Input Current Ripple Research Articles

Analysis of High Step-Up Quasi-Z-Source-Based Converter With Low Input Current Ripple

Analysis of High Step-Up Quasi-<i>Z</i>-Source-Based Converter With Low Input Current Ripple

High-Efficiency Resonant DC-DC Converter With Low Input Current Ripple for DC Power Distribution Systems

High-Efficiency Resonant DC-DC Converter With Low Input Current Ripple for DC Power Distribution Systems

A high step-up multiphase interleaved boost converter for fuel cells power system

The fuel cells need the high step-up DC/DC converter with low current ripples to interface to the high voltage DC grid. A novel zero voltage switching high step-up multiphase interleaved boost converter (ZVS HSMIBC) is proposed in this paper. This new converter employs advantages of low input current ripples, high voltage step-up ratio, soft-switching operation, and low switching harmonics and noise. In this paper, the two-phase interleaved structure of the proposed ZVS HSMIBC is analyzed and researched in detail as a representative topology. The relevant conclusions also can apply to multiphase (3 and above) interleaved structure of the HSMIBC. Finally, an experimental prototype is built and test, the experimental results show that the proposed converter can operated under ZVS conditions with low input current ripples and low switching noise and harmonics. In addition, this converter can obtain high voltage step-up ratio up to 45 (mn = 8, d = 0.8) with high efficiency, and proportion of the experimental ratios to theoretical ratios is also high (not less than 0.8).

An ultra‐high voltage gain interleaved converter based on three‐winding coupled inductor with reduced input current ripple for renewable energy applications

AbstractThis article proposes an interleaved high step‐up DC–DC converter topology designed for renewable energy applications, featuring an ultra‐high voltage conversion ratio. The converter employs an interleaved structure, resulting in a low peak‐to‐peak ripple in the input source current, which is particularly advantageous for solar PV sources. To enhance the output voltage, the topology utilizes voltage multiplier cells (VMC) and coupled inductor techniques. Two coupled inductors with three windings are integrated into the proposed topology, with the secondary and tertiary windings combined with VMC. This combination effectively reduces the maximum voltage stress across power switches, enabling the use of low‐rated and cost‐effective power switches for implementation. The article offers comprehensive operation modes and steady‐state analyses to demonstrate the converter's performance. A comparison is made between the suggested structure and other similar converter topologies. To validate the mathematical analysis, a 200‐W prototype is constructed, operating at a frequency of 25 kHz and achieving a voltage conversion range of 20 to 409 V. The experimental results are presented to support the findings.

Advancing Renewable Energy: An Experimental Study of a Switched-Inductor, Switched-Capacitor Luo Boost Converter for Low-Voltage Applications

Photovoltaic (PV), battery, and fuel cell (FC) technologies are emerging forms of renewable energy gaining popularity. However, one of the key limitations is their production of direct current (DC) voltage, which hinders the connectivity and integration with the electrical grid. To address this issue, various DC/DC boost converters have been introduced. This study presents an innovative Luo converter with a switched-inductor–capacitor (SLC) cell at the input and a switched-capacitor (SC) cell at the output. The SLC cell not only increases the input voltage, but also enhances the source’s lifespan and reliability. The SC cell further amplifies the voltage, especially for high-gain applications. The proposed converter simplifies control processes by using a single power switch, significantly boosting the input voltage by 21 times with a duty ratio of 0.8. This surpasses the gains achieved by conventional boost converters by over fourfold and Luo converters by sevenfold. The second challenge when a converter is connected to these voltage sources is the potential reduction in the lifespan of the sources and the overall system due to large input current ripples. The proposed converter addresses this issue by incorporating a switched-capacitor cell on the input side. This cell charges the inductors in parallel and discharges them in series, reducing the magnitude of the input current. Another advantage of the proposed converter is its simplicity, as it employs only one power switch, minimizing the complexity of the controller system. Additionally, the distribution of the output voltage passing through the diodes between the switch and output capacitor helps mitigate voltage stress for all semiconductor devices and capacitors. The study includes thorough mathematical analyses, simulations, and laboratory tests to validate the research’s theoretical foundations.

