Variable on‐time controlled boundary conduction mode single‐ended primary inductor converter power factor correction converter

In this paper, a digital-based pulse train (PT) control technique for a boost power factor correction (PFC) converter operating in a discontinuous conduction mode (DCM) is presented, which can achieve nearly unity power factor (PF) over a universal input voltage range. Different from traditional digital control techniques, which usually require complex arithmetic operations, the digital-based PT control technique only needs a simple operation. Besides, a DCM boost PFC converter with digital PT control can operate at a high switching frequency, which is less dependent on the processing speed of a digital controller. Thus, the proposed control strategy can be implemented with general purpose digital controllers, such as low-speed and low-cost microcontroller unit, for the DCM boost PFC converter where the cost is a focus. The operation principle of the digital PT controlled DCM boost PFC converter is analyzed. Experimental results are provided, which show that high PF and low input current total harmonic distortion can be maintained over a universal input voltage range of 90–264 V ac.

To reduce total harmonic distortion (THD) and improve the power factor (PF) of a boost power factor correction (PFC) converter, here, the authors propose a non‐linear control algorithm that includes the feedforward correction (FC) algorithm in the continuous conduction mode (CCM) and the non‐linear frequency variation (FV) algorithm in the mixed conduction mode (MCM). The proposed FC algorithm achieves current out of distortion through zero crossing with a lower current loop bandwidth. The proposed non‐linear FV algorithm achieves high PF and low THD under minimal load conditions. The non‐linear FV algorithm comprises a third harmonic extraction algorithm, a harmonic control loop for reducing THD and a frequency production algorithm. By using this non‐linear FV algorithm, the inductor size is reduced, which leads to lower cost and also achieves better THD and PF. The proposed algorithms are verified experimentally in terms of current tracking, current THD, PF, heating and loss on a 2000‐W boost PFC converter hardware prototype.

In this paper, a (PF) Power factor correction and power quality (PQ) improvement based BLDC motor drive proposed. Normally the permanent magnet BLDC motor drive connected with the diode bridge rectifier and high value of the capacitor due to which poor power factor and higher THD (Total harmonic distortion) value at the input side To overcome this difficulty SEPIC (Single-ended primary inductance converter) converter use to optimize the PF and THD value. The converter operates in discontinuous conduction mode to get the desired result. This scheme also used for speed control of BLDC motor by controlling the VSI (voltage source inverter) feeding the BLDC drive.

When the on-time is constant during a line cycle, the input power factor (PF) of critical conduction mode buck-buck/boost power factor correction converter is low. A variable on-time control (VOTC) scheme is put forward in this paper to realize high PF. By utilizing the input and output voltage to modulate the on-time of buck and buck/boost switch, we can realize high-input PF with low-total harmonic distortion within the universal input voltage range. The operating principles and the comparative analysis of the converter with conventional constant on-time control (COTC) and VOTC are analyzed. The proposed control scheme achieves high PF and efficiency as compared with the COTC. A 100-W prototype was built up to verify the effectiveness of the proposed control strategy.

There is a need to improve the power quality of the grid as well as the power factor implied on the grid due to the nonlinear loads connected to it. A new single phase bridgeless AC/DC power factor correction (PFC) topology to improve the power factor as well as the total harmonic distortion (THD) of the utility grid is proposed in this research. By eliminating the input bridge in conventional PFC converters, the control circuit is simplified; the total harmonics distortion THD and power factor PF are improved. The controller operates in multi loop fashion as the outer control loop calculates the reference current through innovative filtering and signal processing. Inner current loop generates PWM switching signals through the PI controller. Analytical derivation of the proposed converter is presented in detail. Performance of the proposed PFC topology is verified for prototype using PSIM circuit simulations. The experimental system is developed, and the experimental results agree with simulation 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.

In order to break limited step-down ratio range and poor regulation capacity in the conventional resonant switched-capacitor converters for rectifier application, a single-stage ac/dc rectifier based on the dual-resonance switched-capacitor converter is proposed in this article. Through utilizing a dual-resonant structure and nonoverlapping strategy to realize wide continuous voltage gain of the proposed converter, high power factor (PF) and low total harmonic distortion (THD) based on the narrow dead zone are guaranteed by operating at high step-down conversion ratio in this converter topology. Moreover, the voltage gain is concentrated between resonant frequency and double resonant frequency to achieve a narrow switching frequency range for rectifier application. Furthermore, operating at flat voltage stress curves to obtain low voltage stress character. Comprehensive mode analysis, input PF and THD, and stress analysis are given, and analysis results indicate that the proposed power factor correction converter can work with soft turn <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> and zero-current turn <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> ; high efficiency is realized. Finally, an experimental prototype with 85–130 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ac</sub> input and 47 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dc</sub> /44 W output is built and tested for verifying the operation modes and PFC performance, and the comparison between different rectifiers and the proposed one is provided.

In response to the growing need for efficient power conversion in renewable energy applications, this study addresses the issue of harmonic distortion and low Power Factor (PF) values caused by non-linear loads, such as electronic devices. Low PF results in reduced efficiency, increased energy consumption, and higher costs for both consumers and utilities. Active correction, typically involving an active circuit implemented using a power converter, provides an optimal solution by offering high performance, precise regulation, and low harmonic distortion. This research proposes a Power Factor Correction (PFC) solution utilizing an Interleaved DC-DC Single Ended Primary Inductance Converter (SEPIC) for the power stage and a Proportional Integral Derivative (PID) controller for the control block, tuned by a Quorum Sensing (QS) bacterial-based search algorithm. The PID controller parameters are derived using a frequency-domain approach, which presents advantages such as reduced design complexity, improved stability margins, and enhanced SEPIC performance. Simulation results indicate reduced overshoot, settling time, rise time, and Total Harmonic Distortion (THD) percentage, as well as increased efficiency and power factor nearing unity. The proposed scheme also demonstrates improved dynamic performance for variations in load, line, and reference voltage. Owing to its high efficiency, precise voltage regulation, and minimized impact on the electrical grid, this solution is well-suited for renewable energy applications, where optimizing energy conversion and ensuring stable operation are crucial for the overall performance of renewable energy systems.

