AC Input Power Research Articles

Research on Mine Wide Voltage Adaptive Power Supply

To solve the problem of multiple voltage levels and wide range of variations of underground power supply in domestic coal mines, this paper putting forward four wide power supply of adaptive design options with wide input voltage (AC 80-850 V), including phase shifted rectification based on fully controlled bridge, direct voltage adjustment based on AC power supply, voltage adjustment based on AC power supply rectification followed by chopping control, and a power supply voltage adjustment based on magnetic coupling transformer and thyristor automatic switching. After experimental comparison, the preferred scheme for automatic switching between magnetic coupling transformer and thyristors is preferred. The main circuit of this scheme adopts magnetic coupling transformer and thyristor control method, and the control circuit adopts a three way drive circuit based on MCU control, while adopting the strategy of instantaneous voltage tracking control. This scheme achieves stable operation of the output DC power supply voltage at 24V when the input AC power supply voltage varies from 80 to 850 V. The experimental results showed programme was stable and reliable, and it’s worth applying and has practical significance.

A Novel Integrated Electronic Lighting Driver Circuit for Supplying an LED Projection Lamp with High Power Factor and Soft Switching Characteristics

The traditional light source of projection lamps adopts a halogen lamp, which has the advantages of high brightness, but its luminous efficiency is not good and consumes energy. A light-emitting diode (LED) has the characteristics of high luminous efficiency and energy savings and can be used as a new light source for projection lamps. The conventional two-stage electronic lighting driver circuit for supplying an LED projection lamp is composed of an AC-DC converter with power factor correction (PFC) as the first stage and a DC-DC converter for providing rated lamp voltage and current as the second stage. The conventional LED projection lamp driver circuit has more circuit components, a higher cost and limited efficiency. Therefore, this paper proposes a novel electronic lighting driver circuit for supplying an LED projection lamp with PFC function, which integrates a modified stacked dual boost converter and a half-bridge LLC resonant converter into a single-stage power-conversion circuit. The inductor inside the modified stacked boost converter is designed to operate at discontinuous conduction mode (DCM) for the driver circuit achieving PFC. Wide bandgap semiconductor devices silicon carbide (SiC)-based Schottky diodes are utilized to reduce power diode losses, and soft switching is implemented in the proposed LED projector lamp driver circuit to reduce the switching losses of the power switches and thus improve circuit efficiency. This paper has completed a single-stage prototype driver circuit for an LED projection lamp with PFC function, and the prototype circuit has a high power factor (PF > 0.98), low input current total-harmonic-distortion (THD < 6%) and high efficiency (>89%) in the case of an AC input power supply with an RMS value of 110 volts, and both power switches have the characteristics of soft switching.

A Single-Stage Three-Mode Reconfigurable Regulating Rectifier for Wireless Power Transfer

This article proposes a reconfigurable regulating rectifier with a wide operational range for wireless power transfer. The proposed 3-mode rectifier achieves a broad range voltage regulation without global loop control to minimize the chip area occupation. Compared with previous work, more working modes and greater voltage gain allow the proposed rectifier to regulate lower input power, which extends the voltage regulation range. A local loop control scheme is proposed for voltage rectification with three modes. It adaptively senses the duty cycle of the mode signal to determine the working mode of the rectifier, and configure the rectifier to the desired mode for voltage regulation. The proposed system was designed and fabricated in a 180-nm BCD technology with an active area of 1.17 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$mm^{2}$</tex-math></inline-formula> . The measurement results show that the proposed system can rectify wide-range input AC power to a regulated output. The achieved voltage conversion ratio (VCR) is between 0.95X and 2.68X, with a peak power conversion efficiency (PCE) at 87.4%.

Dry Reforming of Methane Using a Swirl-Induced Plasma Discharge Reactor

This study reports the dry reforming of methane (DRM) using non-thermal plasma in a swirl-induced point-plane electrode discharge reactor to produce syngas. This reactor geometry facilitates better mixing of the reactant gases in the plasma region, thus increasing the residence time and conversion of the reactants. The effect of varying flow rates and compositions of CO2/CH4 (v%/v%) on conversion was studied. A high-voltage AC power input of 50 W and 70 W at a frequency of 19 kHz was provided. The voltage–current characteristics with respect to time were studied. The results show that with an increase in the flow rate of the gas mixture from 0.5 to 2 LPM the conversion of both CO2 and CH4 decreases, while an increase in the concentration of CO2 or CH4 (from 25 to 75%) increases the conversion of the respective reactant. The products, viz. syngas (CO and H2), C2 hydrocarbons, and solid carbon, were characterized and quantified. The maximum total conversion of 44% was obtained for a CO2:CH4 ratio of 25:75 (v%/v%) at a flow rate of 0.5 LPM. The solid carbon collected from the reactor walls was analyzed, and it was found to be 89.9% pure with traces of oxygen functionality. The increase in flow rate decreased the specific energy input, which eventually resulted in lowering the energy cost.

