In this paper, a new embedded Z-H (EZ-H) buck-boost converter is proposed. In this topology, two identical dc voltage sources are embedded in a LC network in a series connection with the inductors. The proposed converter eliminates the shoot-through (ST) switching state and there is no need for a front-end diode. Other advantages of the proposed topology are having capability of buck and boost operations in one structure; reaching the maximum gain in the duty cycle near 0.5; lowering ripples of voltage and current; and particularly reducing the voltage stress on the capacitors. In this paper, the voltage and current equations of all the components are extracted with considering all the operation modes. In addition, a suitable switching method is presented for the proposed converter to generate the desired output voltage. The ripple values of inductors and capacitors are calculated. Simulation results by the PSCAD/EMTDC software show accuracy and performance of the proposed converter.

Background and Objectives: Power electronics infrastructures play an important role in charging different types of electric vehicles (EVs) especially Plug-in Hybrid EVs (PHEVs). Designing appropriate power converters is the topic of various studies. Method: In this paper, a novel bidirectional buck-boost multifunctional integrated converter is presented which is capable of handling battery and fuel cell stack in plug-in hybrid electric vehicles. The proposed converter has the ability to work in five different operating modes (Charging/Propulsion (only battery)/ Propulsion (battery and FC)/ Regenerative braking/ V2G). The introduced multifunctional two-stage converter has the ability to work in all the above-mentioned modes in buck-boost condition, the feature that does not exist in the previous works. It is possible to control active and reactive power by using the effective dual-loop PI control method which is introduced in this paper. Working as an on-board charger and DC-DC converter (which interfaced between power sources and motor drive system) causes a decrease in the counts of the total components and an increase in system efficiency. Results: Operation principle and steady-state analysis of each stage of the proposed converter in all operating modes are provided in detail and in order to design an appropriate applicable converter, the design considerations and procedure are also explained for capacitive and inductive components. The proposed converter is simulated in MATLAB/SIMULAIN environment and results are provided. Voltage and current waveforms in all operating conditions are provided with their transient. FFT analysis of the input current (in the operating modes in which the converter absorb or deliver power from/to the grid) is also mentioned. A reduced-scale setup of the presented converter is built and tested and experimental results confirm simulation ones. Conclusion: A bidirectional buck-boost integrated converter in PHEVs applications is introduced in this paper. The design procedure of the presented converter is provided and also an effective control method to control active and reactive power during charging and V2G modes is introduced. A comparison study of the proposed converter with other similar converters introduced in recent years in terms of the number of high-frequency switches in each mode is also done. Simulation and experimental results are also provided.

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.

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 new single-stage power factor correction (PFC) converter is presented. In the input stage of this structure, a buck converter is used to correct the power factor. So, the voltage stress of bulk capacitor reduced, and one of the main problems in the single stage PFC converters is solved. Moreover, by employing a compensator circuit, the input current dead angle which is the main drawback of the existing buck type PFCs is obviated, thus the total harmonic distortion is very low. In converters with buck PFC, input current dead angle results in high THD. In the proposed converter, using an inductor coupled with the main transformer, this problem is solved. A part of input power is transmitted directly to the output that helps to improve efficiency. The proposed converter is analyzed and the validity of the proposed solution is proven in the form of theoretical analysis, simulation and practical results.

In this paper, a soft switching buck dc/dc converter applicable for fuel cell has been analyzed and the complete details of designing have been presented. Reduction in switching losses and the elimination of voltage/current stresses of the switches are the major advantages of the aforementioned converter. In this converter, the switches are to be ON under zero voltage and zero current conditions, whereas they are to be OFF under zero voltage condition. This converter can be used in high switching frequency. In this paper, the principles of the performance, full details of the analyses of conduction modes, and designing approach have been presented. The performance and correct operation of the converter are validated by the experimental and simulation in PSCAD/EMTDC software.

This paper addresses a key challenge in designing a suitable controller for DC-DC converters to regulate the output voltage effectively within a limited time frame. In addition to non-minimum phase behavior of such type of converter, a significant issue, namely parametric uncertainty, can further complicate this task. Robust control theory is an efficient approach to deal with this problem. However, its implementation often requires high-order controllers, which may not be practical due to hardware and computational constraints. Here, we propose a low-order robust controller satisfying the robust stability and performance criteria of conventional high-order controllers. To tackle this issue, a constraint optimization problem is formulated, and the evolutionary algorithms are adopted to achieve the optimal parameter values of the controller. Both simulation and experimental outcomes have been documented, and a comparative analysis with an optimal Proportional-Integral (PI) controller has been conducted to substantiate efficiency to the proposed methodology.