A modular multilevel converter based high-power high-current power supply

This paper presents a power supply for high power and high current DC applications. Presently thyristor rectifiers along with passive filters are used in these applications, which suffer from poor input power factor and input current quality problems. The proposed power supply utilizes a modular multilevel rectifier and inverter, medium-frequency transformer and diode rectifier to convert medium-voltage AC to low-voltage DC via a medium-frequency AC link. Configuration provides unique advantages like high efficiency, high input power factor, good input current quality and controlled output current over the full operating range. Circuit configuration, design, control and performance of the proposed system are discussed in detail. Simulation results are presented to verify the performance and effectiveness of the system.