Single Stage Active Power Factor Correction Circuit for Street LED Light with Battery Backup

This paper proposes a single-stage active power factor correction circuit for street LED light with battery back-up. The buck–boost converter and flyback converter are combined to achieve optimal performance. The first part of the integrated LED driver, the buck–boost converter is used to adjust the power while operating in the discontinuous conduction operation. The second part of the driver, the flyback converter provides regulated voltage to the LEDs. The battery backup circuit charges the battery when ac input power is available and provides power to LED lamp when input power supply is not available. The proposed LED driver was designed for 100 W output power and tested by PSpice simulation. The simulation results obtained are given in the paper to demonstrates the functionality of the proposed LED driver system. The result show good operation and performance of proposed LED driver.

Multi-Pulse Rectifier Based on an Optimal Pulse Doubling Technique

This paper presents pulse multiplication technology based on an optimal Pulse Doubling Technique (PDT) to upgrade a 28-Pulse Rectifier (28-PR) to a 56-PR. The optimal PDT comprises a Tapped Interphase Reactor (TIPR) with a low kVA-rating and two diodes. The number of pulses can be increased from 28 to 56 using the PDT so that the input current harmonics are reasonably mitigated. Additionally, the 14-phase Polygon-Connected Autotransformer (PCA) is designed in such a way that it can be used for retrofit applications. A detailed simulation analysis in the MATLAB/Simulink environment is carried out, and the results show that the improved quality indices of the final AC input and DC output power are equivalent to the IEEE 519-2014 standard and meet sensitive industrial application requirements with an input current Total Harmonic Distortion (THD) lower than 3%. Moreover, the power factor also maintained unity for a wide operating range. The optimal PDT scheme is affordable and easy to implement as only a small-capacity PDT (only 1% of the output power) is needed to double the pulse number. An experimental prototype is developed to verify the simulation results.

Design of DC Accumulator Charging using Backup Accumulator Based on Inverter and Converter Device

&lt;p&gt;The charging of DC accumulator that&lt;br /&gt;experiences a lack of electric charge energy, usually&lt;br /&gt;utilizes an AC input power from the PLN network. When&lt;br /&gt;the AC input power from the PLN network is unavailable,&lt;br /&gt;a DC power source is used from the backup DC&lt;br /&gt;accumulator as a substitute. The research objective is to&lt;br /&gt;design an internal DC accumulator charging using a&lt;br /&gt;backup DC accumulator equipment based on inverter&lt;br /&gt;and converter equipment. The charging system will use&lt;br /&gt;input power from the backup DC accumulator to replace&lt;br /&gt;the AC input power from the PLN network. The electric&lt;br /&gt;voltage of the internal DC accumulator that is filled&lt;br /&gt;(charged) is the initial condition of V&lt;br /&gt;DC(Acu.Int.)= 8.76 Volts&lt;br /&gt;until it reaches the normal condition of 12.05 Volts with a&lt;br /&gt;capacity of charging current of 5 Ah (Ampere.hours)&lt;br /&gt;absorbs electrical energy of W(Acu.Int.)&lt;br /&gt; = 16.45 Wh(Watt.hours). The results show that the equipment supply&lt;br /&gt;a DC charger of 13.0 volts and PDC&lt;br /&gt;of 21.32 watts to theinternal DC accumulator. The comparison of W&lt;br /&gt;(Acu.Int.) to PDC produces time charging, t(charging)of 46.29 minutes&lt;/p&gt;

Design and Control of Ultra-High-Speed Sensorless Drive with Two-Input Power Source for Portable Consumer Electronics

