Goodbye to the Transformer

PHOTOVOLTAICS Goodbye to the transformer

An even more diverse range of inverters was presented at Intersolar than last year. There were no sensational novelties, but a few trends may be recognised which constitute logical answers as to how PV technology will continue to delevop.

In the words of the boss: Managing board member Günther Cramer presents the Sunny Boy 5000TL from SMA, Germany. Photos (6): Wilhelm Breuer

162 Sun & Wind Energy 3/2007 PHOTOVOLTAICS

he fi rst point was easy to recognise in Frei- burg: the trend is still towards overall higher capacities and higher currents on the input side – a consequence of more powerful modules with larger cells. For DC circuit breakers the integrated variant is taking hold, which was to be expected, once older devices without a circuit breaker, which therefore had components T fi tted to the outside, had been sold off . In the race to reach higher effi ciency, more and more manufacturers are saying goodbye to an important component: the output transformer. This is also be- cause several countries are giving up their rigid stance on transformerless devices. Industry leader SMA sees a movement on the Spanish market towards transfor- Happy families: Riello from merless designs, and the same tendency in other Euro- Wandering through the exhibition halls Italy is putting a whole sextet pean countries and even Korea. Only the USA is stand- of new inverters on the mar- ing tough. Inverters without output transformers still The German company Delta Energy Systems GmbH ket, four of which can be seen have no chance over there, recording to SMA. »It is un- presented itself with its own inverters for the fi rst time here. derstandable when you know about the qualifi cations in Freiburg. The company, which belongs to the Taiwan- of the local installers,« says SMA managing board mem- ese group Delta, has been producing inverters since ber Günther Cramer. By the way: US inverter supplier 2001, but only as OEM products up to now. Delta lines Power One confi rms: »Our transformerless devices with up with two series of inverters: The Top Line models 5 and 6 kW are approved in California.« are to deliver optimum performance in every respect, Whilst market leader SMA has set itself an export tar- whilst the new Value Line off ers devices for »less de- get of 50 %, Asian companies continue to force their manding environments«, as the company puts it. Sever- way onto the German market. They have been doing al models are transformerless devices, and with its Top some homework, making the sometimes weak per- Line, Delta shows that respectable levels of effi ciency formance features of their products conform to German are also reachable with this component. The new SI expectations. Long-established manufacturers are try- 5000 with an output power of 5 kW extends the range ing to counter with increased convenience and compre- upwards from the SI 3300, bringing it up to 96 % peak hensive after-sales service – and with good perform- effi ciency. The European standard effi ciency stands ance too, of course. just 1 % under this. Like the other Delta inverters, the

