AX / Dynamics 365 For Finance and Operations blog

You can use DateTimeUtil::time(MyDate);

Retrieves the number of seconds that have elapsed since midnight as a timeOfDay value from the specified utcdatetime value.

TimeOfDay   secondsElapsed = DateTimeUtil::time(MyDate);

info(time2str(secondsElapsed, TimeSeparator::Auto, TimeFormat::Auto));

info(time2StrHM(secondsElapsed));

info(time2StrHMLeadingZero(secondsElapsed));

info(time2StrHMS(secondsElapsed))