This paper focuses on introducing a transformerless DC/DC converter with low total switching device power in dual working modes including step-up and step-up/down modes. The proposed converter is analysed in terms of the continuous conduction mode, steady state, and efficiency with the replacement of parasitic resistance effects. The proposed converter in the step-up mode has a high voltage gain ratio and a continuous input current. Then, the other working mode of the proposed converter with relevant DC/DC converters is compared. By this comparison, the proposed converter has a high voltage gain ratio. Also, the converter characteristics such as voltage stress on power switches and charge pump capacitors are in a good condition in this mode. Finally, the experimental results from a laboratory made prototype and the obtained waveforms from the simulation in PLECS are presented for validation such as higher voltage gain ratio, lower total switching device power and better efficiency.

This paper presents a review of non-isolated DC-DC converters of voltage enhancers. Relevant review details are presented about the topologies of converters, including Boost, hybrid Boost, three-level Boost, multi-level Boost, and three-level hybrid converters that are most commonly used in photovoltaic systems. In the end, there are also several voltage level enhancers that can replace the converters provided in photovoltaic systems. Finally, a comparison is made between the converters in terms of the number of elements used in the circuit and the complexity of controlling the switches in the converters with their advantages and disadvantages being presented in a table. Since the use of multi-level Boost converters reduces the switch voltage stress, weight, and cost compared to the conventional mode and as they are also better at higher powers, they have been used significantly in different systems.

Photovoltaic (PV) panels rely on environmental conditions such as irradiation or temperature, and thus they require an interface Boost converter. Non-isolated DC-DC Boost converters have a lower volume, lower costs and lower power dissipation compared with isolated converters. In this study, a novel high efficiency non-isolated DC-DC Boost converter is proposed to be used in PV systems. The converter includes only one semiconductor switch which causes lower switching losses. The main advantages of the proposed converter include low input current ripples, low voltage stress on semiconductor switches, high efficiency and low conduction losses. Moreover, maximum power is achieved from PV panels. A prototype of the proposed converter has been built, and experimental results are presented which explicitly validate theoretical results, suggesting that this Boost converter is desirable for PV applications.

A novel transformer less high step-up buck–Boost dc-dc converter is proposed in this paper. The output voltages of some sources such as fuel cell, photovoltaic are not regulated. Therefore voltage regulation is required to fix the DC-link voltage. Hence, a buck Boost DC/DC converter is suitable to regulate the output voltage of these sources. The presented converter voltage gain is higher that of the conventional Boost, buck Boost, CUK, SEPIC and ZETA converters and high voltage gain can be obtained with a suitable duty cycle. In this converter, only one power switch is utilized. The voltage stress across the power switch and diodes is low. Hence, the low on-state resistance of the power switch can be selected to decrease conduction loss of the switch and improve efficiency. The low voltage stress across the diodes allows the prevent the reverse-recovery current problem. The proposed converter can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). The presented converter has simple structure; therefore the control of the proposed converter will be easy. The principle of operation and the mathematical analyses of the proposed converter are explained. The validity of the presented converter is verified by the experimental results.

In this paper we proposed, a new zero voltage switching isolated buck-Boost DC-DC converter with active clamp circuit. The active clamp circuit in this converter not only absorbs voltage spikes across the main switch but also provides soft switching conditions for all switches. All switches are Pulse Width Modulation controlled which simplifies the control implementation. One of the main advantages of this converter is operating at high power levels while soft switching conditions exist in both buck and Boost modes of converter operation. Since this converter can operate over a wide input voltage range, it can be employed in power factor correction. The experimental results obtained from a 150W prototype circuit operating at 100 KHz are presented to confirm the integrity of the proposed circuit.

The interleaved Boost converters are the power circuits that provide high-voltage, high-power with regulated output voltage for renewable energy systems which are generally suffer from low-voltage and unregulated output voltages. The soft switching methods reduce electromagnetic noises and switching losses in these converters. In this paper, a ZVT interleaved Boost converter with a simple auxiliary circuit is proposed. The proposed converter has a simple structure with low size and cost. In the proposed converter, soft switching condition is provided without any extra voltage and current stress on the main switches. The auxiliary circuit comprises two diodes and one auxiliary switch. The leakage inductance of the utilized coupled inductors is used as resonant inductor. The auxiliary switches benefit from significantly reduced voltage stress without requiring floating gate driver. The proposed converter can achieve zero voltage switching operation for the main switches and zero current switching for diodes and auxiliary switches, which causes to alleviate the reverse recovery problems of all diodes.