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Abstract Recently, the renewable energy applications require the development of highly efficient DC-DC converters with higher voltage transfer gain capability to meet out the increased global power demand. The non-isolated DC-DC converters are preferred due to certain drawbacks of isolated structures. The traditional boost, SEPIC (single-ended primary-inductor converter), and CUK based DC-DC converter structures are modified with additional power switches, diodes, and passive components in order to achieve high voltage gain. However, the modified structures with large number of active and passive elements suffer from the drawbacks of increased complexity of control algorithm, reduced power conversion efficiency and higher converter cost. Hence, the researchers started to explore more on single power switch configured non-isolated high step-up DC-DC converter topologies using hybrid concept. The research work presented in this paper explores such a high gain single-switch hybrid DC-DC converter structure that combines the conventional SEPIC and CUK topologies to achieve enhanced voltage gain. In the proposed hybrid topology, the input current is continuous during all modes of converter operation. Moreover, the power switch experiences only low voltage-current stress. The closed-loop configuration of the proposed hybrid converter is implemented using classic PID (Proportional+Integral+Derivative) and FOPID (Fractional Order PID) controllers, and simulated in MATLAB / SIMULINK environment with duty ratio D = 0.7 for the power switch. The results demonstrate that the dynamic performance of the converter with FOPID controller is much improved in terms of reduced settling time, overshoot, and ripples for the output voltage, as compared to that with classic PID controller.

In this paper, linear quadratic regulator (LQR) control is applied to a Cuk converter, and mathematical modeling of the converter is done using state space averaging (SSA) in continuous conduction mode (CCM). The primary focus is to design a controller for the converter and maintain output voltage within 1% of the prescribed value when there is a unit step disturbance in the input. The design done by using MATLAB improved control of the converter from that with a conventional controller when tested with disturbances. The controller did not influence the system's stability, when assessed from the Bode plot. Despite the existence of disturbances, the findings prove the efficacy of the suggested approach, and the proposed controller can track the desired output voltage in less than 14 ms. The LQR control was developed for various applications of the Cuk converter, such as in a photovoltaic system and a wind system.

A new family of single-switch dc–dc converters with simple structure are introduced in this paper. Firstly, using the approach of a simple switching dual structure, a switched-capacitor–inductor (SCL) cell was presented. Then, a SCL cell can be combined with the conventional circuits (Buck, Boost, Buck–Boost, Sepic, Zeta, Cuk) to provide a wide voltage conversion ratio. Taking the derived Cuk converter as an example, the comparisons among another buck–boost converters are listed, the voltage gain of the derived converter is higher than other converters, and the voltage stress on the power device is less than other converters. Furthermore, the features of single switch, common ground, continuous input, and output current are satisfied simultaneously under the condition of using few components. Finally, the converter’s performance and the correctness of the analysis are validated with results from the experimental prototype.

The problem of voltage regulation in power systems has been well studied. There exist numbers of stabilization model discussed in literature which consider input and output voltage. The methods suffer to achieve higher performance in power stabilization. To handle this issue, an efficient Real-time Capacitance and Absorption based voltage regulation model (RCAVRM) is presented in this paper. The model has been fabricated with different MOFSET and cuk converter connected in serial where the Mofset are designed to maintain the traces of voltage present in different capacitors and inductors. At each duty cycle, the method collects the number of circuits being used and number of other circuits not triggered. Based on these details, the method computes Capacitance Power Stabilization Factor (CPSF) and Voltage Absorption Factor (VAF). Using these two factors, the method computes the value of power stabilization weight (PSW) for different circuits. Based on the value of PSW, a unique circuit is selected to regulate the power supply to the electric system. The proposed model improves the performance of power stabilization with least voltage loss.

This paper presents a theoretical analysis of steady-state operation, control-oriented modeling for voltage control, and the experimental results of a DC–DC bidirectional converter based on a Cuk converter using a voltage-doubler concept. Due to the voltage-doubler concept, the voltage stress across semiconductors is reduced when compared with the conventional Cuk converter; this allows for the use of semiconductors with reduced drain–source on-resistance. Moreover, due to the input and output current source characteristics, the converter presents advantages, such as draining/injecting currents on both sides with low-ripple currents. Furthermore, the theoretical analysis is verified by experimental results obtained from a proof-of-concept prototype designed with a 250 V input voltage, a 360 V output voltage, 2 kW rated power, and 100 kHz switching frequency.

