Cuk Converter Research Articles

Cuk PFC Converter Based on Variable Inductor

When the input inductor operates in discontinuous current mode (DCM), the Cuk converter can automatically achieve power factor correction (PFC) function with only a simple voltage mode control loop. However, the conventional Cuk PFC converter suffers from high intermediate capacitor voltage because of the lack of feedback of the intermediate capacitor voltage and relatively low power factor (PF). In this paper, a Cuk PFC converter using variable inductor which varies with the transient rectified input voltage is proposed to enhance the PF and reduce the intermediate capacitor voltage by injecting a controlled DC bias current into the auxiliary winding of the variable input inductor. The operating principles of the proposed Cuk PFC converter based on variable inductor are analyzed in detail, and the analysis of PF, the voltage of intermediate capacitor, and design considerations are provided. To verify the feasibility of the proposed scheme and compare the characteristics of both the traditional and proposed Cuk PFC converter, a 108W experimental prototype of the proposed converter is built and tested. The experimental results show that the proposed Cuk PFC converter can significantly enhance the PF, decrease the intermediate capacitor voltage, and increase efficiency compared with the traditional Cuk PFC converter.

A Bridgeless Cuk-BB-Converter-Based BLDCM Drive for MEV Applications

This article presents a brushless DC motor (BLDCM) drive for a maritime electric vehicle (MEV) application. The presented BLDCM drive uses a bridgeless Cuk-buckboost (BL-Cuk-BB) converter for input-side power factor (PF) improvement. The BL-Cuk-BB converter uses the buckboost converter for the negative half-cycles of the input AC voltages and the Cuk converter for the positive half-cycles. In the case of MEVs, the drive systems are generally fed by diesel engine generators (DEGs). The asymmetric BL-Cuk-BB converter is operated in a discontinuous inductor current mode (DICM) in the present work to attain better power quality. The usage of a second-order buckboost converter with a fourth-order Cuk converter results in a decrement in the net order of the system. Additionally, the input inductor of the Cuk converter also participates as the filter component along with capacitor C2 during buckboost converter operation to enhance the power quality. The total component count reduction in the BL-Cuk-BB converter is also achieved by eliminating the usage of extra/external back-feeding diodes, which are generally used in bridgeless schemes. The present scheme uses the inbuilt anti-parallel diodes for the same purpose. The lesser components requirement in the BL-Cuk-BB-converter-based BLDCM drive implies lesser cost and volume, along with greater reliability, lower conduction losses, and lower weight of the BLDCM drive, which adds to the merits of the model. The paper includes a detailed mathematical model and stability analysis using pole-zero maps and bode plots of the BL-Cuk-BB converter for each half-supply AC voltage cycle. The BL-Cuk-BB-converter-based BLDCM drive for an EV application has been developed on the MATLAB/Simulink platform for a DICM operation, and the MATLAB simulation results have been presented for validation of the BL-Cuk-BB-converter-based BLDCM drive.

Analysis of the high-gain BOCUK DC-DC converter-based PFC using an LQR controller for SMPS applications

This research work emphasizes on the development of a unique high-gain BOCUK DC-DC converter for Switched Mode Power Supply (SMPS) applications. The high-gain BOOST-CUK (BOCUK) DC-DC converter combines the benefits of both Boost and Cuk converters for attaining instantaneous line current shaping and load regulation. The proposed BOCUK converter provides a non-inverted output and improves the voltage gain and efficiency. The modes of operation of the high-gain BOCUK DC-DC Converter in a Continuous Conduction Mode (CCM) with parasitic elements in the circuit are examined and a state-space model is constructed. The second-order model is derived using the Modified Hankel Matrix Method (HMM) to make the controller design easier. Dual-loop Control employing an inner Linear Quadratic Regulator (LQR) current Controller and an outer Atom Search Optimization (ASO)-tuned Proportional Integral (PI) controller is used to analyze the performance indices of the high-gain converter and fluctuations in line, load and setpoint are investigated. Simulation results prove that the LQR controller is robust in tracking the load voltage and provides excellent line current shaping with low % Total Harmonic Distortion (THD) and nearly Unity Power Factor (UPF). The hardware model for 200W is built and implemented using the TMS320F28027F microcontroller to verify the simulation results.

