Advantages of SEPIC converters with ESBT? in 3-Φ main universal input PFC

摘要

The possibility to operate with large variation of input voltage and load current has recently characterized thedesign activity in low-medium power management applications. In this scenario, PFC pre-regulators operating inTransition Mode or in Continuous Mode as step up and down converters had been essentially limited to low maininput voltage applications because of performance offered by traditional power switches.Recently introduced in the market and offering an excellent trade-off among the forward voltage drop, thebreakdown voltage and switching speed, the ESBTs (Emitter Switched Bipolar Transistors) permit to go over theabove mentioned limits.This article analyzes the advantages and drawbacks of SEPIC converters in high voltage main applications with anew monolithic 1500V/6A ESBT as main switch. Particular emphasis has been given to the high efficiency andlow THD achieved with the proposed solution. Comparison with the more traditionally used 2 stages buck-boostconverter is also carried out.Finally, the results have been validated on 120W SEPIC converter used as PFC pre-regulator in 347 – 480Vacindustrial ballast application.