PWM Control of a High-Gain N-Phase Interleaved Current-Fed Topology

Non-isolated high-gain dc-dc converters are essential for applications with low input voltage, such as solar PV modules and fuel-cells. Due to the high step-up conversion ratio, the input current increases significantly with increase in power rating. This leads to considerable conduction loss in the non-ideal elements of the converter, degrading the efficiency. Moreover, peak-to-peak ripple of the input current also increases with an increase in power rating. This increases the size of the passive elements, thereby limiting the power density. An n-phase Interleaved Complementary Current-fed Topology (n-phase ICCFT) is proposed in this article to address the aforementioned limitations. Two pulse width modulated (PWM) schemes are proposed to implement the interleaving of the n-phases. Detailed steady-state analysis with various operating modes and the gain characteristics of the proposed converter are analyzed in the article. A comparative analysis of the two PWM schemes in terms of ripple characteristics, capacitor current stress, and power loss is reported. Operation of a two-phase ICCFT with the proposed PWM schemes is verified using PLECS simulation and experiments using a proof-of-concept hardware.