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Constant current to the load

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neonwarrior

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Hello everyone,
I have read this paper:

**broken link removed**

It is about using a T-LCL immitance converter at the output of a DC-AC inverter.

I think I understand that this immitance converter is a constant output current (vin constant), so it is independent of the load.
Ioutput = Vin/Zo

I saw this LCL immitance converter in grid tie inverters (other IEEE papers).

The doubt...
But if I have output voltage =110 VAC and I change the load I want the grid tie inverter to obey ohm's law 110 VAC / R; it seems the current will always be 1 Ampere for example.

Please help me
Thanks
 

A grid tied inverter is usually controlled so that the generated power (e.g. of a solar panel or a wind turbine) is completely supplied to the grid. The grid impedance can be expected much lower than Vgrid/Iinverter. In so far, ohms law doesn't apply.

An inverter which is operating as a controlled AC voltage source, e.g. a H-bridge with voltage bus, needs a coupling impedance to the grid to be able to control the output current. In most practical cases, a series inductance is playing this role.

The linked paper assumes a high Q 50 Hz resonant circuit as coupling element between inverter and grid. This might work in theory but is a rather unrealistic idea related to real inverter designs. The supposed 4A 100 mH inductor is huge related to the small inverter power.
 
Hey FvM thanks for your excellent reply!!

The inductance could be built with iron core (because of the 50 Hz cut-off frequency ) or it must be built with ferrite with air gap?
 

The series inductor of a grid tied inverter will use an air gap in any case. Choice of core material (laminated iron, iron powder, ferrite) is a matter of pwm frequency and residual high frequent AC current. It's usually small compared to mains fundamental current, in most cases laminated or cut tape iron core is preferred.
 
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