How To Choose The Right PV Power Inverter

For those new to photovoltaic systems, the various components that make up a system may be confusing. Inverters are one of those components that some may know they need, without knowing why. This guide will help to clear up some confusion about inverters.

What is an inverter?

Inverters are devices that convert direct current (DC) voltage from photovoltaic cells into alternating current (AC) voltage.

Why do you need an inverter?

Inverters are necessary components of any photovoltaic systems where the load is an alternating current (AC) instead of a direct current (DC). PV modules produce electricity in the form of DC voltage. This electricity is then stored into a battery in that form. Most household applications require AC voltage. This device will allow you to convert your electricity so it will be useful for your household appliances, or for any devices that require AC voltage as opposed to DC voltage.

Are inverters efficient?

Today, inverters have can have efficiencies greater than 90%. They are highly cost effective for those looking to use them for situations requiring AC voltage.

What to take into consideration when choosing an inverter:

Usage – what application will you be using the inverter for (off grid, or grid-tie)?

Size of your PV System – Inverter should match size of your PV power system or appliance you need it for. If you have a 2,500W PV system, and must choose between a 2,000W inverter or a 3,000W inverter, you should go the next size up and get the 3,000W inverter.

However, if you need an inverter for specific needs such as an appliance, and do not know the power rating but know the amperage, a simple formula is:

Amperes * 120 V = Watts

For example, if you have a simple 5 ampere appliance that requires AC voltage, then you would need a 600 W inverter.

Manufacturer – Some well known manufacturers are Xantrex, SMA, and OutBack.

Sine-wave – Currently, modified sine wave converters dominate the market and are useful for most purposes requiring AC voltage. However, certain equipment, such as laser printers, may require the better quality of power offered by a true sine wave converter. When choosing between the two, consider the equipment that the inverters will be supplying.

There are many factors to take into consideration when choosing the right inverter for your needs. If you are not sure about which inverter may be right for your needs, it may be a good idea to work with an inverter dealer or manufacturer to determine which inverter would work for you.

Multi-Tracking Solar Inverter Has Three-Phase Power

The new multi-tracking (MT) series adds three devices to Sputnik Engineering’s product portfolio in the power output range of 10 to 15 kilowatts. Unlike the smaller string inverters of the SolarMax S series, the MT series feeds the grid with three-phase power.

The maximum feed voltage of the MT inverters is 900 volts. This permits longer modular strings than before, which means a reduced need for wiring and less line loss as well as greater flexibility. The new multi-string concept also permits building plants with only one inverter on roofs whose surfaces, orientations and inclinations vary. The European efficiency of the inverters is 97,5 percent.

Full power at temperatures as high as 50 degrees

Sputnik’s developers have again optimised their cooling concept. At ambient temperatures up to 50 degrees Celsius the inverters still deliver full power. The protection type IP54 permits indoor as well as outdoor installation. And installation is simplified by the device’s light weight and the installation bracket included in the delivery. DC circuit breaker, graphics display with integrated data storage, a status signalling contact along with the usual communications interfaces RS485 and Ethernet are already integrated.

The new inverters are certified by the VDE Institute and bear the GS mark of conformity. A renewal of the five-year standard warranty to ten or twelve years is available as an option. Sputnik Engineering will unveil its new developments at the Intersolar trade fair, which runs from 9 to 11 June in Munich.

SolarMax MT series technical data

All specifications are preliminary, from April 2010.

PV Inverter Delivers Up To 97% Energy Output

This photovoltaic grid connected inverter incorporates two input positions with two MPPTs with an operating range of 90 to 580 VDC for maximum power harvesting and delivers up to 97% energy output. The PVI-6000-OUTD-US inverter is installed in a IP65 rated enclosure to endure tough weather conditions. The incorporated front-mounted heat sink prevents pollution, increases the cooling efficiency for long term usage.

The AURORA PVI-6000-OUTD-US inverter manufactured by Power-One has the input parameters such as a nominal DC power of 6.18 kW, a max recommended DC power of 6.4 kW, an operating MPPT input voltage range of 90 to 580 V, a max input voltage of 600 V,  and a nominal activation voltage of 200 V. The output parameters of this model include a nominal AC power of 6000 kW, a max AC power of 6000 kW, a maximum AC voltage range of 187.2-224.6; 216-259.2; 249.3-299.2 V, a nominal AC frequency of 60 Hz.

The height x width x depth dimensions of this Photovoltaic grid connected Inverter is 38 5/8 inches x 12 13/16 inches x 7 11/16 inches and weighs 66 lbs. This inverter has a two lines alphanumeric display. For the purpose communication this model incorporates a RS485 and an USB connection. This inverter meets the certification and standard requirements of UL1741/IEEE1547 & CSA -C22.2 N.107.1-01, VDE0126, CEI 11-20, DK5940, CEI64-8, IEC 61683, IEC 61727, EN50081, EN50082, EN61000, and CE certification.

power-one.com

Mitsubishi Electric Develops New PV Inverter To Maximize Solar Output

Mitsubishi Electric Corporation has developed a new maximum power-point tracking (MPPT) system in PV inverters to maximize output power in photovoltaic (PV) . The technology, which works with a single PV inverter, achieves the maximum power point even when part of a PV array is hidden by shadow or dust.

PV system characteristics such as output power are greatly influenced by the amount of sunlight and temperature. Conventional PV arrays, which are groups of PV modules connected either in series or parallel, use MPPT systems to help achieve their maximum output-power points. But if part of a PV array is hidden by shadow and the rest is still in sunlight, resulting in multiple peak points, a conventional MPPT system has difficulty tracking the maximum point. Especially in urban areas where PV systems are likely to be installed near buildings or other obstructions of sunlight, shadow can greatly decrease output power.

The technological breakthrough by Mitsubishi Electric allows the MPPT system to automatically measure the PV array’s output power characteristics and then control the array to operate at its maximum output-power point, thereby ensuring that the PV system receives maximum output power from the array. In some cases, this technology will be able to more than double the output power compared to a PV inverter equipped with a conventional MPPT system.

Mitsubishi Electric will continue its research and development with aims to incorporate this technology in its products in the near future.

www.mitsubishielectric.com