Use of multiple transformer windings for efficiency enhancement in the series transistor-array based linear AC voltage regulator

RMS AC voltage regulators are used in situations where consumer electronic devices are badly effected by AC line voltage fluctuations. Typical commercial AC regulators are based on four design approaches: (i) ferro-resonant regulators (ii) servo-driven variacs (iii) transformer tap changers and (iv) solid-state regulators. The patented linear AC regulator technique is a fifth and different approach in designing RMS AC voltage regulators to eliminate major issues related to above four traditional designs such as (a) low efficiency and flattened-output waveform (b) slow response time (c) tap dancing and related switching issues (d) harmonics and RFI/EMI at the output, respectively. However the linear AC voltage regulator has a low efficiency profile for the higher input line voltages. This paper presents a commercially useful multi-winding transformer based approach to address this issue and enhance the efficiency at higher AC input voltages while developing a potential commercial prototype.