Sun & Wind Energy 3/2007 163 PHOTOVOLTAICS

tion element, together with its settings and cabling, can remain in place. Stand-out features of the IG Plus are its high permissible input current of 18.3 A per four kilo- watts of output, its high MPP adaptation effi ciency of 99.99 %, and its own consumption at night: This is held to stand at 0 W. With a maximum effi ciency of 96.1 %, the devices do not belong to the leading group, but they do have a typical Fronius trick up their sleeve: The inverter adapts, via connecting to the boost chopper, to diff erent sub- ranges of the input voltage between 230 and 500 V, bringing about three peak effi ciencies rather than just one. Fronius argues that this should also facilitate system planning for the installer. He just has to make sure he knows exactly where these peaks lie. There is no room for confusion here. Fronius gives the installer free rein for choosing the earthing, which can be connected variously according to the module type in the inverter. Kaco Gerätetechnik GmbH, Germany, is launching the Powador 8000xi, whose 8 kW AC output makes it a device in the medium performance class for solar power systems of up to 9 kWp. In fact, with the 8000xi, the company from Neckarsulm wants to mount an off en- sive on the central inverter sector. When three of the new Kaco devices are connected together, they advance into this sector’s sovereign territory, yet they should un- dercut it in price terms. However, the »band of three« then also competes with the company’s own 25000xi central inverter, as the outputs of the devices are almost matched. Like other manufacturers have done with their con- cepts for split inverters, Kaco uses the selling point of damage limitation in case of a crisis: If any one of the inverters operating as a triumvirate should stop working, the integrated imbalance recognition turns down the two other devices until the point is reached where they keep to the maximum permissible output difference of 4.6 kW between two phases – at least their yield is then saved for the time it takes for the service engineer to arrive. Nice casing: Sunways, Ger- Kaco reports to have increased the effi ciency rating SI 5000 also works with IP 65, without a fan, and prom- many, exhibited a design of of its circuit thanks to new IGBT (insulated-gate bipolar ises full output between -25 and +57 °C – that is re- the PT 30k. The inner work- transistor) with »extremely low conduction losses«. The markable. The two MPP trackers move between 150 and ings are still taking shape. new inverter reaches a maximum of 96.2 % and a Euro- 450 V, the device should reach its maximum output be- pean standard effi ciency of 95.4 %. Its own consump- tween 175 and 450 V. tion during operation stands at 11 W. Both models of the new Value Line, the VL 2000 and In its product information, Kaco approaches the sub- the VL 3600, make slight compromises on certain fea- ject of the »MPP window« with some aggression: Whilst tures: The optimal MPP range only extends from 210 to with many devices one is confronted with input voltage 400 V, the derating begins at 45 °C, and the effi ciency is ranges whose lower limit is nowhere near the voltage down 0.6 % from those of the SI 5000. at which the rated output is reached, and – what is more Fronius International GmbH from Austria took its serious – whose upper limit is unrealistically near to the time with its new generation of inverters. By the end of destruction voltage, Kaco specifi es a sensibly usable last year the devices were already being mentioned un- range of 350 to 600 V. It also keeps a safe distance from der the family name IG Plus, at the Intersolar they made the maximum voltage of 800 V. A triad of 8000xi devic- their fi rst appearance. es comes around 5 to 6 % cheaper than the 33000xi The idea behind the new concept is to combine dif- central inverter including generator connection box. ferent power elements with each connection area. Kaco has carried out further development on the al- They are attached via a simple power plug, and then ready familiar central inverters 25000xi, 30000xi and determine the output power of the IG Plus 50, 100 and 33000xi for use in solar parks – Spain sends its regards. 150 at values of 4, 8 and 12 kW. If a fault occurs in the The new version fi ttingly receives an added »Park« on power element, only this is disconnected, the connec- the end of its model description, and distinguishes itself

164 Sun & Wind Energy 3/2007 Not everything has to be as efficient as a SolarMax!

C-Series, the new PV inverter generation by SolarMax

SolarMax – innovative, reliable and above all efficient! With a maximum degree of efficiency of 96%.Therefore SolarMax is among the top three on the European market for grid-connected PV inverters. The youngest, innovative generation of SolarMax PV inverters offers you unique advantages with installation, functions and efficiency with its newly thought out design. Thanks to carefully selected materials, SolarMax guarantees optimal longevity and a great deal of opera- tional reliability. We’ve been on the market since 1992 Central Inverter SolarMax 100C and over 3000 of our inverters are in operation - so we can guarantee you a product that’s on the technical cut- ting-edge. Our service contract will, furthermore, gua- Highlights of the new SolarMax C-Series: rantee that your SolarMax central inverter will operate Compact PWM grid tied PV Inverter trouble-free for 20 years. Maximum degree of efficiency SolarMax inverters offer you unique advantages in effi- MPP efficiency of over 99% ciency as well as in savings. Digital signal process control (DSP) Attractive price/performance ratio Guarantee extension up to 20 years possible Sputnik Engineering AG Integrated interface for MaxCommBasic Höheweg 85 2502 Biel Switzerland Phone + 41 (0)32 346 56 00 Fax + 41 (0)32 346 56 09 [email protected] www.solarmax.com Always a sunbeam ahead PHOTOVOLTAICS

