Abstract
A new three-phase constant voltage transformer is presented. In this circuit, unbalance of loads and asymmetry of input voltages can be removed in principle by ring connected compensation windings. When the triac of Automatic Voltage Regulator (AVR) is controlled to give a constant output voltage, phase differences between output voltages are kept at 120 degrees. This principle can also be applied to the conventional three-phase constant voltage transformer with magnetic shunts or the three-phase Triport UPS system.