Improved Interleaved Boost Converter with Soft-Switching: Analysis and Experimental Validation

This paper proposes a novel interleaved boost converter for renewable energy applications. The two-phase interleaved boost converter was improved with lossless passive snubber cells to ensure the Zero Voltage Switching (ZVS) condition. The ZVS condition is contributed by a resonant inductor, a resonant capacitor, and two diodes. The proposed converter was operated in continuous current mode on its primary side. The significant merits of this converter are reduced switching losses, better efficiency, and reduced input current ripples without auxiliary switches. The soft-switching ability of this converter is maintained under both light- and heavy-load conditions. This paper also presents the operating principles and design analysis of the proposed converter. Furthermore, a 50-320V prototype was operated at 250 W to validate the soft-switching operation and theoretical analysis, and the experimental results are presented.

An extendable multicell quasi Z‐source converter topology using an active switched network

SummaryThis paper proposes a new extendable multicell topology based on the conventional quasi‐Z‐source converter (QZSC). The proposed topology has a multicell scheme and employs an active switched capacitor/inductor (ASC/SL) network. Therefore, it is entitled extended multicell ASC/SL QZSC (EMc‐ASC/SL‐QZSC). The proposed topology is augmented by cascading a modular cell consisting of two capacitors, an inductor, and a diode. The EMc‐ASC/SL‐QZSC offers significant advantages over existing QZSC‐based configurations. It has a high boosting capability that results in a wider output voltage range while simultaneously reducing voltage stress on capacitors and switching devices, all without losing voltage gain. Furthermore, this topology effectively reduces input current ripple, which contributes to a smoother charging current profile for capacitors, reducing electromagnetic interference (EMI) and improving overall efficiency. The practicality and performance of the EMc‐ASC/SL‐QZSC topology are comprehensively assessed through extensive numerical simulations and experimental verification, utilizing a laboratory‐built prototype.

MSC converter with optimized input current ripple for fuel cells applications

This article focuses on the analysis of a newly introduced DC-DC converter structure suitable for applications in fuel cell generation systems, the Modified Series Capacitor (MSC) converter. An interleaved-type converter with high voltage gain. The converter was proposed with a particular PWM scheme in which their two transistors operate with equal duty cycle, but the switching signals are 180° out of phase, and it uses two equal inductors. This article suggests a different way to design and operate the MSC converter with unequal inductors and unequal duty cycles. The primary benefit of the proposed approach with independent duty cycles and inductances is that it allows for the application of a numerical optimization algorithm to minimize the converter's input current ripple without the need to increase the stored energy in inductors. For example, it was possible to reduce one of the two inductors while maintaining (or even improving) the power quality of the input current. To prove the concept, an experiment was set up, executed, and confirmed.

Design and experimental validation of an artificial neural network-SVPWM controller for a novel micro grid-tied fuel cell-based 3-phase boost inverter

A grid-tied fuel cell (FC) system demands efficient power conversion, power quality preservation, grid stability, power flow management, renewable energy source (RES) integration, and enhanced grid resilience. Achieving these goals requires a precise inverter circuit switch approach. A boost power converter connected to the FC stack ensures voltage regulation, power conditioning, efficient power transfer, system integration, control, and protection. This enhances FC system adaptability and compatibility across various applications, minimizing input current ripples for prolonged FC lifespan.This study introduces a novel DC-DC boost converter with an artificial neural network (ANN) controller to reduce FC input current ripples and enhance FC stack-generated voltage for grid applications. It also presents a space vector sinusoidal pulse width modulation (SVPWM) technique for FC-based three-phase grid-tied inverters. This offers improved voltage utilization, precise voltage and current control, reduced harmonic distortion, rapid response, flexibility, scalability, reduced total harmonic distortion (THD), and over-modulation capability. The proposed SVPWM technique utilizes a digital signal processing (DSP)-based controller, combining high-speed processing, precision, and real-time capabilities to enhance system performance and efficiency.

