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In this article, the coupled inductor is designed using a litz wire, an enameled litz wire, and a solid wire separately. All the coupled inductors wound with litz and solid wires are tested in a Cuk converter operated in DCM with a 25 kHz switching frequency for 15 W power, and winding losses of each wire, including proximity and skin effect loss, are calculated analytically without using any software, by using different techniques presented in literature, and the results are compared. Also, state-space modeling of the converter using a coupled inductor for DCM is derived as a contribution of the article because such a modeling is not derived for the Cuk converter in the literature. Thanks to the applications, inductor currents, switch voltage, input–output voltage, and output current are measured for coupled inductors with different wires. In addition, FEM simulation and co-simulation of all coupled inductors are realized, and the results obtained by applications are verified by them. Besides, it is shown that while the number of turns is the same, increasing the bundle of wires increases efficiency and inductance, reducing the window area and coupling coefficient. [ABSTRACT FROM AUTHOR]

The bidirectional DC-DC converter was selected as the research object. Based on the connection topology of energy storage and consumption components in the hybrid energy storage system, power demand indicators were determined for different energy flow directions, and the parameters of the main converter components and appropriate circuit components were established. A circuit model of buck/boost was constructed, and an adaptive fast terminal sliding mode control strategy was designed. The controller parameters were optimized using an improved genetic algorithm. Different control parameters have different control effects. In order to obtain better voltage output characteristics, the parameters of the adaptive fast terminal sliding mode control strategy were optimized.The proposed method can be verified to exhibit good control performance through simulation. [ABSTRACT FROM AUTHOR]

Renewable energy sources play a great role in the sustainability of natural resources and a healthy environment. Among these, solar photovoltaic (PV) systems are becoming more economically viable. However, as the utility of solar energy conversion systems is limited by the availability of sunlight, they need to be integrated with electrical energy storage systems to be more sustainable. This paper aims to improve the control performance of a hybrid energy storage system (HESS) with PV power generation as the primary power source. HESSs stabilize DC microgrid systems by compensating for demand generation mismatches. Batteries and supercapacitors are chosen as energy storage elements; batteries have a high energy density and are capable of supplying and absorbing energy over a long duration, while supercapacitors can store and deliver energy very quickly. To enhance the stability of the system, each storage element is connected to the DC bus using a bidirectional Ćuk converter, which offers high efficiency, a continuous current, and minimal switching losses. This study proposes a proportional–integral (PI) controller combined with the fast nonsingular integral terminal sliding mode control (FNITSMC) for HESSs to adjust the power balance in a DC microgrid. FNITSMC has the advantage of enhancing the system states to reach the equilibrium point of a long sliding surface with a fast convergence rate. The reference current for FNITSMC is obtained using a PI controller combined with a low-pass filter (LPF), which eliminates the peaking current spikes on the battery and diverts them towards the supercapacitor. The effectiveness of the proposed control scheme is validated through the real-time hardware-in-the-loop (HIL) simulations on Typhoon™ HIL-402 with added uncertainties, including load variations at various temperatures and irradiances. [ABSTRACT FROM AUTHOR]

