Soft Switching DC Converter for Medium Voltage Applications

• Main Author: Bor-Ren Lin
• Format: Article
• Language: English
• Published: MDPI AG 2018-12-01
• Series: Electronics
• Subjects: soft switching; asymmetric pulse-width modulation (APWM) converter; current doubler rectifier
• Online Access: https://www.mdpi.com/2079-9292/7/12/449

A dc-dc converter with asymmetric pulse-width modulation is presented for medium voltage applications, such as three-phase ac-dc converters, dc microgrid systems, or dc traction systems. To overcome high voltage stress on primary side and high current rating on secondary side, three dc-dc circuits with primary-series secondary-parallel structure are employed in the proposed converter. Current doubler rectifiers are used on the secondary side to achieve low ripple current on output side. Asymmetric pulse-width modulation is adopted to realize soft switching operation for power switches for wide load current operation and achieve high circuit efficiency. Current balancing cells with magnetic component are used on the primary side to achieve current balance in each circuit cell. The voltage balance capacitors are also adopted on primary side to realize voltage balance of input split capacitors. Finally, the circuit performance is confirmed and verified from the experiments with a 1.44 kW prototype.