Power Factor Correction Circuit Research Articles

Versatile Control of Unidirectional AC–DC Boost Converters for Power Quality Mitigation

This paper introduces a versatile control scheme for unidirectional ac–dc boost converters for the purpose of mitigating grid power quality. Since most power factor correction circuits available in the commercial market utilize unidirectional ac–dc boost converter topologies, this is an almost no-cost solution for compensating harmonic current and reactive power in residential applications. Harmonic current and reactive power compensation methods in the unidirectional ac–dc boost converter are investigated. The additional focus of this paper is to quantify the input current distortions by the unidirectional ac–dc boost converter used for supplying not only active power to the load but also reactive power. Due to input current distortions, the amount of reactive power injected from an individual converter to the grid should be restricted. Experimental results are presented to validate the effectiveness of the proposed control method.

A Novel Control Algorithm for Conversion ofAC-DC with Improved Power Factor andEfficiency

A Single power-conversion ac–dc converter with high power factor and high efficiency. The proposed converter is derived by integrating a full-bridge diode rectifier and a series-resonant active-clamp dc–dc converter. To obtain a high power factor without a power factor correction circuit, this paper proposes a novel control algorithm. The proposed converter provides single power-conversion by using the novel control algorithm for both power factor correction and output control. Also, the active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. Moreover, it provides zero-voltage turn-on switching of the switches. Also, a series-resonant circuit of the output-voltage doubler removes the reverse-recovery problem of the output diodes. The proposed converter provides maximum power factor 0.995 and maximum efficiency of 95.1% at the full load.

Direct Power Control of a Three-Phase Inverter for Grid Input Current Shaping of a Single-Phase Diode Rectifier With a Small DC-Link Capacitor

This paper describes motor drive system fed by a single-phase diode rectifier without power factor correction (PFC) circuit or the input filter. The system considered in this paper consists of a single-phase diode rectifier, a three-phase inverter, and a small dc-link capacitor. Since dc-link capacitance of the proposed system is few microfarads, the shape of the grid input current is directly affected by electrical output power of the inverter. Using this aspect, two goals of the drive system, controlling torque of the motor and suppressing the grid input current harmonics, can be simultaneously achieved by controlling the output power of the inverter. The proposed method includes the motor current reference generation and the direct output power regulation by modifying the output voltage reference. With the proposed method, the harmonic components of the grid input current can be reduced under the limits of the regulation IEC61000-3-2, lower than those in the conventional method. Also, the cost and size of the inverter system can be significantly reduced by removing electrolytic dc-link capacitor and input filter from the system. The performance of the proposed shaping method was validated by the experimental results using the motor drive system with a 5μF film capacitor at dc link.

GaN FET을 이용한 토템폴 구조의 브리지리스 부스트 PFC 컨버터

The superiority of gallium nitride FET (GaN FET) over silicon MOSFET is examined in this paper. One of the outstanding features of GaN FET is low reverse-recovery charge, which enables continuous conduction mode operation of totem-pole bridgeless boost power factor correction (PFC) circuit. Among many bridgeless topologies, totem-pole bridgeless shows high efficiency and low conducted electromagnetic interference performance, with low cost and simple control scheme. The operation principle, control scheme, and circuit implementation of the proposed topology are provided. The converter is driven in two-module interleaved topology to operate at a power level of 5.5 kW, whereas phase-shedding control is adopted for light load efficiency improvement. Negative bias circuit is used in gate drivers to avoid the shoot-through induced by high speed switching. The superiority of GaN FET is verified by constructing a 5.5 kW prototype of two-module interleaved totem-pole bridgeless boost PFC converter. The experiment results show the highest efficiency of 98.7% at 1.6 kW load and an efficiency of 97.7% at the rated load.

A Modified Bridgeless Converter for SRM Drive with Reduced Ripple Current

<p>Single Phase Switched Reluctance Motor is more popular in many industrial purposes for high speed applications because of its robust and rugged construction. For low cost and variable speed drive applications SRM are widely used.Due to doubly salient structure of motor, the torque pulsations are high when compared to other sinusoidal machines. The major drawback in using SRM drive is torque pulsations and increased number of switching components. In order to overcome these drawbacks, a bridgeless Single Ended Primary Inductor Converter (SEPIC) is proposed. The major advantages of this converter are continuous output current,smaller voltage ripple and reduced semiconductor current stress when compared to the conventional SEPIC converter. The ripple free input current is obtained by using additional winding of input inductor and auxiliary capacitors. To achieve high efficiency, active power factor correction circuits (PFC) are employed to precise the power factor. Further, the unity power factor can be obtained by making the input current during switching period proportional to the input voltage is proposed. The proposed system consists of reduced components and it is also capable of reducing the conduction losses. The working principles and the waveforms of proposed converter are analyzed. To analyze the circuit operation, theoretical analysis and simulation results are provided. Finally, the comparison between the waveforms of conventional SEPIC and proposed system is presented by using MATLAB/Simulink tools.</p>

