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The purpose of the work is to develop continuous mathematical models of power factor correctors for switch-mode power supplies. The models are designed to solve optimization problems aimed at increasing the energy efficiency of these devices. This goal was achieved by developing a universal continuous averaged model of switch-mode voltage converters, which are an integral part of any active power factor corrector. State-space averaging method was proposed for constructing such a universal model. It has been shown that such a model adequately reproduces the processes in any of the main types of DC-DC voltage converters. The possibility of constructing a mathematical model of an active power factor corrector based on the proposed universal model of a DC-DC voltage converter is substantiated. The features of the structures of active power factor correctors for switching power supplies are considered and the problems that arise when studying their energy efficiency are shown. By simulation in the time domain with using the constructed model, diagrams of transients of the power factor corrector during load and primary network voltage disturbances are obtained. The most important result is the creation of a universal continuous mathematical model of switching voltage regulators. This model, unlike previously proposed models, is suitable for use in the analysis, modeling and design of any power factor correctors without the need to modify it in each specific case. The significance of the results obtained lies in accelerating the design process of active power factor correctors built on the basis of any type of pulsed DC-DC voltage converters. The developed model is intended for use in the Micro-Cap electronic circuit analysis program. However, since it is ultimately a software module in the SPICE language, this model can be used in many circuit analysis programs that support this language.

Induction motor drives (IMDs) can achieve high performance levels comparable to dc motor drives. A major problem in getting high dynamic performance in an IMD is the coupling between the flux and torque producing components of stator current. This is successfully overcome in FOC (Field-Oriented Control) IM, making it to the industry standard control. The performance of an IMD with an improved power quality converter at the front end is presented in this study. In the IMD, boost converter is employed to reduce power quality difficulties at the utility interface. As the boost converter contains only one switch, it results in a low processing time and cost. To ensure sinusoidal supply currents with high PF (Power Factor) and minimal THD (Total Harmonic Distortion), a novel PFC (Power Factor Corrector) control technique is proposed. To enhance the performance of the converter and to lower distortions at the motor side, PI (Proportional Integral) controller is incorporated at the PFC side. Thus it controls the DC bus voltage. The proposed boost converter improves power quality by lowering overall harmonic distortion of AC mains current, improving power factor correction, and regulating dc-link voltage. It is designed, modelled, and simulated in the MATLAB/simulink platform. Using a DSP (Digital Signal Processor), the suggested system’s performance is experimentally validated. The system’s performance is evaluated for speed and load torque, and the power quality indices are determined to meet IEEE-519 standards under all operating conditions. From the obtained results, it is evident that the proposed system mitigates the power quality issues effectively. [ABSTRACT FROM AUTHOR]

Three-phase power factor correction (PFC) converters are the front-end stage of the power conversion that are required to be connected to the grid with a proper filter to meet international standards. A high-order LCL filter is a widely used solution to reduce the component size of the filter although it requires six inductors. In this article, a novel reconfigurable LCL filter that consists of only three inductors is proposed. The principle of the reconfigurable filter is to fully utilize the converter-side inductors by changing their position from the converter side to the grid side and vice versa. The filter is reconfigured by using three low-frequency (LF) bidirectional switches. The ultimate goal of the proposed topology is to reduce the magnetic components by half and achieve comparable grid current quality as the conventional topology. The proposed PFC topology is verified by a 1-kW experimental prototype. All the experimental results agree with the theoretical concepts and prove that the grid current quality of the proposed topology is comparable with the conventional topology. [ABSTRACT FROM AUTHOR]

The growing use of power converters connected to the grid motivates their study in power electronics courses and the prototype development in the degree final project (DFP). However, the practical realization of using state-of-the-art components and conversion techniques is complex due to the numerous multidisciplinary aspects that students must consider in its design and development and the workload associated with the DFP. An example of this is that, unlike a conventional power factor correction (PFC) design, the individual dedication of students to complete the design and validation of modern bridgeless PFC stages exceeds the number of credits of the DFP. The reason for this is that it includes system modeling, becoming familiar with the devices used, discrete selection, circuit design, control development, and programming, to build the converter and verify the operation of the complete system. To reinforce the individual skills needed for the DFP and reduce this time, a novel strategy is proposed. It allows the student to focus their efforts on integrating the individual skills achieved in the degree at the appropriate competence level during the modeling and construction of the power converter while carrying out part of the tasks out of the lab, if necessary, as was the case during the pandemic restrictions. For this, the rapid prototyping technique is introduced to speed up the overall design and speed up the tuning of digital controllers. This manuscript presents a teaching experience in which students build digitally controlled power converters using Texas Instruments microcontroller boards and PLECS®. The example of a bridgeless totem-pole power factor corrector is shown. Although it began to develop and was motivated due to the restrictions during the COVID-19 pandemic, the experience has been verified and is maintained over time, successfully consolidating. [ABSTRACT FROM AUTHOR]