A mathematical model of the Cuk converter has been developed using the state-space averaging method based on La-grange theorems for the mode of continuous currents and voltages at storage reactive elements. Analytical expressions are obtained based on relative variables, making it possible to calculate processes in the converter in a wide range of parame-ters at the control zone of the duration of switching intervals. The limiting dependences of converter parameters between the modes of discontinuous and continuous currents and voltages in storage elements are calculated to determine the effec-tive modes of operation of the device. Analytical dependencies are obtained, making it possible to determine the maximum values of currents and voltages in the elements of the converter over the entire switching range and allowing choosing these elements of the device with acceptable parameters at the stage of its design. Ref. 14, fig 5, table.

This paper proposes a design of energy balance circuit for two adjacent Lithium-ion battery cells in the cell string based on the modifying of the bidirectional CuK converter principle. This design only uses one MOSFET to transfer energy between two cells in a direction controlled by the first relay, second relay controls the cutting energy balance circuit off the cells when they have the same energy level. The control command sent by the management battery system (BMS) to the energy balance circuit via an RS485 communication protocol controls the direction of transferring energy, the amplitude of the balance current, the frequency and duty of PWM, the PWM signal applied to MOSFET is programmed by a microprocessor PIC18F2685. This design overcomes some disadvantages caused by applying the principle of bidirectional CuK converter to design the energy balancing circuit, these are the need for a multiple level DC source to open MOSFETs and issue of the energy loss on the elements of energy balance circuit. This design is also easy to expand for the battery string with a large number of cells. The energy balance control strategy can be implemented directly by each the energy balance circuit or remotely by BMS using RS485 communication. The experimental results of online optimal energy balance control based on state of charge (SoC) feedback for 07 SAMSUNG 22P battery cells connected in series are presented to prove the efficiency of the energy balance circuit design for two adjacent cells proposed in this paper.

A new combined boost-Cuk-forward (CBCF) converter with ripple-free input current and low switch voltage stress is proposed for high step-up applications. Two coupled inductors are applied to achieve low switch voltage stress as well as balanced dc-link voltages, wherein the former is placed in series with the boost diode, and the latter is formed as a forward converter. Because these inductors are coupled with the output Cuk inductor, a ripple-free input current is also attained. The proposed converter is run at discontinuous conduction mode (DCM) by applying a low output-side Cuk inductance to reduce the switching loss by providing a ZCS turn-on of MOSFET and removing the diode reverse recovery current. In addition, the proposed converter does not have a problem with ground leakage current. The practical results verify the performance and effectiveness of the proposed CBCF high step-up converter.

In current scenario, the challenging task in designing a DC-DC converter has high voltage gain and small output ripple waves, which researchers deal with highly complicated. Because of its topological and Continuous Conduction Mode (CCM), the KY converters have developed a better converter than all the traditional DC-DC converters to overcome this intricacy of voltage transfer gain and output ripple waves. The KY converters had comparative and various qualities when compared with the boost converter with Synchronous Rectifier (SR). The KY converter is used in photovoltaic and sustainable power applications, which are examined in this study. KY converter incorporates mode-1 and mode-2 operation and its types, for example, one plus D and one plus 2D where the KY can deliver the Nth type of KY converters. This article provides a comprehensive review and investigation of the KY converters, which incorporates their topology with control methodologies, Pulse Width Modulation (PWM) techniques, working activity of KY converters, and types for mode-1 and -2; it interprets the few strategies the KY converter is executed and its applications.

The use of and interest in renewable energy have increased in recent years due to the environmental impact of the technologies currently used to generate electricity. Switched converters play a fundamental role in renewable energy systems. The main goal is to manipulate the output signal of the renewable energy source to meet the requirements of different loads. Therefore, the increase in research on renewable energy sources has resulted in an increase in studies on switched converters. However, many DC–DC converters can be used in a particular application, and there is no clear guidance on which converter to use. The choice of whether to use one converter over another is highly reliant on the expertise of the researcher. Two examples of DC–DC converters are the Sheppard–Taylor converter and the Cuk converter. In this work, a critical comparison is made between these converters. The parameters considered in this comparison are the number of components, gain, stress on parts, and others. The simulation results were obtained to evaluate the performance of the converters in different scenarios. Finally, we conclude that the only application for which the use of the Sheppard–Taylor converter is justified are those that require high specific power and power density.

