Low Output Current Ripple Research Articles

A stacked interleaved DC-DC buck converter for proton exchange membrane electrolyzer applications: Design and experimental validation

Since the two last decades, hydrogen production has been attracting the attention of the scientific community thanks to its inherent very low pollution when energy coming from renewable energy sources (RESs) are used. However, it implies the use of DC/DC converters to interface source and load. These conversion systems must meet several requirements from current ripple point of view, energy efficiency, and performance to preserve the sustainability of hydrogen production. This article proposes the design and realization of a stacked interleaved buck converter to supply a proton exchange membrane electrolyzer. The converter is designed to ensure a low output current ripple and a suitable dynamic response to guarantee the reliability of the electrolyzer. A theoretical analysis of the converter, taking into account the dynamic model of the electrolyzer, and the design of the control system based both on feedforward and a feedback action is provided. The stability of the control system is discussed as well. The effectiveness of the model and the control algorithm has been verified by simulation and experimental results on a PEM electrolyzer at laboratory scale; the extension to higher power levels is discussed at the end.

Markov Chain Modeling for Reliability Analysis of Multi-Phase Buck Converters

In recent years, the structure of multi-phase buck converter also called Interleaved Buck Converter (IBC) has gained considerable attention. The advantages of the IBC in comparison to the conventional Buck converter (CBC) are the lower output current ripple, higher efficiency, fast transient response, lower electromagnetic interference and higher reliability. Since more than one stage is employed in the IBC, this converter is highly reliable. In this paper, the reliability and mean time to failure (MTTF) of the CBC, and two- and three-stage IBCs are figured out. Using the obtained results and considering various scenarios, a comprehensive comparison is provided. In addition, the operation of the converter in case of fault occurrence for high and low capacities is analyzed and reliability is evaluated in each state. The relation between the reliability and temperature of semiconductor elements is discussed. Furthermore, a laboratory-scaled prototype is used to extract the experimental results of the temperature variation of the elements during a fault. Markov model is used to evaluate the analyzed reliability.

Research on a multilevel corrector magnet power supply based on a buck cascade circuit

To solve the contradiction between the response speed and output stability of a fast corrector magnet power supply, a topology based on the buck cascade circuit is used and tested in this paper. A multilevel circuit is realized with only a small number of switching metal–oxide–semiconductor field effect transistors (MOSFETs). This multilevel topology allows for better response speeds and a lower output current ripple than conventional H-bridge topologies. This article introduces the design concept based on the buck cascade circuit in detail and carries out a simulation analysis. Finally, a prototype is fabricated according to the design principle, and the results of the prototype test are consistent with the simulation results.

A Turn-off Delay Controlled Bleeder Circuit for Single-Stage TRIAC Dimmable LED Driver With Small-Scale Implementation and Low Output Current Ripple

A single-stage TRIAC (TRIode for alternating current switch) dimmable LED (light emitting diode) driver using a buck converter fed through a capacitor input rectifier provides many advantages such as small-scale implementation, low output current ripple, and stable dimming operation. This circuit topology, however, has a serious issue: A large inrush current to the smoothing capacitor. To solve this issue, this paper focuses on a bleeder circuit in the TRIAC dimmable LED driver. This paper presents the mechanism of the large inrush current issue and its relationship to a conventional bleeder circuit. Moreover, this paper proposes a turn-off delay controlled bleeder circuit. The proposed bleeder circuit is analyzed by using its discrete-time state-space model in order to set proper circuit parameters for inrush current reduction. Experimental results demonstrate the inrush current reduction by the proposed method, which leads to a 37% reduction of maximum input current, as well as proper dimming operation and low output current ripple. The proposed method achieves further small-scale implementation, which enhances the advantages of the intended main circuit topology.

