Multi-state and interleaved converters with passive impedances for current sharing

This paper presents multi-state and multilevel switching cells to generate high power non-isolated interleaved DC-DC, AC-DC, and DC-CA converters. The cells are classified in two groups; multistate switching cell (MSSC) based on autotransformer, and interleaved switching cell (ISC) based on inductors. Each switching cell has impedance based on small inductor, L_sh, connected between the legs, named current sharing circuit (CSC), which guarantees a zero average voltage between the terminals of the involved magnetic components, and thereby absorbs the PWM duty cycle differences. The small inductor causes duty cycle reduction; therefore its value should be very small. To verify the current sharing through the magnetic components, two Buck DC-DC converters with 1 kW output power, 200 V input voltage, 60 V output voltage, and 25 kHz switching frequency, was assembled and tested in laboratory.