Period-doubling bifurcation in two-stage power factor correction converters using the method of incremental harmonic balance and Floquet theory

In this paper, period-doubling bifurcation in a two-stage power factor correction converter is analyzed by using the method of incremental harmonic balance （IHB） and Floquet theory. A two-stage power factor correction converter typically employs a cascade configuration of a pre-regulator boost power factor correction converter with average current mode control to achieve a near unity power factor and a tightly regulated post-regulator DC-DC Buck converter with voltage feedback control to regulate the output voltage. Based on the assumption that the tightly regulated postregulator DC-DC Buck converter is represented as a constant power sink and some other assumptions, the simplified model of the two-stage power factor correction converter is derived and its approximate periodic solution is calculated by the method of IHB. And then, the stability of the system is investigated by using Floquet theory and the stable boundaries are presented on the selected parameter spaces. Finally, some experimental results are given to confirm the effectiveness of the theoretical analysis.

A new high-performance AC/DC power factor correction switching converter based on one-cycle control technology and active floating-charge technology

A new family of converters,high-performance AC/DC power factor correction(PFC) switching converters with one-cycle control technology and active floating-charge technology,was derived and experimentally verified.The topology of a single-phase CCM and DCM Boost-PFC switching converter was also analyzed.Its operating prniciples and control methods were expounded.Based on these,a new type of AC/DC switching converter circuits for PFC combined with one-cycle control technology was presented herein.The proposed AC/DC switching converter significantly helps improve the converter efficiency and its power factor value.

Performance Evaluation of a Permanent Magnet Electric-Drive- Reconfigured Onboard Charger with Active Power Factor Correction

This paper presents a comprehensive charging operation for an electric-drive-reconfigured onboard charger(EDROC)with active power factor correction(APFC).The charging topology exclusively utilizes the three-phase permanent magnet synchronous motor(PMSM)propulsion system as a three-channel boost-type converter in which only a contactor and a small diode bridge are added.First,the operation scenario of the EDROC is introduced.Second,the relationship between electromagnetic torque and rotor position is investigated.Third,the current ripple cancellation of the EDROC is discussed in detail.Moreover,to implement the single-phase APFC along with charging voltage/current regulation of propulsion battery,control strategies including current balancing and synchronous/interleaving PWM strategies are incorporated.Finally,200W proof-of-concept prototype-based tests are conducted under different operation scenarios.

Single-stage active clamp power factor correction AC/DC converter

A simple single-stage AC/DC converter circuit with active clamp is presented. The operation theory and state are analyzed. The experimental results show that the voltage across main switch can be clamped to a certain value,and zero voltage switching (ZVS) can be achieved. The voltage stress and switching loss are both decreased. In range of the whole load,power factors can be always more than 97%,and the highest efficiency can reach 88%.

New DCM Operated Single Phase Bridgeless Cuk Derived Converters for Power Factor Correction

This paper presents a power factor corrected (PFC) new bridgeless (BL) Cuk Topologies for low power applications. A BL configuration of Cuk converter is proposed which eliminates the usage of diode bridge rectifier at the front end of the PFC converter, thus reducing the switching and conduction losses coupled with it. This new BL Cuk converter has two semiconductors switches. The current flow during each switching cycle interval of the converter reduces the conduction losses compared to the conventional Cuk PFC converter. It also reduces the input current ripple and Electromagnetic Interference (EMI). The inrush current during the starting period is limited and the input, output currents of the converter are continuous with minimum current ripple. Hence it is preferred mostly compared to other PFC circuits. The proposed topology works in the Discontinuous Conduction Mode (DCM) with simple control circuitry to achieve almost a unity power factor with less distortion in the input AC current. The switching of the power switches is done under zero current. The proposed PFC topologies are theoretically investigated and performance comparisons are made with the conventional rectifiers. The proposed PFC converter is simulated in MATLAB/SIMULINK with Fuzzy Logic Controller (FLC) and results are demonstrated to evaluate the effectiveness of the controller.