Summary: Traditional multiple‐output AC‐DC power supply with power factor correction (PFC) function usually employs a two‐stage cascaded topology that is composed of prestage PFC converter and N independent poststage DC‐DC converters to achieve PFC and voltage or current regulation of N outputs. Hence, the conventional two‐stage cascaded multiple‐output AC‐DC power supply needs N + 1 magnetic components as power inductors or transformers and N + 1 controllers, which increases the cost and size of the multioutput converters. The conventional multiple‐string AC‐DC LED driving circuits usually employ a two‐stage topology to realize PFC and independent current regulation of each LED string. To address the issue of complexity, high cost, and large size of the two‐stage multistring LED driving circuit, a single‐stage triple‐output Cuk PFC converter is proposed by cascading boost converter and single‐inductor triple‐output buck converter with sharing main power switch in this paper. The topology operation principle, control strategy, design consideration, and operation characteristics of the proposed circuit are investigated in detail. With the switch sharing and inductor multiplexing technologies at the same time, the proposed converter utilizes only single‐stage converter to achieve PFC function, independent regulation of triple‐channel output current, and flicker‐free with low twice line frequency LED current ripple. The proposed converter is verified by a 50‐W experimental prototype of LED driver for triple string LEDs. The proposed converter only uses two power inductors and a set of controller to achieve greater than 0.945 PF, up to 90.5% efficiency, low LED current ripple, and independent current regulation for triple LED strings with different forward voltage, which may significantly reduce the cost and size of the traditional AC‐DC multistring LED driving circuit. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper, an impulsive control algorithm with time-delay is proposed to alleviate the issue of interrelated state variables and the adverse effect of input voltage or load perturbations on output in the highly nonlinearity of the DC converter. The impulsive control is introduced concerning the state information of the control system, while the stability criterion is established by employing the average dwell time. The control principle similarity of the delayed impulsive effect and the spiking neural network are elucidated. Unlike the already existing control methods, such as proportional–integral (PI) control and sliding mode (SM) control, we leverage the state information of the switching state drive system in recent history at every sampling moment to conduct impulsive control with accurate and swift error feedback. Three typical controls are executed on the output load and source voltage operating point, characterizing the advantages superior to the PI and SM control algorithms. Hence, the proposed algorithm outperforms others in system performance indicators such as output voltage step-up, step-down, settling time and ripple. In terms of the variation of source voltage and irradiance in the photovoltaic system, the verification of voltage control stability is given in the case of the maximum power point module of the photovoltaic system, exhibiting minor output voltage ripple and shorter transient change time. [ABSTRACT FROM AUTHOR]

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.

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The voltage output of an energy storage device utilized in electric vehicles (EVs) is modulated in response to the load, and the elevated voltage of the DC link poses challenges for vehicle engineers when integrating energy storage components with the traction drive system. DC-DC converters are commonly employed in electrical powertrain systems within industrial settings to facilitate the integration of various components. The Cuk converter is widely acknowledged as a viable alternative requiring thorough deliberation, including battery management systems (BMS) for EVs technology. This is because of a continuous flow of current in both the input and the output, and it has a high efficiency compared to the buck-boost topology. Additionally, there is a low ripple in the output load voltage. The present work uses an analysis, model, and control of the Cuk converter circuit using a hybrid fuzzy logic-based ant colony optimization (ACO) method. The transient response and the steady-state performance specifications are objective functions in the fuzzy controller design process. After a comprehensive evaluation of the obtained results, it was observed that the fuzzy-ACO controller successfully achieved the desired reference with reduced rise and settling time. This study implements modeling and controlling applications of the Cuk converter by utilizing the MATLAB/SIMULINK program. The proposed controller's effectiveness is demonstrated during load variations and changes in the reference voltage. [ABSTRACT FROM AUTHOR]

