A novel step-up/step-down DC-DC converter based on flyback and SEPIC topologies with improved voltage gain

Due to rising environmental challenges and complicated emission regulations, electric vehicles have been seen as an alternative to traditional transportation. Modern electric vehicles use electronic circuits powered by electrical energy (PECs). DC to DC converters and DC to AC inverters are both classed as PECs. DC to AC inverter: It delivers utility power while also driving electric motors; the DC to DC converter serves as a source of low voltage utility electricity. DC to DC converters are categorised according to application requirements. In order to charge a high-power electric load, an increase in output is needed. It is because of this that it uses the SEPIC converter. DC-DC converter designates the single-ended primary-inductor converter (SEPIC). The electrical potential may be any value, such as less than, equal to, or greater than the input voltage. Duty cycle of the control transistor governs the SEPIC output. In SEPIC, voltage conversion is accomplished by transferring energy between inductors and capacitors. SEPIC boost converter relates to buck-boost converter modification. Both are comparable. The SEPIC converter has a few benefits. They are non-inverted input- same polarity of input and output voltage, between output and input, energy is linked using a series capacitor- to a short circuit output, producing greater responsiveness, genuine shutdown is possible- output goes to 0V if switch is off. This converter is simple to control while operating in CCM mode. Because both switches use the same gating pulse, the duty cycle may be adjusted to obtain a broad range of output voltage. In terms of number of components, diode and switch voltage stress, and voltage gain, recent non-coupled inductor converters are compared to the proposed converter. With regard to output voltage, the suggested converter produces a lower proportion of voltage stress on switches. When compared to existing converters, the suggested converter produces a high voltage gain with fewer components.

<span lang="EN-US">In this work, a fuzzy logic controller is used to control the output voltage of a photovoltaic system with a DC-DC converter; type Single Ended Primary Inductor Converter (SEPIC). The system is designed for 210 W solar PV (SCHOTT 210) panel and to feed an average demand of 78 W. This system includes solar panels, SEPIC converter and fuzzy logic controller. The SEPIC converter provides a constant DC bus voltage and its duty cycle controlled by the fuzzy logic controller which is needed to improve PV panel’s utilization efficiency. A fuzzy logic controller (FLC) is also used to generate the PWM signal for the SEPIC converter. </span>

SEPIC (Single Ended Primary Inductance Converter) is a dc-dc converter which can provide an output voltage either greater than or less than the input voltage. Basically it is similar to a buck-boost converter. The output voltage polarity of a SEPIC is non-inverted whereas the output voltage polarity is inverted in a buck-boost converter. SEPIC converters are widely used in battery operated equipment, power supplies for laptops and computers, power factor correction etc. Rapid development of computing technologies lead to great use of simulation tools for the planning and design of electrical systems. Nowadays complex electrical systems can be simulated with less time. There are mainly two types of simulations. One is offline simulation and other is real time simulation. In real time simulation both physical time and simulation time are same. Real time simulators are extensively used in many engineering fields. Statistical power grid protection tests, aircraft design and simulation, motor drive controller design methods and space robot integration are a few examples of real-time simulator technology applications. In this paper an average model of the SEPIC is derived at first. Then an offline simulation and real time simulation of SEPIC using miniature full spectrum simulator is explained.

Regularization in power production increasing global need of power the renewable energy resource brings more attention. These resources are responsible for deducing carbon dioxide emission during burning coal, deforestation due to extension and installation of hydroelectric power plants, ozone layer depletion. Among hydro, tidal, wind, solar, geothermal; solar is preferred due to affordability and availability, compact in structure. The structure of Single ended primary inductor converter (SEPIC) interfaced with renewable energy resource to obtain high voltage gain is proposed in this paper. The SEPIC converter has several benefits such as low voltage distortion, reduction in noise level, low switching stress, and continuous input current. Also, high voltage gain and input current continuity make the presented converter suitable for renewable energy sources. The modified structure provides high gain ratio with a single power semiconducting switch. With less number of active and passive components enrolled within proposed system deduce capital cost and improves efficiency. The system efficiency is also analyzed with voltage gain under continuous and discontinuous conduction mode. Depending upon the reactive component’s voltage-current ratio of active and passive components is chosen respectively. The circuit topology is verified is through MATLAB software and experimental analysis.