A flexible load adaptive control strategy for efficient photovoltaic hydrogen generation system

The adaptive adjustment of the input current in proton exchange membrane electrolyzers (PEMEL) can provide several benefits, including the enhancement of PEMEL efficiency and the extension of its operating lifespan within an optimal range. This study presents a novel configuration for a photovoltaic (PV) hydrogen generation system that allows for the direct integration of PV. Moreover, the utilization of the triple-phase shift (TPS) modulation technique is implemented in order to achieve maximum power point tracking (MPPT) control within dual active bridge (DAB) DC/DC converters. The proposed strategy offers a pre-control approach for active adjustment of flexible loads to mitigate the mismatch between power output and load caused by fluctuations in renewable energy sources. This mismatch can lead to excessive current ripple, which in turn can impact the safe functioning of the PEMEL. In tandem with the analysis of the factors that contribute to ripple and the properties of the Electrical Spring (ES), relevant multiple variables are selected as control signals for the control strategy. This is done to effectively regulate the magnitude of non-essential loads and consequently reduce the ripple in the PEMEL system. The use of the ES pre-control technique effectively addresses the issue of delayed response of the PEMEL to PV oscillations, which is attributed to the large time-lag characteristics of electrolyzers. The simulation results at steady-state conditions and sudden changes in lighting conditions demonstrate concurrently that the overall control strategy yields a reduction in current stress in the DAB to 30.09% and 51.59%, respectively, enables MPPT in PV systems, and decreases the input current ripple of PEMEL to 80.1% and 57.67%, showing stronger anti-disturbance ability.

Improved Duty Compensation Control-Based Bidirectional Resonant DC−DC Converter With Reduced Input-Current Ripple for Battery Energy Storage Systems

This paper proposes an improved duty control-based resonant bidirectional dc–dc converter (BDC) to remarkably minimize input-current ripple for battery energy storage systems. The proposed converter offers a resonant-boost operation using a pulse-width-modulation (PWM) full-bridge circuit with a push-pull transformer under the forward-mode. Whereas, in the backward-mode, a resonant-buck operation is implemented with a PWM neutral-point-clamped (NPC)-type circuit. Unlike conventional current-fed BDCs, the most appealing characteristic of the proposed converter is the NPC-type structure with a push-pull transformer, which can significantly mitigate the input-current ripple without using extra input-inductors. Moreover, the proposed BDC minimizes the conduction-loss of the low-voltage side bottom switches by alleviating unbalanced DC offset-currents via proposed duty-compensation control under mismatched magnetizing inductances of the transformer's primary-windings. The designed circuit operation is analyzed in detail and its practicability has been fully confirmed with the proportional-integral and spider-monkey-optimization control techniques-based experimental verifications using a prototype 1-kW test-bed.

Design Considerations of Multi-Phase Buck DC-DC Converter

The main objective of this article is to propose a rational methodology for designing multi-phase step-down DC-DC converters, which can find applications both in engineering practice and in power electronics education. This study discusses the main types of losses in the multi-phase synchronous buck converter circuit (transistors’ conduction losses, high-side MOSFET’s switching losses, reverse recovery losses in the body diode, dead time losses, output capacitance losses in the MOSFETs, gate charge losses in MOSFETs, conduction losses in the inductor, and losses in the input and output capacitors) and provides analytical dependencies for their calculation. Based on the control examples for applications characterized by low voltage and high output current, the multi-phase buck converter’s output and input current ripples are analyzed and compared analytically and graphically (3D plots). Furthermore, graphical results of the converter efficiency at different numbers of phases (N = 2, 4, 6, 8, and 12) are presented. An analysis of the impact of various parameters on power losses is conducted. Thus, a discussion on assessing the factors influencing the selection of the number of phases in the multi-phase synchronous buck converter is presented. The proposed systematized approach, which offers a fast and accurate method for calculating power losses and overall converter efficiency, reduces the need for extensive preliminary computational procedures and achieves optimized solutions. Simulation results for investigating power losses in 8-phase multi-phase synchronous buck converters are also presented. The relative error between analytical and simulation results does not exceed 4%.