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.

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.

This paper presents a modular grid-connected single-phase system based on series-connected current-source module integrated converters (MICs). The modular configuration improves the reliability, redundancy and scalability of photovoltaic (PV) distributed generators. In this system, each PV panel is connected to a dc/ac inverter to permit individual Maximum Power Point Tracking (MPPT) operation for each panel. Thus, the harvested power from the PV system will increase significantly. There are four different inverter topologies suitable to be used as MICs with different performances in terms of filtering elements size, power losses, efficiency, output voltage range, and high frequency transformers' size. For the MPPT control, the oscillating even order harmonic components should be eliminated from the inverter's input side otherwise the maximum power cannot be extracted. The proposed modulation scheme in this paper will ease the control of inverter's input and output sides. Therefore, the 2nd order harmonic in the input current can be eliminated without adding new active semiconductor switches. A repetitive controller coupled with proportional-resonant controllers are employed to achieve accurate tracking for grid side as well as input side currents. Comparisons and performance evaluations for the proposed MICs are presented and validated with 1 kVA prototype controlled by TMS320F29335 DSP.

Supplying shipping vessels with electricity at the ports can improve the air quality of the ports, reduce the greenhouse gas emissions from the shipping industry, contribute to the economic growth, and increase the political dependency of the countries by reducing the dependence on conventional fossil fuels. Several countries promote supplying the vessels when they are docking at ports from renewable energy systems by establishing dedicated funding mechanisms to remove the obstacles facing the shore power systems. In this context, this paper presents a new modular power electronic converter for shore power systems at shipping ports, which can perform three functions. Firstly, it will harvest the energy from a renewable energy source, such as hydroelectric and solar photovoltaic (PV) sources and ensure maximum energy extraction. Secondly, it will control the power flow from these sources to the battery storage. Finally, it will control the power flow from the battery to the vessels and/or the utility grid when necessary. A current-source converter based on isolated Cuk converter is used as the submodule (SM) of the proposed modular converter due to several features. The Cuk SM can provide high efficiency, minimised dc capacitance, and flexible output voltage higher or lower than the input voltage from the PV modules. To verify the mathematical analyses and computer simulations, experimental results are obtained from a small-scale modular prototype controlled by a TMSF28335 DSP.

In this paper, a new method based on signal flow graph is proposed for modeling a Cuk converter. Furthermore, the original signal flow graph based method suggested in literature is also implemented on the Cuk converter. The proposed method is very simple in the process, compared to other methods of modeling and the old method of signal flow graph. By using signal flow graph approach the three models of small signal, large signal and steady state are extracted. Also, without adding any additional computation, the desired transfer function between any two state variables of the circuit is extractable. After modeling the converter, a controller design problem for the Cuk converter will be discussed. A robust control method is proposed for controlling the system. It will be shown that, although the switching converter has a nonlinear nature, but this does not affect the controller design problem. By using a linear controller with parameters tuned with a robust method of mixed sensitivity type, controlling the converter is possible.

This study proposes a novel modified Cuk converter. The proposed converter attempts to resolve the limitations of the conventional converters, such as voltage gain limitations of a canonical Cuk converter. Therefore, the mentioned improvement has made the proposed converters more compatible for renewable energy applications. Moreover, the increase of the voltage gain in the proposed converter has not impacted the efficiency or the voltage stress of the switches, which is common in other voltage boosting techniques, such as cascading methods. Furthermore, the advantages of a Cuk converter, such as continuity of the input current, have been maintained. The average voltage/current stresses of the semiconductor devices and various types of power losses have been calculated and compared with the existing topologies. Moreover, the non-ideal voltage gain of the proposed converters was compared with the other high step-up topologies. Eventually, the simulation results with PLECS, along with the experiments on an 120 W prototype, have been presented for validation.

Maximum power point tracking (MPPT) algorithms are employed in photovoltaic (PV) systems to provide full utilization of PV array output power. Among all the MPPT algorithms, the Incremental Conductance (INC) algorithm is widely used in PV systems due to the high tracking speed and accuracy. In this paper an improved variable step size algorithm which is based on incremental conductance algorithm is proposed that adjusts the step size according to PV output current. The result of this adaption is to make the algorithm suitable for practical operating conditions due to a wider operating range of irradiation changes. Simulation results confirm that the proposed algorithm increases convergence speed and efficiency in comparison with conventional fixed and variable step size INC algorithms.

