Techniques based on bipolar power transistor arrays for regulation of AC line voltage

Use of a series transistor array in an AC voltage regulator could substantially reduce the weight and volume and also lower the manufacturing costs by eliminating special transformers (in ferro-resonant systems) and servo mechanisms (in servo driven auto transformers). This nonswitching analogue technique has advantages over thyristor driven tap change systems too. This basic technique could be further improved to achieve higher overall efficiency, higher power ratings and to achieve a harmonic and spike free sinusoidal output. The author outlines the proposed circuit enhancements for a bipolar power transistor array technique for achieving a clean sinusoidal output with high overall efficiency