In LLC-based onboard battery charging architectures used in plug-in electric vehicles (PEV), the dc link voltage can be actively regulated to follow the battery pack voltage so that the LLC converter can operate in proximity of resonant frequency and achieve high efficiencies over the wide range of battery pack voltage. However, conventional boost-type power factor correction (PFC) converters are unable to provide ultrawide dc link voltages since their output voltages should always be larger than their input voltages. This paper proposes a Silicon Carbide (SiC)-based onboard PEV charger using single-ended primary-inductor converter (SEPIC) PFC converter followed by an isolated LLC resonant converter. With the proposed charger architecture, the SEPIC PFC converter is able to provide an ultrawide range for dc link voltage, and consequently enhance the efficiency of the LLC stage by ensuring operation in proximity of resonant frequency. A 1-kW SiC-based prototype is designed to validate the proposed idea. The experimental result shows that the SEPIC PFC converter achieves unity power factor, 2.72% total harmonic distortion, and 95.3% peak conversion efficiency. The LLC converter achieves 97.1% peak efficiency and always demonstrates a very high efficiency across the ultrawide dc-link voltage range. The overall efficiency of the charger is 88.5% to 93.5% from 20% of the rated load to full load.

A TRIAC dimming LED driver that can control the brightness of LED arrays for a wide range of source voltage variations is proposed in this paper. Unlike conventional PWM LED drivers, the proposed LED driver adopts a TRIAC switch, which inherently guarantees zero current switching and has been proven to be quite reliable over its long lifetime. Unlike previous TRIAC type LED drivers, the proposed LED driver is composed of an LC input filter and a variable switched capacitance, which is modulated by the TRIAC turn-on timing. Thus, the LED power regulation and dimming control, which are done by a volume resistor in the same way as the conventional TRIAC dimmers, can be simultaneously performed by the TRIAC control circuit. Because the proposed LED driver has high efficiency and a long lifetime with a high power factor (PF) and low total harmonic distortion (THD) characteristics, it is quite adequate for industrial lighting applications such as streets, factories, parking garages, and emergency stairs. A simple step-down capacitive power supply circuit composed of passive components only is also proposed, which is quite useful for providing DC power from an AC source without a bulky and heavy transformer. A prototype 60 W LED driver was implemented by the proposed design procedure and verified by simulation and experimental results, where the efficiency, PF, and THD are 92%, 0.94, and 6.3%, respectively. The LED power variation is well mitigated to below <TEX>${\pm}2%$</TEX> for 190 V < <TEX>$V_s$</TEX> < 250 V by using the proposed simple control circuit.

Experimental investigation on the design of a three-phase power factor corrector utilizing a SEPIC converter

In the last decade, the amount of electronic equipment connected to the AC line has been increased; this equipment presents low values of power factor (PF) and high total harmonic distortion (THD) due to their nonlinear behavior. The personal computer (PC) is one piece of electronic equipment that has these problems, the main reason being because it was decided to develop a switching mode power supply (SMPS), for the PC, with power factor correction (PFC). In this paper, the experimental results of the SMPS prototype for PC applications, which includes a PFC feature, are presented. Analysis of the design compromises that must be kept in mind in order to develop a SMPS with PFC has been included. This analysis evaluates the compromises that must be considered when in the design of a SMPS with PFC, we try to obtain the best power factor (PF), total harmonic distortion (THD) and construction cost.

This paper studies a repetitive controller design scheme for a bridgeless single-ended primary inductor converter (SEPIC) power factor correction (PFC) converter to mitigate input current distortions. A small signal modeling of the converter is performed by a fifth-order model. Since the fifth-order model is complex to be applied in designing a current controller, the model is approximated to a third-order model. Using the third-order model, the repetitive controller is designed to reduce the input current distortion. Then, the stability of the repetitive controller is verified with an error transfer function. The proposed controller performance is validated by simulation, and the experiment results show that the input current total harmonic distortion (THD) is improved by applying the proposed controller for an 800 W bridgeless SEPIC PFC converter prototype.

This paper presents the design guidelines of electronic ballast for HID lamps. High efficient electronic ballast with high power factor and low THD (total harmonic distortion) is presented. The use of input current shaper converters (ICSC) working in Discontinuous-Conduction Mode (DCM) to stabilize the discharge arc in High Intensity Discharge (HID) lamps is proposed. The analysis of how the ICSC stabilizes the lamp current through the analysis of the output capacitor Co and model lamp is presented. The results indicated the feasibility to stabilize the lamp and obtaining high efficiency, high power factor and low THD in a single stage is presented.

In this paper, one AC light-emitting diode (LED) driver with high power factor (PF) and low total harmonic distortion (THD) is adopted, which is added with the proposed switched LED module and is controlled based on the field-programmable gate array (FPGA). By doing so, the efficiency of such an AC LED driver can be improved significantly. This switched LED module is constructed by several LED strings, which have individual series-connected MOSFET switches. As the switch of the switched LED module is turned on, the corresponding LED string is short-circuited and hence is not conducted, whereas as the switch of the switched LED module is turned off, the corresponding LED string is conducted due to the redundant input voltage across this LED string. Therefore, the redundant input voltage across between the collector and emitter of the BJT current source can be reduced, that is, the unwanted power dissipation in the BJT current source can be decreased, so as to upgrade the efficiency of the overall system.