Importance

Loading Importance Indicators...

Abstract

A three phase voltage regulator system uses a transformer having primary, secondary and tertiary windings for each phase which are closely magnetically coupled to each other and are connected to provide a four wire (wye) three phase output on three hot lines with a neutral line, and a three phase input which is also wye connected, but where the neutral need not be connected to an input neutral line. The voltage across each primary phase winding is regulated by a series connected regulator circuit. The regulator circuit may derive voltages from the respective tertiary winding which either bucks (subtracts from) or boosts (adds to) the input voltage so as to maintain the primary winding voltage substantially constant. A controller which is responsive to the output voltage from the secondary windings controls the regulators and responds to output voltages of their respective phases. The system output line to neutral voltages and line to line voltages are isolated from the input supply voltage and are not substantially affected by loading conditions (variations in the load connected to the secondary windings). The tertiary windings are connected in delta configuration to provide a path for the input neutral current, avoiding the need for a connection to an input neutral line, and help stabilize the output of the regulator system, while also extending the range of input voltages which can be regulated under unbalanced input voltage conditions.

Loading the Abstract Image...

First Claim