Provider Series/product Number System of Inverter Transformer type Feed-in system max. AC European DC voltage Market launch Manufacture Website of devices protection type power [kW] eﬃ ciency [%] range [V] Delta SI 5000 1 IP 65 string high frequency single-phase 5 95 150 to 450 Germany: autumn 2007, own production in Slovakia www.solar-inverter.com rest of the world: n/a VL 3600 / VL 2000 2 IP 54 string high frequency single-phase 3.6 / 2 94.4 210 to 400 Germany: autumn 2007, rest of the world: n/a Fronius Fronius IG Plus 4 IP 43 string high frequency single-phase (4 / 8 kW), 4 / 8 / 12 96 230 to 600 Germany / Austria: middle of 2007, own production in Austria www.fronius.com two-phase (8 kW), worldwide: 2007 three-phase (12 kW) Kaco Powador 8000xi 1 IP 54 string without single-phase 8 94.5 350 to 600 France / Germany / Italy / Korea / own production in Germany www.kaco-geraetetechnik.de Spain: September 2007 Powador 33000xi Park / 3 IP 54 central without three-phase 33.3 / 29.9 96.5 350 to 800 France / Germany / Italy / Korea / Powador 30000xi Park / / 25 Spain: summer 2007 Powador 25000xi Park Motech 4600MS 1 IP 65 string without single-phase 4.6 95.4 150 to 450 Germany / Italy / Spain / Taiwan and own production in Taiwan www.motech.com.tw Instruments other Asian countries: summer 2007 Power One PVI-4200S-OUTD 1 IP 65 string without single-phase 4.2 96.4 90 to 580 France / Germany / Greece / Italy / own production in Italy www.power-one.com Spain / USA: end of 2007 PVI-Central-100 1 IP 20 central without (LV trans- three-phase 100 96.9 (95.7) 460 to 850 France / Germany / Greece / Italy / former optional) Spain / USA: end of 2007 Riello UPS Helios Power 10065 1 IP 65 string without three-phase 10 96.3 300 to 800 Germany / Italy / Spain: end of 2007 own production in Italy www.riello-ups.com Sanyo SSI-TL27AE1 1 IP 65 string without single-phase 2.7 95.5 100 to 600 Japan: available, own production in Japan www.sanyo.com Germany: early 2008 SMA Sunny Boy 5000TL 1 IP 65 string without single-phase 4.6 96 125 to 550 n/a own production in Germany www.sma.de (electronic) Sputnik Solarmax 2000 S / 4 IP 54 string without single-phase 1.8 / 2.5 / 95.4 / 95.5 / 100 to 550 all European countries: August 2007 own production in Switzerland www.solarmax.com 3000 S / 4200 S / 6000 S 3.8 / 4.6 95.8 / 96.2 Solarmax 20 S / 2 IP 54 central without three-phase 20 / 35 96.5 400 to 800 all European countries: end of 2007 own production in Switzerland Solarmax 35 S

New off -grid inverters at the from the basic model on three points: Firstly, the new The input voltage range, at 150 to 450 V, does not Intersolar fair 2007. IGBT were also employed here. Secondly, in order to turn out to be particularly extravagant, but this does Source: manufacturers’ information increase the effi ciency, Kaco has also lowered the tran- not rule out the devices having a good design. The in- sistor clock frequency to 9 kHz. This reduces switching verters incorporate two or three (4600 MS) strings, each losses, but also pushes the operating noise of these of which is controlled via its own MPP tracker. Motech components into the human hearing range. The noise also claims that the PV Mate 4600 MS reaches respect- apparently resembles the chirping of crickets, and does able effi ciency levels at partial loads, giving values of not exceed 35 dB. Finally, with an eye to the heat at over 96 % from 1.7 kW output power. their installation location, the central inverters were According to Motech, the devices show no derating given new fans in order to improve the cooling of the (output limitation with rising temperatures) up to 55 °C. sensitive components. It is somewhat contested that This is above average, and makes them an interesting the operators have the option of supplying the fans option for hot installation locations, particularly as the with electricity from the grid, so that they can feed surrounding humidity can be as high as 95 %. more solar energy back in – and they are by no means As a target for 2007, Motech aims to introduce trans- the only manufacturer to integrate this option into their formerless devices for the US market. It also wants central inverters. With these three tricks, Kaco has been to have more performance classes. With these, one able to increase the peak effi ciency from 95.5 % to feels well-equipped »to move into the ODM business,« 97.1 %, and the European standard effi ciency to a re- says Marketing Manager YM Yen. An ODM (Original De- markable 96.5 %. The Park devices are now available, sign Manufacturer) designates a manufacturer who and cost 3 to 5 % less than their predecessor. The Tai- develops devices from scratch according to customer wanese manufacturer Motech Industries Inc. did not needs, rather than one which modifi es standard prod- present any new models, but there have been changes ucts (OEM). to the inner workings of the familiar devices PV Mate The manufacturer name Magnetek is a thing of the 3300MS, 3800MS and 4600MS. Last year the effi ciency past. Since the takeover of the company by the US still fl uctuated within a range which put a question group Power One, the inverters are also sold under mark over the product for the interested parties. Mo- this company name. The family name for the devices – tech has done away with this and labelled the pre- Aurora – has, however, remained. In Freiburg the new decessors »prototypes«. This year, the PV Mates are owner also exhibited two new inverters from the presented with peak effi ciencies of 96.3 % and Europe- Power One Aurora series, one string inverter and one an standard effi ciencies of between 95.2 and 95.4 %. central inverter. The fi rst, the PVI-4200S-OUTD, with its

