Hello Diego,

First you have to decide the maximum allowable ripple voltage on your DC-link. As a start I would suggest the ripple voltage (Vrip, peak-peak) to be 10% of the DC-link DC voltage.

Then you have to calculate the combined (DC/DC output ripple and DC/AC input ripple currents) ripple current (Irip) at the DC-link.

By using Irip peak-peak value you can calculate the maximum required capacitor ESR as:

ESR = Vrip,pk-pk / Irip,pk-pk

The ripple voltage in the capacitor depends on both its capacitance (C) and its ESR. However, considering only the ESR is adequate since to obtain the desired ESR you will need a capacitor whose capacitance is much larger (in practice) than the calculated value.

Hi, Please find in attached my paper. Guidelines for designing the DC-Link capacitor has been given In section 4 in single-phase H-bridge inverter.

Regards,

Manel Hammami

Conference Paper Single-Phase Grid-Connected Photovoltaic System Based on Boo...

http://ieeexplore.ieee.org/document/7877589/

Article Realization of Single-Phase Single-Stage Grid-Connected PV System

http://vbn.aau.dk/files/235439115/UEMP_2014_1325.R1_Sourcefile.pdf

Use the equation given in the 8 th page of this paper Jain S, Agarwal V. A single-stage grid connected inverter topology for solar PV systems with maximum power point tracking. IEEE transactions on power electronics. 2007 Sep;22(5):1928th pp22(5):1928-40.

Michalis Florides What should be the maximum allowable input ripple voltage magnitude to design pwm inverter. Please provide any links if possible

Rajat Khandelwal The allowable ripple depends on the design needs and how much you want to spend on the cost of the capacitors.

I would say start with a ripple voltage of 5% of the DC link voltage. If this creates any issues to your design reduce it depending on the available space you have (if you are building a real circuit) and the available budget.

Michalis Florides So, the only parameters of selection are cost and space? Because application of input capacitor will definitely reduce voltage ripple.

Rajat Khandelwal An input capacitor shall be included in the design. Its size though will depend on cost, space and allowable ripple voltage. There is no standard ripple voltage limitation but it depends on the design goals.

As I said, as a starting point, assume a ripple voltage of 5% of the DC link voltage and calculate the size of the capacitors based on that.