Circuits' and in particular DC/DC converters' switching behavior is analyzed in this paper using the equivalent control modeling of the dynamic systems' sliding mode regime. As a representative example and also being one of the0 most complex circuits among DC/DC converters, the Ćuk converter is chosen. It is shown how the converter's behavior in the steady state regime can be studied and analyzed by the linear matrix inequalities based stability conditions for linear dynamic systems with nonlinear sector bounded perturbations. The maximization of the nonlinear sector bound provides a limit for applying the linear ripple approximation in the converter operation analysis. Furthermore, our approach is validated by providing simulation results for two different switching surfaces of practical interest.

The Cúk converter, which has voltage buck and boost ability, offers high flexibility as an interface device for solar panels. In addition, current ripple can be more reduced because of two input and output inductors at both sides. This paper presents a new application of current-variable inductors in a Cúk converter that reduces the size and capacity of storage elements. Because of two inductors in structure, implementation of these variable inductors is important; therefore, the proposed design leads to cost and size savings, increases the performance interval of tracker to gain solar energy at lower sunlight levels, and simplifies control strategy. To validate the effectiveness of this structure, the analytical analysis, simulation results using PSCAD/EMTDC software and experimental results are presented.

Maximum Power Point Tracking (MPPT) is a method that can be used to optimize the electrical power output from solar panels. The performance of the MPPT method on solar panel systems can be influenced by many variables. One of them is the selection of a DC-DC power converter. DC-DC-DC Converter is a component that is used to optimize the performance of solar panels. Several types of DC-DC Converter are Buck, Buck-Boost, Single Ended Primary Inductance Converter (SEPIC), and CUK. Each converter has a different effect on solar panels output power. In order to observe and make a comprehensive analysis, simulations are performed through PSIM (Power Simulator) software on the performance of several DC-DC Converters that use Flower Pollination Algorithm (FPA) as the MPPT algorithm. Variables that observed are the output power characteristic, the response of the voltage-current ripple signal, and the accuracy of the converter in the process of reaching the maximum power point condition. As a result, CUK converter can obtain the highest value of solar panel output power, 145.02 W. A low ripple level with a stable power value response is entirely generated by CUK and SEPIC Converter. Overall, for this system, the CUK converter has better performance than the other converters.

This paper presents a new architecture of a driver of high brightness LEDs, with low cost and high yield. Employs a CUK type converter in continuous mode with current compensation rate to feed the high-brightness LEDs through the grid, from 85V to 265V, operating at high frequency switched Pulse Width Modulation (MLP) and connected to a series LC resonant filter for load feeding entry in protection against voltage surges. Twenty LEDs High Power OSRAM 720-GWPSL and a circuit with constant current in Offline mode were used. The proposed architecture aims to present a proposal for a lowcost and low current consumption driver. The comparative study between the prototype of this device from the graphs obtained from the results of laboratory measurements.

Brushless DC motor (BLDC) adalah mesin listrik yang sangat serbaguna. Secara konstruksi, BLDC adalah motor sinkron dengan gulungan ketat dan magnet permanen dipasang pada rotor. Dengan tidak menggunakan sikat dan komutator, sikat kerusakan dan percikan api tidak ditemukan di motor ini dan membuat BLDC lebih efisien daripada jenis lain dari motor listrik. BLDC digunakan dalam berbagai aplikasi, seperti aplikasi rumah tangga, transportasi, aerospace, pemanasan, ventilasi, robotika, dan banyak lainnya. Dalam operasi BLDC menggunakan sumber AC, rectifier ​​dan menghubungkan kapasitor umumnya digunakan. Dan juga, karena BLDC perlu gelombang saat persegi untuk bekerja, penggunaan inverter diperlukan. Inverter juga digunakan untuk tujuan kontrol kecepatan di kontrol kecepatan BLDC konvensional. Kontrol kecepatan konvensional yang hanya menggunakan DBR dan inverter menghasilkan harmonik yang besar yang berarti mengurangi faktor daya juga. Untuk mengatasi masalah ini, dapat digunakan DC-DC konverter antara rectifier dan inverter. Pada penelitian ini akan diteliti pengaruh mode Cuk Converter sebagai penghubung antara DBR dan inverter terhadap faktor daya sumber.

