Single Ended Primary Inductance Converter Research Articles

DESIGN AND ANALYSIS OF CONTROLLED SEPIC AND LLC CONVERTERS FOR PHOTOVOLTAIC SYSTEMS

Solar photovoltaic (PV) energy, a nonconventional source, has been a good replacement and best utilized electric source which is clean, non-polluting, safe, and renewable. A power converter is needed to regulate and control the harvested solar power and achieve the required output voltage for various applications. In this paper, two power converters are presented and discussed for PV systems, which are SEPIC (single-ended primary inductor converter) and LLC resonant converters. Control systems are designed and developed to tune, regulate, and control the output voltage of the SEPIC and LLC converters under various conditions with respect to the load requirements. These proposed control systems are PID (proportional integral derivatives) and FLC (fuzzy logic controller) that are investigated for the nonlinear models of the power converters. MATLAB/SIMULINK is used to model and simulate the proposed PV systems, where the performance of the open loop and closed loop (PID/FLC) systems for the SEPIC and the LLC are analyzed with respect to solar radiation and load conditions. The system efficiency values for SEPIC and LLC for open loop model are 93.3% and 80.3%, respectively. The simulation results of the proposed PV systems show that the output voltage is controlled and stabled successfully to the required voltage for various loads/applications while the input power from the solar panel and the load applications are varying. The FLC system yields the faster and more robustness response than PID systems.

SEPIC Converter with an LC Regenerative Snubber for EV Applications

A Single-Ended Primary-Inductor Converter (SEPIC) converter with an Inductor-Capacitor (LC) regenerative snubber is proposed to reduce Electromagnetic Interference (EMI) for Electric Vehicle (EV) applications. The switching energy is transferred through a capacitor to an inductor which is coupled to SEPIC inductors. This technique reduces the number of components and also returns some of switching energy to SEPIC converter. The mathematical analysis and optimization of LC snubber with respect to number of turns is also presented. Spice simulations and experimental results are provided to verify its performance. The proposed LC regenerative snubber reduces the peak voltage by 16 V on the switching transistor during the switching transient. It is also indicated that 8 dB reduction is achieved in the EMI measurements at ringing frequency and 10 dB reduction at high frequency band.

Novel distortionless dimming in high power LED lighting using isolated SEPIC converter

A new low-cost energy-saving concept in the modern light-emitting diode (LED) illumination system is developed and implemented using an isolated single-ended primary inductance converter (SEPIC). The dimming scheme presented in this study is a single-step with negligible distortion in the AC mains current as compared to the traditional low-cost triode for alternating current (TRIAC) dimming system, which distorts the AC mains current wave-shape beyond sinusoidal nature due to the phase-cut techniques. This dimming concept is completely retrofitted, no additional arrangement is required to initiate the dimming as compared to a TRIAC dimmer or other controllers. The isolated SEPIC converter is modelled and analysed in detail using the state-space average technique. The stability of the designed converter and overall closed-loop control are verified using Bode-plot analysis. The full load converter efficiency is found around 93%, which is much higher than the conventional flyback topology-based LED driver. The concept presented in this study is tested with the help of a laboratory prototype with an LED load of 60 W.

New modular high‐voltage pulse generator based on SEPIC converter for electroporation applications

High-voltage (HV) pulses are widely used in many applications. This study proposes a new HV unipolar pulse generator based on Single-Ended Primary-Inductance Converter (SEPIC) for electroporation applications. The converter in the proposed pulse generator operates in discontinuous conduction mode with continuous input current. The proposed structure uses voltage-boosting modules that are fed from a relatively low voltage DC source with a reduced number of semiconductors. The number of semiconductor devices and the voltage stress across them are important issues for HV pulse generators. The proposed approach does not have any chopping switches at the output stage, which greatly affects cost, efficiency, and system control. The employed semiconductor switches and diodes in the proposed topology have low voltage and current stresses, so the structure can be implemented with the market-available semiconductor technology. Mathematical analysis is presented along with a full design of the system components. Finally, simulation and experimental results are presented to validate the proposed concept.

