Authors: HÜSEYİN KÖSE, MEHMET TİMUR AYDEMİR
Abstract: For some industrial converter applications such as battery chargers, a DC/DC converter is needed to stepdown the high DC (direct current) voltages generated by PWM (pulse with modulated) rectifiers to lower voltage levelssuch as 110V/220V. These both complicate the design and decrease the efficiency. In this paper, a novel topology thatincludes a step-down transformer and a novel control algorithm is proposed. The proposed current, which is synchronized,look-up table based, sinusoidal PWM control method (CS-LUT-SPWM method) using switching frequency-orientedsynchronization (SWFOS) results in a very fast PWM generation and stable operation. Finally, a new thyristor-basedstart-up circuit providing safe operation when there is energy black out is proposed. A 32-kW converter has been designed,built, and tested to prove the concepts. The proposed converter has an e?iciency higher than 94%, an input current totalharmonic distortion (THDi) less than 5%, and a power factor closer to 0.99. Theoretical calculations and experimentedresults show that proposed converter has better e?iciency (94%-96%) compared to classical PWM boost rectifiers witha series DC/DC converter topology (92%) in the literature. Fast PWM control algorithm, less complexity, low switchingnoises, one-stage conversion circuit, and novel start-up circuit are other advantages of the proposed converter.
Keywords: Start-up of boost rectifier, six switch boost rectifier, current synchronized look-up table based controlmethod, isolated boost rectifier
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