Analysis of a high power factor rectifier based on discontinuous capacitor voltage mode operation

The buck converter with LC input filter operating in discontinuous capacitor voltage mode has inherent power factor correction properties and continuous input current. The paper presents a detailed analysis of the converter operating in this mode, leading to design criteria. Finally, experimental results for a 48 V/sub dc//100 W converter are presented.

In this paper, a new bridgeless single phase ac-dc power factor correction (PFC) rectifiers based on Buck topology operating in Discontinuous Capacitor Voltage Mode (DCVM) is proposed. The bridgeless topology and the presence of only one or two semiconductor switches in the current flowing path during each interval of the switching cycle result in lower conduction losses compared to the conventional DCVM Buck PFC rectifier. The DCVM operation offers additional advantages such as: zero-voltage turn-off in the power switches, zero-voltage turn-on in the output diode, and continuous input current. Hence, the electromagnetic interference (EMI) noise emission is minimized. The converter achieves high power factor naturally with low total harmonic distortion (THD) in the input current. Theoretical analysis and experimental results for 100 W/48 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dc</sub> at 100 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> line voltage are provided to evaluate the performance of the proposed scheme. The measured conversion efficiency reached 96.4%.

A LC filter can be added to the input of the conventional buck converter to make the converter operate in discontinuous capacitor voltage mode. In this mode, the converter obtains the inherent power factor correction. Besides, both the input and output current will be continuous. This makes it possible for the converter operating at a high power level range. The input current will follow the input voltage automatically by a simple constant duty cycle control. This paper presents a detailed operation analysis of the converter operating in discontinuous capacitor voltage mode. And a 36V/100W prototype was built to verify the theoretical results.

In this paper, a series-capacitor-based interleaving buck power factor correction (PFC) converter is proposed, the intermediate energy storage capacitance of which is operated at discontinuous capacitor voltage mode (DCVM), and automatic power factor (PF) correction for this converter is obtained. Moreover, the voltage across the series capacitor of the proposed PFC converter is clamped at the input voltage, and thus peak voltage stress existed in the traditional DCVM buck PFC could be relieved. By effectively regulating the charge/discharge time for the series capacitor, ultrahigh step-down conversion ratio of the proposed converter is achieved, the conversion ratio of which is independent of the duty cycle and only related to the switching frequency and circuit parameters. Therefore, high PF can be obtained due to very narrow deadtime of the input current. Meanwhile, the proposed PFC converter can realize the soft turn- on of part power switch and soft turn- off of part power diodes. In addition, comparing with the traditional discontinuous inductor current mode PFC, the input current of the proposed PFC converter is continuous so that the peak value and root-mean-square value of input current can be reduced. The operational principle, performance analysis, and parameter design principle are given in this paper. The analysis results show that the PF and total harmonic distortion are also independent of the duty cycle. Finally, a 220-Vac input, 60 W/15 V output experimental prototype is built to verify the validity of the theoretical analysis.

SummaryThis paper proposes a single‐ended primary‐inductor converter (SEPIC)‐based DC‐DC converter with higher voltage gain, continuous input current, and lower voltage stress. Suggested converter uses three‐winding coupled inductors and voltage multiplier for boosting function. The proposed structure stores lower amount of energy due to lower current magnitudes of used inductors. Moreover, using voltage multiplier reduces the voltage stress of the elements connected to the output terminals of the proposed converter. By reducing the voltage stress, in addition to reducing the rating of output elements and costs, the overall efficiency will also be increased. Also, a clamping circuit is used to diminish the voltage stresses on power switch. In order to represent the advantages of the proposed converter over some other converters in the viewpoints of the number of the used elements, continuity of input current, voltage gain, the voltage stress on power switch, and output diode, a comparison study is provided. To validate the practicability of the proposed converter, a 200‐W prototype is implemented and the experimental results are provided.

This paper presents a new single phase front-end ac-dc bridgeless power factor correction (PFC) rectifier topology. The proposed converter achieves a high efficiency over a wide range of input and output voltages, a high power factor, low line current harmonics and both step up and step down voltage conversions. This topology is based on a non-inverting buck-boost (Zeta) converter. In this approach, the input diode bridge is removed and a maximum of one diode conducts in a complete switching period. This reduces the conduction losses and the thermal stresses on the switches when compare to existing PFC topologies. Inherent power factor correction is achieved by operating the converter in the discontinuous conduction mode (DCM) which leads to a simplified control circuit. The characteristics of the proposed design, principles of operation, steady state operation analysis, and control structure are described in this paper. An experimental prototype has been built to demonstrate the feasibility of the new converter. Simulation and experimental results are provided to verify the improved power quality at the AC mains and the lower conduction losses of the converter.

A power factor correction (PFC) based bridgeless Sheppard-Taylor converter for feeding brushless DC (BLDC) motor dive is presented in this work. The voltage of DC bus of the voltage source inverter (VSI) feeding BLDC motor is adjusted for speed control. The BLDC motor is electronically commutated to operate the VSI in low switching frequency for reducing the switching losses in it. The proposed PFC converter is operated in discontinuous inductor current mode (DICM) for inherent power factor correction using a single voltage sensor. The performance of the proposed PFC converter feeding BLDC motor drive is evaluated for control of speed over a wide range. A unity power factor is achieved with power quality indices acceptable within the limits of IEC 61000-3-2.