A Single-Stage DC Uninterruptible Power Supply

A single-stage DC uninterruptible power supply (UPS) is proposed in this paper. Basically, the proposed converter is an integration result of a power factor correction circuit with a dc-to-dc converter to achieve simple hardware circuit, high efficiency, and low cost for extra UPS function. Under normal operation, a novel two-switch SEPIC converter operates as an ac to dc converter with sinusoidal input current, unity power factor, and low ripple dc output voltage, and as a battery charger if a battery is added. Since both the input boost supply and the output supply can be controlled independently, a fast transient response can be maintained at both the input for active current wave shaping and at the output for good output regulation. When the ac source is in an outage condition, the proposed converter functions as a dc-to-dc buck-boost converter; therefore, the desired dc output voltage can be provided. Finally, some experimental results are presented for verification.

Design of an LLC Resonant Converter for Driving Multiple LED Lights Using Current Balancing of Capacitor and Transformer

In this study, to achieve the constant current drive and brightness control without a separate pulse width modulation (PWM) converter, a single converter is designed and verified by experiment under the condition of a multiple LED light load with different output voltage (Vf) characteristics. In the case of the input of 140 Watt class level, the proposed converter can drive two voltage type 95 Vdc (300 mA) light emitting diode (LED) lights loads and 120 Vdc (300 mA) LED lights loads simultaneously. In addition, to improve commercial compatibility, the proposed converter is operated in a wide range of the input voltage 90~264 Vac; also, the Power Factor Correction (PFC) circuit with the input power factor of more than 0.9 is added. In order to maximize the power conversion efficiency, a LLC resonant converter is applied to the PFC block with the output voltage of 380 Vdc and to a DC-DC conversion block. Finally, reliability of the proposed converter is verified through total harmonic distortion (THD) and electromagnetic interference (EMI) tests.

A Single-Phase AC/DC Conversion Circuit with APFC

This system uses the MSP430F6638 and FPGA as the core, includes full bridge rectifier circuit, power factor correction circuit, Boost/Buck circuit and sample circuit. According to the sampling voltage and current value, The FPGA adjusts PWM wave duty ratio of power factor correction chip UC3854, completing single phase AC/DC conversion circuit with a voltage outer closed-loop and current inner closed-loop and active power factor correction (APFC). Test shows that the output voltage can stable in a setting value, with amplitude range ±0.05V, and when load’s impedance changes, this circuit can keep a small voltage adjustment rate and load adjustment rate. We use electronic parameter measurement device to measure the efficiency of AC/DC converter in a specified condition (voltage input Us=24V, current output Io=2A, voltage output Uo=36V), result demonstrates it’s a relatively ideal value. At the same time, under the control of UC3854, the power factor of alternating current input is 0.9734.And when we set the range of power factor between 0.8~1.0, The circuit can automatically adjust the power factor to track the set value.

Comparative Study of Open Loop and Closed Loop of Three Phase Active Power Factor Correction Based Buck Converter

Here with rapid growth in semi conducting devices the power loss is reduced and efficiency is increased.In this paper a open loop and closed loop of new three phase single switch active power factor correction (APFC)circuit based on quadratic (square)buck converter is proposed and analysed, through which we get extensive step down ratio and high power factor.The single-switch, quadratic step down dc-dc buck converter that can operate with input active power factor correction in both open loop and closed loop.Finally, this three-phase single switch quadratic buck APFC circuit was simulated using MATLAB/Simulink software. This result show that the power factor is high to 0.976 & 0.999 in open loop and closed loop circuit and the total harmonic distortion (THD) is low to 3% of the APFC converter. Comparative study of open loop and closed loop system of three phase single switch base on quadratic buck converter is showed & Simulations and experimental results are given to verify the converter characteristics.

Analysis and Design of a High-Frequency Isolated Dual-Tank LCL Resonant AC-DC Converter

An integrated single-phase single-stage high-frequency transformer isolated dual-tank LCL-type series resonant ac-dc converter with fixed-frequency phase-shift control strategy is presented. The circuit configuration combines a diode rectifier, a boost converter, and two identical half-bridge dc-dc LCL resonant converters. A high power factor and a low total harmonic distortion are achieved by discontinuous current mode operation of the front-end power factor correction circuit. The output voltage is regulated by the fixed-frequency phase-shift between two identical half-bridge LCL resonant converters. Soft-switching operation is achieved for all of the switches. The operation of intervals and steady-state analysis are presented briefly. A design example of a 100-W proposed converter is given, together with its simulated and experimental results for different input voltages.