A novel arc welding inverter with unit power factor based on DSP control

A novel inverter power source is developed characterized with constant output current and unit power factor input. Digital signal processor （ DSP ） is used to realize power factor correction and control of back-stage inverter bridge of the arc welding inverter. The fore-stage adopts double closed loop proportion and integration （PI） rectifier technique and the back- stage adopts digital pulse width modulation （ PWM） technique. Simulated waves can be obtained in Matlab/Simulink and validated by experiments. Experiments of the prototype showed that the total harmonic distortion （THD） can be controlled within 10% and the power factor is approximate to 1.

Intelligent power factor compensation equipment of three phase low voltage loads

An intelligent power factor correction scheme is presented for three phase low power factor loads. This new scheme is able to perform individual phase sensing of parameters by monitoring at all times to sense a change in system parameters and affects individual phase correction by applying the exact amount of reactive components needed for each phase, and can also reduce negative sequence current caused by the load to improve system balance. An optimization criterion is used for the proper calculation of reactive power steps in a power compensation installation of capacitor banks. The criterion is enabled by sampling measurements performed on the electrical plant examined within specific interval of time.

Isolated single stage high power factor AC/DC converter

The problem of harmonic pollution has brought wide attention with the increase of power customers. The adoption of the technology of active power factor correction (APFC) with advanced high frequency power converter is a more efficient solution to the problem of harmonic pollution. A single stage isolated high power factor AC/DC converter, which features wide range DC output, high power factor, lower harmonic pollution in input current, and phase shift PWM full bridge circuit can achieve soft switching. The principle of the circuit topology and the reasons of voltage surges across the power switch are analyzed. Experiment results illustrate that this circuit has the advantages of high power factor and lower harmonic distortion.

Fault Diagnosis and Phase Disposition Reconfiguration of a 5-Level Double-Boost Power Factor Corrector with Fault-Tolerant Capability

A 5-level PFC （power factor correction） topology with fault-diagnostic and fault-tolerant capability is proposed and compared to known structures. It is derived from a 3-level non differential double-boost PFC including fly-cap cells. The series-connection of the two low-voltage switching-cells is decoupled by a single flying capacitor that provides a direct fault-tolerant capability and a post-failure operation increasing the availability of converter. The monitoring of the voltages across flying capacitors allows a rapid detection and localization either for open circuit failure or short-circuits failure. A PWM （pulse width modulation） phase-disposition type reconfiguration is also used and presented in order to optimize both normal operation and post-fault continuation. The design and the most important features are highlighted thanks to a digital control frame and a mock-up rated to： AC voltage network 115 V-load 400 V-nominal power 4 kW-switching frequency 62 kHz.

A New Zero-Voltage Transition Power Factor Corrected Single-Phase Single-Stage AC-to-DC Converter

This paper presents a new ZVT （zero-voltage transition） single-stage ac-to-dc converter using PWM （pulse width modulation） and HF （high frequency） transformer isolation with capacitive output filter. In this converter a front-end power factor corrected boost stage integrates with a cascaded dc-to-dc bridge HF converter. The front-end boost converter operates in discontinuous current mode and ensures natural power factor correction with very simple control. The auxiliary circuit of this topology deals with very small power and is placed out of the main power path. As a result, the auxiliary circuit components have smaller power rating as opposed to main converter components. Also, output rectifier voltage is clamped to output voltage due to capacitive output filter. Identification and analyses of different operating modes of this converter are presented. Based on these analyses design example of a 50 kHz, 48 V, 1 kW ac-to-dc converter is presented. PSPICE simulation results of the designed converter are presented and explained to verify the performance of this converter.

A RESEARCH TO HIGH-PERFORMANCE MULTI-LEVEL SINGLE-PHASE AC/DC POWER FACTOR CORRECT SWITCHING CONVERTER

This letter studies and analyzes the working features of main circuit of tri-level boost Power Factor Correct(PFC) converter and the advantages of tri-level switch converter in aspects of bearing high-voltage of power components,overall system loss and magnetic component selection based upon the single-level boost PFC switch converter.Besides,relying on the application of mi-croprocessor in power converter technology and DSP(Digital Signal Processing) chip's strong cal-culating capacity,the letter presents the adoption of modified scheme of tri-level boost PFC converter under the control of predictive control algorithm.Moreover,the operating principle and control method are specified,the results of circuit test and analysis are provided and the advantages of pre-dictive control technology-based multi-level boost PFC converter is verified.

