ODU MINI-SNAP Series L (IP50 and IP68)

Locking Concept Keying with Pin and Groove
• Shell size 0 to size 6;
• Up to 40 contacts per connector;
• Temperature range - Silicone version -50°C up to +250°C.

ODU MINI-SNAP Series K (IP68)

LP-Locking Concept Keying with Pin and Groove
• Shell size 0 to size 4;
• Up to 40 contacts per connector.

ODU MINI-SNAP - Series B (IP50 and IP68)

Locking Concept Keying with Pin and Groove
• Shell size 0 to size 3;
• Up to 40 contacts per connector;
• Temperature range - PUR version -40°C up to +80°C (Short-term up to +120°C);
• Temperature range - Silicone version -50°C up to +200°C (Short-term up to +230°C).

ODU MINI-SNAP® - Series F (IP50 and IP68)

Locking Concept Keying with Half-shells
• Shell size 0 to size 3.5;
• Up to 27 contacts per connector.

ODU MINI-SNAP - Series S (IP50 and IP68)

Locking Concept Keying with Insulation Body
• Shell size 0 to size 2;
• Up to 14 contacts per connector.

ODU MINI-SNAP

MINI-SNAP housings are made out of brass and are nickel plated with a a matt-chromate surface finish (sand-blasted). Nickel-plated or black chromate - finished housings are available on special request.
The nature of the push-pull connector is easy to explain:
• During insertion, the connector locks itself into the receptacle;
• It can no longer be separated by pulling on the connector cable.
The connector can, however, easily be separated from the receptacle by pulling back the outer sleeve.

Push-pull connector advantages:
• Quick and easy connect and lock;
• Quick and easy separation;
• Blind insertion and withdrawal are easy, even in hard-to-access locations;
• Low space requirements for devices;
• Unambiguous, certain locking states;
• Low energy expenditure;
• Suitable for robots.

Contact:
Eng. Alina Mitea
E-mail: alina.mitea@odu-rom.ro
www.odu-rom.ro
ODU ROM Manufacturing - Sibiu, Romania
Tel: 0748144488; Fax: 0269 221006
For general information visit: www.odu.de

The energy supply of the future requiresinnovative system technology to ensure grid and load management across all grid levels. For this purpose, RUTRONIK offers well-tried system solutions with tomorrow's technology already today.
By Dipl. Ing. (FH) Andreas Mangler, Director Strategic Marketing Rutronik Elektronische Bauelemente GmbH

In view of continuous cost reduction and efficiency increase in photovoltaic technology, a share of 12 percent in the European energy mix is by no means utopian and is also profitable for the economy of a country. For Germany alone, being the largest European PV market, this target means that installed PV power must be improved significantly: It would have to increase from presently 5.5 gigawatts to about 80 gigawatts in 2020. With its study on grid integration of up to 50 gigawatts of PV power, the Institut für Solare Energieversorgungstechnik (Institute for Solar Energy Supply Technology, ISET) has clearly demonstrated that an excellent correlation between PV power and grid load exists: Consumption and generation are so well coordinated in terms of time that solar power of this scale can be fed in without the need for any additional measures. Consumers, producers and the grid must in future be connected to one intelligent energy supply system. This is because generation will in future increasingly take place decentrally and at all voltage levels - requiring grid management across all levels. Already today, Rutronik offers innovative technology for the requirements of the energy supply of the future and the diverse options of application-specific system solutions. For this, the company utilises synergies of the extensive know-how and the market knowledge of the distributor Rutronik and of the PV specialist RUSOL, a100-percent subsidiary of Rutronik.

Grid management at all voltage levels
Innovative backup systems especially for the off-grid market, which is set to increase significantly in future, ensure 100 percent supply security, integrating important functions for intelligent grid and load management.
The grid management begins with the solar panel and the individual system components within the system and ends with intelligent energy storage. But also the coordinated load management by the consumers contributes to ensuring supply security in all situations and at any time of the day.
Already today, solar inverters of the latest generation fulfil the task of reactive power compensation in the grid. The reactive power is used for stabilising the grid voltage, on the one hand, while any existing phase shifts at the grid connection point must be compensated, on the other hand. The reactive power compensation reduces the load on the grid infrastructure - an important task in the frequently highly stressed low-voltage grid. However, it is also possible to feed in inductive reactive power to reduce the voltage in the low-voltage grid. Background: Due to the more Ohm resistive load, feeding active power into the low-voltage grid results in a voltage increase. The Ohm resistive characteristic reduces the voltage-lowering influence of the reactive power, but between 20 and 50 percent of the increase can still be compensated so that in total more PV active power can be fed in.