166 Sun & Wind Energy 3/2007 Provider Series/product Number System of Inverter Transformer type Feed-in system max. AC European DC voltage Market launch Manufacture Website of devices protection type power [kW] eﬃ ciency [%] range [V] Delta SI 5000 1 IP 65 string high frequency single-phase 5 95 150 to 450 Germany: autumn 2007, own production in Slovakia www.solar-inverter.com rest of the world: n/a VL 3600 / VL 2000 2 IP 54 string high frequency single-phase 3.6 / 2 94.4 210 to 400 Germany: autumn 2007, rest of the world: n/a Fronius Fronius IG Plus 4 IP 43 string high frequency single-phase (4 / 8 kW), 4 / 8 / 12 96 230 to 600 Germany / Austria: middle of 2007, own production in Austria www.fronius.com two-phase (8 kW), worldwide: 2007 three-phase (12 kW) Kaco Powador 8000xi 1 IP 54 string without single-phase 8 94.5 350 to 600 France / Germany / Italy / Korea / own production in Germany www.kaco-geraetetechnik.de Spain: September 2007 Powador 33000xi Park / 3 IP 54 central without three-phase 33.3 / 29.9 96.5 350 to 800 France / Germany / Italy / Korea / Powador 30000xi Park / / 25 Spain: summer 2007 Powador 25000xi Park Motech 4600MS 1 IP 65 string without single-phase 4.6 95.4 150 to 450 Germany / Italy / Spain / Taiwan and own production in Taiwan www.motech.com.tw Instruments other Asian countries: summer 2007 Power One PVI-4200S-OUTD 1 IP 65 string without single-phase 4.2 96.4 90 to 580 France / Germany / Greece / Italy / own production in Italy www.power-one.com Spain / USA: end of 2007 PVI-Central-100 1 IP 20 central without (LV trans- three-phase 100 96.9 (95.7) 460 to 850 France / Germany / Greece / Italy / former optional) Spain / USA: end of 2007 Riello UPS Helios Power 10065 1 IP 65 string without three-phase 10 96.3 300 to 800 Germany / Italy / Spain: end of 2007 own production in Italy www.riello-ups.com Sanyo SSI-TL27AE1 1 IP 65 string without single-phase 2.7 95.5 100 to 600 Japan: available, own production in Japan www.sanyo.com Germany: early 2008 SMA Sunny Boy 5000TL 1 IP 65 string without single-phase 4.6 96 125 to 550 n/a own production in Germany www.sma.de (electronic) Sputnik Solarmax 2000 S / 4 IP 54 string without single-phase 1.8 / 2.5 / 95.4 / 95.5 / 100 to 550 all European countries: August 2007 own production in Switzerland www.solarmax.com 3000 S / 4200 S / 6000 S 3.8 / 4.6 95.8 / 96.2 Solarmax 20 S / 2 IP 54 central without three-phase 20 / 35 96.5 400 to 800 all European countries: end of 2007 own production in Switzerland Solarmax 35 S

