0885-8993 (c) 2019 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TPEL.2019.2962325, IEEE Transactions on Power Electronics IEEE POWER ELECTRONICS REGULAR PAPER/LETTER/CORRESPONDENCE Analysis and Modeling of a New Coupled-Inductor Buck-Boost DC/DC Converter for Renewable Energy Applications S. Hasanpour, A. Baghramian, and H. Mojallali Abstract- A New Coupled-Inductor Buck-Boost Converter (CIBuBoC) is proposed in this paper. In the proposed CIBuBoC, an ultra-high step-up/step-down voltage conversion ratio and step- up/step-down boundary adjustment are achieved compared to the other related buck-boost converters using two power switches with simultaneous operation along with a coupled-inductor. This circuit has a simple structure with two cascade semi-stage and some features including ultra-extended output voltage, continuous input current with low ripple, positive polarity of the output voltage and common ground. These features make the CIBuBoC more suitable for many applications such as photovoltaic (PV) systems. Moreover, the voltage stress across each power switches is much lower than the other buck-boost converters led to power MOSFETs selection with lower drain-source ON resistance (Rds). Therefore, the proposed converter has also enough high efficiency. All steady-state and stress analysis and also comparisons with other related converters in Continuous Conduction Mode (CCM) are provided in detail. Also, using the state-space averaging technique, the low-frequency behavior of the proposed CIBuBoC is studied completely. Experimental results of a 100W step-up 30V-200V and a 35W step-down 30V-22V confirm the theoretical advantages of the proposed circuit. I. INTRODUCTION DC/DC buck-boost (step‐up/step‐down) converters that have adjustable output voltage with a wide range of variety, are used as an important component for many power electronic applications such as renewable sources, portable devices, car electronic devices, mobile phones, LED products and ADSL modems [1]-[6]. The desired features of these converters are non-inverting wide high step-up/step-down voltage gain with proper efficiency, continuous input current with low ripple, low number of components and low cost. However, because of the simple structure along with higher efficiency and cheaper implementation, the non-isolated structures of DC/DC converters are often used in low power applications [7]-[8]. The conventional single switch step-up/step-down converters consisting of CUK, ZETA, Single-Ended Primary Inductance (SEPIC) and the classic Buck-Boost converter are capable of converting the input voltage to both higher and lower voltages level in the output. However, these conventional converters suffer from strong limitations on voltage gain ratio Manuscript received Jun 6, 2019; revised Jul 28, 2019 and Oct 14, 2019; accepted Dec 17, 2019. (Corresponding author: Sara hasanpour) The authors are with the Electrical Engineering Department, University of Guilan, Rasht 4199613776, Iran (e-mail: hassanpour.58.sh@gmail.com; alfred@guilan.ac.ir; mojallali@guilan.ac.ir). and component stresses, which limit their applications [9]-[11]. To improve the performance of the buck-boost converters, many modified non-isolated buck-boost converters are introduced in recent years [10], [12]-[17]. In [10], [12]-[14], new types of single switch buck-boost converters with high voltage gain are introduced. Using a large number of components and discontinuous input current are common constraint for these topologies, which limits their applications. In [15] and [16] continuous input current single switch buck- boost converters are suggested. In these converters, a high voltage conversion ratio using a large number of storage components has been provided. In addition, negative polarity of the output voltage and lack of common ground between the input and output voltages are the main disadvantages of the converter in [15]. The double-switch buck-boost topologies reduce component stresses and increase the voltage gain simultaneously with a lower number of storage components. Two types of the double- switch buck-boost converter with low component stresses and a few numbers of storage components are suggested in [17] and [18]. However, the mentioned converters have demerits including limited voltage gain, input current with high ripple, lack of common ground and non-simultaneous switching process. Recently, because of the importance of the step-up mode operation, further extension of voltage conversion range in buck-boost converters as a quadratic or semi-quadratic coefficient has been paid more attention. A group of single- switch buck-boost structures with quadratic voltage gain ratio are introduced in [19]. However, these converters act more in step-down mode due to the use of clamp diode. To solve this problem, in [20] a new transformer-less buck-boost converter with quadratic high voltage gain along with common ground is suggested. Discontinuous input current with high ripple is the main disadvantage of this converter, which limits its application. Moreover, novel single and double switch buck- boost converters with semi-quadratic voltage gain are introduced in [9], [21]-[23]. The output voltage with negative polarity along with high voltage stress across the switch and input current with high ripple are the main limitations of these mentioned converters. In [11], a new type of single-switch quadratic buck-boost topology with low input current ripple is proposed. This topology has been created from cascade connection of boost, buck-boost and buck converters. The negative polarity of output voltage and the use of a large number of semiconductor components are demerits of this