The convenience and usability of portable consumer electronics that require a motor, such as vacuum cleaners and hair dryers, will be greatly improved if both ac and dc two-input power sources can be used. The dc input power is mostly composed of a dc battery, and single-phase voltage is used as ac input power. A converter system capable of converting ac and dc voltage with control technology is required to supply the voltage for motor driving to apply both ac and dc input to the product. Because a limited number of batteries are used to decrease the weight and size of portable products, a system such as a dc converter is necessary to supply the voltage required to operate the motor and to keep the voltage fluctuation according to the usage time constant. When ac power is used in the product, a voltage drop system that can step down the ac voltage to supply voltage to the dc link is necessary to supply the voltage required to operate the motor to the dc-link. In addition, it is important to reduce the size of the system through ultra-high-speed motor operation by increasing the rotation speed because portable consumer electronics that include a motor drive should be light and portable. This paper proposed a system that can supply a stable dc-link voltage required for ultra-high-speed motor control by applying a phase control method to the ac input side and a dc boost converter to the dc input side. Furthermore, the 1-shunt sensorless method was applied to the inverter for ultra-high-speed motor design and ultra-high-speed motor control system that contributes to product miniaturization and material cost reduction, experimental verification. The ultra-high-speed motor driving evaluation under ac and dc input power conditions and the conversion to dc power input when ac power interrupt occurs were performed to more stably verify the system according to the input power change.

The emission of H− ions from Penning-type ion source with metal hydride cathode in pulsating regime

The operation in pulsating regime of gas-feed-free Penning-type H− ion source with metal hydride cathode and extraction in the longitudinal direction has been investigated. Hydrogen is stored in metal hydride in atomic state followed by the formation of rovibrationally excited H2* molecules due to the process of nonequilibrium desorption. It impacts on a Penning discharge ability to emit negative hydrogen ions in the longitudinal direction and provides local gas injection to the discharge without any external gas supply. The AC power input of 65 W during τ≈15 μs was performed against the background DC one of 5 W. The extracted axial flux of charged particles was separated in an electromagnetic filter followed by the registration of H− current. The H− ion current of about 0.22 mA was obtained. In the DC regime it was only 5uA, which is order of magnitude below the current obtained with the present pulsating regime of source implementation.

Design of Double-Line-Frequency Ripple Controller for Quasi-Single-Stage AC–DC Converter With Audio Susceptibility Model

Power factor correction (PFC) converter suffers from serious double-line-frequency output voltage ripple due to the difference between instantaneous ac input power and dc output power. To suppress such double-line-frequency output voltage ripple, a ripple cancellation circuit (RCC) is utilized to generate the same magnitude but 180° phase shifted double-line- frequency voltage ripple. This paper provides an insight into the relationship between control scheme and double-line-frequency ripple suppression from the perspective of audio susceptibility model. For the purpose of reducing the double line frequency ripple, the closed-loop audio susceptibility of series RCC should be designed relatively low at double line frequency. According to such requirement, a ripple controller with improved voltage feed-forward (FF) scheme and quasi-proportional-resonant (QPR) compensator is designed. As QPR compensator can increase the denominator of the closed-loop audio susceptibility, while voltage FF scheme can reduce its numerator, its magnitude at double line frequency is thus greatly reduced and double-line-frequency ripple is also significantly suppressed. Moreover, due to the flexibility of QPR compensator, the proposed ripple controller presents good ripple suppression in a different line frequency application. Finally, experimental results of a flyback PFC with buck-type RCC quasi-single-stage ac–dc converter are provided to verify the validity of the proposed ripple controller.

Double-Line Frequency Ripple Suppression of a Quasi-Single Stage AC–DC Converter

Owing to the instantaneous difference between variable AC input power and the constant DC output power, power factor correction (PFC) converter suffers from serious double-line frequency (DLF) output voltage ripple. A Ripple-Suppressor (RS) in series with the PFC converter, which generates same magnitude but 180° phase shifted voltage as PFC converter output voltage ripple, is utilized in this brief to suppress the DLF output voltage ripple. The relationship among output impedance, audio sensitivity and output voltage ripple coefficient is analyzed, the closed-loop audio sensitivity and the stability of DLF ripple suppressor with constant on-time (COT) control are investigated. RS using a COT-controlled Buck converter can suppress DLF voltage ripple effectively with fast dynamic response and improved efficiency. Simulation and experimental results are given to verify the theoretical analysis.

