Multiphase Interleaved Boost Converter With Frequency Modulation for Sensorless Current Sharing

In industries, conventional multiphase interleaved boost converters are used to divide current stresses in semiconductors and increase the processed power. However, owing to the high sensibility of current division under variations in parasitic resistances and differences in duty cycles between phases, techniques are required to guarantee the division of input currents. This article proposes a multiphase interleaved boost converter with soft switching based on the switching cell with pulse-frequency modulation (SC-PFM) to solve this problem. This proposal presents a self-balance of the currents between the phases without a current control loop and soft switching. Moreover, the output diodes do not suffer from reverse recovery. The converter operates with only one output voltage control loop and one voltage sensor. The currents are naturally balanced owing to the input characteristics of the converter with low impact from differences between parasitic parameters of the modules. The experimental results of a 2-kW prototype with two modules of the interleaved boost converter (IBC)-SC-PFM validate the effectiveness of this solution with an efficiency of approximately 98%.