In order to improve the charging speed and reduce the occupied volume of an electric vehicle charger, a single-phase boost power factor corrector (PFC) system with cascade CHB (cascaded H-bridge) topology was adopted. Due to the periodic fluctuation of single-phase AC input, there is a large double power frequency ripple component in the output voltage of an AC-DC converter. When capacitor voltage is used as output for feedback control, the control system has the characteristics of a non-minimum phase system. In light of these factors that affect the dynamic stability of the system, a control method is proposed to improve the dynamic characteristics of the system without affecting its steady-state performance. The predictive PI control strategy was adopted to predict the error input signal of the lag process to attenuate the jitter in the control system and improve the dynamic performance and anti-interference of the system. Finally, the feasibility of the scheme was verified by experiments. [ABSTRACT FROM AUTHOR]

Domestic induction heating appliances have improved the final user experience due to the advantages that this technology offers, such as flexibility, fast heating, cleanness, and safety. Currently, these appliances are implemented using several isolated electronic boards to be able to be powered from one or several mains phases, enabling their use in regions with different connections. In order to enhance this approach, a multiphase power factor correction rectifier is proposed in this article, improving significantly induction heating cookers. The topology is described, and a wide variety of modulation strategies are presented and analyzed, discussing their main advantages and disadvantages according to the conduction mode, operating frequency, switching mode, and control strategy. In order to validate this proposal, an 11 kW and up-to three-phase high power-density converter for domestic induction heating applications is implemented and experimentally analyzed, including its main waveforms and efficiency. Finally, a comparative evaluation is performed to enable the selection of the optimum modulation strategy for each specific application. [ABSTRACT FROM AUTHOR]

The purpose of this study is to develop a variable frequency brushless DC motor drive for the compressors of refrigerated cabinets. It is based on the microcontroller unit (MCU) produced by Renesas Co., Ltd. using the space vector pulse width modulation (SVPWM) for the modulation of the inverter. In addition, at the AC power supply side of the inverter developed, a circuit for suppressing electromagnetic interference (EMI) and a power factor corrector (PFC) are integrated to control the power factor (PF) at the AC power supply side to be above 0.95, which is far better than the commercially available inverters with a power factor of only 0.5. Finally, an intelligent variable frequency control approach based on the extension theory is designed to classify the rotational speed difference and the rate of change in rotational speed difference between the rotational speed commands and the actual rotational speed of the compressor into 20 zones. Then, for the rotational speed difference and the rate of change in rotational speed difference actually measured, their correlations to the 20 zone categories are calculated to determine an appropriate rotational speed command. The temperature of the refrigerated cabinets can quickly be determined to reach the set target value. The proposed extension speed control is simple in computation and does not require much learning data, making it easy to implement. Furthermore, the drive developed is verified by actual testing and its performance is compared to the compressor drives of the refrigerated cabinets commercially available. It is proved that the performance of the drives developed is indeed far better than that of the drives commercially available.

In order to improve the charging speed and reduce the occupied volume of an electric vehicle charger, a single-phase boost power factor corrector (PFC) system with cascade CHB (cascaded H-bridge) topology was adopted. Due to the periodic fluctuation of single-phase AC input, there is a large double power frequency ripple component in the output voltage of an AC-DC converter. When capacitor voltage is used as output for feedback control, the control system has the characteristics of a non-minimum phase system. In light of these factors that affect the dynamic stability of the system, a control method is proposed to improve the dynamic characteristics of the system without affecting its steady-state performance. The predictive PI control strategy was adopted to predict the error input signal of the lag process to attenuate the jitter in the control system and improve the dynamic performance and anti-interference of the system. Finally, the feasibility of the scheme was verified by experiments.

This paper presents the design, simulation, and implementation of an off-board charger of medium and low capacity batteries that incorporates a power factor corrector, reaches a low THD current with the advantage of providing higher robustness against network frequency variations, and allows the implementation of three different charging strategies. On the one hand, this charger consists of a galvanic isolation stage, followed by a bridge rectifier connected to a Boost converter, which regulates the power factor and THD. On the other hand, a Buck converter cascaded with the Boost serves as a current or voltage source, depending on the operating charging strategy. Subsequently, results obtained in the testing phase are presented, placing great emphasis on obtaining a power factor of 0.978 and a THD of 5.7%, which are compared to standard IEC 61000-3-2. Finally, the efficiency of the prototype, which reaches a maximum of 91.1%, is evaluated; conclusions are therefore presented.