4.2 kW AC output, fi lls the gap between the or as a multi-master combination with two more powerful models, which start at 5.0 separate MPP trackers. The central inverter kW, and the lightweight models of up to 3.6 can be extended modularly in steps of 50 to kW. Beneath the thick cowling there is no 300 kW. One advantage of this kind of archi- fan, cooling is purely passive. The transfor- tecture is that if one 50 kW module stops merless device can claim a very good sepa- working, the others continue to operate un- ration between the maximum and the Euro- perturbed. Depending on whether or not pean standard effi ciency: 97.0 % and 96.4 %. the system is to be connected to the grid, In fact, according to the gradients supplied, the PVI-Central-100 can be purchased with at its »optimal« input voltage of 345 V, the a low-voltage transformer, or as the trans- inverter already reaches an effi ciency of formerless PVI-Central-100TL for direct con- 95 % at a load of under 10 %. nection to the medium-voltage grid. This It is commendable that the Power One model gains around two percent on its effi - supplies a colour diagram with the data ciency: instead of 95.7 % (ηmax) and 94.9 % sheet for the new PVI-4200, which plots the (ηeuro), the transformerless version reaches effi ciency against the input voltage and 97.5 % (ηmax) and 96.9 % (ηeuro). output. This gives a comprehensive picture Power One says that both devices should of where the effi ciency ranges are situated be available in the last quarter of the year, and how far they extend, and thus of the be- the prices will be around 0.34 €/W for haviour of the inverter in various working the PVI-4200S-OUTD and 0.29 €/W for the states. This makes system planning signifi - PVI-Central-100. cantly easier. The picture shows that the So far, Italian Riello Elettronica had in- peak effi ciency – as usual – only takes up a troduced six inverters in their Helios Power very small area, but the range of 96.8 % ex- series. Now the company »ramps up« to a tends so far that a system may comfortably whopping 10 kW with the new Helios Pow- be fi tted to it. er 10065. Basically the same design as its six The newly presented PVI-Central-100 in- siblings this new inverter comes equipped verter, in its basic version, is made up of two with a fan due to its higher output power. 50 kW units which may be connected in a Also, it feeds into the grid on all three phas- master/slave network with an MPP tracker, es whereas its predecessors had been single phase units. Still it operates without a transformer which enables it to deliver 96.3 % European efficiency, which is even more than the maximum efficiency the earlier Helios Power had to offer. The three MPP-inputs operate between 300 and 800 V which leaves the reader somewhat puzzled since the maximum input voltage is said to be 800 V, as well. This is either an inaccuracy or Riello here defines its own terms: For safety reasons you would expect the upper MPP-limit quite a bit lower than the maximum input voltage. Also remarkable, but in a good way, is the 10065’s ability to swallow peak currents up to 27 A per input. Riello’s latest product is announced for the end of this year. And there is the company’s hint that Riello is out for » big« business in 2008 – with a 40 and a 100 kW central inverter. At least the model description of the long-awaited inverter from Sanyo Component Europe GmbH has already been decided: SSI-TL27 AE1. It will not come onto the market, however, before 2008. Nevertheless, it is operating in field trials in several German systems. The transformerless device will supply 2.7 kW of output power, and with a peak efficiency of 96 % and a Euro- pean standard efficiency of 95.5 %, it should deliver very respectable performance. The data on the MPP range and the maximum input voltage, on the other hand, does not appear to be coherent. The MPP tracker covers from 100 to 600 V, yet according to the data sheet, the latter value should also be the upper voltage limit. This is confusing for the German customers – enter marketing employee Christian Comes explains: »Sanyo defines the MPP limit as the maximum input voltage. But of course the inverter can withstand higher voltages.« A better point of reference for planning is offered by the INTRODUCING... nominal voltage figure of 350 V. This may be the value at which the device reaches its best performance. Well packaged in metal housing, with the protection degree IP 65, the 17 kg device is entirely suitable for Two Battery Solar Controller outdoor use. However, the data sheet gives no informa- with Remote Meter tion on the permissible environmental conditions for the fanless inverter. Incidentally, the device is only real- 25 Amps at ly new to us Europeans, as in Japan it has already been 12 volts DC selling very well for some time. Amongst the changes NEW! made for the German market was the reprogramming of the control software which had been carried over from air conditioning technology. Sanyo remains tight- lipped on prices for the moment. Germann SMA AG presented with great aplomb their • Ideal for RV’s, new generation of inverters, represented at the fair caravans, boats by the first of the offspring, the Sunny Boy 5000TL. and cottages. Managing board member Günther Cramer personally • Independently guided visitors through the presentation, saying that charges both the new generation embodies »over 20 years of experi- the “house” and ence with photovoltaic system technology«. The single- engine battery. phase device, with an AC output of 4.6 kW, supersedes • Charging priority the 5000TL HC and brings with it, amongst other things, is user selectable. a newly developed power element. This is apparently • Remote meter one of the reasons for the peak efficiency, which stands displays digital and Phone: +1-215-321-4457 at a good 97 %, with an input voltage range of 125 to pictorial system Fax: +1-215-321-4458 550 V, which is also greater than that of the predecessor. information. [email protected] www.morningstarcorp.com The European standard efficiency stands at 1 % under the maximum.

