Power transformer voltage regulation by core flux biassing - using feedback control network which generates biassing currents through auxiliary windings on transformer core

摘要

The three phase power transformer output voltage regulation circuit uses current through two auxiliary coils to bias the magnetic flux through the core and thus to affect the coupling coefficient of the transformer. The three phase transformer (1) output voltage is fed via a six diode bridge to a voltage measurement circuit (4) and a signal proportional to that voltage is fed to two intermediate amplifiers (7, 14) and thence to current amplifiers (10, 17). These generate current in two specialized bias windings (11, 18) on the transformer core and affect the output voltage according to the main flux path. A mains driven power supply (19) supplies the circuitry with current.