Single Ended Primary Inductor Converter Converter Research Articles

Investigation of a power factor correction converter utilizing SEPIC topology with input current switching

The single-ended primary-inductor converter (SEPIC) is a popular converter topology that can be employed in diverse application fields where the needed output voltage is greater or lesser than the input voltage. The non-inverted output voltage of a SEPIC converter provides additional advantages when compared to a buck-boost or Ćuk converter. Furthermore, the position of the capacitor in the SEPIC converter provides inherent isolation and circuit safety. One drawback in the conventional bridge-diode SEPIC AC-DC converter is the lack of controllability which can be overcome by adding extra active switch(es) or by replacing the passive diode(s) with active switch(es). However, introducing more active switches increases the control complexity and may increase the requirement for additional driver circuits. To address this trade-off, this article proposes a single-phase AC to DC modified SEPIC converter with input current-switching capability without adding any extra active switch(es). The existing active switch of the DC-DC SEPIC converter was shifted towards the input side and thus no additional switch has been introduced. This allows the option of input-current switching without any additional complexity in the control or driver circuit. The circuit topology, principles of operation, and ideal voltage gain equations for the suggested circuit have been derived and included in this research work. The proposed circuit has been simulated in both open-loop conditions and closed-loop control with varying duty cycles and output load. Results from the simulation show that the proposed converter provides better efficiency (∼90 %) and lower total harmonic distortion (THD) (10 %) for varying duty cycles when compared to a conventional converter. The converter also shows good dynamic response. A low-power 15V hardware prototype has been built to experimentally validate the performance of the proposed converter. Experimental results illustrate that the suggested converter can improve the power factor by up to 0.968 while operating at an efficiency above 75 %. This converter topology can be suitable for applications where high output voltage gain, high power factor, and lower THD are needed without isolation requirements.

Robust control of a single-ended primary inductor converter using adrc technique

Control of a single-ended primary inductor converter (SEPIC) is a challenging task as it is a fourth-order non-linear system. In this paper, an active disturbance rejection control (ADRC) scheme is proposed for the SEPIC converter with a high switching frequency. Selection of the observers and controller bandwidth is done according to the maximum sensitivity requirement to achieve robust performance towards varying input voltage and load. The effectiveness of the suggested ADRC is shown by calculating power and efficiencies for different loading conditions.

Soft Switching Technique in a Modified SEPIC Converter with MPPT using Cuckoo Search Algorithm

Abstract:: MPPT refers to the process of continuously tracking and adjusting the operating point of a photovoltaic (PV) system to maximize the power output from the solar panels. The operating point at which a PV system produces the most power under a specific set of environmental circumstances is known as the maximum power point (MPP). The Maximum power point tracking (MPPT) technique is used to overcome the challenges of PV arrays with variable irradiance levels, which collects the greatest power from the PV array. Standalone PV systems, as well as gridconnected systems, can benefit from a DC-DC converter with MPPT. This study compares the standard perturbation and observation (P&O) technique with the soft-switching method used in the SEPIC converter utilizing the cuckoo search (CS) algorithm using MATLAB/Simulink. Reviewing the simulation results and assessing the SEPIC converter's performance. Background:: SEPIC soft-switching converter, the soft-switching technique is applied to the SEPIC converter topology. It typically uses additional components, such as inductor and capacitors, to enable soft-switching operation. These additional components help to control the voltage and current waveforms across the main switching devices, reducing switching losses. Methods:: The proposed method uses a soft switching technique to reduce switching losses and to improve efficiency. Soft switching is used in SEPIC (Single Ended Primary Inductor Converter) converters, a type of DC-DC converter, to enhance their performance. The projected solution further addresses the maximum power point tracking (MPPT) issue in PV systems using the Cuckoo Search (CS) method. Results:: Soft switching technique is implemented in SEPIC converters to reduce these switching losses. In this system, Zero Voltage Switching (ZVS) involves turning on the switch when the voltage across it is zero. This allows the current to flow through the switch without creating any significant switching losses. CS algorithm can track the MPP quickly and accurately, it exhibits less prone to oscillations, easily monitor the MPP under a variety of weather circumstances. However, it exhibits negligible oscillation in a steady state, which results in significant power savings. Conclusion:: The modified SEPIC converter with a soft-switching MPPT cuckoo algorithm is used with a solar-powered system. A prototype comprising a solar panel, a SEPIC converter, a driver, and a controller circuit was created. A soft-switching SEPIC converter with an MPPT cuckoo algorithm for the PV system is implemented, as are the converter operation, converter analysis, and theoretical analysis, and a controller circuit is analysed. The PV system, MPPT controller with tracking algorithm, and PMSM load were used in the system simulation. A 60-watt SEPIC converter prototype is built, and the outcomes are also tested experimentally.