An Adaptive Estimator Based Sliding Mode Control of Nonisolated Single-Input Double-Output Cuk Converter

This article presents an adaptive estimator based sliding mode control (AESMC) for a single-input dual-output (SIDO) converter used in applications requiring multiple regulated output voltages. The proposed SIDO converter is synthesized from the conventional Cuk converter by inserting an additional switch and inductor. However, the coupled capacitor present in the proposed converter topology leads to cross-coupling (CC) and cross-regulation (CR) issues, resulting in the instability of the converter. Furthermore, these issues increase the parameter design and control complexity of the converter. Therefore, this article proposes AESMC to address the CC and CR issues present in the converter. The adaptive estimator of AESMC facilitates the design of adaptive law for effectively estimating the system disturbances. Then, based on the estimated parameters, the input of the SMC is designed to generate switching pulses. Furthermore, the effectiveness of the AESMC in eliminating CC and CR effects is validated by comparing the results obtained with the decoupler+PI controller. Moreover, the system stability analysis with the proposed control technique is presented by considering the Lyapunov direct method. The effectiveness of the proposed control algorithm is evaluated in MATLAB/Simulink, and the obtained results are validated in a hardware prototype developed in the laboratory.

PV Integrated UPQC with Intelligent Control Techniques for Power Quality Enhancement

The configuration and control of a Unified Power Quality Conditioner (UPQC) coupled with Photovoltaic (PV) system is proposed in this work. By integrating PV to UPQC, the twin advantages of decarbonized clean energy generation in addition to enhanced Power Quality (PQ) is obtained. The series and shunt compensators, which together constitute the UPQC are sequentially interfaced to the common dc-link. In addition to infusing active PV generated power, the UPQC shunt compensator diminishes the load side power quality concerns. The role of a series compensator is to ensure that both the load and source voltages are in-phase perfectly. The PV system is integrated to the UPQC through a DC/DC Interleaved Cuk converter and by regulating the duty cycle of the Interleaved Cuk converter, utmost possible power is derived from the PV using Crow Search Algorithm (CSA) assisted Perturb and Observation (P & O) Maximum Power Point Tracking (MPPT) technique. The designed hybrid MPPT technique is capable of operating at Maximum Power Point (MPP) under both Partial Shading Condition (PSC) and uniform insolation condition. A d-q theory-based control is employed with the assistance of Proportional Integral (PI) controller for controlling the working of UPQC. The dynamic working of the PV based UPQC is evaluated on the basis of simulation outcomes attained from MATLAB.

Modified Bridgeless PFC-Based Cuk-Sepic Converter With Improved Power Quality for Arc Welding Applications

The novel single-phase Cuk and Sepic power factor correction converter attracted toward arc welding application is highlighted in this paper. The preferred converter is outlined to function in DCM concealed by variations in load voltage and supply voltage to ensure better performance. The control strategy includes a voltage loop, which ensures arc welding process stability and improved input power quality. The designed system is validated with a hardware prototype of 100 W, 48 V, and Matlab/Simulink is used to simulate the arc welding power supply under different working conditions. The reduced input line total harmonic distortion of 1.527% with unity power factor is attained for the rated load in the investigational study. The experimental performance of the propounded converter is bestowed with operating conditions of AC mains (90–270 V) to cohere to the limits delineated by the IEC61000-3-2 standards.

Flicker-Free LED Driver Based on Cuk Converter with Integrated Magnetics

Electric vehicles contain various types of light emitting diode (LED) devices. A significant twice-line-frequency ripple current is usually produced in a conventional offline LED driver with a high power factor. In this paper, a flicker-free LED driver based on isolated Cuk converter with integrated magnetic technique is proposed. Two inductors and power transformer are combined into one magnetic core to eliminate the wave current as much as possible. With time domain analysis in electrical circuit and magnetic circuit, the operation principle, operational waveforms, and transfer function are analyzed in detail. Finally, experimental results from a 30 W laboratory prototype supplied by a 220 V grid validate the effectiveness of proposed LED driver.