Design and Implementation of Solar OLED Lighting Driver Circuit with Frequency Modulation Control

This paper proposes a single-stage single-ended primary inductor converter (SEPIC) converter circuit, which is applied to the organic light-emitting diodes (OLED) driver circuit. The circuit proposed in this paper replaces the output Schottky diode from the original SEPIC with a power switch. Deadtime is added to prevent the on-state overlapping of two switches with zero voltage switching (ZVS), and the circuit operates in triangular current mode. The digital control methods are maximum power point tracking and frequency modulation using a battery to supply the converter and illuminate the OLED at night. Finally, a prototype is implemented to show the feasibility under the DC input voltage range of 10–40 V. The DC output is 12 V/1 A/12 W, and the conversion efficiency is up to 96.3%.

Trinary Hybrid Cascaded H-Bridge Multilevel Inverter-Based Grid-Connected Solar Power Transfer System Supporting Critical Load

Higher power rating solar photovoltaic systems are emerging in the power system owing to the reduction in the cost of photovoltaic arrays and environmental concerns of the conventional power generation systems. Multilevel inverters are reported at high power levels due to reduced switching frequency and increased efficiency. Cascaded H-bridge (CHB) multilevel inverters have been reported in the literature due to its redundant structure compared to other multilevel topologies. When CHBs with dc sources are in the ratio of 1:3, it is named as a trinary hybrid multilevel inverter, and it generates a maximum number of equal output voltage levels. In this article, a trinary CHB multilevel inverter-based grid-connected solar power transfer system using modified second-order generalized integral control is proposed. A two-stage solar PV system consists of a single-input-multiple-output single-ended primary inductance converter and two CHB structures per phase used to verify the proposed system. A modified second-order generalized integral control is presented for active power control and grid synchronization. The controller is designed to eliminate dc-offset from the sensed load currents and to ensure balanced, sinusoidal, and unity power factor grid currents. Moreover, the shunt-connected system mitigates the reactive power and harmonic demands of the local load, thus maintaining the grid current power quality within the standard prescribed by IEEE-519. The performance of the proposed system is validated with an experimental prototype, and the test results validate the theoretical claims.

Design and Implementation of High Reliability Electrical Power System for 2U NutSat

This article proposes the design and implementation of an electrical power system (EPS) for 2U CubeSat using a single-ended primary-inductor converter (SEPIC) along with the perturbed and observe method for the maximum power point tracking (MPPT). SEPIC converters have the advantages of input current continuity, voltage boosting and bucking, short-circuit protection, low-side driver, and noninverted input and output voltages. When the battery voltage is too low, by adding a low power consumption latching relay to develop a novel topology, the battery can be directly charged with solar panels without the MPPT algorithm and to improve the system reliability. In addition to the on-board computer subsystem, we can independently control whether to turn on the power according to the battery capacity and importance priority for each subsystem of CubeSat. The satellite is operated in outer space that the environment is wide temperature variation, vacuum, and high electromagnetic radiation. Therefore, the satellite was subjected to various types of tests, such as vacuum, thermal cycling, and radiation tests, to verify the system's capacity for enduring the aforementioned environmental changes. Finally, implementations and various tests were carried out to verify the viability and the accuracy, and reliability of the EPS of the satellite.

A Nonisolated High Step-Up Three-Port Soft-Switched Converter With Minimum Switches

In this article, a nonisolated high step-up three-port converter is proposed based on the single-ended primary-inductor converter. The proposed converter includes two switches, which are turned <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> under zero voltage switching or low-voltage condition intrinsically. The overall number of elements used in the converter is small. Furthermore, the conduction losses are reduced by reducing the number of the semiconductor elements in both battery and photovoltaic (PV) current flow paths. The input inductor is not coupled to any inductors to reduce the PV current ripple and enhance the realization of maximum power point tracking (MPPT). Since low-voltage switches with low <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> -resistance are selectable, conduction losses are reduced. All modes of operation in the steady-state condition are discussed and design considerations in each mode are presented. Finally, the experimental prototype of the proposed converter with a 24 V PV source, 36 V battery pack, and a 380 V-200 W load is presented.