Generalized Technique of Compensating Low-Frequency Component of Load Current With a Parallel Bidirectional DC/DC Converter

The first stage of a battery charger in electric vehicles is a power factor correction (PFC) circuit, which creates a second harmonic in the dc link. This harmonic is typically filtered through a bulky dc-link capacitor. In the conventional battery chargers, another dc/dc stage is utilized to regulate the battery current. In this paper, the second harmonic in the dc link is analyzed in detail and a new load current compensation technique is proposed. The proposed technique replaces the second stage dc/dc converter with a bidirectional dc/dc converter connected in parallel with the load, and requires a secondary energy source, i.e., a small-size capacitor. The capacitor injects 180° phase-shifted second harmonic current to the dc link. Thus, the dc-link capacitor can be reduced significantly as it is only sized for high-frequency ripples rather than being sized for low-frequency content. The proposed method is generalized for resistive and battery loads with voltage- and current-source PFC circuits. A 360 W prototype is developed to experimentally verify the proposed technique. A 72 V/10 A·h battery module is charged by filtering an oscillating power of 360 W using a two-quadrant bidirectional dc/dc converter and an UC module, demonstrating a peak charging current of 16 A.

Design and Implementation of a High Power Dual-module Parallel Charging System

This paper presents a high-power dual-module parallel charging system which consists of a power converter and digital control software. The power converter consists of an active power factor correction (APFC) circuit and a resonant voltage fed full-bridge converter (RVFFBC). The APFC circuit is used for AC/ DC conversion and power factor correction for improved power quality. The RVFFBC is used to provide stable power for charging the battery by converting the high voltage of the power stage to a lower value. The system software was designed by combining the power control loop into a voltage and current loop to achieve current sharing of the dual-module charging system and to overcome the effect of differences in hardware components. Finally, this paper demonstrates the implementation of a high-power dual-module charging system with a widely varying AC input voltage ranging from 85 ~ 265 Vac. Experimental results verified that the maximum power factor of the system and the Total Harmonic Distortion (THD) were 0.99 and 2.8% respectively. The proposed charging system possesses very high expansibility. The parallel dual-module output DC current of the system is 70 A and the total output power is 4 kW.

A Low-Distortion Self-Oscillating Power Factor Correction Circuit for Low-Cost Applications

Self-oscillating converters operating in the critical conduction mode are popular in low power applications because of their simplicity and low cost. However, these converters are not suited for Power Factor Correction (PFC) because the peak switch current is controlled to regulate the output voltage and does not follow the shape of the line voltage waveform. A new control circuit implementation is proposed for a self-oscillating boost converter to achieve power factor correction. A full featured design example is provided which can be simplified for use in various cost sensitive applications such as electronic lighting, etc. This wide input voltage range self-oscillating PFC prototype achieves less than 10 percent line current distortion in the defined load range (10 W to 40 W).

High-voltage AlGaN/GaN Schottky barrier diodes on silicon using a post-process O2 treatment

High-voltage AlGaN/GaN Schottky barrier diodes (SBDs) were fabricated using on a silicon (111) substrate, and a post-process O2 treatment was carried out to reduce the leakage current and increase the breakdown voltage. Time-of-flight secondary ion mass spectroscopy revealed that, following the post-process O2 treatment, oxygen diffused into an AlGaN barrier and AlO was generated. A significant suppression of the leakage current (of approximately 6 orders of magnitude) occurred in the buffer isolation structures following the O2 treatment. Our method also resulted in suppression of the surface leakage current through the mesa-etched surface. A virgin GaN SBD exhibited a leakage current of 1.76×10−2A/cm2, whereas the equivalent O2-treated device had a leakage current of 1.75×10−4A/cm2 (the anode–cathode distance was LAC=10μm, and the applied bias was −100V). This reduction in the leakage current was caused by surface passivation at the anode and cathode. The post-process O2 treatment also increased the breakdown voltage from Vb=808V to Vb=1590V for a device with LAC=10μm. GaN SBDs with and without the post-process O2 treatment exhibited low specific on-resistance of Ron,sp=2.51mΩcm2 and Ron,sp=2.48mΩcm2, respectively, with LAC=10μm. Devices with the post-process O2 treatment exhibited a figure of merit of Vb2/Ron,sp=1006MW/cm2, whereas devices without the O2 treatment exhibited a figure of merit of Vb2/Ron,sp=263MW/cm2. These high-voltage GaN SBDs employing the post-process O2 treatment are suitable for applications including DC–DC converters, inverters, and power factor correction circuits, where high voltage operation is required with low leakage currents.

