With Form 2555, you cannot claim the Additional Child Tax Credit refund. However, with Form 1116, you can.
Here at MyExpatTaxes, our expat tax software allows you to claim the tax credit and will help you determine whether you can receive the new fully refundable credit of $3,000-$3,600 on your taxes.
We can also help you start using the Foreign Tax Credit to receive the Child Tax Credit instead of the Foreign Earned Income Exclusion. Learn more about the Child Tax Credit for American families.