Model Predictive Control of DC–DC SEPIC Converters With Autotuning Weighting Factor

In this article, a model predictive control (MPC) method for dc–dc single-ended primary-inductor converters with autotuning weighting factor capability is presented. The conventional MPC requires retuning of the weighting factor when the operating condition of the converter is changed. The effect of this change is observed as inability of the controller in maintaining the switching frequency constant. The weighting factor avoids excessive switching frequency in the dc–dc converters. Based on the relation between the inductor current ripple and switching frequency, an autotuning weighting factor based MPC is proposed. The effect of the weighting factor on the switching frequency is investigated. The proposed MPC eliminates the need for retuning the weighting factor when the operating point of the converter is changed. The proposed control strategy is verified experimentally under input voltage, load, and parameter variations. The results obtained from conventional and proposed MPC methods are compared. It is shown that the proposed MPC method controls the average switching frequency when the operating mode of the converter is changed. Furthermore, parameter mismatch results are presented for both conventional and proposed MPC methods.

Total-dose Effects on Power MOSFET in SEPIC Converter for Nanosatellite Applications

Background: Power converters used in nanosatellite application required to be more tolerant to radiations including proton, electron and heavy-ion radiation. Methods: A Single-Ended Primary Inductance Converter (SEPIC) is selected for the nanosatellite application because of the availability to step up and down the input voltage as well as having a non-inverting polarity between the input and output voltage. In this paper, remodeled SEPIC converter proposed with an improved performance at radiation environment to work for nanosatellite application. In addition, the analysis is carried out for the irradiated power MOSFET in SEPIC converter to check its impact on converter behavior. Results: Experiments conducted with the help of power MOSFET switch used in converter, irradiated with Cobalt60 gamma ray dose level from 50krad to 300krad and output characteristics analyzed by chancing the duty cycle of converter. Investigations shown that conventional converter output characteristics were virtually constant from 10% to 60% duty cycle when different radiated MOSFETs used in the converter. Conclusion: The electrical characteristics started to fluctuate at 60% duty cycle and onwards, while the remodeled converter circuit was less distorted when increasing the radiation dose.

Power quality improvements of arc welding power supplies by modified bridgeless SEPIC PFC converter

This paper proposes an efficient bridgeless power factor corrected (PFC) modified single ended primary inductor converter (SEPIC) for arc welding power supplies (AWPS). The overall configuration is composed of two converters: (1) a modified bridgeless SEPIC PFC converter, which is controlled by a PI controller to achieve a high power factor and fast response; and (2) a full bridge buck converter with high-frequency transformer for high-frequency isolation to ensure arc welding stability. The proposed system is simulated under different operating conditions of an AWPS. It is also tested in real time by a hardware-in-the-loop system based on a dSPACE DS1103 control board. The system performances are evaluated based on power quality indices such as power factor, total harmonic distortions of the AC grid current, and voltage regulation. The obtained results show that the proposed controller enhances the weld bead quality by keeping a constant current at the output and a stable arc, meet the international power quality standards and robustness for voltage regulation.

Configurations of DC–DC converters of one input and multiple outputs without transformer

This study describes the methodology and the basic procedure developed by the patent entitled New Configurations of DC -DC Converters of One Input and Multiple Outputs without Transformer and Power Converter that Apply Them. The invention is related with new configurations of DC -DC converters of single input and multiple outputs (SIMO), without a transformer, with a single power switch, and therefore a single control circuit, which results in a smaller size, lower weight and simplicity compared to other known SIMO DC–DC configurations. In a novel form, it comprises at least two converters which share the DC source, an inductor and the power switch. This is obtained by the combination of basic converters: step-down (buck), step-up (boost) and step-down/step-up (buck–boost) as ?uk converter, SEPIC (single ended primary inductance converter), Zeta, CSC (canonical switching cell) and buck -boost single-inductor. A generalisation of the methodology developed in this invention allows to obtain modular converters with 2N, 3N, 4N and 6N outputs and single input, from N converter modules. The paper also relates to a power converter, comprising N (greater than or equal to 2) DC converters connected in parallel, whose control signals have a phase shifting of 2π/N radians.