DC-DC converters play a crucial role in recent and advanced applications, enabling efficient power conversion and management for renewable energy systems, electric vehicles, portable devices, and advanced communication systems. In line with this, the objective of this paper is to introduce a new DC-DC configuration based on the Cuk converter named as Mahafzah converter, which utilizes a coupling capacitor with a lower rated voltage. The paper aims to demonstrate the effectiveness of the proposed converter in terms of improved efficiency, reduced size, and reduced semiconductor device currents compared to the conventional Cuk converter. The proposed configuration comprises the same components as the Cuk converter, but in a different arrangement, without any additional elements. The main advantage of the proposed converter is using a coupling capacitor with a much lower rated voltage than the Cuk converter, resulting in a smaller capacitor size, reduced printed circuit board (PCB) size, and manufacturing cost. Additionally, the proposed converter reduces the currents of the semiconductor devices compared to those in the Cuk converter. To demonstrate its effectiveness, the converter is operated under continuous current mode (CCM) with a constant duty cycle and switching frequency. The study provides an in-depth discussion of the various operating modes by making use of equations relating to currents, voltages, duty cycles, and voltage gains. It also provides detailed illustrations of the limits between CCM and discontinuous current mode (DCM). The effectiveness of the proposed converter is demonstrated through a design example with operating parameters of 1 kW, 200 V/−300 V, and 20 kHz. Additionally, a low voltage–low power prototype (12/−18 V, 3.24 W, 20 kHz) is established to verify the operation of the proposed converter. Simulation and experimental verification of the proposed configuration achieved the desired results to improve efficiency and reduce the rate. The results clearly indicate that the efficiency of the proposed converter surpasses that of the conventional Cuk converter under identical operating conditions, reaching approximately 88% at rated load conditions. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper proposed an improved jellyfish Search (ImpJS) technique for torque ripple minimization on CUK converter based BLDC motor. In this paper, crossover and mutation operator are utilized to improve searching behavior of the JS algorithm. Hence, it is named as improved jellyfish algorithm (ImpJS). At first, BLDC motor is considered along with the Cuk converter is improved through the switched inductor. Simultaneously, the execution of the BLDC motor operation includes speed and torque control strategy is also analyzed. In order to improve these two strategies, the proposed ImpJS system is introduced. The best gain parameter is tuned to upgrade the controller operation considering the objective function. Finally, the proposed technique-based BLDC motor is performed on MATLAB/Simulink platform in order to analyze the performance is compared with other existing system to determine the effectiveness. The existing techniques like particle swarm optimization (PSO), ant lion optimizer (ALO) and salp swarm algorithm (SSA). In case 1 and case 2, the MSE for proposed technique achieves the value of 0.01093 and 0.01095. In case 1 and case 2, the voltage deviation for the proposed system achieves the value of 2 and 2 • An improved technique for torque ripple minimization in cuk converter based BLDC motor. • Crossover and mutation operator are utilized to improve the JS algorithm. • Execution of the BLDC Motor operation includes speed and torque control. • Best gain parameter is tuned to upgrade the controller operation. [ABSTRACT FROM AUTHOR]

As one of the important energy conversion systems in renewable energy power generation, the two‐stage DC‐DC converter cascaded system composed of source converter and load converter has been widely used in industrial applications. Different from the constant voltage load of the traditional DC‐DC converter, the load converter in the cascaded converter, as the constant power load of the source converter, has an obvious impact on the stability of the source converter. In this paper, the cascaded system composed of Cuk converter as source converter and buck‐boost converter as load converter is studied. Analyses results show that with increasing of power load, a Floquet multiplier of monodromy matrix belongs to the converter cascaded system traverses the unit circle from outside to inside along negative real axis and will suddenly jump out of the unit circle when the power load reaches a specific value. Correspondingly, the entire system gradually moves from period‐doubling bifurcation state to period‐1 limit cycle and then suddenly jumps to chaos state. With application of monodromy matrix theory and sinusoidal voltage compensation method, stability boundary of the system is extended and nonlinear behaviors are stabilized. Finally, simulation and experimental results verify the feasibility of analytical technique and conclusions. [ABSTRACT FROM AUTHOR]

This work proposes an improved DC–DC converter having modular multiport configuration for bipolar outputs using single switch. This converter has capability to be scaled for n bipolar or 2n unipolar outputs. It uses only one DC source and single switch to achieve the above-mentioned modularity, and each bipolar level employs a combination of SEPIC and Ćuk converter. This helps in generating one bipolar or two unipolar outputs, having opposite polarity at every port. The modularity of this converter depends on the switch rating. The proposed converter can have n outputs depending on the voltage and current rating of switch used. Key advantages of the proposed converter are (1) reduced component count, (2) Self-balancing of output side capacitor voltage levels, (3) no cross-regulation and (4) low ripple in input and output current both. It makes this converter suitable for low voltage application. To improve the system response during dynamic load change, control scheme has been designed. Stability analysis for the control system has been presented. The proposed converter is validated experimentally up to 2 kW load rating to analyse the feasibility of the proposed modular configuration. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper proposes a novel electrolytic-free quasi-Z-Source Ćuk LED driver for automotive applications. Compared to the traditional Ćuk converter, the first merit of the novel converter is higher gain, which makes it apt to switch between multiple applications. Secondly, the proposed converter combines the inherent characteristics of LED load to operate in a wide range in Continuous Conduction Mode (CCM), so the inductors can assist in energy storage, and only small capacitance is required. Thirdly, inductors can be integrated and use only one core, and capacitors are electrolytic-free, which will benefit integration and long life. All merits are important to automotive application. Detailed analysis and design steps are presented. Then, with the help of the simulation software Saber, several key parts of the converter are simulated. Finally, a prototype controlled by the micro control unit stm32f103c8t6 is built, and the feasibility is verified by the experiment results. [ABSTRACT FROM AUTHOR]