More supply security in the integrated grid
Another important component of grid control is the continuous balance of energy generation and consumption as the grid itself, unless designed as stand-alone solutions or partially independent structures, cannot store energy. Even though a power failure in the local low-voltage grid has no noticeable effect on the frequency - in the integrated grid as a whole, however, the frequency is the decisive control variable: Any imbalance between generation and consumption will result in frequency deviation, which is compensated in conventional large power plants. For this purpose, the European Union for the Coordination of Transmission of Electricity UCTE currently holds three gigawatts of power as primary control reserve - enough for compensating the simultaneous failure of two large nuclear power plants. If the integrated grid is divided into several control zones, no more load compensation takes place. Grid areas with over - or underfrequency are created - in accordance with the current regulations, all PV systems would immediately shut down in both cases. For ensuring the supply security in the integrated grid, it is therefore indispensable that also the PV inverted rectifies that feed into the low-voltage grid reduce the supplied power when the grid frequency increases.

Grid and load management by intelligent load control
Regardless of the reason why PV power is reduced: It is always only the second best solution because ultimately, this results in valuable energy not being utilised. The alternatives: consume excess energy sensibly or store it for later use. For this, the load on the regional medium and low-voltage grids must be reduced - at least until the restructuring to a modern integrated grid - meaning a grid that can distribute varying energy amounts in all directions at only little loss - has progressed further. One possibility is own consumption. It reduces the load in two ways: Energy that is consumed directly at the point where it is generated no longer needs to be transported off via the electricity grid. In addition, the energy required for consumption does not have to be procured via the grid. Furthermore, when used for own consumption, a photovoltaic system can make full use of one of its special advantages: The excellent time correlation of energy generation and requirement. Especially around noon, when solar power systems supply most energy, most of it is normally needed. Apart from its grid load reducing effect, own consumption is generally a topic relevant for the future - in particular in view of the grid parity that will be reached in Germany already in a few years time. Because as soon as solar power has the same price as or even a lower price than conventionally supplied electricity it makes sense for every owner of a solar system to consume as much as possible of the self-generated power.
However, when we combine the power monitoring of the PV system with an electrical switchgear, we can also implement automatic solutions for increasing own consumption. The same basic rules apply: Consumers are only activated when sufficient generated power is available and the latter cannot be used differently - otherwise, they are switched on only later or successively. For this, however, the system must not only know the generated power but also the current energy consumption. Otherwise, there is a risk that consumers already in operation, which already consume the entire or part of the available PV power, are not considered. In the least favourable case, a peak load would be generated in this case that exceeds the energy provided by the solar system and the connected consumer would have to obtain at least some percent of its energy from the grid. Consequently, a sensible technical solution must not only detect the PV power but also monitor the electricity supply meter. This is because the latter measures exactly the part of the generated power that is not consumed in the house. If feed-in takes place, the PV power exceeds the consumption and additional consumers can be connected.

Energy storage instead of power reduction
In the medium term, however, temporary storage of PV energy with battery systems and Supercaps will also become attractive. If you are capable of freely choosing the time of consumption of the PV electricity, you can increase the own consumption rate even further. In future, load transfer processes will play an increasingly important role in this context. Intelligent controls that build up so-called smart grids on the side of the consumer are thinkable: They switch the various electricity consumers on or off depending on the available energy, taking both the energy requirement of the respective devices and the forecast generation into account. In the energy scenario of the EPIA (European PhotoVoltaic Industry Association) for 2020, however, adjusting consumption and generation in terms of time alone will not suffice for compensating generated excess energy. This is because as soon as the installed power of the generators under the REL (Renewable Energies Law) is greater than the minimum consumption load in the grid, the generated energy cannot always be consumed completely. Also the infrastructure of the low-voltage grid represents a limiting factor as it is only designed for medium power of about one kilowatt per connected residential unit. For the expected 40 gigawatts of PV power, it could reach its capacity limits in periods of strong radiation and low loads.
Instead of once again reducing the generation at this point, it makes sense to implement temporary storage additionally to load management. With today's technology, it can already be implemented without difficulty, it is easy to scale, reliable and tried out. By temporary storage of energy it is possible to absorb variations in generated power - at the same time, it allows for continuous energy consumption irrespective of the time it is generated. However, to ensure a purposefulstorage that truly reduces the load on the grid it must take place near to the consumption and generation. Besides, only generated peaks should be stored as any storage naturally involves costs. As far as energy that would otherwise be “wasted” by power reduction is concerned, storage pays already today: Using the latest battery technology, it costs only 10 to 20 cents per kilowatt hour - this is less than the purchase price for electricity for household clients. The first solutions for storing solar energy are already available on the market and will see significant technological progress in the years to come.
Using temporary storage, it is also possible to fulfil the corresponding requirements of grid and load management. Three functions are most important in this regard: Firstly, an uninterrupted energy supply that is capable of switching to solar-supported battery power supply in the event of a grid failure, thus ensuring the operation of important consumers. Secondly, the possibility to freely choose the time when PV energy is consumed by temporarily storing it. By this load transfer, the direct consumption rate can be increased even further. At the moment, the battery capacity and the power of the backup inverted rectifier are limiting factors. A corresponding number of backup systems could thus contribute to the active power/frequency control of the integrated grid beyond the low-voltage grid - and this 24/7. Such decentralised primary and secondary control would be both cost-efficient and reliable. Thirdly, the decentralised buffering of the PV panels on the roof, e.g. for compensating local shading and still function at the quasi maximum operating point of the panel.

