January 14, 2015
inverter-charger

CENTRAL INVERTER VS MICRO INVERTER

Micro Inverters are individually connected to either one or two PV solar modules. This is relatively newer technology compared to the traditional central inverter. There are different types of Micro and Central inverters in the market.

Micro Inverter Examples: Enphase, Enecsys, Solarbridge, Aptonic, etc.

Central Inverter Examples: SMA, Fronius, Xantrex, Solectria, etc.

Micro inverters are connected to the solar panels.

Central Inverters are mounted on the wall while Enphase goes on the roof or underneath the solar module with the mounting. There are options with central inverter as far as where you can put the inverter. You can either put central inverter on your wall outside the house or inside.

Central inverters have been in the market for a long time and companies such as SMA and Fronius have been producing grid-tied inverters and have history of 30 plus years. Fronius started building inverters from as early as 1981 and SMA started about the same time.

   Central inverters are comparatively cheaper for example if you are building a 3KWDC, grid tie system

         Micro Inverter                                                                                               Central Inverter

FOR Approx. 3000W DC GRID TIED SYSTEM.

For example: M-215 (Enphase)                                                             For example: SB3000US (SMA)

You need about 13 inverters.                                                                  You need one inverter

Cost = 13 X $150.00 = $ 1,950                                                               Cost = $ 1,600.00

$ 1,598 at Sun Electronics, sunelec.com

FOR Approx. 5000 W DC GRID TIED SYSTEM.

For Micro Inverter                                                                                For Central Inverter

Example: M215 ( Enphase)                                                            Example: SB 5000US(SMA)

You need about 12 inverters .                                                         You need 1 inverter

Inverters cost = 150 X 22 = $3,300.00                                         Inverter Cost = $ 2,600.00                                                                                                                                                        $ 2,587 at Sun Electronics, sunelec.com

You have more flexibility in terms of which panel to choose to go with central inverters.

The Use of Micro inverters, sort of limits you with certain modules. For example you need to have modules with certain number of cells or certain amount of voltage etc. For example: Enphase’s M215 or some of the other micro inverters are only compatible with 60 cell modules only. Aptonic has one that is compatible with 72 cells.

Micro Inverters are a better option when there is a shading effect as the individual inverters are producing power independently. In central Inverter, if the performance of one PV Solar module drops, due to shading, breakage, hail stone, etc., it reduces the performance of the whole string and that affects the output of the entire inverter.

 

Central inverters are economically a better option where this is no shading effect.

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