A Review on Control Methods of SEPIC Converters

In recent years, electric vehicles have witnessed a surge in popularity due to their energy-saving and eco-friendly attributes. Unlike conventional internal combustion engine vehicles, electric vehicles exhibit superior performance and operational efficiency. Within the realm of modern electric vehicles, power electronic circuits, notably including DC-DC converters, play a pivotal role. Among these converters, single- ended primary-inductor converters (SEPIC) find extensive use in scenarios where minimizing input and output ripple currents is essential. The primary objective of this project is to conceive and put into action advanced controllers for SEPIC converters, catering to a diverse range of applications, encompassing battery-powered devices, solar energy systems, and LED lighting systems. Key Words: DC-DC converter, SEPIC converter, PID, SMC, ASMC, Fuzzy logic Control.

Ultra‐high gain quadratic boost DC–DC converter based on a three‐winding coupled inductor with reduced voltage stress for fuel cell‐based systems

AbstractHere, an ultra‐high gain quadratic boost DC–DC converter (UQBC) based on the conventional quadratic boost converter (CQBC) and a three‐winding coupled inductor (TWCI) has been proposed. It benefits from an extensive voltage gain range and low voltage stress on semiconductors. In addition, the converter requires a reasonable number of components. This structure is suitable for connecting renewable DC power sources like fuel cells to a DC‐bus in DC microgrids. Unlike CQBC, the produced conversion ratio has been improved to [1+n+m+d(1+n)]/(1−d)2 thanks to integrating a TWCI into CQBC. As a result, the proposed quadratic boost converter gives a better step‐up factor than previously presented quadratic boost converters (QBC). Meanwhile, the employed improvement method has not adversely affected some critical parameters like voltage stress on semiconductors or the input current ripple. This paper presents the mathematical analysis and operating principle of the proposed topology for both continuous and discontinuous current modes (CCM and DCM). Experimental results are represented to validate the converter theory and its performance. Results indicate that a high gain and efficiency have been obtained. Also, the voltage stress on the power switch is reduced by one‐fourth by choosing a proper duty cycle and winding coefficient.

Performance of a novel DC-DC low voltage stress boost converter for fuel-cell vehicle

Air pollution, global warming, depletion of fossil fuels and the lack of access to them due to potential political conflicts are some of the challenges that have forced governments to take necessary measures to promote and invest in the development of electric vehicles (EVs). One of the most important parts of EVs is dc-dc converter. A novel step-up single-switch unidirectional topology for a dc-dc converter is proposed in this paper. Some of the advantages of the proposed topology are the use of single-switch, ground switching, low input current ripple, wide range of voltage gain (VG), high level of VG, low stress level for semiconductor components, low input current ripple, small number of semiconductor and passive elements, high efficiency, and no need for high frequency transformer or coupled inductors. Topology analysis is done in continuous current mode (CCM) and calculations related to efficiency and appropriate design are performed to select the converter parameter values. Also, the proposed topology is compared with other similar topologies to show its high performance and superiority. To confirm the theoretical basis, laboratory prototype waveforms are evaluated and an efficiency of 93.2% is obtained.

Enhanced quadratic DC–DC boost converters with super‐wide voltage gain ranges and ultra‐low voltage stress for renewable energy systems

AbstractAs the promising and ideal clean energies, wind and solar energy systems are in desperate need of high‐performance DC–DC converters to realize efficient and reliable energy transformation. Conventional DC–DC converters for renewable energy systems will work at extreme duty cycles and affect the system efficiency and reliability owing to their limited voltage gains and high‐voltage stress. In this paper, by adopting the hybrid voltage multiplier cells, two enhanced quadratic boost converters (EQBCs) which are highly desirable for renewable energy applications are proposed and analyzed. The EQBCs possess super‐wide voltage gain ranges and ultra‐low voltage stress; therefore, small duty cycle conditions can be achieved and components with low‐rated voltages can be chosen to decrease system volumes and increase system efficiencies. Besides, the EQBCs possess continuous input currents, which can realize small input current ripples and avoid the serious effect of pulsating current on the input sources. What's more, stable output voltages and simple controller circuits are realized by the EQBCs because of the common grounded structures of the input terminal, the single active switch and the output terminal. Detailed principle analyses, parameter designs, performance comparisons and experimental prototypes are conducted to verify the characteristics and feasibilities of the EQBCs.