An Investigation of Power Converters Fed BLDC Motor for Adjustable Speed

This paper reports the converter topologies which are employed for better Power Factor Correction at the input side. The Power Factor Correction is an important factor when considering the Power Quality. Based on the converter topologies, the Bridgeless converters are preferred in order to reduce the number of switching devices, losses associated with it and improve the Power Quality further more. This paper investigates about the Power Factor performances and conduction losses of the Bridgeless Power Factor Corrector Converters which see through the benefits and limitations by analyzing the Bridgeless Buck-Boost Converter, Bridgeless SEPIC converter and Bridgeless CUK converter. The resultant voltage is fed to the BLDC motor which is rapidly replacing the Induction motor for its better operating characteristics. These strategies are being analyzed using the MATLAB/Simulink software and the results are verified through the experimental analysis. The converter choice is preferred through the performance characteristics and Power Factor Correction at the supply. The Power Factor obtained should be within the acceptable limits under IEC 61000-3-2 standards.

Optimisation of Electrical Distribution System by Using Solar Thermal Powered Systems and Its Impact on Electrical Distribution Feeders

In this research, the performance of the solar thermal powered systems (STPS) is analyzed with different models (without inserts, with inserts and with Nano fluids with different concentrations) and its impact on the Electric load in a residential/Institutional Electrical Distribution system. For this purpose, the electrical and solar thermal water heater is tested and validated. Solar thermal powered systems and its impact on the Institutional electrical distribution feeders are tested and compared with the energy efficiency (EE) and cost optimization. The goal of this paper is to analyze the impact of solar thermal energy on electrical energy consumption in the electrical distribution feeder level. The electrical system cost and energy consumptions are tabulated and observed that there is a considerable savings.

High Power Density Three-Level Three-Phase AC-DC 48 V Power Supply

International standards impose several constraints concerning the electric power quality and require that the harmonic content of the line current of grid connected equipment is below assigned limits; for this reason, operating of AC-DC converters with high power factor and low line current distortion has become essential. In this paper, the prototypal realization of a three-phase AC-DC 48 V power electronic converter for telecom system supplying is described and experimental testing results are discussed. The main constraints in the power supply design are the required power density of about 900 W per dm3 as well as the absence of the neutral wire in the supply grid. The carried out investigation is focused on three-level power converter configurations which are considered in order to reduce voltage rating of power switches. As a result of the reduced voltage, low on-resistance metal-oxide-semiconductor field effect transistors can be used in the power stage, solution which allows to achieve improved efficiency as well as increased switching frequency with respect to the insulated gate bipolar transistors based two-level topologies.

Digitally Controlled Boost PFC Converters Operating with Large Scale Load Fluctuations

When boost power factor correction(PFC) circuit works with large scale load fluctuations, it is easy to cause a higher total harmonic distortion and a lower power factor because of traditional controllers and inductor current mode. To solve this problem, this paper proposes a PFC control system, which can operate with load fluctuations up to 1 000 W by using duty cycle feed-forward control theory to achieve smooth switching mode. The duty cycles in the next period of the control system are pre-estimated in the current cycle, which enhances the speeds of AD samplers and switching frequency, and reduces the cost and volume of the equipment to some extent. Introductions of system decoupling and feed-forward of input-voltage greatly improve the system performance. Both theoretical simulation and experimental results prove the advantage of the proposed scheme.