Supercaps for covering the peak energy requirement
These modern capacitors are optimally suited for storing electrical current. Their indicated energy density is 5 - 20 kWs/kg while powers of up to 10 kW can be achieved. The number of cycles over the lifetime amounts to approx. 1 million, the energy efficiency is about 95 %. The Supercaps can be charged within three to five minutes and supply a lot of energy during a short period. Unlike conventional batteries, their function is based not on chemical but on merely physical processes. Any signs of wear and tear, which can occur in conventional storage batteries, can thus also be prevented. The heart of the Supercaps developed by Maxwell Technologies is an aluminium electrode.
A layer of activated carbon powder is applied on top of it. If voltage is applied to the electrodes, the electric charges adhere to it and - as they attract each other - remain stored there for a while even if the power source is removed. The smaller the distance between the electrodes and the larger their surface, the more electric charge can be stored.
The carbon powder on a single Supercap coil has a surface of about 130 soccer fields. Already in mid 2006, Maxwell made a name for itself with its 2.7V Supercaps ranging between 5 and 3,000 farad. A 10 farad cap can operate a red LED for more than an hour. The energy storage density is over 3Wh per kg and is to be increased to about 15Wh per kg in the next few years. However, for use in electric cars, more than 100Wh per kg would have to be achieved.
At present, lead-based accumulators are used in stand-alone systems; these are technically mature and, on principle, work reliably but frequently require high maintenance and reach only a relatively short lifetime. A major reason for the high stress on the battery is the very large number of shortly successive charging and discharging cycles, even on days with good but highly fluctuating radiation. As the respective time periods could not be resolved sufficiently accurately, they were not identified as the reason up to now. As a result, the used accumulators are worn already after a few years and need to be replaced. This problem can be solved by combining short-term accumulators (Supercap with more than 1,000,000 charging and discharging cycles) and a long-term accumulator (battery) with a correspondingly adapted power electronic charging management.
Fig. 3 shows, by way of example, a highly time-resolved radiation curve the decrements of which are shown in Table 1.
This is accompanied by a stochastic purchasing behaviour of the consumer using the example of a real day profile of a household. The storage system is stressed accordingly with highly fluctuating charging and discharging processes. The two central curves show that the Supercap is capable of buffering the fluctuations during which the battery storage takes over the long-term storage. If the storage system consists only of one battery, the total number of changes will obviously result in limit stressing of the battery after a few years. Also in long-term accumulators to be used in the future consisting of electrolyser and fuel cell, the Supercap can increase the lifetime by reducing the dynamic stress on the system and also buffer a steep load gradient. The two bottom curves show the respective energy content of the two storage components. The long-term storage must consequently be dimensioned smaller as it does not have to supply the entire power. Supercaps will undoubtedly be used increasingly in future as power electronic components in intelligent accumulator assemblies. Their use in PV systems (grid managed and stand-alone system) significantly improves the energetic characteristics and market chances of these. Supercaps are the ideal components for improving the grid dynamics both for fluctuating supply and consumers. They are only at the beginning of their technological development, having an immense potential for improvement.

