Continuous Conduction Mode Research Articles

A New Three‐Port DC–DC Converter: Analysis, Design, and Verification for Hybrid Energy Systems

ABSTRACTA research study on the three‐port DC–DC converters is done in this article. The proposed converter is a power electronic unit with a low‐voltage, high‐voltage, and battery port. The power of the input ports can be transferred to the output port simultaneously and individually. In this converter, the power can flow bidirectional. In other words, the battery can be charged not only by the low‐voltage port but also by the returned energy from the high‐voltage port. Hence, the proposed converter can operate in step‐up and step‐down modes. Continuous input current, the low voltage stress on semiconductors, and the low count of the devices are other advantages of the converter. These features and the benefits mentioned above make the proposed converter proper for hybrid energy systems. This converter is analyzed in continuous conduction mode, resulting in mathematical equations. To validate these theoretical analyses, a laboratory scale of the converter performs at 50 kHz, 200 W, and 115 V.

Enhanced High‐Gain Switched Capacitor DC–DC Converter Optimizing Renewable Energy Integration

ABSTRACTA novel high‐gain switched capacitor (HGSC) DC–DC converter for carbon neutral energy applications is presented in the scientific paper. It consists of two MOSFET switches, and utilization of a simultaneous switching approach for the switches enables simplified control. The switched capacitor (SC) technique is utilized to extract high gain from the proposed HGSC topology; the basic idea is periodic charging and discharging of the capacitor. The proposed HGSC topology operational mode is carried out in Continuous Conduction Mode (CCM) along with the steady‐state analysis, and different switching stages are discussed in detail. Then, an analysis is carried out to demonstrate the proposed HGSC converter's special feature with other high‐gain converters. An averaging state‐space technique is used to determine the suggested converter's dynamics performance, and a small signal analysis is used to verify its stability. Furthermore, the HGSC topology is thoroughly analyzed in terms of power losses. For comparing the practical efficiency of the designed converter, nonidealities voltage gain is derived. The maximum efficiency of 96.7% is obtained at 150 W output power with the help of the dSPACE 1104 controller. Whenever the HGSC converter is fed with an input voltage supply of 20 V. It generates output voltages between 140 and 240 V. Extensive experimental investigation is carried out on a 200 W laboratory prototype model to verify the practicability and feasibility of HGSC DC–DC converter topology.

Advancing Renewable Energy: A Quadratic High-Efficiency High Gain Step-Up DC/DC Converter

Presenting a new high-gain converter that incorporates a coupled inductor, this paper offers a range of advantages over existing designs. The circuit features a simple structure with two cascade semi-stages, two power switches operating in sync, and a coupled inductor. It provides an extensive output voltage range, ensures continuous input current with minimal ripple, maintains positive output voltage polarity, and follows a standard ground configuration. These features make it well-suited for various applications, particularly in photovoltaic systems. Additionally, the voltage stress across each power switch is significantly lower than that of other boost converters, allowing for the selection of power MOSFETs with reduced drain-source ON resistance to ensure high efficiency. This research presents comprehensive assessments of the steady-state and stress conditions as well as thorough comparisons with other similar converters operating in continuous conduction mode. Theoretical advantages of the proposed circuit design are further reinforced by experimental results obtained from a 200-W step-up 25–370 V arrangement.

Modelling and DPWM control of continuous switched boost inverter

ABSTRACT In this paper, a new type of three-phase continuous switched boost inverter (CSBI) is proposed. The proposed inverter has a new impedance network that can obtain a high voltage boost ratio. It also can make the system work in continuous conduction mode (CCM). The shoot-through is allowed in the operating mode of the CSBI, which eliminates the dead time and leads to better EMI immunity. The modified discontinuous pulse-width modulation (DPWM) strategy is proposed to operate the CSBI. Compared with the space vector pulse-width modulation (SVPWM) method, the new modulation strategy can reduce the switching loss effectively. Meanwhile, the state space averaging method is used to design the inverter structure and calculate the impedance parameters. To investigate the dynamic performance of the CSBI impedance parameters, the small signal model analysis is used. A test bench of CSBI is built in laboratory. The operating strategy and the theoretical analysis of the proposed inverter are validated by the results of simulation and experiment.