Modified SVPWM-Controlled Three-Port Three-Phase AC–DC Converters With Reduced Power Conversion Stages for Wide Voltage Range Applications

Three-port three-phase rectifiers (TPTPRs) are proposed by introducing a new low-voltage (LV) dc power port into the three-phase six-switch boost rectifier. An ac input port, an LV dc load port, and a high-voltage (HV) dc bus port are provided simultaneously by TPTPRs. A dc load, whose voltage is lower than the peak amplitude of the ac line voltage and varies over a wide range, can be connected to the LV dc load port of the TPTPR directly. A modified space vector pulse width modulation (SVPWM) strategy is proposed for the TPTPR to accomplish voltage and current regulations, based on which part of the ac input power can be directly fed to the LV dc load within single power conversion stage. As a result, the power rating and losses of the downstream dc-dc converter, which is connected to the HV dc bus port of the TPTPR, are reduced significantly. The conversion efficiency of the TPTPR-based ac-dc converter benefits not only from the reduced power conversion stages, but also from the reduced switching losses due to the multilevel characteristics of the TPTPR. Operation principles and characteristics of the proposed TPTPRs and modified SVPWM strategies are analyzed in detail and verified with experimental results.

Three-Port Bridgeless PFC-Based Quasi Single-Stage Single-Phase AC–DC Converters for Wide Voltage Range Applications

Quasi single-stage single-phase ac–dc power converters based on a three-port bridgeless power factor corrector (TPB-PFC) are proposed in this paper. The TPB-PFC, which is able to provide an ac input port, a dc load port, and a dc bus port simultaneously, is derived by introducing a new dc load port into a conventional bridgeless PFC. The load, whose voltage can be either lower or higher than the peak amplitude of the ac line voltage, is connected to the dc load port of the TPB-PFC directly. Therefore, the ac input power can be fed to the dc load with the single-stage power conversion when the instantaneous ac voltage is lower than the voltage of the dc load. Although another dc–dc converter is required to accomplish the power transmission between the dc bus port and the dc load port of the TPB-PFC, the power rating and losses of the dc–dc converter are reduced significantly, in comparison with a two-stage ac–dc converter. Furthermore, the switching losses of the TPB-PFC are reduced thanks to the three-level characteristic of the proposed converter. The topology derivation, operation principles, modulation strategies, and characteristics of the proposed ac–dc converter are analyzed and verified experimentally with a 2-kW prototype.

A Phase-Shift-Controlled Direct AC-to-AC Converter for Induction Heaters

This paper proposes a new control method of a direct ac-to-ac converter consisting of two half-bridge converters and a series-resonant circuit. This circuit converts the ac input power from the utility grid to a high-frequency ac output without any dc stage. This circuit does not require a diode bridge rectifier and, thus, makes it possible to reduce forward voltage drops and power losses in the diodes. A new switching sequence for phase-shift control is proposed to regulate the capacitor voltage in each half-bridge converter and to achieve both zero-voltage switching and synchronous rectification. The proposed phase-shift control is theoretically discussed and is also verified by experimental setup using superjunction power MOSFETs. As a result, the proposed direct ac-to-ac converter exhibits a good power conversion efficiency as high as 97.7% at the rated power of 1.3 kW.