The integration of a Single-Ended Primary-Inductor Converter (SEPIC) combined with a Genetic Algorithm (GA) characterizes a significant improvement in the domain of efficiency and overall performance of photovoltaic (PV) systems. This novel approach involves the SEPIC converter which has the ability to deliver a high-efficiency conversion mechanism which helps in enabling the optimization of the power extraction from solar panels. This can function in both step-up and step-down modes which helps in making it more suitable for photovoltaic applications where the panel output can vary generally due to changes in sunlight intensity and temperature. The Genetic Algorithm, on the other hand, is a search heuristic that mimics the process of natural selection to identify optimal solutions. When applied to the SEPIC converter in PV systems, the GA continuously adjusts the converter's parameters to find the optimal operating point even under fluctuating varied environmental conditions. This safeguards maximum power output from the solar panels by dynamically adapting to changes, thereby improving the overall energy harvesting efficiency. This combination of the SEPIC converter and Genetic Algorithm leverages the strengths of both: the SEPIC converter's flexibility in handling varying input voltages and the GA's ability to find the optimal solution in a complex search space. As a result, the energy harvesting process in photovoltaic systems becomes more robust, efficient, and capable of delivering improved performance, ultimately leading to higher electricity generation from solar energy sources. This approach not only enhances the sustainability of power systems but also contributes to the reduction of dependency on fossil fuels by optimizing renewable energy sources.

In this paper, a (PF) Power factor correction and power quality (PQ) improvement based BLDC motor drive proposed. Normally the permanent magnet BLDC motor drive connected with the diode bridge rectifier and high value of the capacitor due to which poor power factor and higher THD (Total harmonic distortion) value at the input side To overcome this difficulty SEPIC (Single-ended primary inductance converter) converter use to optimize the PF and THD value. The converter operates in discontinuous conduction mode to get the desired result. This scheme also used for speed control of BLDC motor by controlling the VSI (voltage source inverter) feeding the BLDC drive.

This paper presents modelling and simulation of artificial neuro-fuzzy inference system (ANFIS)-based maximum power point tracking (MPPT) algorithm for PV system with modified SEPIC converter. The conventional existing MPPT methods are having major drawbacks of high oscillations at maximum power point and low efficiency due to uncertain nature of solar radiation and temperature. These mentioned problems can be solved by the proposed adaptive (ANFIS)-based MPPT. The proposed work involves ANFIS and modified single ended primary inductor converter (SEPIC) to extract maximum power from PV panel. The results obtained from proposed methodology are compared with other MPPT algorithms such as perturb and observe (P&O), incremental conductance (INC) and radial basis function network (RBFN). The improvement in voltage rating of modified SEPIC is compared with conventional SEPIC converter. The result confirms the superiority of the proposed system.

The basic operation of a solar cell, module or photovoltaic generator under different irradiation and temperature conditions is characterized by its I-V characteristic curve. Only the experimental measurement of the I-V curve allows us to know with precision the electrical parameters of a photovoltaic cell, module or array. This measure provides very relevant information for the design, installation and maintenance of photovoltaic systems. Currently, the I-V characteristic curve is obtained by connecting a variable charge to the panel terminals in order to achieve that the current of the terminals ranges from zero to the short circuit current. In this paper we propose a new experimental way to measure this characteristic curve by using Buck-Boost-Derived DC-DC converters. It has been proved that the optimal topologies for this purpose are the SEPIC (Single-Ended Primary Inductance Converter) and Cuk converters. The theoretical analysis performed has been validated by means of simulation and experimentally. Additionally, a comparison between three known conventional methods and the proposed one is provided.

This paper proposes a capacitor switching logic for a multi input Single Ended Primary Inductance Converter (SEPIC) with efficient Maximum Power Point Tracking (MPPT) scheme for multiple non aligned solar panels. The proposed scheme is an improvement of time division multiplexing control of multi input converters for low power solar energy harvesters. In the proposed design, the capacitor switching logic gives the flexibility of selecting panels on demand providing additional advantage of isolation. For better accuracy an efficient algorithm has been implemented for determining MPPT. The MPPT is practically determined in each cycle when the corresponding capacitor is connected to converter. Using SEPIC converter at the output provides a constant 15V for charging the battery for solar panel voltage range from 8V to 25V. The design improvements will bring increased efficiency for medium power solar systems.

The photovoltaic (PV) stand-alone system requires a battery charger for energy storage. This paper presents the modeling and controller design of the PV charger system implemented with the single-ended primary inductance converter (SEPIC). The designed SEPIC employs the peak-current-mode control with the current command generated from the input PV voltage regulating loop, where the voltage command is determined by both the PV module maximum power point tracking (MPPT) control loop and the battery charging loop. The control objective is to balance the power flow from the PV module to the battery and the load such that the PV power is utilized effectively and the battery is charged with three charging stages. This paper gives a detailed modeling of the SEPIC with the PV module input and peak-current-mode control first. Accordingly, the PV voltage controller, as well as the adaptive MPPT controller, is designed. An 80-W prototype system is built. The effectiveness of the proposed methods is proved with some simulation and experimental results.