Shunt semi‐active power factor correction circuit for permanent magnet synchronous motor driver

This study developed a shunt-based, semi-active power factor correction (PFC) circuit for a sensor-less speed controller applicable in permanent magnet synchronous motors (PMSM). The objective of this novel approach is to increase the PF of the control circuit in order to improve the effectiveness of controlling the speed of the motor. The proposed circuit includes two parallel rectifiers capable of providing good PFC while maintaining simplicity. This study discusses the relevant theories, introduces the components and provides a simulation of the system. Experimental results, involving a sensor-less PMSM rotary compressor for an air conditioning unit, demonstrate the efficacy of the proposed device over a wide range of speeds and duty times. The performance was further compared with two other circuits, the results of which prove that this system accomplished the objectives of the study.

Improved Bridgeless Interleaved Boost PFC Rectifier with Optimized Magnetic Utilization and Reduced Sensing Noise

An improved bridgeless interleaved boost power factor correction (PFC) rectifier to improve power efficiency and component utilization is proposed in this study. With combined conventional bridgeless PFC circuit and interleaved technology, the proposed rectifier consists of two interleaved and magnetic inter-coupling boost bridgeless converter cells. Each cell operates alternatively in the critical conduction mode, which can achieve the soft-switching characteristics of the switches and increase power capacity. Auxiliary blocking diodes are employed to eliminate undesired circulating loops and reduce current-sensing noise, which are among the serious drawbacks of a dual-boost PFC rectifier. Magnetic component utilization is improved by symmetrically coupling two inductors on a unique core, which can achieve independence from each other based on the auxiliary diodes. Through the interleaved approach, each switch can operate in the whole line cycle. A simple control scheme is employed in the circuit by using a conventional interleaved controller. The operation principle and theoretical analysis of the converter are presented. A 600 W experimental prototype is built to verify the theoretical analysis and feasibility of the proposed rectifier. System efficiency reaches 97.3% with low total harmonic distortion at full load.

Single Power-Conversion AC--DC Converter With High Power Factor and High Efficiency

This paper proposes a single power-conversion ac-dc converter with high power factor and high efficiency. The proposed converter is derived by integrating a full-bridge diode rectifier and a series-resonant active-clamp dc-dc converter. To obtain a high power factor without a power factor correction circuit, this paper proposes a novel control algorithm. The proposed converter provides single power-conversion by using the novel control algorithm for both power factor correction and output control. Also, the active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. Moreover, it provides zero-voltage turn-on switching of the switches. Also, a series-resonant circuit of the output-voltage doubler removes the reverse-recovery problem of the output diodes. The proposed converter provides maximum power factor 0.995 and maximum efficiency of 95.1% at the full load. The operation principle of the converter is analyzed and verified. Experimental results for a 400 W ac-dc converter at a constant switching frequency of 50 kHz are obtained to show the performance of the proposed converter.

역률보상회로를 이용한 이동통신 중계기의 에너지 절감에 관한 연구

역률보상회로를 이용한 이동통신 중계기의 에너지 절감에 관한 연구

Study and design of a novel three‐phase bridgeless boost power factor correction

A novel three-phase bridgeless boost power factor correction (PFC) circuit is studied and designed. First, the operating principle of the three-phase bridgeless boost PFC is analysed. Then, the simulation model of the three-phase bridgeless boost PFC based on the average current control is given. Finally, the simulations are conducted to demonstrate the validity and feasibility of the theoretical analysis. The simulation results show that the proposed system could realise high input power factor, low input current harmonic and low output voltage ripple, and the experimental results show it is effective and feasible in three-phase circle.

Effect of Maximum Voltage Angle on Three-Level Single Phase Transformerless Photovoltaic Inverter Performance

This paper presented a new topology of three-level single phase transformerless photovoltaic inverter (TPVI). It consisted of three main circuits; they were a pulse driver circuit, a full bridge inverter circuit and a power factor correction (PFC) circuit that had functions as production of pulse waves, to develop alternating current (AC) waveform and to stabilize voltage of photovoltaic (PV) array, respectively. In this research, AC three-level waveform single phase TPVI was developed and created by a microcontroller PIC16F627A-I/P with varied maximum voltage angle from 20 0 to 180 0 and observed on 28 th February 2014 between 9.00 am to 17.00 pm, and also analyzed effect of maximum voltage angle on the three-level single phase TPVI performance. The result showed that maximum voltage angles of the TPVI effected on root mean square value of AC voltage, current and power. If the maximum voltage angle was increased, therefore value of the AC voltage, current and power would increase. The maximum voltage angle would effect on the current total harmonic distortion (CTHD), the lowest CTHD of 15.448% was obtained when the maximum voltage angle was 134 0