168 Sun & Wind Energy 3/2007 An old friend from Japan: In its native country, the Sanyo inverter has long been a fast seller; newly programmed, it is set to break onto the German market.

SMA is marketing its new inverters under the slogan: »Complete. Simple.« The technology is held to be complete, and the installation and operation simple. For ex- ample, the inverter can be adapted to country-specific conditions using two rotary switches located under the cowling. The installer just has to choose the identifica- tion which corresponds to the code supplied with the product. The device then configures itself and also sets the display to the language of the country. Further- more, the grid connection and wiring of the two strings is made easy by special spring-coil clamps, tools are no longer necessary. With one fifth less weight on the ribs than its predecessor – just 25 kg – the device should be comparative- ly light. The new inverters communicate with the outside world, for instance in order to carry out the wireless system diagnosis, via the somewhat outdated radio standard Bluetooth, which nevertheless carries the advantage of being globally recognised and unlicensed. The Bluetooth signals can only reach up to 100 m, however. With IP 65, the 5000TL is suitable for outdoor use, and for this reason SMA has given it an extra bolt-cut- ter-proof U-lock as theft prevention. German Mannhe- imer Versicherung insurance has already given a posi- tive appraisal of this add-on, and recognised it as »pre- mium-reducing«. The Sunny Boy 5000TL and its smaller brother the 4000TL should be on the market from January 2008. The list price of the 5000TL will stand at € 2,450, making it less expensive than its predecessor. There were a few new things on show from Sputnik Engineering AG: The Swiss firm has brought out a new series (Solarmax S) and taken the opportunity to depart from plain aluminium grey, presenting the new devices in snazzy yellow. The rated output of the four transformerless newcomers, at 1.8 to 4.6 kW, corresponds fairly accurately with that of the C series, and the same goes for the efficiency level. The S series devices have an MPP range of 100 to 550 V, and reach European standard efficiency levels of between 95.4 and 96.2 % – comparable with the predecessors of the C series. PHOTOVOLTAICS

Sunrise with Power One: The Power One inverters are called Aurora (the red of dawn), and begin to work at 120 V.