Examining the Design of Different Types of DM EMI Filters and Their Effect on EMI Noise and Control Characteristics for Cuk DC-DC Converter

In this paper, DM EMI filters including LC, LC with damping, and Pi and LCL filters are designed for DC-DC Cuk converter operated in BCM. Although, DM EMI is so important for any power converter, the effect of DM filter is not investigated in detail in literature with respect to control characteristics and DM noise reduction. The main contribution of this paper is comparisons of DM EMI filter topologies regarding control characteristics and EMI noise reduction which is not presented in the literature. Another contribution is to give a practical design methodology for EMI filter design avoiding complex mathematical procedures. Besides, the paper designs an LCL filter, popular for inverter applications, for Cuk converter that is not introduced in the literature. Examining the filter effect on the converter from the control point of view is a very complicated issue because a linearized model of the converter which is naturally nonlinear should be obtained. To do so, the converter’s small signal analysis must be derived. Therefore, for examining the effect of filters, a small signal analysis of the Cuk converter is made through an average state-space model. After that, transfer functions of each filter topology are obtained. Lastly, the entire transfer functions of the system using both the Cuk converter and each filter are acquired, separately. By using the transfer functions of overall systems, the effect of each filter topology is investigated by root locus and bode plots. Moreover, experimental verification of all filters is realized over a 15 W Cuk converter with a 25 kHz switching frequency. It is validated by applications that the LCL filter provides better control characteristics on the Cuk converter, the total inductor value is reduced by 30% and the total capacitor value is reduced by 25% compared to other filters. However, with respect to DM noise Pi and LC filters give better results.

Optimized PV Fed Zeta Converter Integrated with MPPT Algorithm for Islanding Mode Operation

One of the sustainable energy sources available everywhere is solar energy. Solar energy may be transformed into electrical energy using photovoltaic cells; it can also be utilized in various applications like domestic, agricultural, industries and traffic lights. The power produced from solar energy is at a minimum level. Hence, the tracking maximum power point and converters are employed to step up the power from solar. Most of the research works utilized the Maximum Power Point Tracking (MPPT) with modified methods of perturb and observe and Swarm intelligence algorithms. The converters like buck boost converter, cuk and cuk-sepic converter are utilized to step up the voltage and it suffers from the harmonic distortion. Hence, in this, the Hybrid GA based PSO used for MPPT and the Zeta converter used for reducing the harmonics and maintaining the quality of power in the output side. The total operation was performed in Island mode and it was realized in MATLAB Simulink under Windows 10 environment. Then, the performance is evaluated for MPPT and total harmonic distortion.

Bipolar DC output fed grounded DC-AC converter for photovoltaic application

Introduction. In recent years the usage of electricity has increased tremendously as the electrical needs and loads got increased. Hence the researchers focused on the electricity generation from renewable sources in order to promote sustainable green environment. Owing to the lesser cost and more reliable high efficiency system with reduced use of equipments became prominent for the grid connected photovoltaic single phase systems. The novelty of this proposed converters are to reduce total power loss and to analyze the performance of the converter under various modulation index and to have lesser harmonics using sinusoidal pulse width modulation technique for both T-type and F-type inverter. Interest of the work is to merge two DC-DC converters which have same output voltage in order to have transformer less utilization of power. This has given pathway to develop a new DC-DC converter network by merging the common input nodes of CUK and SEPIC converter. Purpose. This similar structure of both converters made it easy to combine the input stages of and to get bipolar output. Methods. Here we can get bipolar output without the utilization of transformer which minimizes the overall size of the proposed system. In this paper, a combined CUK-SEPIC based grid connected transformerless inverter for photovoltaic application is suggested. Results. The suggested converter is simulated using MATLAB and the results were discussed. Further the circuit is extended with a 1 kW F-type inverter to demonstrate grid connection of the converter. Practical value. This converter can be implemented for photovoltaic applications for obtaining the bipolar DC output from the DC source.