Average current mode controller for bridgeless PFC SEPIC converter with second-order model reduction operated in continuous conduction mode.

This paper proposes an average current mode controller (ACMC) for a single-phase bridgeless power factor correction (PFC) circuit using a single ended primary inductor converter (SEPIC) via second-order model reduction. The superiority of the proposed controller is PFC accomplished at power up to 350 W with high efficiency via the second-order model reduction. The design and implementation of ACMC on the converter operated with continuous conduction mode (CCM) is explained in detail. ACMC forces input current to follow sinusoidal current reference at different power levels and sustain high power factor (PF). The proposed controller is designed based on the theoretical analysis operation of the circuit. For verification, MATLAB/Simulink simulations are carried out and validation through an experiment test rig for 110-220 Vrms input, 100 Vdc/ 350 W output prototype at 20 kHz switching frequency. It is proven that the proposed controller strategy accomplishes high PF, high efficiency and conformity with the simulation.

Design and Implementation of Closed Loop SEPIC Converter for PV System Based Smart Home Application

The design, simulation, and analysis of the Single- ended primary-inductor converter (SEPIC), one of the least known Switch mode power converters, are presented in this study. By adjusting the switching element's duty cycle, this dc-dc converter may be utilized as a buck-boost converter. With minimal strain on components, SEPIC offers the specific benefit of offering positive polarity output voltage and ripple-free input and output current. This contrasts with conventional buck-boost converters, which have negative polarity output voltage along with extremely irregular currents and increased component stress. This makes it perfect for both commercial and personal uses, such as smart home gadgets that use PV energy. Under various input circumstances, extensive simulation has been performed in continuous conduction mode (CCM) utilizing SIMULINK-MATLAB. A PI controller has been added to optimize the responsiveness, reduce steady state error, and keep the output voltage constant. The SEPIC converter's hardware implementation verifies the simulation's findings.

Performance numerical evaluation of modified single-ended primary-inductor converter for photovoltaic systems

<span lang="EN-US">Single-ended primary-inductor converter (SEPIC) was considered a good alternative to a DC-DC converter for photovoltaic (PV) systems. The SEPIC converter can operate with an input voltage greater or less than the regulated output voltage, or as a step-up or step-down. As a step-up converter, SEPIC boosts PV voltage to specific levels. However, gain limitation and voltage stress continue to reduce the efficiency of conventional SEPIC converters. Because of this, researchers created a modified SEPIC converter to improve performance. In this paper, six modified SEPIC converters were compared and evaluated. To compare fairly, all modified SEPIC converters are non-isolated and use a single switch. Power simulator (PSIM) software was used to simulate each converter with a BISOL BMO-250 PV module and maximum power point tracking (MPPT) P&O controller. The converter with the highest static voltage gain and lowest duty cycle has been identified. It results in up to ten times voltage increment with a 0.8-duty ratio. All topologies have the same voltage stress, with maximum and minimum values of 30.1 and 29.5 V, respectively. On the other hand, each topology produces different average efficiencies, with the highest and lowest efficiency at 99.5% and 97.2%, respectively.</span>

Efficiency Enhancement of a Hybrid Sustainable Energy Harvesting System Using HHHOPSO-MPPT for IoT Devices

The Internet of Things (IoT) is a network of interconnected physical devices, vehicles, and buildings that are embedded with sensors, software, and network connectivity, enabling them to collect and exchange data. This exchange of data between the physical and digital worlds allows for a wide range of applications, from smart homes and cities to industrial automation and healthcare. However, a key challenge faced by IoT nodes is the limited availability of energy to support their operations. Typically, these nodes can only function for a few days based on their duty cycle. This paper introduces a solution that aims to ensure the sustainability of IoT applications by addressing this energy challenge. Thus, we develop a design of a hybrid sustainable energy system designed specifically for IoT nodes, using solar photovoltaic (PV) and wind turbines (WT) chosen for their multiple benefits and complementarity. The system uses the single-ended primary-inductance converter (SEPIC) and is controlled using a hybrid approach, combining Harris Hawks Optimization and Particle Swarm Optimization (HHHOPSO). Each SEPIC converter boost the electrical energy generated to attain the required voltage level when charging the battery. The proposed methodology is implemented in MATLAB/Simulink and its performance is measured using appropriate metrics. In terms of efficiency and average power, the results show that the suggested method outperforms previous strategies. Our system powers also many sensor nodes, leading to a high level of sustainability and lowering the carbon footprint associated with traditional energy sources.