Recently, the voltage fed type PWM converters have been investigated from ideal and inherent properties as DC power source. But, the current control system generally used may be somewhat complicate due to the DC voltage detection.In this paper, we propose the simple control system of the PWM converter by means of power factor control in which the DC voltage detection is not always needed. In this system, the DC voltage is given by the line voltage and the modulating index of the PWM converter.The principle of the PWM control system is shown at first. From the simplified circuit model and its phasor diagrams, some basic relations of the PWM converter system are obtained and some fundamental characteristics are shown. From these investigations, it is seen that the phase control region is restricted to a certain angle, which depends on the setting power factor, the modulating index of the PWM and the load. Under the operating condition of unity power factor, it is given by ±π/4 for both the converting and inverting operations. The system can be operated over the all control range of the modulating index by restricting the angle to this critical value for the angle over this control range.The ideal operating characteristics as DC power source can be verified by some experimental results such as the operating waveforms of line current, the steady state characteristics and the transient responses between both operations of the converter and inverter.The features of the system are in the simple construction of the control circuit and some inherent and excellent characteristics as a voltage fed type DC power source.This control system may be applicable to any types of PWM converter used now.

This paper presents a direct single-stage power converter using single-phase isolated full-bridge converter modules, with inherent power factor correction (PFC) for a 12 kW switched mode power supply (SMPS). The advantages of the proposed converter are its simple control strategy, reduction in number of conversion stage, low input line current harmonics, and improvement in power factor. Analysis of the single-stage converter is carried out in continuous conduction mode of operation. Steady-state analysis of the proposed converter is conducted to obtain converter parameters. A systematic design procedure is also presented for a 12k W converter with a design example. The effect of load variation on SMPS is also studied in order to demonstrate the effectiveness of the proposed converter for the complete range of load conditions. A set of power quality indices on input ac mains for an SMPS fed from a single-stage converter is also presented for easy comparison of their performance.

A novel ZVZCS-full-bridge converter compounding the three-phase power factor corrector in a single-stage is presented. As the pseudo-phase-shifting control (PPSC) mode, the voltage on the dc link is restrained, not more than 800 V. Computer simulation and experiment results of the prototype show that the zero switching, power factor correcting and the output regulating are completed simultaneously in use of one converter.

This paper presents a switched capacitor-based converter to drive high power light emitting diodes (LEDs). Unlike the traditional switched capacitor based one, the proposed converter uses an inductor to avoid the forced charging and discharging operation reducing stress current in circuit. The proposed converter provides inherent power factor correction (PFC) and the switched capacitors are used as isolation capacitors. The proposed converter also uses a LC filter to reduce the output current ripple through LED array instead using a bulk electrolytic capacitor. The basic description of the topology is presented and a laboratory prototype of 48 W has been implemented. The experimental results presented demonstrate the technical feasibility of the proposed converter applied as LED driver.

In this work, a new PFC (Power Factor Correction) Bridgeless Buck-Boost converter is designed and proposed for BLDC (Brushless Direct Current) Motor Drive applications. In this topology, two power electronic devices are used to control negative and positive cycles of input single phase supply. This alternately controls the input DC voltage of the inverter. Speed control of BLDC machine is achieved by varying the inverter DC link voltage. In this design, inverter consists of only two legs instead of three legs and third phase of the motor is connected to the midpoint of capacitors and inverter is operating at fundamental switching frequency. This topology is designed to operate in DICM mode (Discontinuous Inductor Current Mode) to provide an inherent power factor correction at input AC supply side. Proposed circuit is modeled in Matlab/Simulink tool by using Simpower system and Xilinx block set.

This study proposes a comprehensive analysis of a novel non‐isolated step‐up converter with continuous input current and common ground. The proposed topology provides high voltage gain besides insignificant voltage and current stress across switches and diodes. Consequently, using switches and diodes with low current and voltage withstanding is achievable, leading to high converter efficiency and cost reduction. The voltage and current stress besides steady‐state and efficiency analysis are surveyed. Moreover, the converter's non‐ideal voltage gain analysis employing different components is discussed and compared with recently suggested converters. Additionally, the component losses, efficiency, normalized voltage, and current stresses of the studied converters are collected in tables to simplify the comparison between different topologies. Finally, a 100 W prototype converter is implemented to confirm theoretical performance, and the results are investigated in detail.

Step‐up converters are increasingly developed for renewable energy and storage systems in order to raise the output voltage of those resources to higher voltage levels. Conventional step‐up structures, such as P‐type boost converter, provide low voltage gain, and they must be cascaded with the same modules to produce higher boost factors. This conversion method reduces overall efficiency. Affording higher gains with lower duty cycles and single‐stage conversion increase efficiency. This paper proposes a new step‐up P‐type dc/dc converter with high voltage gain even with lower duty ratios. Additionally, it has continuous input current, high efficiency, and common ground between the input and the output. Detailed analysis is presented, and the performance of this new topology is compared with other high‐gain step‐up converters. Simulations and experiments evaluate the achievements of this topology. Results prove the proposed structure.

A new single‐switch, single‐stage power factor correction (PFC) converter based on discontinuous capacitor voltage mode (DCVM) is presented in this study. The conventional single‐stage PFC converters have high voltage across their bulk capacitor which imposes high voltage stress on the switch and also the bulk capacitor voltage stress increases at light load condition. The most important advantage of the proposed topology is that the voltage across the bulk capacitor is low and the input current is continuous. Furthermore, this topology does not have high voltage stress across the bulk capacitor at light loads. The proposed topology is derived from a DCVM buck converter integrated with a flyback converter. The proposed PFC topology contains low number of passive components and employs only one switch, resulting in reduced complexity and cost. The presented simulation and experimental results of the proposed converter justify the theoretical analysis.