Control of Cuk-Based Microinverter Topology with Energy Storage for Residential PV Applications

This paper proposes a modular inverter based on Cuk converters for solar photovoltaic (PV) systems to mitigate the voltage and current mismatch issue at the PV module level. The proposed modular Cuk inverter (MCI) is formed by connecting several low-voltage (LV) microinverters (MIs) in series and linking their output sides to the distribution network. This architecture does not require a central inverter, and hence, it eliminates the need for large dc-link intermediate capacitors. The proposed MCI provides more controllability over the PV system by having a decentralized structure. The MCI will improve the PV system efficiency by reducing the voltage and current stresses in the MIs and will enable better voltage regulation due to the provided controllability. Since the proposed MI topology is based on the Cuk converter, it offers continuous input and output currents that will reduce the required filtering capacitance and will provide a wide range of voltage regulation for either supplying the loads or charging the storage batteries. The paper presents the associated control scheme for the proposed MCI that employs two controlling loops. The input loop at the PV side is designed and tuned to eliminate the ripples from the input current, while the outer loop at the grid side will control the output ac current and hence the MCI power. Computer simulations are presented using MATLAB/SIMULINK software to examine the validity of the suggested inverter for distributed generation PV residential applications. A scaled-down experimental prototype controlled by TMS320F28335 DSP was built and used to validate the mathematical analyses and simulation results.

DC-DC Converters Topology

In this paper the various perspectives on different dc-dc converters are reviewed . The various advantages and disadvantages of both Converter topologies that are classical and recent converters and overview of dc micro grid are discussed. From the data we found that every Converter has some advantages and disadvantages also but the Buck, Boost, Cuk and zeta Converter have less ripple. And Buck and Boost has the best efficiency as per cost. The dc micro grid has lots of advantages over AC microgrids; they can perform reliable operation, higher efficiency, low power loss and no skin effect. Theoretical and practical implications were discussed. Advanced dc converters are also reviewed.

Soft-Switched Boost–Cuk-Type High Step-Up Converter for Grid-Tied With Half-Bridge Inverter

In this study, a novel two-stage grid-tied high step-up inverter is proposed. The first stage (dc–dc) is a combination of boost and cuk converters as well as a simple dc-link voltage balancing circuit. The balancing circuit is connected in series with the output of the cuk converter to compensate for the output voltage difference between boost and cuk converters. The second stage (dc–ac) comprises a conventional half-bridge inverter. The ground leakage current is eliminated in the proposed topology by the simultaneous grounding of the photovoltaic (PV) module and the grid. A lossless passive snubber with the minimum elements is also proposed and analyzed to provide the soft-switching conditions. In this snubber circuit, the snubber capacitance discharges to the output dc link to decrease the converter circulation losses. The main attributes of the proposed dc–dc converter with lossless passive snubber are the simple structure of the dc–dc converter and snubber circuit, simple control scheme, and high efficiency. Various operation modes of the proposed topology are theoretically analyzed and investigated. The experimental results substantiate the effectiveness and performance of the proposed boost–cuk-based high step-up inverter with the lossless snubber.

Fully Soft-Switched Non-Isolated High Step-Down DC–DC Converter With Reduced Voltage Stress and Expanding Capability

In this article, a fully soft-switched expandable high step-down dc–dc converter is presented. In order to achieve a high step-down voltage conversion ratio and low component count, the synchronous buck and Cuk converters are integrated. Lower switches’ voltage stress is realized by splitting the input voltage, which can considerably decrease the switches’ conduction loss. Moreover, switching losses along with the reverse recovery problems are mitigated due to the soft-switching operation of all semiconductor devices. The switch utilized for soft-switching operation is also used to replace the output diode as a synchronous rectifier, which reduces the conduction loss. The mentioned features have considerably contributed to the converter efficiency. Furthermore, the converter shares a common ground between the input and the output, which is desirable in many applications, while the converter output current is continuous without adding current ripple cancellation methods. Finally, the number of converter cells can be expanded or reduced; therefore, the converter can be applied to a wide range of loads. The operating principles and analysis of the proposed converter are presented, and the results from the implemented prototype are provided to verify the converter operation and performance.

Simplified Nonlinear Current-Mode Control of DC-DC Cuk Converter for Low-Cost Industrial Applications.