A new forward‐flyback converter without right half plane zero

AbstractDue to its unique features, the flyback converter is widely used to convert DC to DC power. This converter has a non‐minimum phase (NMP) dynamic behavior, which is one of its most significant disadvantages. By changing the topology of the flyback converter to a forward‐flyback (FF) converter, the dynamic behavior of the converter can be minimum phase (MP) while the main advantages of the flyback converter such as isolation of the output from the input and simple topology are maintained. This article proposes an innovative FF converter topology by doubling the forward path and adding only one diode and one capacitor. In addition to better dynamic behavior, the proposed double FF (DFF) converter has the same advantages as the conventional FF converter. A new method is used to obtain the transfer function of the output voltage to the duty cycle of the proposed converter. The converter is designed in continuous conduction mode (CCM) with minimum phase dynamics. Finally, simulation and experimental results of both conventional FF and the proposed DFF converters are obtained and compared to validate the superiority of the proposed converter.

High efficiency AOT-controlled boost converter with pseudo-constant switching frequency

An on-time generator for boost converters is proposed to achieve an adaptive on-time (AOT) control with pseudo-constant frequency in continuous conduction mode (CCM). Since the first-order parasitic effect of the components and devices is considered in the design of the on-time generator, the switching frequency (fsw) variation of the boost converter in CCM can be better suppressed with the load current (ILOAD), input voltage (VIN) and output voltage (VOUT) changes, which can effectively solve the EMI noise problem. In addition, the idea of capacitor pre-charging is applied to simplifying circuit complexity. Meanwhile, an on-demand modulation strategy is applied to improve the conversion efficiency. Simulation results show that the boost converter based on the proposed on-time generator can realize the fsw variation of 0.4 % in case of 200 mA ILOAD change. Moreover, the VIN may range from 0.8 to 1.5 V, the VOUT is set to 1.8 V, and the peak efficiency of the simulation is 96.9 %.

A Flyback Converter with a Simple Passive Circuit for Improving Power Efficiency

This paper proposes an effective method to improve the power efficiency of the flyback converter in the continuous conduction mode (CCM). The proposed converter uses a simple passive circuit to reduce the switching power losses. The current through the output diode can be shifted to a new branch where one diode, one inductor, and one auxiliary winding of the transformer are included. The output diode current can be reduced to zero for the zero-current switching of the output diode. The additional inductor is used to control the changing rate of the additional diode current to reduce the reverse-recovery current. Keeping the simplicity of the passive method, the proposed converter improves the power efficiency compared to the conventional converter. The circuit configuration and the operation principle are described. The design considerations are presented, including the simulation verification. The experimental results for a 45 W prototype are discussed to evaluate the performance of the proposed converter. The proposed converter has achieved a power efficiency of 93.5% for the rated load condition, improving the power efficiency. The applications of the proposed converter are also discussed for the future research directions.

A dual-stage high-gain converter with dual inputs and dual outputs for electric vehicle charging

The DC-DC converter is an essential subsystem in electric vehicle (EV) chargers, and most converters depend on a single-input single-output structure, which can be costly when multiple charging units are needed. Additionally, these converters offer limited voltage gain, restricting charging configurations. This paper proposed a dual-stage high-gain converter that operates in a boost mode with reduced components, using an inductor, capacitor, and 2-diodes (LC2D) to provide high-gain output. The proposed Dual Inputs and Dual Outputs (DIDO) converter tied with Photovoltaic (PV) and constant DC acting as inputs and two different voltage levels EV chargers are serving as the output. The proposed converter operates at continuous conduction mode (CCM), achieving high efficiency and reliability with fewer losses. The proposed work was designed for 418V and 85V systems in MATLAB/Simulink, and the results were validated with hardware implementation. The proposed converter delivers high-gain output to the electric vehicle application with 92.2 % efficiency.