This paper presents the design, simulation and implementation of a small scale battery charger with low harmonic distortion in current. It was proposed a design composed of two boost converters in cascade, the first operating as PFC and second as a regulator of the injected current to the batteries. Additionally, it was presented the procedure for the controllers design of each stage. In the first stage was used a control in average current mode and in the second stage were used two controls that enable you to employ the method of constant current - constant voltage in order to charge the batteries. In both stages were used the PI controllers and with the power electronic circuit were simulated in the PSIM® and MATLAB® software and validated experimentally In this tests, power factors close to 0.98 and harmonic distortion in current below 10% were obtained, complying with the requirements of the IEC 61000-3-2 standard. Finally, the conclusions are presented. [ABSTRACT FROM AUTHOR]

Traditionally, power electronics has been a complex training field for undergraduate students in the electrical area of the Universidad Distrital Francisco José de Caldas. In this course, multiple theories and concepts are difficult to assimilate due to the distance from other program courses and the complexity of conceptualizing abstract elements. A fundamental learning tool corresponds to the laboratory practices, which allow visualizing concepts, facilitating their understanding and assimilation. However, the mobility restrictions imposed at a global level have prevented access to these learning spaces, restricting fundamental elements of the process, such as direct interaction with circuits and power equipment and critical socialization among students. The effectiveness of the learning process is linked to the resources available, today these resources have been reduced as a result of the social isolation that is expected to continue in the coming months. To reduce this impact, the development of a computer tool has been initiated, capable of replacing the work of students in the laboratory in terms of direct interaction with the circuits, analysis of behavior, and design of applications. The tool is a circuit simulator specifically oriented to the area of power electronics, which is why it is preferable for specific training compared to traditional simulators, since it allows simplifying the behavior of the elements at the switch level, eliminating their parasitic analysis, and therefore reducing the demands on processing capacity, storage memory and simulation time. The first circuit implemented corresponds to an active power factor corrector on a Boost type converter, an application that in itself justifies the use of the tool. As preliminary results, educators have observed increased commitment and motivation of students in their autonomous work. [ABSTRACT FROM AUTHOR]

In this paper, a novel bridgeless power factor corrector (PFC) is proposed. The PFC can shape the waveform of the input current to be sinusoidal and in phase with the AC input voltage simply by sensing of the AC voltage, input current, and output voltage. That is, it is able to achieve a unity power factor. As compared with conventional PFCs, the proposed PFC possesses the particular features of high step-down voltage ratio, being bridgeless, galvanic isolation, and leakage energy recycling. All the active switches in the proposed PFC can be operated under an identical control signal. In addition, the output voltage can be regulated only by single-loop control, instead of dual- or multiloop control. Therefore, the control scheme for the PFC is simple and much easier to carry out. The operation principle, theoretical analysis, and hardware validation to verify the proposed PFC are described. [ABSTRACT FROM AUTHOR]

Flexible cooking surfaces, eg. fully active surfaces, have gained lately an increasing importance in the domestic induction heating. Multi-inverter structures are a cost-efficient solution to develop this technology. However, they add control restrictions that can be solved with a power factor corrector (PFC) stage as proposed in this work. The proposed converter and modulation strategy work with zero voltage switching (ZVS), decreasing the switching losses, enabling a higher working frequency and, therefore, decreasing the magnetic devices size. The bus voltage is controllable and can be increased, easing the load power control and decreasing current through load and inverter and, so, the power losses. Besides, the switching frequency is constant in the mains cycle and can be modified to synchronize the load inverter and the PFC stage avoiding intermodulation noise. A 3.6 kW prototype has been implemented fulfilling the EMC requirements. The experimental waveforms and efficiency have been measured to prove the feasibility of this proposal. [ABSTRACT FROM AUTHOR]

It is proposed to apply an adaptive hysteresis band that allows to reduce the total harmonic distortion, the ripple and the deformation in the zero crossing of the input current of a bridgeless boost AC-DC converter with power factor correction (PFC). A procedure for calculating the hysteresis band based on the dynamic states of the converter is presented, in such a way that it is possible to keep fixed the switching frequency. The band is applicable to the sliding mode control that allows to improve the dynamic performance of the power converter in the presence of bounded perturbations and significant changes in operating region. The results of the simulation of a 1 kW converter are presented. It is shown that it is possible to raise power factor up to 0.996, to decrease the deformation of the zero crossing and to reduce the total harmonic distortion in the input current down to 2.8%, keeping it below the maximum permissible limits of the standard EN / IEC 61000-3-2 (1000-3- 2). [ABSTRACT FROM AUTHOR]

