Solar inverters will always expect a DC input as that is what solar panels produce. Depending on the type of generator used, wind turbines might produce AC, requiring a slightly different input circuit in the inverter. But all the control algorithms would be the same.

Hi Mahdi,

I would differ just a bit with Andres and Tony.

As far as steady state operation is concerned, I would agree with them. As far as transient capability and fault capability (viewing from grid side) are concerned, again I would tend to agree.

However, the source side short duration variability in case of wind turbines (controlled say, according to pitch angle or stall mechanisms) and PV panels (controlled by one of the many available MPPT techniques) can lead to different DC side dynamics. Ideally, it is expected that the DC link (inclusive of the support capacitors) should be able to absorb all such effects.

But in practice, depending on the configuration of the two sources, this need not always be true. In which case, the inverter control (and to some extent, design) for the two cases may differ depending on the short duration variability of generated power.

-Sanjay

while the voltage fluctuation level range of the output from solar panels are reasonable (from sunrise to sunset), the voltage fluctuation range of wind turbines could be quite wide, as wind flutuates in the field.

Hence the grid tie invertors for wind turbines need to contain this large fluctuating voltage level as compared to the solar invertors, where the voltage fluctuation range is reasonably narrower as compared to its counterpart ....the wind

Although both units are so-called grid-tied inverters, control algorithms are different. Solar Photovoltaic grid-tied inverters are ready to get the maximum power of a photovoltaic (PV) panel. In this case the curve Current-Voltage is the typical from a PV panel. That is, you know your open circuit voltage system and your Short circuit current. PV inverters will extract the maximum power from the dynamic input power source implementing a Maximum Power Point Tracking (MPPT) algorithm.

On the other hand, wind inverters may have the output of a small wind turbine with a AC voltage that changes the value of frequency and voltage depending on the speed of the wind. In this case a AC/DC converter is needed. Once the AC/DC stage is included, the inverter will extract the maximum power taking into account that the curve Power-speed of a wind generator is different for every wind speed, and that the optimum speed of the wind generator will be controlled by the output power the inverter is able to extract.

Therefore, a wind interface device will be required if the wind generator provides AC voltage and, very important, a security device to divert power in case of inverter switches off from the grid is mandatory. Otherwise all the energy will not be dissipated and the wind generator may result damaged. This could be named diversion load.

Once all these issues are taken into account and the abovementioned control stage is introduced, the rest of the stages may be consider equivalent.

In my opinion there is a huge difference in saying PV grid-tied inverter or Wind grid-tied inverter.

Thank you, my friends, I appreciate your valuable inputs.