DC Regulation and Loop Gain Analysis of a DC-DC Switch Mode Power Supply: A Case Study on a Synchronous PWM Controlled Buck Converter

This study investigates the DC regulation of a DC-DC buck converter operating with pulse width modulation (PWM), taking into account the internal resistance of the coil and the on-resistance of the switching device. The effect of these parameters on the input/output disturbances is analyzed in continuous-conduction mode under constant frequency voltage mode control. The study also explores the effect on loop gain using the IRU3037 8-pin IC synchronous PWM controlled buck converter. The transfer function of the IRU3037 IC is derived from datasheet values using state-space averaging and AC small signal methods. A Type II compensator is then designed based on the derived transfer function. In addition, the step response characteristics of the open-loop and closed-loop circuits are investigated by time domain analysis.

Predictive control method with conduction mode detection to suppress input current distortion of three‐level power factor correction

AbstractA novel predictive control method with conduction mode detection is proposed to suppress input current distortion of three‐level power factor correction (PFC) converters. In PFC converter, the input current is mostly distorted in continuous conduction mode (CCM) with conventional control methods. The proposed predictive control method comprises of a predictive CCM algorithm, a predictive discontinuous conduction mode (DCM) algorithm, and a conduction mode detection technique. By analysing four switching states of PFC converter and based on the inductor current ripple, predictive control duty cycles in CCM and DCM are derived, and the optimal duty cycle is determined by forecasting the next cycle current. According to the duty cycle characteristics, the conduction mode is detected without additional detection algorithms and circuits, achieving the input current tracking the input voltage. Finally, the effectiveness and correctness of the proposed predictive control method are validated through simulation and experiment.

A new positive output DC–DC buck–boost converter based on modified boost and ZETA converters

A new DC–DC buck–boost converter with a wide conversion ratio is presented in this paper. The proposed buck–boost converter consists of a combination of modified boost converter and ZETA converter, which has the advantages of both converters such as continuous input/output current and positive polarity of the output voltage. The combination of these two converters achieves semi-quadratic voltage gain and makes the proposed converter suitable for industrial and renewable energy applications. With a voltage gain higher than that of the ZETA converter and modified boost converter, the proposed converter also reduces input current stress due to its continuity. Two operating states are available for this converter in continuous conduction mode. This converter has two switches that operate simultaneously and can be easily controlled. The converter's output voltage ripple and output capacitor current stress are reduced as a result of continuous output current. Computational analysis and the introduced structure efficiency considering the influence of parasitic elements are presented in this paper. The small signal modelling and closed-loop control, as well as simulation and experimental results are also presented. This converter has also been compared with other similar and recently presented topologies. Finally, a 40–60 W, 20–76 V for boost mode and 10 V for buck mode prototype was implemented to verify the accuracy of the computational analysis.

Switching regulator based on an adaptive DC-DC buck converter for a lithium-ion battery charging interface

A switching regulator based on an adaptive DC-DC buck converter for a Li-ion battery charging interface is introduced in this paper with the aim of improving the efficiency of charging the Li-ion battery during the whole charging process. By using the battery voltage as feedback, an adaptive reference is generated. This reference is employed by the converter, which is in continuous conduction mode (CCM), to produce a wide adaptive output voltage that closely tracks the battery voltage, intended to serve as the power source for the multimode charging interface. The converter was implemented in a 180 nm complementary metal oxide semiconductor (CMOS) process and simulated using the Cadence Virtuoso tool. With an input voltage of 5 V and a switching frequency selected at 500 kHz, the simulation results show that the converter produces different charging currents for each battery charging mode, and an adaptive output voltage ranging from 2.8 V to 4.38 V, with the current ripple of 38 mA in CC mode and voltage ripple factor less than 1% in constant voltage (CV) mode. The average converter efficiency is 83.5%.