This paper presents a high power factor (PF), low total harmonic distortion (THD) light-emitting diode (LED) driver with dimming capability. In addition, the proposed technique ensures a high PF and low THD at any dimming level. The driver is implemented by using an interleaved capacitor, which is placed between the rectifier and the integrated buck flyback converter (IBFC). In this way, the line current conduction angle is increased, which in return increases the PF and decreases the THD. The operation of the proposed converter ensures that one diode of the conventional IBFC will not conduct, so that it can be removed. Moreover, owing to the continuous power flow, the proposed technique makes a significant reduction of the converter output ripple. The paper presents a prototype of the proposed converter supplying an LED luminaire of 37 V/ 0.67 A. The prototype shows a high PF of 0.997, small THD of 2.5%, output current ripple of 6%, and an efficiency of 80%. [ABSTRACT FROM AUTHOR]

This paper analyzes a Digital Signal Processor (DSP) based One Cycle Control (OCC) strategy for a Power Factor Corrector (PFC) rectifier with Common-mode Voltage (CMV) immunity. It is proposed a strategy that utilizes an emulated-resistance-controller in closed-loop configuration to set the dc-link voltage to achieve unity power factor (UPF). It is shown that if the PFC can achieve UPF condition and if the phase voltage is only affected by CMV, then phase current is free from CMV, as well as a lead-lag compensator (LLC) to average phase current.

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents the design, simulation, and implementation of an off-board charger of medium and low capacity batteries that incorporates a power factor corrector, reaches a low THD current with the advantage of providing higher robustness against network frequency variations, and allows the implementation of three different charging strategies. On the one hand, this charger consists of a galvanic isolation stage, followed by a bridge rectifier connected to a Boost converter, which regulates the power factor and THD. On the other hand, a Buck converter cascaded with the Boost serves as a current or voltage source, depending on the operating charging strategy. Subsequently, results obtained in the testing phase are presented, placing great emphasis on obtaining a power factor of 0.978 and a THD of 5.7%, which are compared to standard IEC 61000-3-2. Finally, the efficiency of the prototype, which reaches a maximum of 91.1%, is evaluated; conclusions are therefore presented. [ABSTRACT FROM AUTHOR]

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, light emitting diode (LED) has changed the scenario of residential and commercial lighting. Day lighting applications has huge scope for power saving by use of solar photovoltaic (PV) based LED lighting with DC distribution system. In this paper, a hybrid system with combination of PV and grid power has been presented. In proposed system, PV source and grid power sourced converter (GSC) operate in parallel and both are directly connected to load. GSC is mainly used for supplying the gap between the maximum PV generation and load demand. Power converter is realised using single stage high power factor grid-source converter (GSC). Maximum power point (MPP) of PV source is tracked by incremental conductance (INC) algorithm and used as feedback to control power from utility bus to load. Proposed topology is validated using 150 VA laboratory prototype and results of experimentation are given in the paper. [ABSTRACT FROM AUTHOR]

У статті представлено інверторне джерело живлення з трифазним входом і активною корекцією коефіцієнта потужності. Схему побудовано з використанням принципу прямого перетворення, що дає можливість знизити втрати енергії в перетворювачі. Джерело живлення забезпечує гальванічну розв’язку виходу за допомогою високочастотних прямоходових трансформаторів.

This paper deals with switching-frequency modulation (SFM) for conducted electromagnetic interference (EMI) suppression in active power factor correctors (PFCs) operating in discontinuous conduction mode (DCM). The effect of SFM on different performance characteristics of DCM PFC is studied in details. It is shown that the use of SFM in PFC with conventional control approach leads to significant increase in total harmonic distortion (THD) and harmonic content of input current. Moreover, SFM leads to noticeable increase in peak power components currents. In order to use SFM for EMI reduction more effectively without significantly worsening THD, power factor, and harmonic content of DCM PFC, an improved control technique and a control circuit are proposed and verified by simulations and experimentally. The technique is based on the use of specific time delay injection to power MOSFET control signal. As show simulations and experiments, SFM PFC with the proposed delay technique in comparison to PFC without SFM has noticeably lower conducted EMI and THD of input current, at the cost of slightly decreased efficiency and moderately increased peak currents. [ABSTRACT FROM AUTHOR]