Implementation strategy for soft switching PFC with low output voltage

This paper proposes a novel implementation strategy for soft switching PFC whose circuit is simple and can achieve low voltage output directly. The main circuit adopts current mode full-bridge converter and all the power switches can realize ZCS or ZVS in the way of phase-shlfted control, using the leakage inductance of the transformer, the junction capacitor of the switches and the stored energy of the output capacitor. The problems such as the function of phase-shlfted link in control circuit, the implementation conditions of soft switching and bias restrained are analyzed. The adoption of constant frequency PWM control makes the design of the input and output filter link and the high frequency transformer simple. The transformation ratio regulation so as to achieve low voltage output and electrical insulation can be realized by using high frequency transformer.

Average modeling of Single Stage Flyback PFC ＋ Flyback DC／DC converter

With the use of this novel average model for Single Stage Flyback PFC+Flyback DC/DC converter, voltage control mode, peak current control mode and average current control mode can be simulated easily by changing the model's parameters. It can be used to do various analysis not only for small signal and static behavior but also for large signal and dynamic behavior of the converter. By using this average model the simulation speed can be improved by 2 orders of magnitude above that obtained by using the conventional switched model. It can be applied to optimize the trade\|off between high power factor, voltage stress, current stress and good output performance while designing this kind of single stage PFC converter. A 60W single stage power factor corrector was built to verify the proposed model. The modeling principle can be applied to other Single Stage PFC topologies.

DC boost converter with buck buffer

For a conventional high-power active power factor correction(APFC)boost converter,its output capacitor needs to be precharged,which means that two power switches of the main circuit and the control circuit are needed to be respectively turned on and turned off in a fixed order.After the main circuit switch is turned on,it is necessary to wait for precharging before turning on the control circuit power switch.Once an inadvertent operation is performed,an overcurrent phenomenon from the output capacitor will occur.In this study,the buck circuit is used as the pre-stage snubber circuit,which can directly supply power to the circuit without precharging the output capacitor.As a result,potential safety hazard caused by the overcurrent due to the capacitor and the charging maloperation during the start-up stage can be avoided.Theoretical analysis and simulation experiment show that the DC boost converter with buck buffer can maintain the peak value of the main circuit within the safe range when the device boot does not precharge the output capacitor,and thus the safety and stable operation of the DC boost converter are ensured.

A double closed loop APFC control with feed-forward

In order to improve the steady state performance,dynamic response and power factor of traditional power factor correction(PFC)digital control method and reduce the harmonic distortion of input current,a double closed loop active power factorcorrection(APFC)control method with feed-forward is proposed.Firstly,the small signal model of Boost PFC control systemis built and the system transfer function is deduced,and then the parameters of the main device with Boost topology is estimated.By means of the feed-forward,the system can quickly respond to the change in input voltage.Furthermore,the use ofvoltage loop and current loop can achieve input current and output voltage regulation Simulink modeling shows that this methodcan effectively control the output voltage in case of input voltage largely fluctuating,improve the system dynamic response abilityand input power factor,and reduce the input current harmonic distortion

Efficient Supply Current Control Strategies for Bridgeless Interleaved AC-DC Converter

This paper presents an efficient supply current wave shaping technique for bridgeless interleaved Single Ended Primary Inductor Converter(SEPIC).The SEPIC converter converts an Alternating Current(AC)to Direct Current(DC)with the boost converter.Power Factor Correction(PFC)is progressively significant to achieve high energy efficiency.The overall system efficiency can be increased as the bridgeless topology has less conduction losses from rectifying bridges.Also,the bridgeless and interleaved techniques are incorporated in this study to achieve better performance.The performance of the system is analyzed on both current control and sensor-less techniques.Different controllers such as Proportional Integral(PI)control,peak current control,Non-Linear Carrier(NLC)control,and sensor-less current control are integrated.All the above controllers are implemented using MATrix LABoratory(MATLAB)/SIMULINK.The performance parameter,namely Power Factor(PF),Total Harmonic Distortion(THD),is computed for both open loop and closed loop condition.The sensor-less current control method is implemented using the DsPIC30F2010 controller.The circuit performance is also verified from the simulation and hardware results.The proposed controller has inbuilt Analog-to-Digital Converter(ADC),Digital-to-Analog Converter(DAC),Pulse Width Modulation(PWM)generator,and provides fast responses.