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.

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.

In this paper, a sensorless flatness based controller with nonlinear observer for non-ideal BOOST CONVERTER is proposed. Losses are modeled with a voltage source series with input and a current source parallel to output. By a one-loop control structure with flatness property, both output voltage and inductor current is regulated. But, flatness based control is a model based method and requires extra sensors for obtaining data of all system parameters. For reducing numbers of sensors, a nonlinear observer is used to estimate output current and input voltage. So, sensors of these two parameters are eliminated. Simulation and experimental results are given to validate the proposed controller and robustness of proposed controller to variation of system parameters is obvious. In addition, simulation results of proposed controller are compared with a two-loop controller including PI and energy control

The quadratic BOOST CONVERTER is a DC-to-DC voltage CONVERTER with higher voltage gain compared to the conventional BOOST CONVERTERs. This CONVERTER is considered as a bilinear class system and there are some challenges to control its output voltage because it is a non-minimum phase system with limited input signal. In this research, a quadratic BOOST CONVERTER was controlled under variable load and input voltage with a passivity-based controller. The basis of this nonlinear controller was applying a damper to the closed-loop system. To improve the performance of the controller and the degree of freedom of design, in addition to adding losses to the closed loop system, its internal connections were also changed so that the controller could stabilize the output voltage. To maintain the output voltage stable under the conditions of input and load changes, an error integrator was used in addition to the proposed controller. Simulation of the quadratic BOOST CONVERTER circuit and the proposed controller was carried out in MATLAB Simulink software and the performance of the proposed controller was compared with a classic PI controller. The simulation results showed that the proposed controller regulates the output voltage while the input voltage and load change is kept stable, leading to a better performance compared to the PI controller.

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.

In this article the structural analysis of a single-input-multiple-output DC-DC BOOST CONVERTER including only one inductor is presented. The outputs of the CONVERTER are independent and detached from one another and, hence, the CONVERTER can be employed in such applications that require multiple and independent voltage levels (individual) with unidirectional current flow. Moreover, the size of the proposed CONVERTER is decreased because of having only one inductor. The main advantages of the proposed structure is the lack of transformer which leads to allowing for modular construction and the possibility for switching at high frequencies. In this paper, the operating principles of mentioned structure are explained and accurate analysis of this structure are conducted. Finally, the experimental results of this single-input-multiple-output DC-DC multiplier CONVERTER are presented in detail verifying the operation of this structure.

In the present paper the structure of a single inductor double output CONVERTER (SIDO) has been studied. One of the major challenge, to design a controller in SIDO CONVERTERs, is removing the cross-regulation among the outputs. On the other hand, the multi-stages operation of SIDO CONVERTERs cause, to achieve the model which predicts their all behaviors, be more difficult than typical CONVERTERs. In this paper a SIDO BOOST/BOOST CONVERTER is modeled by a systematic signal flow graph (SFG) modelling. Based on obtained model a multivariable control scheme has been proposed to reduce the cross regulation of the output. Finally Simulation results are included to show the validity of the obtained model and the designed Controller.