This paper presents a robust nonlinear current-mode control approach for a pulse-width modulated DC-DC Cuk converter in a simple analog form. The control scheme is developed based on the reduced-state sliding-mode current control technique, in which a simplified equivalent control equation is derived using an averaged power converter model in continuous conduction mode. The proposed controller does not require an output capacitor current sensor and double proportional-integral compensators as in conventional sliding-mode current controllers; thus, the cost and complexity of the practical implementation is minimized without degrading the control performance. The simplified nonlinear controller rejects large disturbances, provides fast transient response, and maintains a constant switching frequency. The nonlinear control scheme is developed using an analog circuit with minimal added components, which is suitable for low-cost industrial applications. The control law derivation, control circuit design, controller gains selection, and stability analysis are provided. The proposed control methodology is verified via simulating the closed-loop nonlinear power converter model in MATLAB/SIMULINK under abrupt changes in load current and input voltage. The simulation results show that the proposed control scheme provides robust tracking performance, a low percentage overshoot, fast transient response, and a wide operating range. The maximum percentage overshoot and settling time of the closed-loop power converter response during line disturbance are 5.6% and 20 ms, respectively, whereas the percentage overshoot and settling time during load disturbance are 2.8% and 15 ms, respectively.

A Review on New Approach for CUK Converter for Solar/Wind Hybrid Standalone System

A Review on New Approach for CUK Converter for Solar/Wind Hybrid Standalone System

Review on Unidirectional Non-Isolated High Gain DC–DC Converters for EV Sustainable DC Fast Charging Applications

Modern electrical transportation systems require eco-friendly refueling stations worldwide. This has attracted the interest of researchers toward a feasible optimal solution for electric vehicle (EV) charging stations. EV charging can be simply classified as Slow charging (domestic use), Fast charging and Ultrafast charging (commercial use). This study highlights recent advancements in commercial DC charging. The battery voltage varies widely from 36V to 900V according to the EVs. This study focuses on non-isolated unidirectional converters for off-board charging. Various standards and references for fast off-board charging have been proposed. Complete transportation is changed to EVs, which are charged by the grid supply obtained by burning natural fuels, contributing to environmental concerns. Sustainable charging from sustainable energy sources will make future EV completely eco-friendly transportation. The research gap in complete eco-friendly transit is located in interfacing sustainable energy sources and fast DC EV charging. The first step towards clean, eco-friendly transportation is identifying a suitable converter for bridging the research gap in this locality. A simple approach has been made to identify the suitable DC-DC converter for DC fast-charging EVs. This article carefully selected suitable topologies derived from Boost, SEPIC, Cuk, Luo, and Zeta converters for clean EV charging applications. A detailed study on the components count, voltage stress on the controlled and uncontrolled switches, voltage gain obtained, output voltage, power rating of the converters, switching frequency, efficiency obtained, and issues associated with the selected topologies are presented. The outcome of this study is presented as the research challenges or expectations of future converter topologies for charging.

Optimisation of PI controller for design and modelling of Cuk, forward, and SEPIC converter

Optimisation of PI controller for design and modelling of Cuk, forward, and SEPIC converter

Optimization of PI Controller for Design and Modeling of Cuk, Forward, and SEPIC Converter

Optimization of PI Controller for Design and Modeling of Cuk, Forward, and SEPIC Converter

Three-phase AC-DC Converter for Direct-drive PMSG-based Wind Energy Conversion System

In this paper, a wind energy conversion system (WECS) is presented for the electrification of rural areas with wind energy availability. A three-phase AC-DC converter based on a bridgeless Cuk converter is used for power extraction from the permanent magnet synchronous generator (PMSG). The bridgeless topology enables the elimination of the front-end diode bridge rectifier (DBR). Moreover, the converter has fewer components, simple control, and high efficiency, making it suitable for a small-scale WECS. A squirrel cage induction motor (SCIM) is used to emulate a MOD-2 wind turbine to implement the PMSG-based WECS. A direct-drive eight-pole PMSG is used in this study; thus, a low-input-voltage system is designed. The converter is designed to operate in the discontinuous inductor current mode (DICM) for inherent power factor correction (PFC) and the maximum power point tracking (MPPT) is achieved through the tip-speed ratio (TSR) following. The performance of the developed system is analyzed through simulation, and a 500 W hardware prototype is developed and tested in different wind speed conditions.