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

A novel step-up/step-down DC-DC converter with improved voltage gain characteristics is suggested in this paper. The proposed converter combines flyback and single-ended primary inductance converter (SEPIC) converters. The voltage control loop design is simplified due to the use of only a single controlled switch. It has been discussed how switch duty cycle affects voltage gain. This relationship demonstrates that the proposed converter voltage gain is improved compared with flyback and SEPIC converters. However, compared to flyback and SEPIC converters, it has a higher voltage gain at any given duty cycle. The proposed converter operation is thoroughly discussed, the associated equations are derived, and its parameters are expertly designed. Moreover, it is designed to supply a DC load of 2.5 kW, 500 V, and 5 A. The proposed converter efficiency exceeds 84% under rated load conditions. Additionally, it is also presented as an adapter for electric vehicles. The waveforms associated with the simulation of the converter across the universal line voltage of 110-260 Vrms are shown. At both line voltages, the total harmonics distortions (THDs) of the line current are 17.12% and 27.26%, respectively. MATLAB/Simulink is utilized for validation in order to validate the topology for different applications.

Robust current-mode control of bridgeless single-switch SEPIC PFC converter

In this paper, the nonlinear model of the bridgeless single-switch ac-dc single-ended primary-inductor converter (SEPIC) in discontinuous conduction mode is derived. In addition, a robust control method is introduced to accommodate the variations in input voltage and load current. The current-mode controlled power converter is designed to operate in buck and boost modes. The proposed closed-loop SEPIC converter is simulated in MATLAB to validate the design approach. The current-mode control scheme is also compared with the conventional voltage-mode controller. It is confirmed that the proposed control scheme exhibits precise tracking performance and enhanced transient response under large disturbances.

High gain modified SEPIC converter with asymmetrical switched inductor super lift cell for renewable energy applications

ABSTRACT 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.

Analysis and Design of Two-Switch Enhanced Gain SEPIC Converter

A two-switch, enhanced gain single-ended primary inductor converter (SEPIC) is proposed with key benefits of enhanced voltage gain, reduced voltage stress and better efficiency, as it is suitable for low voltage green energy applications. Further, reduced voltage stress between the intermediate capacitors is a notable attribute of this converter. The converter components are designed with proper design procedure and a steady-state analysis is performed to study its operation. A small-signal analysis of the proposed converter is also presented to examine the pole-zero positions. Also, this paper includes the performance comparison with other similar converters. Simulation and experimental results of the proposed converter with a rating of 100 W/50 kHz and input and output voltages of 20 V and 200 V, respectively are provided. Efficiency as well as power loss distribution are also investigated in this study.

High Gain Magnetically Coupled Single Switch Quadratic Modified SEPIC DC-DC Converter

This article proposes, analyzes, and tests an improved high voltage gain dc-dc converter based on a single-ended primary-inductor converter (SEPIC). The proposed magnetically coupled quadratic modified SEPIC converter (MCQ-MSC) employs a coupled transformer with an optimized design to obtain a high voltage boost factor by controlling the transformer's turn ratio along with the switching duty cycle. Thanks to the unique structure of the coupled transformer, high voltage gain is obtained at low turns ratio, which is highly desirable for high voltage applications and the compact size of the converter. In addition to the coupled transformer, a voltage-boosting module is utilized to achieve a very high output voltage for a low switching duty cycle. The proposed inverter has a single switch with a wide control range of duty cycle (0<D<1), causing low conducting losses and high efficiency. Furthermore, a clamping circuit is successfully designed to remove the leakage inductance effects of the coupled transformer on the power switch. The proposed MCQ-MSC drains a continuous current from the input dc source, which makes it a suitable choice for renewable energy sources (RES). The hardware prototype of the proposed converter is tested to verify the mathematical expressions and theoretical results.

