By Krunal Trivedi

Inverter is a device that convert DC(direct current) into AC(Alternative current)

Basically it is very harmful for use the DC supply so inverter is very useful instrument for every place and industry

Solar panels output Direct Current (DC). As DC electricity cannot be used directly by common household appliances nor fed into the mains grid; it first needs to be converted to Alternating Current (AC).

-GRID TIED INVERTERSThere are main three types of this invertersMICRO INVERTERSSTRING INVERTERSCENTRAL INVERTERS

Solar panels convert the sun’s energy into DC electricity

The DC electricity is channelled into a solar inverter that converts it to 240V 50HzAC electricity.

The 240V AC electricity can be used to power home appliances

Surplus electricity is fed back into the main grid.

A microinverter consists of a small box located on the back of or situated very close to a solar panel. Its role is to convert the DC electricity produced by a single solar panel.

Panel level MPPT (Maximum Power Point Tracking) Increase system availability – a single malfunctioning panel will

not have such an impact on the entire array Panel level monitoring Lower DC voltage, increasing safety. No need for ~ 600 V DC

cabling requiring conduits Allows for increased design flexibility, modules can be oriented in

different directions Increased yield from sites that suffer from overshadowing, as one

shadowed module doesn’t drag down a whole string No need to calculate string lengths – simpler to design systems Ability to use different makes/models of modules in one system,

particularly when repairing or updating older systems

Higher costs in terms of dollars per watt, currently up to double the cost compared to string inverters

Increased complexity in installation Given their positioning in an installation, some

micro-inverters may have issues in extreme heat Increased maintenance costs due to there being

multiple units in an array. Power-One is emerging as a leader in micro-

inverter technology.

A string inverter is the type most commonly used in home and commercial solar power systems. It is a large-ish box that is often situated some distance away from the solar array. Depending on the size of the installation, there may be more than one string inverter present.

Allows for high design flexibility High efficiency Robust 3 phase variations available Low cost Well supported (if buying trusted brands) Remote system monitoring capabilities

No panel level MPPT* No panel level monitoring* High voltage levels present a potential safety

hazard As with any other device, the “trusted brand”

issue is an important one. Not all string inverters are created equal; as this video demonstrates.

Central inverters are designed for applications such as large arrays installed on buildings, industrial facilities as well as field installations – they are basically just a very large string inverter.

Low capital price per watt High efficiency Comparative ease of installation – a single unit

in some scenariosCentral inverter disadvantages Size Noise A single potential point of entire system failure SMA (Sunny Central) and Fronius (CL series –

shown above) are leading central inverter brands.

sometimes called PV inverters, are types of electrical inverters which are developed to change a DC (direct current) voltage from photovoltaic arrays into AC (alternating current) currents which in turn are used to power home appliances and some utility grids. These solar inverters are very popular nowadays as electricity costs continue to rise. Also, this helps conserve energy for future use.

which match phase with a utility-supplied sine wave. Grid-tie inverters are designed to shut down automatically upon loss of utility supply, for safety reasons. They do not provide backup power during utility outages.

used in isolated systems where the inverter draws its DC energy from batteries charged by photovoltaic arrays. Many stand-alone inverters also incorporate integral battery chargers to replenish the battery from an ACsource, when available. Normally these do not interface in any way with the utility grid, and as such, are not required to have anti-islanding protection.

, are special inverters which are designed to draw energy from a battery, manage the battery charge via an onboard charger, and export excess energy to the utility grid. These inverters are capable of supplying AC energy to selected loads during a utility outage, and are required to have anti-islanding protection

Solar inverters use maximum power point tracking (MPPT) to get the maximum possible power from the PV array.[2] Solar cells have a complex relationship between solar irradiation, temperature and total resistance that produces a non-linear output efficiency known as the I-V curve. It is the purpose of the MPPT system to sample the output of the cells and determine a resistance (load) to obtain maximum power for any given environmental conditions

A charge controller may be used to power DC equipment with solar panels. The charge controller provides a regulated DC output and stores excess energy in a battery as well as monitoring the battery voltage to prevent under/over charging. More expensive units will also perform maximum power point tracking. An inverter can be connected to the output of a charge controller to drive AC loads.

Advanced solar pumping inverters convert DC voltage from the solar array into AC voltage to drive submersible pumps directly without the need for batteries or other energy storage devices. By utilizing MPPT (maximum power point tracking), solar pumping inverters regulate output frequency to control the speed of the pumps in order to save the pump motor from damage.

Solar pumping inverters usually have multiple ports to allow the input of DC current generated by PV arrays, one port to allow the output of AC voltage, and a further port for input from a water-level sensor.

Type Power Efficiency(a) Remarks

String inverter up to 100 kWp(c) 98%

Cost(b) €0.15 per watt-peak. Easy

to replace.

Central inverter above 100 kWp 98.5%

€0.10 per watt-peak. High

reliability. Often sold along with

a service contract.

Micro-inverter module power range 90%–95%€0.40 per watt-peak. Ease of

replacement concerns.

DC/DC converter

Power optimizermodule power range 98.8%

€0.40 per watt-peak. Ease of

replacement concerns. Inverter

is still needed. About 0.75 GWP

installed in 2013.

Thank you