An Interleaved Nonisolated ZVS Ultrahigh Step-Down DC–DC Converter With Low Voltage Stress

This paper presents a nonisolated ultrahigh step-down dc-dc converter for low-voltage high-current applications. The converter provides extended duty cycle for all power switches while low voltage and current stresses are imposed on semiconductor devices that cause low conduction losses and low output current ripple. In addition, soft-switching condition is achieved for all semiconductor devices without adding any active element. To achieve the improved voltage conversion ratio, a pair of coupled inductors and series capacitors is used in the interleaved step-down structure. The two auxiliary inductors provide zero-voltage zero-current switching turn on for all switches and zero-current switching turn on and turn off for all diodes. Thus, the losses associated with semiconductor components are reduced impressively and the overall efficiency of the proposed converter is improved considerably. The accuracy of the converter operation is confirmed by a 450-W laboratory prototype operating at 400-V input, 12-V output, and 100 kHz switching frequency.

A Deadbeat Current Controller of LC-Hybrid Active Power Filter for Power Quality Improvement

In this article, a deadbeat current controller for an LC -coupling hybrid active power filter ( LC -HAPF) is proposed, which can track with the reference compensation current with low steady-state error and fast dynamic response. Moreover, it can lead LC -HAPF to be operating at a fixed switching frequency with low output current ripples, thus reducing the size of the filtering circuit. First of all, the mathematical model of the deadbeat current controller for the LC -HAPF is deduced based on its single-phase equivalent circuit. Then, the closed-loop control block diagram and its $s$ -domain model is proposed and built. After that, the stability issue and parameter design of the proposed deadbeat current controller are analyzed and discussed. Finally, the compensating performance of the deadbeat current controller for the LC -HAPF is verified by simulation and experimental results compared with the conventional hysteresis band pulsewidth modulation (PWM) control, the proportional-integral (PI) control, and the proportional multi-resonant (PMR) control for the LC -HAPF, which shows its effectiveness and superior compensating performances.

A High-Efficiency Interleaved Ultra-High Step-Down DC–DC Converter With Very Low Output Current Ripple

A nonisolated ultra-high step-down interleaved dc–dc converter with low voltage stress and common ground between the input and output ports is proposed in this paper. In order to extend the extremely narrow duty cycle, series capacitors and transformers are applied to the four-phase interleaved buck converter. In addition to extending the duty cycle, the series capacitors clamp the voltage stress across the switches and diodes, which results in using low voltage rating semiconductor components. Additionally, the main switches are turned on under a soft-switching condition. Hence, the conduction and switching losses are reduced and the overall efficiency of the designed converter is improved. Other important strengths of this topology are very low output current ripple due to interleaving and automatic uniform current sharing. The validity of theoretical analysis and converter operation is confirmed by the implementation of a 150 W prototype at 400 V input voltage and 12 V output voltage.

A New Grid-Connected DC/AC Inverter With Soft Switching and Low Current Ripple

This paper presents a new dc/ac inverter for low-power applications (i.e., high-voltage, low-current applications), which offers soft switching of the power semiconductors and low output current ripple. In the proposed power circuitry, a novel ripple steering approach is used that can provide soft switching for the power semiconductors and significantly attenuate the high-frequency current ripple of the inverter. The proposed ripple steering technique utilizes the switching frequency and the duty cycle in order to perform the aforementioned tasks. Basically, the ripple steering technique steers the energy of the ripple to the output capacitances of the power semiconductors in order to provide the soft-switching condition. Theoretical analysis, simulation results, and experimental results verify the feasibility of the proposed technique and demonstrate the superior performance of the proposed inverter.

Design of Digital Control Phase-Shifting Full-Bridge Switching Power Supply

With the development of switching power supply towards miniaturization and high efficiency, digital and soft switching technology has become the research focus of switching power supply. Phase-shifted full-bridge DC/DC converter is commonly used in medium and high power applications due to its advantages of low switching loss, high efficiency and low output current ripple. Based on the existing switching power supply and digital control technology, a digital control phase-shifting full-bridge switching power supply is designed. Its output voltage ranges from 0 to 12 V.The output current ranges from 0 to 50 A. The voltage and current level can be adjusted according to the user’s power demand, and the output mode of steady voltage or steady current can be set. The parallel operation of multiple power supply is realized by RS485 communication protocol.