Since the Cuk converter is a non-minimum phase system with an unstable internal dynamic, it is challenging to employ control methods such as input–output linearization to ensure the closed-loop system stability. This paper proposes an objective holographic feedback nonlinear control (OHFNC) method without static deviation to regulate fourth-order Cuk converters. A Cuk converter operating in the continuous conduction mode is adopted, and the input inductor current and output capacitor voltage of the system are selected as control target quantities. The OHFNC method aims to configure a nonlinear system with poles near the equilibrium point, and place them in desired positions. The target quantities are separately constrained by feedback coefficients, which forces them to converge to their corresponding reference trajectories. Accordingly, an integration link is introduced to compensate for the reference current error when the system is heavily loaded. Finally, simulation and experimental results show that the OHFNC method has a stronger robustness and a faster transient response than fractional-order PIλ dual-loop control. [ABSTRACT FROM AUTHOR]

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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.

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. [ABSTRACT FROM AUTHOR]

This paper represents the idea of implementing bio-inspired algorithms in designing an optimized PID controller to investigate the stability and improve the performance of the closed-loop CUK converter. Bio-inspired algorithms (BIA) such as Firefly Algorithm (FA), Particle Swarm Optimization (PSO) and Artificial Bee Colony (ABC) are stochastic optimization techniques and have been increasingly applied to attain optimal solution for designing and optimizing power converters in current times. The closed-loop transfer function of the CUK converter has been developed by the State Space Average (SSA) technique. This paper assesses both the cases of converter stability when it is integrated with the conventional PID controller and the BIA-PID controllers (FA-PID, PSO-PID, ABC-PID) and eventually compares the outcomes from all the controllers. For examining the stability of the system, three objective functions (IAE, ITAE, and ISE) and various performance specifications such as percentage of overshoot, rise time, settling time, and peak amplitude are tabulated. MATLAB and Simulink are used to carry out the simulations meticulously. Hence, a comparative analysis is illustrated in this paper to state a clear-sighted evaluation of the performances. [ABSTRACT FROM AUTHOR]

A novel modulation scheme for a bidirectional isolated pulsewidth modulation active-clamp (PAC)-Ćuk converter is presented in this article. In the PAC-Ćuk converter, the clamping circuit consisting of a capacitor, a series inductor, and an active device enables zero-voltage-switching (ZVS) turn-on capability of all the active devices. This additional circuit equips the converter with three independent control parameters. This article discusses power transfer, ZVS region, and circulating current dependency on the control parameters across the converter gain. Minimal circulating current is generally desired to decrease the conduction losses. With the help of the proposed modulation technique, the optimization of the control parameters to achieve lower circulating current while ensuring ZVS operation is also discussed. A 2-kW experimental converter is also designed and fabricated to validate the analysis. [ABSTRACT FROM AUTHOR]

In this paper, a new transformerless buck–boost converter is proposed. This converter is based on combining two basic converters, including Cuk and traditional buck–boost converters, along with a voltage multiplier (VM) at the output side. The proposed semi‐quadratic buck–boost converter operates in continuous conduction mode (CCM) and provides two operation modes by turning the switches on and off. This converter has some merits such as a wide conversion ratio and continuous input current. The proposed converter consists of two switches with simultaneous operation resulting in simplicity in control. A modular configuration and a wide range of duty cycles are available through the proposed converter, which causes higher or lower output voltage and facilitates the converter maintenance. The calculations of the ideal and the real voltage gain, voltage stress of switches and diodes, efficiency, and design consideration of elements are given in this paper. Finally, a prototype is implemented, and experimental waveforms are obtained to prove and validate the simulation results as well as the theoretical analysis of the proposed converter. [ABSTRACT FROM AUTHOR]

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.