Voltage regulation of DC micro grid system using PV and battery coupled SEPIC converter

&lt;span lang="EN-US"&gt;This paper deals with the voltage regulation of DC micro grid system using photovoltaic and battery coupled single-ended primary-inductor converter (SEPIC) converter. SEPIC converter is a DC-to-DC boost converter, it can produce non pulsating DC current with less ripples when compared to buck and buck boost converters. Non pulsating DC current is the demanding condition required in maximum power point tracking (MPPT) applications and battery charging. This paper presents the simulation of the converters for both open and closed loop systems. Firstly, the proposed PV coupled SEPIC converter and the battery coupled buck boost converters are integrated to regulate the voltage in micro grid, and it is compared with the conventional methods in terms of output voltage, ripple voltage and power. The ripple voltage has been reduced to 0.1 V from 0.3 V in the proposed method. Secondly, PI and PID controllers are employed individually to SEPIC and buck boost converter for the voltage regulation of the DC micro grid system. The performance of the closed loop analysis is done in terms of time domain specifications, and it reveals that PID controller has the better response. The proposed system is simulated using MATLAB/Simulink and the prototype has been developed to verify the simulated results.&lt;/span&gt;

An highly efficient optimized PI controller fed SEPIC converter for hybrid renewable sources based microgrid system

This paper proposes an electric power generation that is self-sufficient with the adopting of Hybrid Renewable Energy Sources (HRES) including solar and wind which in turn contributes a cleaner and sustainable environment. The proposed system provides uninterrupted power supply during any weather conditions and the excess energy is stored in battery which energizes the grid at times of deficit power supply from HRES. The incorporation of converter and control approach ensures the balanced flow of power in the grid connected system. A Single-Ended Primary Inductance-Converter (SEPIC) is employed in this work for the enhancing of voltage from the PhotoVoltaic (PV) system. An improved Grey Wolf Optimized (GWO) Proportional Integral (PI) controller facilitates the effective control of SEPIC thereby improving the transient response. A Doubly Fed Induction Generator (DFIG) based wind system is integrated as an alternate source with PI based control. The control of the battery is carried out by the Artificial Neural Network (ANN) and grid synchronization is accomplished with the aid of PI based dq theory. The simulation of the proposed work is carried out by Matlab and the proposed work generates improved outputs with efficiency 95.8% and a reduced THD of 1.3%.

A three‐level isolated dc‐dc SEPIC converter with parallel‐connected output

AbstractThis paper presents a comprehensive theoretical analysis and experimental results for three‐level isolated dc‐dc converter based on the single‐ended primary‐inductance converter (SEPIC) topology. The main advantage of this structure is the reduction of voltage stress on semiconductors comparing it to the conventional SEPIC converter. Voltage stress is the major challenge associated with the conventional SEPIC structure, and contributions in this area can extend the range of applications for the family of SEPIC converters. The analyzed structure contains two switches, and their commands can be either equal or phase‐shifted by 180°. This provides four different modes of operation in discontinuous conduction mode (DCM), which have different operating stages, waveforms, and design equations. In this paper, the topology with parallel‐connected output and the static and dynamic theoretical analysis in DCM, for the four command signal profiles, are presented. The advantages and disadvantages, control strategy, experimental results, and a comparative analysis with the conventional SEPIC converter are discussed. The dc‐dc SEPIC converter was verified by experimental results from a proof‐of‐concept prototype with 500 W rated power, 400 V input voltage, 120 V output voltage, and 50 kHz switching frequency. The converter achieved 94.72% efficiency at rated power.

Combined strategy for tuning sensor-less brushless DC motor using SEPIC converter to reduce torque ripple

The brushless DC motor (BLDCM) is widely used in computer numerical control (CNC) machines, aerospace applications and auto industry applications in the field of robotics. But it is still affected by the transmission torque ripple, which mostly depends on the speed and the transient line current at the transmission interval. This manuscript proposes a combined approach for tuning sensor-less brushless DC (BLDC) motors using a single-ended primary-inductor converter (SEPIC). The proposed technique is a combination of Golden Eagle Optimization (GEO) and Radial Basis Function Neural Network (RBFNN), hence it is called GEO-RPFNN. The control of speed and torque is to reduce the torque ripple in the motor. Here, the modified bridgeless single-ended primary-inductor converter is proposed to improve speed and torque control. The proposed method is used to adjust the parameters of proportional integral derivative (PID) controller and to improve the performance of PID controller. Therefore, the GEO–RBFNN technique is proposed to recover the control loop function. The proposed algorithm is explored to control the speed and torque error as BLDC motor. Nevertheless, the output of the proposed approach is subject to the input of speed and torque controllers. The proposed method is executed in MATLAB Simulink site. The performance of the proposed system is compared with existing FA and PSO methods. As per the state of comparison outcomes, the GEO–RBFNN gives better result than the existing techniques which has higher ability to conquer the related issues. The THD in stator current, power factor and torque ripple gives the value using proposed method is 1.26%, 0.9951 and 7.4.

