A voltage controller also called an AC voltage controller or AC controller. It is an electronic thyristor, TRIAC, SCR or IGBT electronic module that converts a fixed and fixed voltage to obtain variable voltage in the output delivered to a resistive load. This varied voltage output is used to dim street lights, vary heating temperatures in homes or industry, control the speed of fans and winding machines and many other applications, much like an auto-transformer. The voltage control modules are under the domain of power electronics. Because they are low maintenance and highly efficient, voltage controllers have largely replaced modules such as magnetic amplifiers and saturable reactors in industrial use.
Advantages of ac voltage controllers
1. High Efficiency
2. Flexibility in control
3. Less maintenance
Disadvantages of AC Voltage Controllers
The main drawback is the introduction of harmonics in the supply current and load voltage waveforms, particularly at low output voltages.