Q-EDR Hybrid Boost Converter Operation For High Gain With Low Device Stress

Abstract: The hybrid continuous-discontinuous mode (CCM-DCM) operation of non-isolated systems is proposed in this paper. boost converter with quadratic extended duty ratio (Q-EDR) for applications with high gain and low power. The inductors at the input while the EDR was in continuous conduction mode (CCM) The mode of operation of stage inductors is discontinuous conduction. (DCM) in order to reap the advantages of CCM and DCM operation. Interleaving's ripple in the low input current and low voltage The EDR stage switches' stress remains. With what is being half and half method of activity, the inductance worth of EDR stage significant decrease in the inductor. an additional decrease in switch voltage is accomplished during turn-on progress in the proposed activity, prompting huge decrease thus on exchanging losses. This lets the converter run at higher switching speeds. frequency, thereby reducing EDR inductors' size by 45 percent in this instance an experiment confirms the proposed idea. Simulink prototype for a two-phase Q-EDR operating at 30 V-40 V to 400 V output, a gain of more than 12 at duty close to 0.54. The converter has a peak efficiency of 95.5 percent. at a switching frequency of 135 kHz and 300 W for all silicon switches.

New single-switch buck–boost converter with continuous input/output currents and a wide conversion range

The main aim of this paper is to introduce a new high step-up/down buck-boost converter with a minimum number of switches which provides the benefit of having the continuity of the input/output current. This single-switch semi-quadratic converter is suitable for high step-up applications while being able to provide step-down voltage gains. Also, by applying some minor changes to the circuit elements, another single-switch buck-boost converter is suggested which has two operative outputs with different voltage gains. One of the outputs of this topology has quadratic buck-boost converter voltage gain which is appropriate for high step-up/step-down applications. The other output could vary from input voltage to minus infinity, ideally. After studying the steady-state operation of the proposed converters in Continuous Conduction Mode (C.C.M), the simulation results are presented. In addition, a comparison among related converters proposed in the literature is made. Finally, experimental results are evaluated by implementing a laboratory prototype of the proposed converter in both step-down and step-up modes. Theoretical, simulation, and experimental results are compatible with each other.

Control of DC-DC boost converter in discontinuous conduction mode feeding a constant power load

This article presents a new control strategy for a DC-DC boost converter used to supply a constant power load. The designed controller allows regulates the converter output voltage to a required reference value. By designing the controller based on the reduced order averaged model of the converter and using a nonlinear control technique based on feedback linearization, a simple-to-implement and stable controller for both operating modes of the converter (continuous and discontinuous conduction modes respectively) is obtained. The designed control strategy is validated through simulation and experimental results, demonstrating good dynamic performance and stability in both conduction modes, under variations in reference values and significant load changes. In addition, a comparison of the performance and implementation costs between the control strategy proposed in this paper and two strategies proposed by other authors is included.

State Space Average Modeling, Small Signal Analysis, and Control Implementation of an Efficient Single-Switch High-Gain Multicell Boost DC-DC Converter with Low Voltage Stress

This paper presents the closed-loop control of a single-switch high-gain multicell boost DC-DC converter working in a continuous conduction mode (CCM). This converter is particularly designed for applications in photovoltaic systems. One of the main advantages of the proposed converter is that it only employs one active semiconductor switch, which decreases the converter losses and cost, increases the efficiency, and simplifies the control circuit. Moreover, the multicell nature of the proposed converter offers the possibility of obtaining the required voltage gain by selecting the number of cells. State space average (SSA) modeling and small-signal analysis are used to model the switching converter power stages of the proposed converter. The parasitic series resistances of the passive elements of the converter circuit are considered to improve the accuracy of the modeling. Small-signal analysis is used to derive the open-loop transfer functions, input-to-output and control-to-output transfer functions of the proposed converter to examine its dynamic performance. The stability of the converter is analyzed to design the parameters of the voltage controller using the proposed modeling method. The experimental prototype of the proposed single-switch two-cell boost DC-DC converter was implemented. The simulation and experimental results proved the effectiveness of the proposed boost DC-DC converter under different working conditions. It has a fast dynamic response without overshoots. A comprehensive comparison between the proposed converter and previous boost converters is provided. It guarantees a required variable and constant high voltage gain with a wider duty ratio range. It compromises between the required performance, the low number of components, low voltage stress on the components, and cost-effectiveness. The experimental efficiency of the proposed converter is about 96% at a 100 W load.

