Power Factor Correction Converter Research Articles

Enhancement of Power Quality and Speed Regulation of a BLDC Motor Drive using Water Cycle Algorithm

Permanent magnet Brushless DC motors are used in several applications because of its advantages such as high reliability, high power output, constant torque, low maintenance cost, good heat dissipation and better efficiency. Also, rapidly decreasing cost of permanent magnets is an added advantage. Hence, BLDC motors are suitable for many variable-speed drive applications. Various DC-DC converters are used for driving the BLDC motor and Interleaved Boost converter is one of them. BLDC motor drive is fed through a diode bridge rectifier which lowers the power factor. Hence, power factor correction converters are necessary in such applications. In the present work, to improve the power quality of the AC mains and hence the power factor, Interleaved boost converter controlled by PI controller is used. The gains of the PI controller are decided by Water cycle algorithm (WCA) using Integral Time Absolute Error (ITAE) criterion. Speed control of the BLDC motor is done by controlling the output voltage of the converter which acts as a DC link voltage to the Three Phase Voltage Source Inverter (VSI). MATLAB SIMULINK software is used for the design and performance analysis of the BLDC.

A Reconfigurable Totem-Pole PFC Rectifier With Light Load Optimization Control Strategy and Soft-Switching Capability

This article presents a reconfigurable totem-pole bridgeless power factor correction converter employing an auxiliary circuit and a simple control scheme to achieve high efficiency. Under light load condition, instead of delivering the energy through the main switch, the proposed converter utilizes only the auxiliary switches by using a different control scheme. Since the auxiliary switches have much smaller parasitic capacitances than the main switches, the proposed converter can obtain high efficiency under light load condition. Over middle-to-heavy load condition, the proposed converter can acquire both zero-voltage switching operation and relieved reverse-recovery problem thanks to the auxiliary circuit, which leads to high efficiency even with Si-MOSFET in the continuous conduction mode control. As a result, the proposed converter can achieve high efficiency over the entire load condition. The effectiveness of the proposed converter is verified by a prototype with ac 230Vrms input and 750 W output.

Spread-Spectrum Frequency Modulation With Adaptive Three-Level Current Scheme to Improve EMI and Efficiency of Three-Level Boost DCM PFC

Discontinuous conduction mode controlled boosting power-factor-correction (PFC) converters suffer from high differential-mode electromagnetic interference (EMI) and require a large input filter due to high inductor current ripples at a single switching frequency. To remedy the shortcomings, a downward spread-spectrum frequency modulation (SSFM) is proposed in this letter. The SSFM can be used by boosting PFC converters for reduced EMI and improved efficiency. On top of the frequency modulation, a novel adaptive three-level current (ATC) scheme is devised with three-level boost PFC using multilevel capability to obtain further reductions of peak current and EMI amplitude. Analyses and experiments validate that the proposed SSFM and ATC scheme can bring improvements of EMI and efficiency at the cost of increased output-voltage ripple.

Boost-Type Single-Stage Step-Down Resonant Power Factor Correction Converter

Conventional boost power factor correction (PFC) converter is only suitable for two-stage power conversion system due to its high output voltage. Inherent step-up characteristic limits its applications in single-stage low voltage output. In this article, a boost-type single-stage step-down resonant PFC converter, which combines a boost PFC converter and a resonant switched capacitor network by using one active switch, is proposed and analyzed. Similar to conventional boost PFC converter, the proposed converter can achieve unity power factor and low input current ripple in universal-input applications. Moreover, the proposed converter can achieve step-down voltage conversion. Furthermore, high-efficiency is realized due to single-stage power conversion. The proposed converter is studied in terms of operation principle, voltage gain, power factor analysis, and key circuit parameters design. Finally, a 70-W prototype with 96.05% peak efficiency is built to verify the theoretical analysis results.

Semi‐valley switching method for buck LED driver to increase its efficiency and performance

Valley switching is one of the most efficient methods to decrease the switching losses in DC/DC converters. It uses a resonance between the converter's inductor and parasitic output capacitance of a metal–oxide–semiconductor field-effect transistor. In this study, the drawbacks of the valley switching in buck light-emitting-diode (LED) drivers are investigated. It shows that in spite of decreasing the switching losses, the valley switching method reduces its efficiency in some conditions. Also, it is clarified that the valley switching method not only causes current fluctuation in boost power factor correction converters but also malfunctions the buck LED drivers' performance. In this study, a semi-valley switching and its implementation are introduced to solve these problems. In general, it is shown that the proposed method improves both the efficiency and the performance of the buck LED driver, simultaneously. The methodologies are implemented in an experimental prototype to verify the proposed method.