Sputnik has also come up with successors to its large inverters: The two central inverters Solarmax 20 S and Solarmax 35 S – the figures represent the AC output – mark the swing towards transformerless technology, even at high outputs. The resulting devices weigh just one third as much as their predecessors and reach a maximum efficiency of 96.5 %. The European standard efficiency stands just 0.7 % below this value. A patent- ed switching mechanism apparently minimises leakage currents, which is certainly essential for large inverters, since one often wishes to use them in conjunction with thin-film technology. The MPP window extends from 400 to 800 V, setting it comfortably apart from the upper voltage limit of 900 V. The central inverters practise This is how an inverter veritable three-phase grid feeding, and therefore only looks at Motech, Taiwan. have to store a small amount of current in the interme- ODM customers may, diate circuit. Sputnik has taken advantage of this in or- however, request any other der to say goodbye to electrolytic capacitors and to put kind of presentation or, in their place foil capacitors which have, in principle, an above all, construction. unlimited service life. The central inverters will be on Photo: Motech Industries the market from summer 2008, the string inverters So- larmax 2000 S, 3000 S, 4200 S and 6000 S should be available in November. Steca GmbH from Memmingen, Germany, announc- es the arrival of its first large inverter, the Stecagrid 9000 3ph, for 2008. The model description alone reveals What is new, however, is the reduced weight of 2.3 kg, that this is a three-phase device with 9 kW of AC out- improved heat dissipation, and the possibility of inte- put. On the input side, the device can receive up to grating the inverter into the communications network 10.5 kW whilst still accepting a current of up to 32 A. To- via Ethernet. Furthermore, the new string inverters no gether with its MPP range of 300 to 750 V, the Stecagrid longer work with an MSD for grid monitoring, rather allows for diverse system designs. The switching con- they employ the oscillator method, which is apparent- cept with one tracker requires, admittedly, systems ly more effective at preventing unnecessary grid dis- »with an identical module orientation and without connections. With this method, the inverter induces a shadow problems«, as is stressed in the data sheet. phase jump in the grid and uses this to measure the The transformerless device reaches a peak efficiency of angle between current and voltage. It recognises a 96.2 % and a European standard efficiency of 95.3 %. stand-alone set-up in that the current follows the volt- Even without electrical isolation, the device apparently age extremely closely. Sputnik raises the quality of the only produces low DC leakage currents, and is there- electricity fed into the grid by using a digital sine wave fore kind on thin-film modules. The Stecagrid 9000’s generator, with which it is possible to attain a lower dis- own standby consumption makes a good impression at tortion factor. less than 0.5 W. The derating, which takes effect from

170 Sun & Wind Energy 3/2007 PHOTOVOLTAICS

A connection element for device, is supposed to ensure optimal cooling. Not a lot every occasion: In its IG Plus of information was given on the underlying perform- series, Fronius from Austria ance technology – hence the initials PT – but this is like- incorporates a connection el- ly to be based on the NT models. The 30-kW device is to ement with power elements come onto the market in the first quarter of 2008, and of three different strengths. should certainly be more affordable than three 10-kW devices. How long it can actually be before announce- ments turn into products is shown by the AT models, which are just now going into mass production, exactly a year after their first appearance in Freiburg. There is something new and concrete to report from the models of the NT series. The engineers in Constance were able to raise the efficiency once again, it now reaches 97.5 %. The devices reveal an amazingly small gap between maximum and European standard efficiency: for the NT 6000 this is 0.5 %, whilst the NT 4000 leaves a difference of just 0.3 % between the two values. The efficiency curves at various input voltages also lie very close to one another, and all devices reach their maximum at 350 V. The reason for this increase is optimised components, one of which is an inductor 50 °C, leaves room for improvement. With the protec- which has a higher efficiency of its own. The control tion degree IP 54, the device is suitable for protected was also redesigned. »The switching still had poten- outdoor use. In new dimensions: With tial, and was just waiting for better components,« says Sunways AG gave news of a new product with the the Stecagrid 9000 3ph, Martin Buchholz, product manager at Sunways. To Solar Inverter PT 30k – an inverter for larger systems, as Steca, Germany, presents its get up to 98 % will be a tall order, however. To accom- the name gives away. The transformerless device will first inverter for systems plish this, one would have to restrict the input voltage operate with input voltages between 420 and 800 V. with an output of around range, and this would appear to make little sense, says A multi-chamber system, which channels hot and cold 10 kW. Buchholz. ✹ air flows separately through the inner workings of the Photo: Steca Andreas Schlumberger

22nd European Photovoltaiv Solar Energy Conference and exhibition ��

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