Also known as an Automatic Voltage Regulator (AVR) or Voltage Regulator (VR), an Automatic Voltage Stabiliser (AVS) stabilises the mains power supply voltage to a load.
It is a feature of Line Interactive UPS systems and provides protection from power problems such as sags, brownouts and surges.
Automatic Voltage Stabilisers have a wide input voltage window (+20/-40%). If the input supply voltage is too low, the AVS uses a transformer to boost (step up) the output voltage.
On the other hand, if the input supply voltage is too high, the AVS reduces the voltage to a safe operating range (this process is known as buck or step down).
Output voltage tends to track the input voltage window as there’s no need for any voltage regulation.
Some AVS incorporate a filter that provides both the load and the stabiliser itself with limited protection from spikes, transients and electrical noise.