The 2017 and 2018 ASEC Supplement includes the question PREMSUBS – whether or not the respondent received ACA premium tax credits. I can find nothing in IPUMS that corresponds to this.
At the present time, the variables available via IPUMS CPS are only a sub-set of all CPS variables in every sample. The IPUMS CPS Team is currently working on making all of the variables available, but as you might imagine this process takes some time. That being said, I will send a note to the IPUMS CPS Team and ask them to make this variable available as soon as possible.