Three‐phase interleaved high step‐up bidirectional DC–DCconverter

Abstract

A three-phase interleaved high step-up bidirectional DC–DC converter is proposed, which can achieve three times the voltage gain of the traditional three-phase interleaved boost converter only by adding two capacitors. The proposed converter has the characteristics of low switch voltage and current stresses, low output voltage ripple, automatic voltage-balancing and current-sharing abilities. Compared with the traditional interleaved switching strategy, a 180° interleaved switching strategy is proposed, which is more suitable for the proposed converter by widening the working duty cycle range. Closed dual-loop control is used to regulate the output voltage of the converter. The parameter determining the method of the closed-loop controllers based on the Bode diagram is described in order to control the high-order converter. Operating principle, modelling, steady-state analysis, voltage-balancing and current-sharing ability analysis and closed-loop design of the converter are studied in more detail. Finally, experimental verification and efficiency measurements are implemented by a 300 W, 24 V input to 230 V DC bus prototype, which proved that the proposed converter is more suitable than the traditional three-phase interleaved boost converter for some applications where requiring about six to ten times the voltage conversion ratio.