Inverters convert DC power to 220V AC power. There are two main types of inverters, modified sine-wave and pure sine-wave.
You can use modified sine-wave on TV's and other electronic equipment, but for motor based equipment, pure sine wave is better
Inverter-Chargers are similar, but have a built-in battery charger, and some have ATS (automatic transfer switch) or UPS
Inverters are silent running, so ideal for apartments, flats or offices