Green Industrial Hydrogen via Reversible High-Temperature Electrolysis

With its roadmap for moving to a competitive low-carbon economy in 2050, the European Commission sets greenhouse gas emissions targets for different economic sectors. A main challenge will be the integration of renewable energy sources into industrial processes to reduce carbon dioxide emissions. The vision of the GrInHy project is to provide ‘green’ hydrogen via electrolysis using renewable electricity and to provide grid management services as reversible generator in the iron and steel works of Salzgitter Flachstahl GmbH (Germany). Because a significant share of the energy input can be provided in the form of waste heat, high-temperature electrolysis is able to achieve highest electrical system efficiencies and, therefore, is one of the most promising technologies to fulfill this vision. The GrInHy project targets the industrial integration and validation of a high temperature electrolysis with a nominal electrolyser power of 150 kWAC in one scalable module. Based on steam, the project aims at an overall electrical efficiency of more than 80 %LHV. Other objectives are to proof a system lifetime over 7,000 hours and stack lifetimes over 10,000 hours with a degradation lower than 1 %/1000 hours. The prototype is designed as reversible generator (RSOC). In the Solid Oxide Electrolyser Cell (SOEC) mode hydrogen can be produced, whereas the Solid Oxide Fuel Cell (SOFC) mode is able to generate electricity from hydrogen or natural gas. The system consists of the RSOC Unit delivered by Sunfire and the Hydrogen Processing Unit (HPU) delivered by Boeing Research and Technology Europe (Figure 1). Both are integrated in 2 separate 20’ containers including all auxiliary systems. The RSOC shall utilize steam and electricity from the onsite power plant to generate hydrogen. Hydrogen is fed to the HPU which compresses the hydrogen to minimal 8 bar(g) and removes the remaining steam by pressure swing absorption to fulfil the quality criteria “5.0”. Afterwards dry hydrogen is injected an existing ring pipeline that supplies a variety of processes at the steel work. The RSOC prototype is based on a stack unit comprising 1440 3YSZ-ESC-cells. Those cells are set up in 6 Interchangable Modules (ICM) each containing 240 cells. The system is supplied with cold feed gases and/or steam from a so called Coldbox that realizes the fluid controls. The feed gases are further processed and preheated to operating temperature in two separate highly integrated Hotboxes. Each Hotbox supplies 3 of the 6 ICMs with educt gases and recuperates heat from the product gases. For operation in SOFC mode with natural gas, a steam reformer is integrated which uses gas electrode off-gas for humidification. In this mode, the system reaches a power output of 25 kWAC in completely automated operation. At full load the efficiency is > 50 % based on the lower heating value. Details from the system operation in natural gas fuel cell mode (NG-FC), in hydrogen fuel cell (H2-FC) mode and in electrolyser mode (EL) will be presented. In hydrogen fuel cell mode the nominal power is 30 kWAC at an efficiency of more than 45 %LHV. In electrolyser mode the system consumes approx. 50 kg/h steam and 150 kWAC electrical power to produce 40 Nm³/h hydrogen with an overall efficiency of more than 80 %LHV. The RSOC is also able to operate in overload and is therefore able to reach up to 50 Nm³/h hydrogen output at an AC power input of approximately 200 kWAC. This is currently the largest high temperature electrolyser module worldwide. Figure 1

Voltage Ripple Reduction in Voltage Loop of Voltage Source Converter

In order to achieve a good dynamical response of a full-bridge AC-DC voltage source converters (VSC). The bandwidth of PI controller must be relatively wide. This leads to the voltage ripple produced in the control signal, as known that its ripple frequency has twice of the line frequency and cause the 3rd harmonic of an input current. A Ripple Voltage Estimator (RVE) algorithm and Feed-Forward Compensation (FFC) algorithm are proposed and added to the conventional control. The RVE algorithm estimated the ripple signal to subtract it occurring in the voltage loop. As a result, the 3rd harmonic of the input current can be reduced, and hence the Total Harmonic Distortion of input current (THDi) are improved. In addition, the FFC algorithm will offer a better dynamical response of output voltage. The performance evaluation was conducted through the simulation and experiment at 110Vrms/50Hz of the input voltage, with a 600 W load and 250 V&lt;sub&gt;dc&lt;/sub&gt; output voltage. The overall system performances are obtained as follows: the power factor at the full load is higher 0.98, the harmonic distortion at AC input power source of the converter is under control in IEC61000-3-2 class A limit, and the overall efficiency is greater than 85%.

A modular and compact long pulse modulator based on the SML topology for the ESS Linac

The ESS Linac project, phase I, requires 12 long pulse klystron modulators with compact footprint, high pulse power and improved quality both on the output pulse waveform and on the input AC power line. Conventional long pulse modulators are typically based on HV pulse transformers and commonly exhibit poor efficiency, low power density, large footprint and cost, with still limited performance on pulse rise time, pulse flat-top accuracy and AC power line quality (flicker, current harmonic distortion, power factor). This paper presents the Stacked Multi-Level (SML) klystron modulator topology, a novel modular concept based on the association of several HV modules in series at their output, each formed by a high voltage and high-frequency transformer, a HV diode rectifier bridge and a low pass filter. Each HV module is fed from a low voltage power electronic inverter at ground potential since the transformer provides the required galvanic isolation between primary and secondary windings. This topology is believed to better suit the application and better satisfy ESS requirements, directly addressing the mentioned shortcomings of conventional topologies. The development and validation of this new concept has included the design and construction of a reduced scale prototype with the potential of delivering long (3.5 ms) and high quality pulses (0-99% rise time <;120 μs and flat top ripple <;0.15%) with pulse amplitudes up to 115 kV and pulse power up to 2 MW, while maintaining excellent AC grid power quality (low flicker operation <; 0.2%, sinusoidal current absorption with total harmonic distortion <; 3%, and unitary power factor). The paper describes the main features of the topology and the main design aspects, presenting results both from simulation models, including parasitic elements, and from an experimental setup.