This paper presents the regulation of the output voltage and inductor currents in a Single Ended Primary Inductor Converter (SEPIC), operating in the continuous conduction mode (CCM) using a sliding mode controller. Owing to the time varying nature of the SEPIC converter, designing a feedback controller is a challenging task. In order to improve the dynamic performance of the SEPIC, a Sliding Mode Controller (SMC) is developed. The developed SMC is designed by using a state space average model. The performance of the developed controller with the SEPIC converter is validated at different working conditions through Matlab simulations. It is also compared with the performance while using a PI controller. The results show that the designed controller gives very good output voltage regulation under different operating conditions such as a varying input voltage, changes in the load and component variations. A 48V, 46W experimental setup for has been developed in an analog platform to validate the performance of the proposed SMC.

ABSTRACTThis paper proposes quadratic-like single-ended primary inductance converter (SEPIC) converter, a DC/DC converter suitable for wide-input voltage range. This circuit can be gated at higher duty ratio compared with conventional SEPIC converter, while the voltage conversion ratio is low. This feature is beneficial for high-input voltage because it prevents the controller from falling into extremely low duty ratio limitation. A prototype circuit is implemented with Pulse-Width-Modulation (PWM) control to drive the Light emitting diode (LED) strings for demonstration of the circuit application. Recent studies have advocated LEDs as efficient and durable technology for lighting applications. A stabilized output converter is required to regulate the current flowing through the LED lamp. The dimming control of the LED light output is implemented by the controller. This converter can be powered from either a 24-Vdc battery or from the universal AC input voltage (up to 360 Vdc). Such a wide-input voltage application can be found in emergency lighting in which the light is possibly powered either from battery or AC input voltages. Experimental results prove the feasibility of the circuit topology and theoretical analysis.

The efficient management of solar energy requires controllers capable of maximizing the power extracted from photovoltaic panels while ensuring optimum battery protection. This article presents the results of the design, realization and experimentation of a solar controller integrating a Maximum Power Point Tracking (MPPT) technique. This regulator is based on a Buck-Boost DC-DC converter with the SEPIC (Single Ended Primary Inductor Converter) configuration, designed to lower and raise voltage as required, to ensure efficient charging. To evaluate the effectiveness of the design, the regulator’s performance was analyzed by implementing a prototype, and experimental tests show that the system works well.

This study presents an optimisation technique for proportional‐integral‐derivative (PID) controller to achieve maximum‐power‐point tracking (MPPT) of single‐ended primary‐inductor converter (SEPIC). A new weight function is developed to optimise the PID parameters based on gradient‐descent (GD) method by adding low‐pass filter term. The proposed optimisation method does not stick in the local minima, which happens frequently with the traditional weight function used in GD method, where the low‐pass filter term suppresses the noise and smooths the iteration process. The prototype of the proposed optimised PID‐based SEPIC converter for photovoltaic inverter applications is built using DSP‐based TMS320F28335. The performance of the proposed optimised PID‐based MPPT scheme is tested in both simulation and experiment at different operating conditions. A performance comparison of the proposed GD method with the conventional GD PID is also made in real‐time. It is found that the proposed optimised PID‐based SEPIC converter is superior to the conventional GD PID controller in terms of power transfer and efficiency. Furthermore, the proposed optimised PID controller for two‐level inverter can achieve a better total harmonic distortion (THD) level as compared to the multi‐level inverter frequently used by researchers for the same purpose.

This paper provides a modified single-ended primary inductor converter (SEPIC) with an asymmetrical switched inductor super lift cell (ASISLC) for renewable energy applications. Solar, fuel cells, and so on, provide low output voltage, which is not sufficient for high voltage dc grid or dc loads. Therefore, the existence of a high gain DC-DC converter is mandatory. The proposed converter provides high gain, high efficiency, and less voltage stress at a low duty cycle. The proposed converter incorporates switched inductor together with a super lift cell. The super lift cell has a charge pump capacitor is connected in an asymmetrical fashion. The proposed converter offers continuous current at the input together with the above-mentioned advantages. This paper explains the operation of the ASISLC SEPIC converter in continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The operating principle, theoretical analysis, design process, and comparison of the suggested converters with converters from the literature that use similar operating principles are all discussed in this paper. A MATLAB simulation is done and their results are provided. Finally, a hardware prototype for 200W, 50 kHz switching frequency is built and their results are validated to authenticate the effectiveness of the proposed converter.