PFC‐SEPIC converter‐fed half‐bridge LLC resonant converter for e‐bike charging applications

In today's market, electric bikes (e-bikes) are becoming exceedingly popular due to their smaller size, ease of domestic charging and cost-friendly alternative in the category of electric vehicles. So, there is a need for the development of a power factor corrected (PFC) private off-board charger (OBC) to cater to the need of the domestic charging of e-bikes. Traditionally, e-bike chargers powered by a domestic meter are realised by a non-PFC OBC with a power rating of 500–700 W. Such converters draw harmonic currents at very high crest factor and affect the life and performance of other domestic appliances. A private OBC which derives its power from the domestic supply for charging the battery of an e-bike is proposed. The charger has two stages, i.e. the PFC stage for input current shaping and the DC–DC stage for regulating the battery charging voltage and charging current. The PFC stage is based on the single-ended primary inductance converter and the DC–DC stage is based on the inductor inductor capacitor (LLC) resonant converter. A 570 W, 57.6V, 10 A prototype is built using digital signal processor (TMS320F28035) to evaluate and validate its performance for charging a lithium-ion battery pack.

Analysis of bridgeless converter model for power factor correction

In this study, a novel single-stage bridgeless single-ended primary-inductor converter (SEPIC) model is designed to perform effective power factor correction while driving brushless direct current (BLDC) motors. The traditional SEPIC converter model produces a non-pulsating input current that operates with both conductors in a continuous-conduction mode(CCM). However, the proposed SEPIC converter is designed to function as an AC-DC converter; specifically, it is a cascade combination of the boost and buck-boost converters. Functionally, during discontinuous-condution mode (DCM), the boost converter becomes operational, whereas the buck-boost converter operates during the continuous-condution mode. Using the proposed SEPIC model, naturally the computed power factor is improved, which makes it employable for driving BLDC motors. During the implementation of the proposed model, the rotation of the permanent magnet BLDC motor was regulated through the continuous-conduction mode of operation of the bridgeless rectifier. On conducting both the simulation and hardware design process, comparisons were made based on the power factors obtained using the traditional buck-boost converters and those obtained using the SEPIC models presented herein. The SEPIC model proved its higher efficiency over the traditional converters from the viewpoint of the evaluated power factor values and minimized conduction losses. The newly modeled SEPIC model, which was designed for power factor correction, has been noted for its applicability in low power household applications. A power factor of 0.9 is obtained for the hardware implementation of the proposed converter, and a working model of the proposed converter is found to exhibit superior performance when compared with simulated models of the buck–boost converter and SEPIC.

A New Single-Input Multioutput Interleaved High Step-Up DC–DC Converter for Sustainable Energy Applications

In this article, a new single-input multioutput high step-up dc-dc converter is proposed, which is suitable for sustainable energy applications. Basically, the presented converter consists of an interleaved and a modified single-ended primary inductor converter, which uses coupled-inductor and switched-capacitor-voltage-multiplier techniques. Each stage generates a different output voltage using only one input voltage source and one duty ratio. The output voltage gains are effectively increased at low duty ratios by employing coupled-inductors and voltage multiplier cells. Moreover, because of using low voltage rated MOSFETs, the voltage stresses on power switches are very low. Therefore, the conduction losses are reduced and the conversion efficiency will be improved. In order to lighten the reverse recovery problems of the output diodes, the leakage inductance of the coupled inductors can be beneficial. The maximum efficiency that is achieved by the proposed converter is 97.5% and 96.2%, respectively, for both output loads. The operating principles and steady-state analysis are discussed in detail. Finally, experimental results for a prototype of the proposed topology that is implemented under 24 V for input voltage source, 286 and 390 V, respectively, for both output ports are presented to assess the effectiveness of the proposed converter.