A novel metaheuristic approach for control of SEPIC converter in a standalone PV system

Fossil fuels are being replaced by renewables. Most of the renewables are intermittent, to have reliable power the renewables have to be conditioned before injecting into the utility grid. The DC-DC converters are perfect power electronic devices for conditioning the renewables. The single ended primary inductor converter (SEPIC) performs the conditioning with a very high voltage transfer gain and minimum ripples. The maximum power extraction from the PV panels is required for providing good quality DC power. Intelligent controllers can make use of optimization techniques. The particle swarm optimization (PSO) technique can optimize the controller to extract the maximum power. The SEPIC converter duty variation is optimized and a comparative analysis with the Buck-Boost converter is done in a MATLAB/Simulink environment. The proposed SEPIC converter system performed well by improving the power tracking by 40% and the system has been analysed in a battery charging environment.

Modified proportional integral controller for single ended primary inductance converter

The article highlights and optimizes a controller for the single ended primary inductance converter (SEPIC) direct current-direct current (DC-DC) converter. The SEPIC converter adjusts a range of dc input voltages and delivers a constant and stable output voltage. Three different models of the SEPIC converter are presented in order to derive its transfer function. Being a 4th order, an approximation method for the reduction of this transfer function to 2nd and 1st order is implemented. Two methods for controlling the converter are presented, the first one is based on guessing techniques and the second explains the design steps of the controller based on the internal model control (IMC). Furthermore, an improvement on the IMC controller is proposed and results were shown and discussed. IMC is based on integrating the “process model” in the control operation of the actual system. By using an approximation of the original transfer function of the system, it is expected that the IMC control will be able to achieve the desired results. Control schemes of the SEPIC will be presented and results will be shown. The response of the controller was tested with mathematical models for batteries and supercapacitors in MATLAB, as non-ideal DC-sources, and results were presented.

An Isolated Bridgeless Cuk–SEPIC Converter-Fed Electric Vehicle Charger

A single-stage electric vehicle (EV) battery charger with an isolated bridgeless (BL) Cuk–single-ended primary-inductor converter (SEPIC) converter is developed in this article. The design of proposed charger is ensured in discontinuous conduction mode with intrinsic power factor correction (PFC) at ac mains. Compared to the BL Cuk converter topology when used for both positive and negative cycles, the proposed topology has reduced number of components with improved efficiency. This is due to integration of Cuk and SEPIC converters during the individual half cycle. The presence of output inductor at Cuk converter side also smoothens the output current, as compared to SEPIC converter used for both cycles. A high power quality (PQ) operation of new BL isolated PFC converter with an EV battery load of 48 V/100 Ah is verified using single-phase PQ analyzer. A laboratory prototype of proposed charger is developed and validated to corroborate the efficient performance during two charging profiles. Test results are shown under steady state as well as over extreme load and line conditions. Different performance indices such as displacement PF, ac mains PF, and mains current distortion are recorded, which comply the IEC 61000-3-2 standard.

Mitigation of Cross-Coupling Effects in PV String-Integrated-Converters Employing SEPIC Converter with P&O MPPT Technique

Photovoltaic (PV) string-integrated-converter (S-I-C) topology allows each PV string to operate at their respective maximum power point (MPP) corresponding to the variations in solar insolation. The S-I-C topology comprises an individual DC–DC converter integrated into each PV string. The output terminals of the S-I-Cs are connected either in the series or parallel configuration. There are certain limitations in each of the series/parallel configured PV S-I-Cs. By employing DC–DC boost converter as an S-I-C, cross-coupling effect is the main limitation of a series configured S-I-Cs. The cross-coupling effect causes the deviation in operating points (MPPs) of the shaded & unshaded PV strings and this leads to power consumption by the boost type S-I-Cs instead of delivering to the load. This article presents the mitigation of cross-coupling effects by employing a single-ended primary inductor converter (SEPIC) as an S-I-C in a series configuration of S-I-Cs. The conventional perturb & observe (P&O) MPPT technique is used to track the maximum power from PV strings. The results of the series configuration of SEPIC converter-based S-I-Cs are compared with the boost converter-based series configuration along with the mathematical analysis under uneven-row, uneven-column, diagonal, and long & narrow shading patterns.