The paper proposes circuit design of high-frequency transformer-isolated converter and three-phase input without intermediate rectification of input voltage. A system was built using modular approach, i.e. each phase contains identical high-frequency AC/DC transformer-isolated converters, the outputs of these converters have series connection. Application of principle of direct conversion allows reducing amount of elements in the source power circuit, thus, reducing energy loss. Besides, high-frequency energy transformation allows significant improvement of weight-dimension characteristics of the system. Application of special algorithm of power key control provides for the possibility of active correction of input power factor and neutralization of circuit frequency harmonics in source output voltage that significantly reduces the requirements to output filter. The developed source has fast response and can be used for welding processes requiring high rates of change of arc current. [ABSTRACT FROM AUTHOR]

A new control technique for two-stage server power is proposed in this paper. The proposed technique will significantly reduce power consumption under the light-load condition. The basic idea of the proposed control technique is to control both the dc-link voltage of the power factor corrector (PFC) stage and the switching method of the full-bridge stage. Under the light-load condition, the output voltage of the PFC stage is no more fixed and is dynamically adjusted to significantly reduce the switching losses. Moreover, under the light-load condition, the full-bridge stage is with pulsewidth-modulation (PWM) and burst-mode control to reduce the circulating current losses. The former approach will reduce the switching losses due to the reduction of voltage across the power devices. The latter approach will dramatically reduce the circulating current losses caused by the phase-shift control method since phase-shift switching control is replaced by PWM switching control. Moreover, due to the reduction of the dc-link voltage, the switching losses for PWM and burst-mode control can be further reduced, as compared to those for fixed dc-link voltage. Experimental results of 480-W server power are presented. It is shown that the efficiency of the two-stage power converter can be improved up to 8% and 3.9% under light-load and 10% load conditions for \mboxinput voltage=110\ \mboxV, respectively. For the 220-V input voltage, the efficiency improvement using the proposed method is 6.4% and 4.2% under light-load and 10% load conditions, respectively. [ABSTRACT FROM PUBLISHER]

Copyright of Technical Electrodynamics / Tekhnichna Elektrodynamika is the property of National Academy of Sciences of Ukraine, Institute of Electrodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper introduces the adaptive slope compensation method into the digital clamping current control at various input voltages to improve the power factor (PF) and the total harmonic distortion (THD) of the universal input. The controller conducts a phase-management mechanism for various input voltages and load conditions to raise the circuit conversion efficiency. The optimal switching timing for one- and two-phase operations can be determined from the power loss distribution. A digital signal processor chip TMS320F28035 is used to implement the digital platform. A 300-W laboratory prototype with a universal line voltage 80-V dc output voltage is designed and tested to verify the feasibility. The values of efficiency from light load (10% of rated power) to full load at 115- and 230-V inputs are greater than 95%. PF values from medium to full load are greater than 0.94. Input current harmonics also meet the norm of IEC 61000-3-2 Class D. [ABSTRACT FROM PUBLISHER]

This paper presents a single-phase high power factor motor drive system with an active power filter function. Since most of electrical equipment connected to the grid must comply with regulations regarding grid current harmonics, motor drive systems are generally equipped with a power factor corrector which is composed of power switches and reactive components, e.g., inductor and capacitor. The reactive components are bulky and increase the system cost, particularly in low-cost applications such as electrical home appliances. In this paper, a new motor drive algorithm which is capable of both driving a permanent-magnet motor and filtering the harmonic currents produced by other nonlinear loads belonging to the system is proposed. Since the input current of the drive system is directly controlled by manipulating not the motor current reference but the output voltage reference of the inverter, it is possible to achieve exact and immediate control of the grid current. The effectiveness of the proposed algorithms is validated by experiments with a permanent-magnet motor drive system. [ABSTRACT FROM AUTHOR]

The main theme of this paper is to propose a new hybrid control technique to improve the light load efficiency and meet the hold-up time requirement of the server power without additional sensors or auxiliary circuits. The server power consists of a power factor corrector (PFC) and a phase-shift full-bridge converter. The proposed hybrid control technique online controls the dc-link bus voltage of PFC to retain the maximum duty operation of the phase-shift full-bridge converter. Therefore, the efficiency under light load condition can be improved which is contributed by the reduction of circulating loss and switching losses of the converter. To meet the hold-up time requirement, the dc-link bus voltage is controlled to its nominal value under heavy load conditions. The specifications of the server power supply include: ac input voltage = 110/220 V, dc output voltage = 12 V, and output power = 480 W. The experimental results show that the efficiency can be improved up to 3% under light load conditions and meet the hold-up time requirement under whole load conditions. These results confirm the effectiveness of the proposed hybrid control technique. [ABSTRACT FROM AUTHOR]