In this paper, a c ´ uk converter balancing method by using a coupled inductor for lithium based batteries is investigated. The proposed circuit is an active balancing circuit that will equalize eight battery cells in a series. In electrical vehicles (EV), a battery management system (BMS) is a vital task to achieve the best performance of the batteries and longer lifetime. The problem of voltage difference in a battery pack is an important issue to be improved. To overcome the voltage differences in battery string, an equalizing method is mandatory. The conventional c ´ uk converter requires 2(n − 1) switches to balance n cells, while the proposed circuit requires only n switches for n cells in series. In addition, the proposed developed topology uses coupled inductors instead of un-coupled inductors, unlike the traditional c ´ uk converter balancing method. Since the c ´ uk balancing transfers the energy among two adjacent cells, it requires a proportionately long equalization time particularly for long string battery packs, but the coupled inductor c ´ uk converter type overcomes this problem. The switches are N-channel metal-oxide field-effect transistor (MOSFET) to achieve lower drain-source on-resistance, R D S ( o n ) , and less voltage drop as compared to the P-channels. The switches are triggered by complementary signals. The coupled inductor is made in such a way to hold the same magnetizing inductance. It can be done by using five wires in one hand. The circuit contains five inductors, one magnetic core, with five winding for eight cells, and one capacitor for two cells. Therefore, the overall circuitry and complexity of the circuit are reduced, resulting in a more cost-effective and easy to implement circuit. The system also does not demand complicated control for battery equalizing. The experimental circuit was implemented and simulation results were obtained to confirm the validity of the proposed system.

This research work explains the practical realization of hybrid solar wind-based standalone power system with maximum power point tracker (MPPT) to produce electrical power in rural places (residential applications). The wind inspired Ant Colony Optimization (ACO)-based MPPT algorithm is employed for the purpose of fast and accurate tracking power from wind energy system. Fuzzy Logic Control (FLC) inverter controlling strategy is adopted in this presented work compared to classical proportional-integral (PI) control. Moreover, single Cuk converter is operated as impedance power adapter to execute MPPT functioning. Here, ACO-based MPPT has been implemented with no voltage and current extra circuit requirement compared to existing evolutionary algorithms single cuk converter is employed to improve conversion efficiency of converter by maximizing power stages. DC-link voltage can be regulated by placing Cuk converter Permanent Magnet Synchronous Generator (PMSG) linked rectifier and inverter. The proposed MPPT method is responsible for rapid battery charging and gives power dispersion of battery for hybrid PV-Wind system. ACO-based MPPT provides seven times faster convergence compared to the particle swarm optimization (PSO) algorithm for achievement of maximum power point (MPP) and tracking efficiency. Satisfactory practical results have been realized using the dSPACE (DS1104) platform that justify the superiority of proposed algorithms designed under various operating situations.

Permanent magnet brushless DC motor (PMBLDCM) drives are being employed in many variable speed applications due to their high efficiency, silent operation, compact size, high reliability, ease of control, and low maintenance requirements. These drives have power quality problems and poor power factor at input AC mains as they are mostly fed through diode bridge rectifier based voltage source inverters. To overcome such problems a single-phase single-switch power factor correction AC-DC converter topology based on a Cuk converter is proposed to feed voltage source inverters based PMBLDCM. It focuses on the analysis, design and performance evaluation of the proposed PFC converter topology for a 1.5 kW, 1500 rpm, 400 V PMBLDCM drive used for an air-conditioning system. The proposed PFC converter topology is modelled and its performance is simulated in Matlab-Simulink environment and results show an improved power quality and good power factor in wide speed range of the drive.

This paper introduces a sliding mode control (SMC)-based equivalent control method to a novel high output gain Ćuk converter. An additional inductor and capacitor improves the efficiency and output gain of the classical Ćuk converter. Classical proportional integral (PI) controllers are widely used in direct current to direct current (DC-DC) converters. However, it is a very challenging task to design a single PI controller operating in different loads and disturbances. An SMC-based equivalent control method which achieves a robust operation in a wide operation range is also proposed. Switching frequency is kept constant in appropriate intervals at different loading and disturbance conditions by implementing a dynamic hysteresis control method. Numerical simulations conducted in MATLAB/Simulink confirm the accuracy of analysis of high output gain modified Ćuk converter. In addition, the proposed equivalent control method is validated in different perturbations to demonstrate robust operation in wide operation range.