Heteromagnetic Swinging Inductor and Its Application for Power Factor Correction Converters

A variable inductor concept based on a magnetic structure consisting of composite of magnetic materials is introduced to meet the designed inductance function of current. A design of the inductor, termed heteromagnetic swinging inductor (HMSI), was fabricated using a toroid core with a gap that was filled by a custom-developed low-permeability magnetic powder + polymer material. Having the gap filled with the magnetic material allowed for greater flexibility in L–I design with added benefit of low fringe field. The analytical model of HMSI was derived and verified by simulation. And the step-by-step design of arbitrary L–I curve HMSI was posted. We applied this swinging inductor to a critical conduction mode boost power factor correction converter to reduce its switching frequency variation range. First, the required L–I curve of the HMSI needed for narrow range of switching frequency was calculated. Then, the HMSI core structure consisting of two magnetic materials was designed. Finally, a prototype of the HMSI was fabricated and tested. Experimental result showed that for a 110-Vrms input, the converter with the HMSI had a switching frequency variation factor, defined as Δ f / f min, six times less than that of the converter using a linear inductor.

Buck-Type Single-Switch Integrated PFC Converter With Low Total Harmonic Distortion

Conventional buck power factor correction (PFC) converter has the disadvantage of high harmonic currents, which limits its applications. In this article, a buck type single-switch integrated PFC converter is presented and analyzed. It is composed of buck and flyback PFC converters by using only one active switch, which benefits from simple control. The buck and flyback PFC converters are input-parallel and output-parallel connected. With critical conduction mode constant on time control, the effect of dead zone of buck input current is eliminated by flyback unit. Therefore, the input harmonic currents of the proposed converters can easily meet IEC61000-3-2 Class C limits. With the advantages of buck and flyback PFC converters, the proposed converter can achieve high efficiency and low total harmonic distortion in universal-input applications. Simplified steady-state analysis and design considerations are introduced in this article. Finally, a 96-W prototype with 94.5% peak efficiency is built to verify the analysis results.

A Scheme to Improve Power Factor and Dynamic Response Performance for CRM/DCM Buck–Buck/Boost PFC Converter

Buck-buck/Boost power factor correction (PFC) converter is a great choice to compensate the inherent dead zones in the input current of buck PFC converter. However, whether the converter operates with traditional constant on-time control in critical conduction mode (CRM) or with conventional constant duty-cycle control in discontinuous conduction mode (DCM), the power factor (PF) is low, especially at low input voltage. Therefore, fixed on-time ratio control (FOTRC) and fixed duty-cycle ratio control (FDCRC) are proposed for CRM/DCM buck-buck/boost PFC converter to achieve high PF, respectively. Both control methods maximize PF over wide input voltage range by adjusting on-time or duty-cycle of buck/boost mode and buck mode. Compared with the traditional controls, the proposed control methods also have advantage of increasing efficiency. Furthermore, for improving dynamic response performance, smooth and rapid dynamic response control (SRDRC) is put forward, which can reduce the regulation time and output voltage overshoot/undershoot when the load or input voltage changes abruptly. In addition, the implementation circuits combining FOTRC/FDCRC and SRDRC are designed. Two prototypes have been built and tested in the lab to demonstrate the validity of the theoretical analysis.

Quasi-Fixed Switching Frequency Control of CRM Boost PFC Converter Based on Variable Inductor in Wide Input Voltage Range

With traditional constant on-time control, the switching frequency variation range of critical conduction mode boost power factor correction converter is large during a half line cycle, not to mention the wide range of input voltage's rms value. For this issue, this article puts forward a quasi-fixed switching frequency control, which combines the variable on-time and variable inductor technology together. Furthermore, a lower output voltage ripple and a higher efficiency are obtained. In spite of the power factor decrease, the input current harmonics still satisfy the IEC61000-3-2 Class D limits. The detailed theoretical analysis and experimental results are presented in this article.

Single Phase AC to DC Isolated ZETA Power Factor Correction Converter fed LED drives

This paper deals with PFC-isolated Zeta converter fed LED drive to overcome the power factor problems. The proposed circuit topology consists of diode bridge rectifier and isolated Zeta converter with high frequency transformer. A single –phase supply is used to feed a DBR followed by a filter to avoid any switching ripple in DBR and the supply system. An isolated Zeta converter is operated to work under DCM mode. This combination of DBR and PFC converter is used to feed a LED drive. This converter is simulated in MATLAB platform. This converter provides better results such as unity power factor and less current harmonic distortion.