Circuit topology aware GNN-based multi-variable model for DC-DC converters dynamics prediction in CCM and DCM

A regression model based on graph neural network, tailored for electric circuit dynamics prediction is introduced, providing converter performance predictions on converter circuit level and internal parameter variations. Regardless of the number of components or connections present in a converter circuit, the proposed model can be readily scaled to incorporate different converter circuit topologies. Moreover, the model can be used to analyse converter circuits with any number of circuit components and any control parameters variation. To enable the use of machine learning methods and applications, all physical and switching circuit properties such as converter circuits operating in continuous conduction mode or discontinuous conduction mode are accurately mapped to graph representation. Three of the most common converters (Buck, Boost, and Buck-boost) are used as example circuits applied to model and the target is to predict the gain and current ripples in inductor. The model achieves 99.51% on the R2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R^2$$\\end{document} measure and a mean square error of 0.0263.

An Improved Cascaded Boost Converter with an Ultra-High Voltage Gain Suitable for Dielectric Quality Tests

Dielectric quality tests require a high AC voltage with a frequency range of 0.0001 Hz to 1000 Hz. However, providing a high AC voltage with such a frequency variety is challenging. Providing a high DC voltage and then applying such a voltage to an inverter to adjust the frequency can be an acceptable solution for such a challenge. Notably, a high DC voltage is required for DC tests. This study proposes an improved form of the cascaded boost converter, whose merits are as follows: (i) the high voltage gain providing low duty cycles is possible; (ii) the input current is continuous, which decreases the current ripple of the input filter capacitor; (iii) the current stress of the semiconductors is less than the input current, and most of them have a large difference with it; (iv) the voltage stress of the semiconductors is less than the output voltage with a large difference; (v) only one switch with a simple drive circuit is used; (vi) the common ground of the load and input source decreases the EMI noise; (vii) besides the high voltage gain, the voltage density of the converter based on the number of inductors, capacitors, switches, diodes, and whole components is greater than that of the recently proposed converters; (viii) only two stacked connections of the proposed topology can provide a 2.6 kV voltage for a higher DC voltage test of dielectrics. The functional details of the converter are extracted in ideal and continuous conduction (CCM) modes. Moreover, the converter’s voltage gain and density are compared with the recently proposed converters to show the superiority of the proposed converter. Finally, the experimental results are presented to validate the theoretical relations in a 140 W output power.

Machine learning based feedforward voltage control for buck converters in envelope tracking applications

Tracking the voltage envelope of 5G base station power supplies poses a significant long-term challenge. To achieve fast and accurate envelope tracking, an efficient and high-frequency power electronics circuit and an excellent voltage controller are essential. This paper presents a novel machine learning (ML) based feedforward control method for precise voltage reference tracking. The method is exemplified using a standard buck converter in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). A feedforward neural network (FNN) is trained to capture non-ideal and non-linear effects in real circuits. An automated data collection system, developed with MATLAB and Simulink, facilitates data acquisition and model training process. The trained FNN predicts the duty cycle for the buck converter to generate the targeted output voltage and output power. A simulation model is built to validate the effectiveness of the FNN controller in envelope tracking applications.

A Deep Reinforcement Learning Approach to DC-DC Power Electronic Converter Control with Practical Considerations

In recent years, there has been a growing interest in using model-free deep reinforcement learning (DRL)-based controllers as an alternative approach to improve the dynamic behavior, efficiency, and other aspects of DC–DC power electronic converters, which are traditionally controlled based on small signal models. These conventional controllers often fail to self-adapt to various uncertainties and disturbances. This paper presents a design methodology using proximal policy optimization (PPO), a widely recognized and efficient DRL algorithm, to make near-optimal decisions for real buck converters operating in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) while handling resistive and inductive loads. Challenges associated with delays in real-time systems are identified. Key innovations include a chattering-reduction reward function, engineering of input features, and optimization of neural network architecture, which improve voltage regulation, ensure smoother operation, and optimize the computational cost of the neural network. The experimental and simulation results demonstrate the robustness and efficiency of the controller in real scenarios. The findings are believed to make significant contributions to the application of DRL controllers in real-time scenarios, providing guidelines and a starting point for designing controllers using the same method in this or other power electronic converter topologies.