Power Factor Improvement in Modified Bridgeless Landsman Converter Fed EV Battery Charger

This work deals with the design and implementation of a new charger for a battery-operated electric vehicle (EV) with power factor improvement at the front end. In the proposed configuration, the conventional diode converter at the source end of existing EV battery charger is eliminated with the modified Landsman power factor correction (PFC) converter. The PFC converter is cascaded to a flyback isolated converter, which yields the EV battery control to charge it, first in constant current mode then switching to constant voltage mode. The proposed PFC converter is controlled using single sensed entity to achieve the robust regulation of dc-link voltage as well as to ensure the unity power factor operation. The proposed topology offers improved power quality, low device stress, and low input and output current ripple with low input current harmonics when compared to the conventional one. Moreover, to demonstrate the conformity of the proposed charger to an IEC 61000-3-2 standard, a prototype is built and tested to charge a 48 V EV battery of 100 Ah capacity, under transients in input voltage. The performance of the charger is found satisfactory for all the cases.

Analysis and Design of a Unidirectional Resonant Switched-Capacitor Step-Up Converter for OLED Lamp Driving Based on Variable Inductor

This paper presents an analysis and design of a unidirectional resonant switched-capacitor (URSC) step-up converter for organic-lighting-emitting-diode (OLED) lamp driving. The URSC converter includes a very small inductor in series with the SC to improve the switching behavior. Also, the URSC converter presents the advantages of high power density, higher efficiency compared to other SC converters, low output voltage and current ripples, and low electromagnetic interference noise, which make it adequate for driving OLED lamps. URSC is designed to operate in closed loop with constant current variable inductor (VI) control technique. By working the resonant inductor as a VI, the OLED current can be regulated and dimmed because of resonant frequency change. Simulation and experimental results of the VI inductor, which are in a good agreement, and the results of a URSC step-up converter design example for a 21.8-W OLED lamps array supplied from 48 Vdc are presented, where a maximum 92.97% efficiency is obtained.

A 48-V Wide-<inline-formula> <tex-math notation="LaTeX">$V_{\rm in}$ </tex-math> </inline-formula> 9–25-MHz Resonant DC–DC Converter

This paper presents a wide- $V_{\mathrm{ in}}$ step-down parallel-resonant converter (PRC), comprising an integrated 5-bit capacitor array and a 300-nH resonant coil, placed in parallel to a conventional buck converter. Soft-switching resonant converters are beneficial for high- $V_{\mathrm{ in}}$ multi-MHz converters to reduce dominant switching losses, enabling higher switching frequencies. The output filter inductor is optimized based on an empirical study of available inductors. The study shows that faster switching significantly reduces not only the inductor value but also volume, price, and even the inductor losses. In addition, unlike conventional resonant concepts, soft-switching control as part of the proposed PRC eliminates input voltage-dependent losses over a wide operating range, resulting in 76.3% peak efficiency. At $V_{\mathrm{ in}}=48$ V, a loss reduction of 35% is achieved compared with the conventional buck converter. Adjusting an integrated capacitor array, and selecting the number of oscillation periods, keeps the switching frequency within a narrow range. This ensures high efficiency across a wide range of $V_{\mathrm{ in}}$ = 12–48 V, 100–500-mA load, and 5-V output at up to 25-MHz switching frequency. Thanks to the low output current ripple, the output capacitor can be as small as 50 nF.