Design and control of shunt active power filter for power quality improvement of utility powered brushless DC motor drives

ABSTRACT The presence of nonlinear loads like brushless DC (BLDC) motor drives in the distribution system leads to poor power quality (PQ) indices like low power factor, high total harmonic distortion and creates electromagnetic interference. Passive filters and Power factor correction converters are often inserted between the utility and BLDC motor drives to improve the PQ parameters. This paper proposes the shunt active power filter (SAF) for the PQ improvement of medium and high power BLDC motor drives. In this paper, the design steps and control of an SAF for a 20 kW BLDC motor drive are presented. The control of SAF is realized by applying the instantaneous “p–q” theory with the sinusoidal current control strategy. The current control is realized by a hysteresis controller. In contrast to normal electrical loads, the motor drive loads are subjected to continuous speed and load variations. This will result in fluctuations in the DC-link voltage of the SAF capacitor. Hence, the sliding mode controller is used for DC-link voltage control. The proposed methodology is validated in simulations and the experimental prototype. The enhancement of various PQ parameters is analysed for different loading conditions of the motor in the distorted and non-distorted distribution system voltage conditions.

Unified Voltage Balancing Feedforward for Three-Level Boost PFC Converter in Discontinuous and Critical Conduction Modes

This brief presents a unified voltage balancing feedforward (UVBFF) for three-level boost (TLB) power-factor-correction (PFC) circuit in discontinuous and critical conduction modes. In general, the topology in both modes puts emphasis on low-cost system. Thus, electrolytic capacitors with wide-tolerance are commonly used at outputs and voltage unbalance is inevitable even under symmetric operations of two boost cells. In this brief, three-level switching capability of TLB PFC is introduced and asymmetric on-time feedforward for main switches is proposed. The proposed UVBFF can be realized by a single equation and harmonized with conventional feedback voltage-loop so that easy implementation is the key merit. The effectiveness of UVBFF is proven by analyses and experimental results.

Extended Range Bridgeless PFC Converter With High-Voltage DC Bus and Small Inductor

Utility power lines voltage levels vary in different geographical locations, ranging from 208 to 480 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> . Power factor correction (PFC) converters are typically designed for a particular input voltage and do not accept a wide range of line voltages. This results in multiple product designs and revisions and increased production costs to accommodate the various ac voltage levels used around the world. A PFC converter capable of coping with a wide input voltage range, from 90 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> up to 530 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> , would significantly decrease costs and streamline development. In this article, an extended input voltage range PFC converter is proposed, which provides a high and almost flat efficiency curve throughout the entire operating voltage range with an 800 VDC bus voltage. The proposed converter has a flexible bridgeless structure with simple control, low-current ripples, low common mode noise, and startup inrush current handling capabilities. Theoretical analysis and waveforms are discussed and experimental results for a 2-kW prototype are given, thereby validating the expected behavior. The operation of the proposed extended input voltage range PFC converter is also compared to the traditional totem-pole PFC showing more than 1% efficiency improvements at full load and a higher power factor in the proposed design.

Analysis of Sector Update Delay and Its Effect on Digital Control Three-Phase Six-Switch Buck PFC Converters With Wide AC Input Frequency

In this article, the sector update delay (SUD) of the digital control three-phase six-switch (3 ph–6 s) buck power factor correction (PFC) converter is analyzed. SUD of 3 ph–6 s buck PFC converter results in the increase of switching loss and input current distortion at the transition from even sector to odd sector. For applications when ac input frequency is 47–63 Hz, the effect of SUD is relatively small, and SUD is usually ignored. However, for applications of high ac input frequency, e.g., 360–800 Hz, the SUD of 3 ph–6 s buck PFC converter seriously affects its efficiency and input current total harmonics distortion (THD). In order to suppress the effect of SUD and to improve the input current THD and efficiency of 3 ph–6 s buck PFC converter over a wide ac input frequency, a time delay compensation method has been proposed in this article. The effect of SUD is verified by a 1.5-kW prototype with a low-cost microcontroller. Experimental results show that lower input current THD and higher efficiency over a wide ac input frequency have been achieved by the proposed compensation method.

A Computationally Simple Predictive CCM Average Current Controller With Nearly Zero Tracking Error for Boost PFC Converter

Predictive current controllers offer superior control action in power factor correction (PFC) converters, however, cause tracking error in the average inductor current due to the unmodeled circuit parameters and variations which could lead to higher harmonic currents, higher input current THD and impact on the output voltage. Attempts to make the predictive current control equations accurate leads to increased computational complexity, thus limiting the switching frequency of operation or increasing the processing requirements. This article proposes a computationally simple predictive continuous conduction mode average current controller based on the concept of moving averages for the boost PFC converter and achieves nearly zero tracking error in the average inductor current. Additionally, a predictive current controller is derived for performance comparison by considering the effect of major converter nonidealities and digital implementation aspects. The performance of the proposed predictive current controller is compared with that of a PI current controller, an ideal predictive current controller and the derived predictive current controller with nonidealities included. Experimental studies on a boost PFC converter hardware prototype validate the effectiveness of the proposed predictive current controller.