Bidirectional Control With Fitting Model-Based Synchronous Rectification and Input Ripple Current Feedforward for SiC Bidirectional CLLC EV Charger

Conventional CLLC Synchronous Rectification (SR) typically adopts detection circuits to sense the high frequency signals. It can hardly be used in the high voltage SiC applications directly as it is sensitive to high dv/dt and may cause false operation. A bidirectional control is proposed for the SiC CLLC charger to achieve the SR function and mitigate the input ripple current. Considering the switching frequency and load, the SR on-time is calculated by the proposed three-order fitting model with low calculation source and high immunity to high dv/dt. Moreover, an input ripple current feedforward control is proposed in the discharging mode, which adds the extracted double line-frequency ripple current to the bus voltage reference. It not only achieves low SR conduction loss, but also reduces the input ripple current largely in the discharge. A 6.6-kW SiC bidirectional CLLC charger was built. Compared to the conventional SR, the CLLC efficiency of proposed SR improves 0.28% at 6.6 kW in the charge. In the discharge, the reduction of CLLC input ripple current at the double line-frequency is up to 91%. The overall charging and discharging efficiencies are 95.4% and 96.1% at full load, respectively.

A Family of Impedance Source DC-DC Converters With Zero Input Current Ripple

A family of impedance source DC-DC converters with zero input current ripple is proposed in this paper. The proposed converters include one additional input inductor, a capacitor and a winding coupling with the Y-source on the input side of the original impedance source converters. The voltage of the added winding is opposite of that of the input inductor. Accordingly, the input current ripple can be reduced to zero. Moreover, the two input inductors can be coupled, it means only one capacitor and two windings are needed to be added in the proposed converter. Above all, the proposed converters can promote the life of the photovoltaic array due to the reduction of the input current ripple. In addition, the proposed converters inherit all advantages of the original converters, like high voltage gain and low voltage stress. Detailed theoretical analyses and experimental tests verify the validity of the proposed converters.

Bridgeless Filterless Neutral-Point-Clamped Resonant AC/DC Converter

In this article, we present bridgeless filterless neutral-point-clamped (NPC) resonant ac/dc converter. By using the push-pull transformer itself, with the primary-side switching modulation fixed at 0.5, the proposed ac/dc converter accomplishes theoretically zero input-current ripple and so does not need the extra input filter. Semi-bridgeless configuration reduces the conduction loss associated with an input full-bridge diode rectifier. The resonant NPC structure much reduces the voltage stress at turn-off instant; this aspect reduces the turn-off loss occurred at the secondary-side switches. Therefore, the proposed converter features low cost, high power density, and high efficiency. A prototype with 1-kW output power is implemented to verify the superior properties of the proposed ac/dc converter.

Output Voltage Drop and Input Current Ripple Suppression for the Pulse Load Power Supply Using Virtual Multiple Quasi-Notch-Filters Impedance

To balance the instantaneous power difference between the pulsed output power and the constant input power of the pulse load power supply (PLPS), an active capacitor converter (ACC), which can compensate the pulsed current, is connected in parallel with the output of the dc-dc converter in the PLPS. In this paper, based on the Fourier decomposition results of the load current, it is evident that square waves have significant harmonic content. Hence, to provide the lower impedance at the frequencies of the high content harmonics in the load current, a virtual impedance that consisted of the multiple quasi-notch-filters (MQNF) is proposed to be in parallel at the port of the ACC for the suppression of output voltage drop and input current ripple. The virtual parallel impedance is implemented by the output voltage feedforward control (FFC) of the ACC. The design considerations of the virtual parallel impedance are presented to ensure the stability of the PLPS. Finally, a synchronous rectifier buck (SR-buck) converter with a bidirectional buck/boost converter is tested at the pulse repetition frequency (PRF) of 100-300 Hz and the pulse duty cycle of 0.15 to verify the validity of the proposed control scheme.