• A DC/AC converter is generally called an "inverter." Many more specific terms are used depending on the exact application and implementation (switched mode power supply, uninterruptible power supply, etc.) An even more generic term is "electronic oscillator."

    Wikipedia is very helpful for these sort of technical translations, especially if you need to be sure you've been precise enough. Start from the French language page, and then use click "English" in the autres langues section on the left side of the screen. ;)
    For translation of technical terms, the Grand Dictionnaire Terminologique can be very helpful. Check out the many meanings of "onduleur".
    I thing Uninterruptible Power Supply is ok ans cas
    mais pour la traduction direct inverter.
    Merci a tous