Soft-Switching Bridgeless Buck–Boost PFC Converter Using Single Magnetic Core

In this article, a new bridgeless single-phase buck-boost power factor correction (PFC) converter with one magnetic core is introduced. The proposed converter is designed to operate in discontinuous capacitor voltage mode (DCVM) to achieve low total harmonic distortion (THD) and continuous input current with a simple structure. The DCVM operation gives additional advantages, such as inherent PFC, low turn-off losses, and reduced complexity of the control circuitry. Unlike the buck converter, the proposed converter eliminates the dead angle of input current without adding any extra circuits. Also, by eliminating two input diodes in power flowing path, the efficiency is further improved. Due to achieved almost zero current switching at the turn-on and almost zero voltage switching at the turn-off, the switching losses are eliminated. In this article, theoretical analysis and principal operation of the converter are discussed. An experimental prototype is implemented to verify the performance of the proposed converter. Experimental results are presented for a 120-W prototype at 110-V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> input and 48-V output.

Singular Perturbation Method for Boundary Value and Optimal Problems to Power Factor Correction Converter Application

A linear discrete stable control system is considered. The Power Factor Correction (PFC) converter to allow independent control of current and voltage. It converter are fast and slow states to inheres sty present small parameters inductor and capacitor its computes stiffness and to include switching ripple effects. As an alternative a Singular Perturbation Method (SPM) is presented Boundary Value Problem (BVP) and Optimal Problem. It is applied to two state switching power converters to provide rigorous justification of\ the time scale separation. It is modeled as a one parameter singularly perturbed system. SPM consists of an outer series solution and one boundary layer correction (BLC) solution. A boundary layer correction is required to recover the initial conditions lost in the process of degeneration and to improve the solution. SPM is carried out up to second-order approximate solution for the PFC converter model for BVP and optimal control problems. The results are compared with the exact solution (between with and without parameters). The results substantiate the application.

New Bridgeless Power Factor Correction Converter With Simple Gate Driving Circuit and High Efficiency for Server Power Applications

A bidirectional-switch bridgeless power factor correction (PFC) converter (BBPFC) is a fascinating topology for high-power application among various bridgeless PFC (BPFC) converters due to its simple structure and easy control method despite using a floating gate driver. In addition, by varying reverse recovery characteristics of rectifying diodes placed on the conduction path, it is possible to improve common-mode (CM) noise characteristics without additional line filter. However, the BBPFC is difficult to actually use in server power supply product because of high guarantee payment. Thus, in this article, a new BPFC for high efficiency and simple structure without any patent issues is proposed. Moreover, it can be simply implemented since the proposed converter does not require floating gate driver but use a simple bootstrap circuit. Furthermore, in both positive and negative cycles, the proposed converter can have lower power loss characteristics due to utilization of one switch for build-up operation. The proposed converter also uses the relative reverse recovery characteristics resulting in good CM noise characteristics. Thus, the proposed converter can obtain high efficiency and good CM noise characteristics with simple structure and easier control method. The effectiveness of the proposed converter is verified by a prototype in universal input and 800-W/400-V output.

Research on a Bridgeless Interleaved PFC Boost Converter with Voltage Doubler Feature

A current-fed bridgeless interleaved power factor correction rectifier with voltage-doubler characteristic is proposed for a hybrid electric vehicle charging system. The simulated efficiencies, Total current Harmonics current Distortion (THDi), and Power Factor (PF) for the bridgeless interleaved Power Factor Correction (PFC) converter are presented in this paper. The differences of the simulated THD and PF between the proposed PFC boost converter and the conventional interleaved PFC boost converter are significant. The simulation results included a prototype boost converter converting universal AC input voltage 85–264 V to 400 V DC output at up to 3.4 kW load. The simulation results also demonstrate a power factor greater than 0.99 from a universal AC-line input 85–264 Vrms; THD <10% from a universal AC-line input 85–264 Vrms. The proposed converter achieved an average efficiency of 97% at 70 kHz switching frequency, 264 V input, and 0.5–3.4 kW output power. The proposed interleaved boost PFC rectifier exhibits an improved low-line efficiency compared with that of its conventional counterpart under 1.5 kW output power.

Interleaved Isolated Single-Phase PFC Converter Module for Three-Phase EV Charger

This paper presents an interleaved isolated power factor correction (PFC) converter module for three-phase electric vehicle (EV) chargers requiring for wide output voltage ranges. The proposed circuit is comprised of two half-bridge (HB) voltage-fed isolated PFC converters with parallel-input-series -output structure, which is operated in interleaved discontinuous conduction mode (DCM). Due to zero-voltage and zero-current switching (ZV-ZVS) characteristics in the primary side, it is possible to operate IGBTs at a high frequency with several tens of kHz. Also, the voltage ratings of secondary devices can be reduced so that switching devices with low turn-off losses such as MOSFETs are available. The proposed converter has only single voltage loop and the harmonic regulation is accomplished by feed-forward compensation. The feasibility of the proposed PFC module has been verified with a 5 kW prototype.