A Nonisolated Ultrahigh Step Down DC–DC Converter with Low Voltage Stress

In this paper, a new nonisolated interleaved dc–dc converter with ultrahigh step down conversion ratio is proposed. The proposed converter has several main advantages such as extremely low voltage gain, extended duty cycle, automatic current sharing, low voltage and current stress on active switches, and low output current ripple. To achieve these advantages, several techniques are combined. The interleaved method is applied to reduce the current stress and decrease the output current ripple due to the phase shift between two modules. The series capacitors are used to improve the step down conversion ratio and clamp the voltage stress across the active switches due to the capacitive voltage division characteristic. Thus, the conduction losses of the proposed converter are reduced because of using MOSFET s with lower voltage rating. In addition, the coupled inductors are used to reduce the voltage gain and extend the duty cycle without imposing extra voltage stress across the active switches. Hence, the overall efficiency of the proposed converter is improved. A prototype of the proposed converter is implemented to verify the converter operation and the theoretical analysis.

Quadratic-Boost With Stacked Zeta Converter for High Voltage Gain Applications

This paper proposes a different approach to combine stacked and cascaded configuration of dc/dc pulse-width modulation converter cells in order to access the benefits of both structures in a single-stage topology with a single active switch. In addition to presenting and discussing the concepts of cascaded, stacked, and the combination of both, this paper also proposes a new topology derived from these concepts. It provides high voltage conversion ratio with improved efficiency. As the name implies, this converter is obtained from the combination of two well-known dc/dc converter circuits, the Isolated Zeta Converter and the Quadratic-Boost Converter. Hence, it presents the combined features of both, i.e., high step-up voltage conversion, low input current ripple (Quadratic Boost features), and low output current ripple (Zeta’s feature). In order to verify the feasibility and performance of the converter presented, two 250-W prototypes circuits have been implemented.

LMI Control Design of a Non-Inverting Buck-Boost Converter: a Current Regulation Approach

This paper presents an analytical study of an input current-mode control based on a linear matrix inequalities (LMI) for a non-inverting buck-boost converter. The LMI control technique makes better the dynamic response of this converter in comparison with previous research works, where its currents has been regulated using a classical analogue PI controller with an additional pole. The main features of the selected converter are its voltage step-up and step-down properties, high efficiency, wide bandwidth and low input and output current ripples. All of these converter’s properties allows it to be used as a modular converter capable of being positioned at any converter locations in hybrid systems, which are formed by varying-voltage-sources, current controlled dc-dc converters and auxiliary storage devices such as batteries or capacitors. The designed state-feedback controller has the following aims, among others: pole placement constraints, control effort limitation, and decay rate and bandwidth improvement. The use of state-space averaging (SSA) method allows to describe LMI constraints which guarantees stability and provide good performances under a close loop pole region and control signal bound. The theoretical analysis have been simulated by means of Matlab and PSIM on an 800-W coupled-inductor buck-boost dc-dc switching converter.

A Single-Stage High-Power-Factor Light-Emitting Diode (LED) Driver with Coupled Inductors for Streetlight Applications

This paper presents and implements a single-stage high-power-factor light-emitting diode (LED) driver with coupled inductors, suitable for streetlight applications. The presented LED driver integrates an interleaved buck-boost power factor correction (PFC) converter with coupled inductors and a half-bridge-type series-resonant converter cascaded with a full-bridge rectifier into a single-stage power conversion circuit. Coupled inductors inside the interleaved buck-boost PFC converter sub-circuit are designed to operate in discontinuous conduction mode (DCM) for achieving input-current shaping, and the half-bridge-type series resonant converter cascaded with a full-bridge rectifier is designed for obtaining zero-voltage switching (ZVS) on two power switches to reduce their switching losses. Analysis of operational modes and design equations for the presented LED driver are described and included. In addition, the presented driver features a high power factor, low total harmonic distortion (THD) of input current, and soft switching. Finally, a prototype driver is developed and implemented to supply a 165-W-rated LED streetlight module with utility-line input voltages ranging from 210 to 230 V. Experimental results demonstrate that high power factor (>0.99), low utility-line current THD (<7%), low-output voltage ripples (<1%), low-output current ripples (<10%), and high circuit efficiency (>90%) are obtained in the presented single-stage driver for LED streetlight applications.

