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In this paper, the combination of a high step-up boost converter with extended voltage multiplier cell and isolated SEPIC converter with a series output module is presented. Since these converters use the same current source in their inputs, they can share the common parts, so the structure of the proposed converter is simple. In this converter, the high frequency transformer used in the SEPIC converter and the inductor of the extended voltage multiplier cell are coupled, so the volume of the magnetic parts is reduced. In addition, an active-clamp circuit is used to solve the problem of leakage inductor and achieve to Zero Voltage Switching (ZVS) turn on/off for switches and ZCS for diodes. Compared to its high step-up counterpart, the proposed converter has the following: (1) distributed voltage stress on the diodes and voltage of the output capacitors are fair. (2) Higher voltage gain. (3) Voltage stresses on the diodes are lower and the reverse-recovery problem of the diodes is eliminated. (4) Minimum root mean square (RMS) leakage inductor current. The operational principle and characteristics of the proposed converter are presented, and in order to verify the proposed converter, a 200 W, 20–400 V prototype converter is implemented and experimental results are provided. [ABSTRACT FROM AUTHOR]

The paper presents a two-phase interleaved boost converter (IBC) providing higher step-up conversion ratio compared to the conventional IBC. The circuit consists of a crossly connected diode-capacitor cell which provides the extra boost up. The two identical capacitors of the cell are charged in parallel and discharged in series providing high voltage gain at considerably low duty ratio. Switching operations, ripple and average currents through inductors are analyzed in continuous conduction mode (CCM). Ripple in input current is also improved. The voltage stress across the semiconductor devices is less in the proposed converter. Also, boundary load condition is derived. Small-signal modeling is carried out and a control circuit is enabled in the voltage mode control framework. Power losses are analyzed and 96.53 % efficiency is achieved. Finally, the proposed converter is designed and implemented, and experimental results are provided. [ABSTRACT FROM AUTHOR]

In this paper, a novel high step-up single switch DC–DC converter with soft switching is presented. The main application of this converter is the connection of photovoltaic (PV) system to a 400 V DC-bus. The proposed converter achieves high step-up voltage gain with small duty cycle by a combined boost and fly-back topology. Also, its switch voltage stress is lower than the output voltage. Besides, in the proposed converter, any auxiliary switch or magnetic core has not been used — therefore, the number of converter components has not been increased much in comparison with the conventional boost-fly-back converter. The operation principles of the converter and its theoretical operation waveforms are presented. In order to evaluate the theoretical analysis, a prototype of the converter is designed and experimentally implemented. The practical results are presented for a 100 W boost-fly-back converter with input voltage of 40 V and output voltage of 400 V. Also, the output capacitor is designed to have less than 1% ripple on output voltage. [ABSTRACT FROM AUTHOR]