System communication becomes grid communication
In future, system communication will be part of an integrated communication network for managing energy intelligently and depending on the loads.
Using Bluetooth, system control solutions can be implemented particularly easily.
This is because Bluetooth compatible devices connect automatically and quickly to a reliable wireless network. To be able to separate adjacent systems, a uniform network identification must first be defined for all inverted rectifiers of a system so that these form a common wireless network. In the next step, remote monitoring by any smart phone can then easily be implemented. Storage battery operated Bluetooth modules ensure the monitoring function or yield display irrespective of the time of the day (see Fig. 4)
For this application, Rutronik, exclusively with Infineon, now offers an integrated network solution on one chip. It additionally includes USB and many other analysis functions. The essential elements are:
• Integrated system communication
• Module-to-module communication
• Smartphone connectivity via Bluetooth
• Analogue front end for metering and analysis functions
• Characterisation of individual solar panels by impedance spectroscopy and intensity modulated photocurrent spectroscopy
• Photocurrent voltage curve
• Short circuit current Isc
• Idle voltage Voc
• MPP Maximum operating point of an individual panel
• Fill Factor describes the relation of the MPP to the idle running and short-circuit parameters
• Ageing and degradation behaviour of the individual panels or within the string
• Temperature measurement
• Theft detection and/or detection of changes in the network.
With this, Rutronik and Infineon offer the first monolithically integrated solution that can execute most of the analysis of individual solar cells or panels on one chip.

Intelligent PV panel terminal - performance analysis of the solar panels using impedance spectroscopy
The impedance of a solar cell describes the current response of the cell to a small periodically modulated interference voltage in dependence of the interference frequency f. For this, a small sinus-shaped alternating voltage of interference frequency f is superimposed over the solar cell at defined stationary operating conditions (for any operating point on the characteristic curve) after which the resulting alternating current is measured. This is done over a relatively large frequency range (here between 100 mHz and 100 kHz). The amplitude relation and the phase shift between the measured alternating current and the applied alternating voltage are determined. Using impedance spectroscopy, it is possible to characterise the stationary state of the solar cell in more detail. The frequency dependency of the impedance provides additional information. In particular, different processes in the solar cell can have different time constants and can thus manifest in different frequency ranges. Here is an example of a measurement:

Combination of electrochemical impedance spectroscopy and intensity modulated photocurrent spectroscopy - best analysis of the system
The kinetics of electrochemical reactions of semiconductors or metals coated with oxide layers are normally very complex. In particular doping of the semiconductor, adsorption layers and photoeffects may influence the reactions. Consequently, metallic segregations, hydrogen development, etching processes and corrosion of semiconductors may significantly be influenced by minimal variations. The electrochemical impedance spectroscopy is an efficient method for analysing the kinetics even of complex problems. The new system-on-chip solution from Infineon can implement precisely this application. For the electrochemical impedance spectroscopy, an small-amplitude alternating voltage is superimposed over the direct current potential and the alternating current response of the system is measured phase-sensitively. The frequency of the superimposed alternating voltage can be varied between10µHz and 500kHz so that the characteristic time constant for the system become visible. The impedance spectrum of the hydrogen development on GaAs semiconductor electrodes shows, for example, the typical frequency cycle of diffusion processes (“Warburg impedance”) due to the transport of hydrogen ions in the electrolyte, and two time constants that characterise the two-stage electrode reaction of the hydrogen development with atomic surface-adsorbing hydrogen. At the same time, the measuring method allows for a capacity potential (C-V) measurement with that the doping and the flat conductor potential or the energetic position of the line and the valence band of the semiconductor in the electrolyte can be determined.
Compared to metal electrodes, the analysis of the electrochemical kinetics of semiconductor electrodes is particularly complicated because the electron transfer can take place both via the line and the valence band. In highly doped semiconductors, electronic tunnelling is also possible. The intensity modulated photocurrent spectroscopy (IMPS) can be used as complementary addition to the impedance spectroscopy. In this method, instead of an alternating voltage, the light intensity is modulated periodically in sinus shape using LEDs and the alternating current is measured phase-sensitively. The combination of the two methods provides information on the contribution of minority and majority charge carriers in so-called Redox reactions at the silicon cells.

Conclusion
New technologies like the Supercaps will give the use of independent stand-alone solutions, but also self-generated and self-consumed solar power an enormous boost. The intelligent solar panel terminal will combine highly accurate analysis technology with highly precise measurement results and thus provide the subsequent signal chain with information online and at any time. Even ageing and degradation characteristics of PV panels can thus be demonstrated - and all this economically at an affordable price.
www.rutronik.com