one of the most highly anticipated scientific experiments of our time. And you know what they say: your best work comes when you're up against the toughest challenges. Unfortunately, these challenges aren't only in labs, but also in space. To study the Sun and its activity like never before, scientists are sending a probe into orbit around it. Solar Orbiter will be facing temperatures of up to 500°C, which is usually not survivable for complex equipment. But do you know what's even more challenging than getting data from a 500°C hot solar environment? Getting that data with expensive equipment that doesn't work, because you don't have enough reliable components at your disposal! That's why we, at Exxelia, were so happy when we heard that thousands of our capacitors and magnetics were chosen by the European Space Agency to achieve this mission; we're talking about components that will keep working in those kinds of harsh environments! They will help scientists better understand energy flow and particle acceleration within our own solar system and beyond. Shockingly, the Sun is mostly a mystery. We have some understanding of its composition, but it's unclear how the phenomena we see happen. Solar Orbiter is going to help us get a better idea of what makes the Sun tick by taking some of the most detailed images and observations of our star ever taken. Among the instruments on Solar Orbiter are: a Wide-Angle Imager and a Coronal Imager. Each will provide high-resolution images—an order of magnitude higher than those captured by NASA's Solar Dynamics Observatory—and spectacular views of the Sun's polar regions. The Wide-Angle Imager will capture images in five wavelengths, while the Coronal Imager will use seven wavelengths to observe phenomena that affect the upper layers of the solar atmosphere, such as magnetic fields and plasma flows. Our capacitors and magnetics are critical for stabilizing and powering these instruments on their mission to explore our home star! They need to be able to perform in a very hostile environment with temperatures ranging from -150°C (-238°F) to 500°C (932°F). Temperatures will reach their highest during the closest flybys of the Sun—which will take place as close as 15 million kilometers (about 93 million miles) from its surface. Our space capacitors and magnetics are capable of withstanding such high temperatures. They'll even keep functioning in cryogenic conditions, as low as -150°C (-238°F). These components are also very durable, which makes them perfectly suited for this mission.     Choosing the right capacitors for such a mission was not easy. The requirements and technical constraints were very strict. We had also to support and select the materials that could handle the launch vibrations and the shock of the rocket launching phase, we also had to achieve a very long life and high reliability in order to succeed in the mission. This project proves that our EXXELIA components are incredibly reliable and have nothing to envy to other electronic components on the market. Several other tests have been conducted by ESA in this project such as solar radiation, thermal shock... Exxelia ESA QLP Products Onboard Solar Orbiter : 14,400 CNC chips ceramic capacitors 14,400 CEC chips ceramic capacitors 520 of our CNC stacks ceramic capacitors 470 SESI QPL Inductors 380 MSCI RF Inductors  287 ESA qualified CTC21/E Tantalum Capacitors 50 ESA Film Capacitors PM94

What you should know about electrolytic aluminum capacitors ?

1. Basic construction Structure of an electrolytic aluminum capacitor is shown hereunder: Anode: aluminum foil Dielectric: aluminum oxide Papers spacers impregnated with electrolyte Ionic conduction assumed by electrolyte Cathode: aluminum foil   The positive plate is an etched aluminum foil covered with alumina which is the dielectric of the capacitor. The negative plate is constituted by a second aluminum foil which serves as a current supply, and by electrolyte-impregnated papers layers. The metal used for anode is a ≥ 99,98 % grade aluminum. The dielectric has a thickness of 13 Å / V. The aluminum used for the cathode is a ≥ 98 % grade aluminum covered with a dielectric layer with a thickness of about 40 Å.   > See our capacitors in catalog 2. Diagram of the equivalent circuit CA = Capacitance of the anode CK = Capacitance of the cathode Rp = Parallel resistance due to the aluminum oxide f Ilms. RL = Series resistance of connections, plates and impregnated spacer. Ls = Inductance of winding and connections.   A standard simplified diagram is :   Cs is the series capacitance of both anode and cathode capacitances. Electrolytic aluminum capacitors are naturally polarized because of the insulating f Ilm on the anode. Given the very thin aluminum oxide layer, a reversed voltage should not exceed 1.5 V when there is energy supply. Short duration reverse voltages can be absorbed by special construction, second anode replacing the former cathode. 3. Electrical characteristics ✪ Rated capacitance Cr The rated capacitance is defined at 100 Hz and at ambient temperature.   ✪ Rated voltage Ur Ur is the maximum DC voltage which may be applied in continuous operation. When applying a superimposed alternating voltage, the peak value of the resulting waveform should not exceed the rated voltage.   ✪ Peak voltage Up Up is the maximum repetitive voltage which can be applied within short periods. Defined in CECC 30 300 and IEC 60 384-4:  1000 cycles of 30 s charge followed by a no load period of 5 min. 30 s with upper category temperature. Up ≤ 1,15 UR (UR ≤ 315 V) Up ≤ 1,10 UR (UR > 315 V)   ✪ Dissipation factor Tan The dissipation or loss factor is defined by its tangent Tand   ✪ Equivalent series resistance ESR The relation between ESR and dissipation factor Tand.   ✪ Impedance Z - Inductance L The impedance is given by:  Z =g R2 + (Lv –1 )2                         Cv L inductance. Generally L = 5 to 20 nH   Z and ESR as function of frequency typically follows the chart:    ✪ Permissible ripple current (I r.m.s.) The current is defined at the maximum climatic category and at 100 Hz. It is the root mean square value r.m.s. The value I0 is the rated value for calculations of expected life up to3 I0.   ✪ Leakage current Il Il is measured at 20°C after a 5 min. polarization under rated voltage. For CR in μF and UR in V:   Il ≤ 0,01 CR UR or 1 μA* when CR UR ≤ 1000 μC  Il ≤ 0,006 CR UR + 4 μA when CR UR > 1000 μC For UR > 350 VDC it can be specified:  with K = 4, 6 or 8 or  Il ≤ 0,3 (CR UR)0,7 + 4 μA (CECC 30 300) * Whichever is the greater   ✪ Characteristics Versus temperature (typical values).   - Capacitance drift Versus temperature - ESR and Z drifts at 100 Hz Versus temperature - Leakage current drift Versus temperature > See our capacitors in catalog 4. Specification to apply Electrolytic aluminum capacitors are defined in:  NF and UTE French national standard CECC European specifications IEC international specifications Quality insurance procedures are described in these specifications. 5. Endurance tests / life time ✪ Standard endurance test at max category temperature:  Standard endurance tests do not exceed 2000 hours at 125°C. However, present EXXELIA technologies concerning liquid electrolytes have led to endurance tests up to 5000 hours at 125°C (PRORELSIC 125 - FELSIC 125 RS) and even 20000 hours at 125°C (PRORELSIC 145 - ALSIC 145).   ✪ Performance requirements on standard endurance tests Permissible capacitance drift ∆C/C (%) Permissible increase factors on Tand, ESR, Z and Il initial values   (1) Tand or ESR: for initial value, take standard value. (2) Z: for initial value, take specified value (see data sheet ). Specific requirements can be taken into consideration with regards to initial values of dissipation factor or equivalent series resistance and impedance.   ✪ Failure criteria for electrolytic capacitors Failure criteria are defined in CECC 30 301 Non measurable defaults leading to complete failure. Measurable defaults leading to adjustment losses of the load circuit (failure due to variations).   - Non measurable defaults They might be summed up as:  Open circuit Short circuit Operation of pressure relief device Severely damaged insulation Unusable terminations   - Measurable defaults Variations exceeding the values given below characterize a default. Capacitance drift ∆C/C (%): 3 times the limit for standard endurance testing or 50 % (whichever is the smallest). Tand or ESR: 3 times standard max initial values. Z: 3 times standard max initial values. Il: initial limit (under load conditions). Specific requirements can be taken into consideration with regards to lower drifts.   Influence of main parameter on operational life. - Temperature The capacitors operational life is highly dependent upon its internal temperature Ui and therefore upon the ambient temperature and the ripple current. Knowing ESR and dissipated power values one can figure out, the internal temperature rise and then determine the capacitors expected life. With present high boiling point electrolytes Ui max = 125 to 185°C depending on styles. - Ripple current The ripple current flowing through the capacitor increase the internal temperature through power dissipation. Standards define the permissible current at 100 Hz and generally consider a temperature rise of 5 to 10°C of max category temperature. Current waveforms and frequencies make it difficult to clearly determine the capacitors internal temperature rise, which defines the operationally life. Experiments confirm following relationship:  Ui = Ua + (Uc - Ua) K Where:  Ui = Internal hot spot temperature Ua = Ambient temperature Uc = Case temperature K = Parameter depending upon case diameter and cooling Ø ≥ 51 k = 2 ± 0,5 Ø < 51 k = 1,5 ± 0,5    (air cooling - 0,2 m/s)   r.m.s. value according to current waveform.   - Dissipated power versus case dimension For calculations of ripple currents, considering an internal temperature rise of 10°C   P = ESR.I ² P = Dissipated power (mW) (Ui - Ua = 10°C) ESR: Equivalent series resistance (100 Hz 20°C) I: Ripple current (r.m.s. value at 100 Hz) For different frequencies from 100 Hz, I must be multiplied by the factor F, according to above chart.   - Thermal resistance Rth and air cooling Rth is static thermal resistance (without cooling) between capacitor central hot spot and ambient temperature measured at a distance of one capacitor diameter   Forced or not cooling air can lead to a significant decrease of these values. Consequently, r.m.s. ripple current can be increased as a function of air cooling speed:  This parameter shall be applied to one capacitor alone. For capacitors in bank, ambient temperature must be strictly equal around all capacitors. - Quality guaranty We guarantee products manufactured during 2 years from the data of shipment against defaults of material and assembly. This guaranty can be involved by the buyer only if our products are used within normal conditions, always according to the state of the art and taking in account storage conditions. The equipment design should take into consideration possible failures of our capacitors and related effects in order to avoid them. Guaranty is not applicable for damages occurred by surge voltage, irregular use, polarity inversion or maintenance default. Guaranty is exclusively limited to the replacement of individual defective capacitors within the terms of delivery. This rule applied to all cases and particularly to any further consequence of failures. - Reliability Failure rate:  FR = Number of components tested x test duration / Number of failures Failure rate is measured in FIT (failure in time = 10–9 / hour). The failure rate is set up during the life time of the capacitor (phase II) I. Early failure phase (generally excluded during ageing process). II. Operational life time of the capacitors III. End of life   Mean time between failures MTBF = 1/FR mesured in years Multiplying factor of FR with voltage and temperature   > See our capacitors in catalog 6. Information on application ✪ Cleaning solvents Use aliphatic alcohols, such as denatured ethyl alcohol, isopropanol, or butylacetate, or else alkaline d Iluted solutions. Avoid incompatible solvents (halogenous for example).   ✪ Shelf life There is no electrical characteristics variation for long periods of storage except leakage current which can increase. It is caused by chemical reactions between the dielectric alumina and the electrolyte. These reactions are reversible when switched on. Capacitors can generally be stored at temperature between –5° and +50°C without reforming for the following periods of time:  For UR ≤ 100 V, storage time:     5 years (up to 10 years under specific conditions) For 100 V < UR ≤ 360 V storage time:     3 years For 360 V < UR < 500 V storage time:     1 year For UR ≤ 500 V, storage time:     6 months Generally when these periods are overstepped, one hour at rated voltage causes the decrease of leakage current under the specified limits. An other way to avoid this leakage current increase problem is to always limit ava Ilable power through capacitor during first seconds or minutes after storage or transport, according to the following chart:    ✪ Low pressure resistance EXXELIA capacitors can be used with ambient low pressure decreasing up to 10 mbar (altitude 28000 m – 92000 feet).   ✪ Mounting screw terminals capacitors (FELSIC) Capacitors may be used vertically (terminals on top) or horizontally. When used horizontally, the following position in relation to the safety vent, is recommended:  Mounting capacitors in series may be used for operating voltage exceeding Ur. See FELSIC in bank.   ✪ Mounting solder type capacitors They may be used in any position. During mounting, avoid applying excessive force to capacitor pins or wires. There is a risk of damaging internal connections. After soldering and for the same reasons, do not try to move the capacitor&#39;s body. ✪ Electrolytes: safety rules Electrolytes used in EXXELIA capacitors are manufactured by EXXELIA. Main solvents are generally g butyrolactone and ethylene glycol, very stable high boiling point solvents. Ionic conductive salts in electrolyte induce a very weak acidity (pH 5 to 7).   ✪ Environment In aluminium capacitors with liquid electrolyte there is no component showing a pollution risk, in small amounts, of air or water. EXXELIA is always involved in this security field particularly in using chemicals for electrolyte, without well-known risks. Dimethylformamide (DMF) dangerous solvent forbidden in several uses is completely excluded by EXXELIA,since 1990. There is no halogen compound such as chlorofluorocarbon (CFC or FCKW in german) or polychlorobiphenyl (PCBPyralene) or pentabromodiphenylether or octabromodiphenylether. There is neither benzene, toluene or phenyl compound nor explosive such as picric acid, nor asbestos in plastic covers. All the capacitors made by EXXELIA since 1991, can be scrapped or used in raw materials recycling processes without special care in compliance with Community rules. EXXELIA aluminium capacitors with non-solid electrolyte are particularly suitable for different kinds of environment taking in account severity increasing laws. European directives 2003/11/EC, 2002/96/EC (WEEE) and 2002/95/EC (RoHS) applies to all EXXELIA capacitors including every solder type, manufactured with pure tin coated pins or wires, since at least January 2006.   > See our capacitors in catalog