Single-Switch Bipolar Output DC-DC Converter for Photovoltaic Application

Bipolar DC grids have become an adequate solution for high-power microgrids. This is mainly due to the fact that this configuration has a greater power transmission capacity. In bipolar DC grids, any distributed generation system can be connected through DC-DC converters, which must have a monopolar input and a bipolar output. In this paper, a DC-DC converter based on the combination of single-ended primary-inductor converter (SEPIC) and Ćuk converters is proposed, to connect a photovoltaic (PV) system to a bipolar DC grid. This topology has, as main advantages, a reduced number of components and a high efficiency. Furthermore, it can contribute to regulate/balance voltage in bipolar DC grids. To control the proposed converter, any of the techniques described in the literature and applied to converters of a single input and single output can be used. An experimental prototype of a DC-DC converter with bipolar output based on the combination of SEPIC and Ćuk converters was developed. On the other hand, a perturb and observe method (P and O) has been applied to control the converter and has allowed maximum power point tracking (MPPT). The combined converter was connected in island mode and in parallel with a bipolar DC microgrid. The obtained results have allowed to verify the behavior of the combined converter with the applied strategy.

Radial basis function neural network based maximum power point tracking for photovoltaic brushless DC motor connected water pumping system

The integration of artificial intelligence (AI) control techniques for efficient energy extraction will provide the solar energy systems with increased efficiency. Therefore, this manuscript proposes a solar water pumping system topology using a radial basis function neural network (RBFNN) to effectively track the maximum power point (MPP) in a photovoltaic (PV) array fed brushless DC (BLDC) motor drive. The RBFNN maximum power point tracking (MPPT) predicts the duty ratio of a single-ended primary inductor converter (SEPIC) to reach the MPP. The performance of the system under study is compared to trivial MPPT techniques with varying irradiance, temperature and partial shading condition (PSC). The performance in terms of voltage ripple, current ripple, average power loss, MPP settling time, efficiency, torque ripple and stator current total harmonic distortion (THD) is evaluated to show the effectiveness of the proposed MPPT method.

A New SEPIC-Based Step-Up DC-DC Converter With Wide Conversion Ratio for Fuel Cell Vehicles: Analysis and Design

In this article, a new single-ended primary-inductor converter (SEPIC)-based step-up dc-dc converter which integrates discontinuous-current quasi-Z-source (qZS) and switched-capacitor networks is proposed. The proposed converter has a low input current ripple, wide voltage gain range, low voltage stress on the semiconductor devices, and a constant potential difference between the grounds of its input and output ports. These features make the proposed converter an excellent interface between the fuel cell and the dc-link bus inside the electric vehicle. The analysis of the proposed converter for steady-state operations in continuous conduction mode and discontinuous conduction mode are given. Finally, a 3-kW/800-V scaled-down prototype was built using a gallium nitride power switch and silicon carbide diodes to validate the feasibility of the proposed converter and its theoretical analysis.

IMPLEMENTATION AND SIMULATION ANALYSIS OF MODIFIED SEPIC CONVERTER FOR RENEWABLE ENERGY APPLICATION

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.

Variable Structure Controller for Chaos Elimination in a Single Ended Primary Inductance Converter

The paper attempts to off-set the circuit parasitics and the inherent switching nature of the power switch in a SEPIC (Single Ended Primary Inductance Converter) that eclipses its performance from theoretical predictions. The focus orients to design a control strategy that offers a chaotic free operation of the SEPIC. It envisages the use of a Variable Structure Control (VSC) strategy to irradiate the adverse effects of non-linear dynamics and assuage the operating range of the converter. The scheme projects the creation and elimination of this nonlinear property through time domain waveforms and phase portraits. The methodology underscores the theory to ensure an uniform rate of charging and discharging for the inductor current during the process of the converter operating the load. The scheme realizes the benefits of the mechanism through a correlation between the open and closed loop inductor current time domain waveform, with the help of adjustments in the parametric variations. The effort involves evaluating the performance using MATLAB simulation and experimental validation in a DSPIC (Digital signal peripheral interface controller) environment to illustrate its suitability for practical applications.