Transformer less voltage regulator

This paper proposes a single phase ac-ac transformer less voltage regulator. The proposed techniques can operate in buck or boost mode depends on the desired output voltage. The proposed system employs a pulse width modulation (PWM) ac-ac converter along with feed forward and PID close loop control. This technique are used power semiconductor device IGBTs as bidirectional switch of the ac-ac converter and circuit can easily and steadily maintain regulated voltage supply to end user. Power quality problems which are faced transients, sags, surge, harmonics and impulses. Voltage sags is mainly due to the fault occurring in the transmission and distribution system, loads like welding and equipments. A surge voltage is caused by a switching transient or other undesirable voltage source appearing on the power system. These proposed techniques provide steady state output voltage with feed-forward techniques and PID controller, which is verify with theoretical and simulation results.