A Single-Stage LED Tube Lamp Driver with Power-Factor Corrections and Soft Switching for Energy-Saving Indoor Lighting Applications

This paper presents a single-stage alternating current (AC)/direct current (DC) light-emitting diode (LED) tube lamp driver for energy-saving indoor lighting applications; this driver features power-factor corrections and soft switching, and also integrates a dual buck-boost converter with coupled inductors and a half-bridge series resonant converter cascaded with a bridge rectifier into a single-stage power-conversion topology. The features of the presented driver are high efficiency (>91%), satisfying power factor (PF > 0.96), low input-current total-harmonic distortion (THD < 10%), low output voltage ripple factor (<7.5%), low output current ripple factor (<8%), and zero-voltage switching (ZVS) obtained on both power switches. Operational principles are described in detail, and experimental results obtained from an 18 W-rated LED tube lamp for T8/T10 fluorescent lamp replacements with input utility-line voltages ranging from 100 V to 120 V have demonstrated the functionality of the presented driver suitable for indoor lighting applications.

An Expandable Four-Phase Interleaved High Step-Down Converter With Low Switch Voltage Stress and Automatic Uniform Current Sharing

In this paper, a novel four-phase interleaved high step-down converter is presented. The proposed converter can provide an extremely high step-down voltage conversion ratio within a moderate duty cycle. There are four main advantages of the proposed converter. First, the blocking capacitors can store energy as usual. Therefore, they are used as voltage sources to reduce the input voltage as well as to reduce the switch voltage stresses. Second, due to the charge balance of the dc blocking capacitors, the converter possesses an automatic uniform current sharing characteristic of the interleaved phases without adopting any extra circuitry. Third, due to the phase shift between the interleaved phases, the architecture provides a low output current ripple. Fourth, the number of phases can be expanded or reduced to any even phases; therefore, the converter has a wide range of applications. Finally, the operating principles and analysis of this architecture are given, and an experimental prototype is also provided to verify the effectiveness of the proposed converter.

High step‐down interleaved buck converter with low voltage stress

This study presents a four-phase interleaved buck converter with low voltage stress and high step-down conversion ratio. The proposed converter provides an extended duty cycle and low voltage stress for switches and diodes, in high step-down applications. This makes it possible to use switches with lower voltage rating and thus reduce both switching and conduction losses to improve the overall efficiency. Extremely low output current ripple and continuous input current are two other advantages of the proposed converter. Also, the output current can be shared between interleaved modules without using additional current sharing control technique due to charge balance of input and blocking capacitors. All these benefits are obtained without adding any active auxiliary component or using transformers. The experimental results from a prototype of the proposed converter designed for 400–24 V, operating at 0.5 kW, verify the theoretical analysis.

A Parallel Hybrid Soft Switching Converter with Low Circulating Current Losses and a Low Current Ripple

A new parallel hybrid soft switching converter with low circulating current losses during the freewheeling state and a low output current ripple is presented in this paper. Two circuit modules are connected in parallel using the interleaved pulse-width modulation scheme to provide more power to the output load and to reduce the output current ripple. Each circuit module includes a three-level converter and a half-bridge converter sharing the same lagging-leg switches. A resonant capacitor is adopted on the primary side of the three-level converter to reduce the circulating current to zero in the freewheeling state. Thus, the high circulating current loss in conventional three-level converters is alleviated. A half-bridge converter is adopted to extend the ZVS range. Therefore, the lagging-leg switches can be turned on under zero voltage switching from light load to full load conditions. The secondary windings of the two converters are connected in series so that the rectified voltage is positive instead of zero during the freewheeling interval. Hence, the output inductance of the three-level converter can be reduced. The circuit configuration, operation principles and circuit characteristics are presented in detail. Experiments based on a 1920W prototype are provided to verify the effectiveness of the proposed converter.