Degradation of Acid Orange 7 Dye in Two Hybrid Plasma Discharge Reactors

To get an optimized pulsed electrical plasma discharge reactor and to increase the energy utilization efficiency in the removal of pollutants, two hybrid plasma discharge reactors were designed and optimized. The reactors were compared via the discharge characteristics, energy transfer efficiency, the yields of the active species and the energy utilization in dye wastewater degradation. The results showed that under the same AC input power, the characteristics of the discharge waveform of the point-to-plate reactor were better. Under the same AC input power, the two reactors both had almost the same peak voltage of 22 kV. The peak current of the point-to-plate reactor was 146 A, while that of the wire-to-cylinder reactor was only 48.8 A. The peak powers of the point-to-plate reactor and the wire-to-cylinder reactor were 1.38 MW and 1.01 MW, respectively. The energy per pulse of the point-to-plate reactor was 0.2221 J, which was about 29.4% higher than that of the wire-to-cylinder reactor (0.1716 J). To remove 50% Acid Orange 7 (AO7), the energy utilizations of the point-to-plate reactor and the wire-to-cylinder reactor were 1.02 × 10−9 mol/L and 0.61 × 10−9 mol/L, respectively. In the point-to-plate reactor, the concentration of hydrogen peroxide in pure water was 3.6 mmol/L after 40 min of discharge, which was higher than that of the wire-to-cylinder reactor (2.5 mmol/L). The concentration of liquid phase ozone in the point-to-plate reactor (5.7 × 10−2 mmol/L) was about 26.7% higher than that in the wire-to-cylinder reactor (4.5 × 10−2 mmol/L). The analysis results of the variance showed that the type of reactor and reaction time had significant impacts on the yields of the hydrogen peroxide and ozone. The main degradation intermediates of AO7 identified by gas chromatography and mass spectrometry (GCMS) were acetic acid, maleic anhydride, p-benzoquinone, phenol, benzoic acid, phthalic anhydride, coumarin and 2-naphthol. Proposed degradation pathways were elucidated in light of the analyzed degradation products.

Load Dispatching Control of Multiple-Parallel-Converters Rectifier to Maximize Conversion Efficiency

In the context of increasing electric energy consumption in a data center, energy efficiency improvement is strongly emphasized. In a data center, electric energy is largely consumed by DC power supply system, which is based on a rectifier composed by multiple parallel converters. Therefore, rectifier efficiency must be improved for minimizing loss of DC power supply system. Rectifier efficiency can be modulated by load allocation to converters because converter efficiency depends on input AC power. In this paper, we propose a new control method to maximize rectifier efficiency. The method can control load allocation to converters by introducing active power converter control scheme and start-and-stop of converters. In order to illustrate optimal load allocations in a rectifier, a maximization problem of rectifier efficiency is formulated as a nonlinear optimization one. The problem is solved by Lagrangian relaxation method and the computation results provide the validity of proposed method.

A single‐stage integrated bridgeless AC/DC converter for electrolytic capacitor‐less LED lighting applications

SummaryIn this paper, a single‐stage integrated bridgeless AC/DC converter is proposed. As compared to its counterpart that is composed of totem‐pole boost power factor correction (PFC) cascade fly‐back DC/DC converter, the studied circuit has less components number while overcoming the limits of the totem‐pole type. Thus, it is suitable to the low‐power LED lighting applications. Furthermore, when both PFC inductors Lb and magmatic inductance Lm of the transformer TR1 operate at discontinuous current mode, the bus voltage vCB can be used to decouple the ac input and constant dc output power. Thus, the approach of increasing bus voltage ripple is employed to eliminate electrolytic capacitors and obtain long operation lifetime. Additionally, it is able to be compatible with our studied twin‐bus configuration for increasing the overall efficiency. A 50‐W hardware prototype has been designed, fabricated, and tested in the laboratory to verify the proposed converter validity. Copyright © 2014 John Wiley &amp; Sons, Ltd.