Query: ZCS bridgeless boost PFC rectifier using only two active switches

Candidate papers:

abstract: Existing bridgeless boost (BLB) converter with soft switching utilize more than two active switches and extra resonant networks. In this paper, a new zero current switching BLB rectifier with high power factor (PF) using only two active switches is proposed. The proposed BLB converter is based on a totem pole BLB (TPBLB) configuration, which allows the current to flow from high side to low side and vice versa during resonance. Hence, no auxiliary active switch is needed to provide soft switching for all semiconductor devices. The soft switching also reduces the body diode reverse recovery problem, hence allowing the TPBLB to operate in continuous conduction mode. Standard components are used to prove that the proposed converter is working with an acceptable performance compared with other BLB converters with soft switching. In order to achieve smooth input current waveform, high PF, and wide soft switching operations, a pulsewidth modulation controller is proposed and developed, which combines a conventional PF correction average current mode controller with several logic gates and a phase detector. A detailed analysis of the converter operation and control is presented. Design considerations and parameter values calculations are given. An experimental prototype is developed and tested to verify the converter performance.
author_names: Khairul Safuan Muhammad

Dylan Dah-Chuan Lu
title: ZCS Bridgeless Boost PFC Rectifier Using Only Two Active Switches
venue: IEEE Transactions on Industrial Electronics
year: 2015

abstract: In this paper, a new single phase single stage ZCS PFC boost rectifier with reduced switch count is introduced. The efficiency of the proposed converter is improved by eliminating input stage diode bridge. Moreover, only two active switches are used to permit bi directional current flow from high voltage rail to low voltage rail and vice versa. Hence, no auxiliary switch is needed. A resonant inductor and a capacitor are used to make both switches operate at ZCS turn off and soft turn on. The proposed converter is developed by using totem pole bridgeless boost (TPBLB) converter. Standard components are used to prove that the proposed converter is working with acceptable performance compared to other bridgeless boost converters with soft switching. In addition, a PWM controller is proposed, which combines a conventional average current mode power factor correction (PFC) controller, several logic gates and a phase detector. A detailed analysis of the converter operation and control is supported by simulation results. Finally, a 400 W, 50 kHz experimental prototype is built to verify the theoretical analysis and performance of the proposed converter.
author_names: Khairul Safuan Muhammad

Dylan Dah-Chuan Lu
title: Single phase single stage ZCS boost PFC rectifier with reduced switch count
venue: 2014 Australasian Universities Power Engineering Conference (AUPEC)
year: 2014

abstract: A new bridgeless single phase ac dc converter with a natural power factor correction (PFC) is proposed. Compared with existing single phase bridgeless topologies, the proposed topology has the merits of less component counts. The absence of an input diode bridge and less conduction losses; hence, improved thermal management compared to existing PFC rectifiers is obtained. The proposed topology is designed to work in resonant mode to achieve an automatic PFC close to unity in a simple and effective manner. The resonant mode operation gives additional advantages such as zero current turn on in the active power switches. Keywords Bridgeless AC DC Converters, Power factor correction, Resonant power conversion Zero Current Switching, Total harmonic distortion Pseudo boost converters, Voltage gain INTRODUCTION Power factor correction (PFC) techniques are becoming necessary for many types of electronic equipment especially in the telecommunication and computer industries to meet harmonic regulations. Also, higher power density and lower system cost are always very desirable features, especially for low power supplies. Most of the PFC rectifiers utilize a boost or buck boost topology converter at their front end due to its high power factor (PF) capability. However, a conventional PFC scheme has lower efficiency due to significant losses in the diode bridge. During each switching cycle interval, the current flows through three power semiconductor devices. The forward voltage drop across the bridge diodes degrades the converter efficiency, especially at low line input voltage [1].Pseudo boost converters are thus named because the voltage transfer ratio of pseudo boost converter is similar to that of conventional boost converter, with no relation to the resonant parameters and switching frequency. A bridgeless PFC circuit allows the current to flow through a minimum number of switching devices compared to the conventional PFC circuit. Accordingly, the converters conduction losses can be significantly reduced, and higher efficiency and lower cost can be obtained. However, most of the previous proposed bridgeless PFC converters have at least one of the following drawbacks: 1) high components count, 2) Components are not fully utilized over whole ac line cycle, 3) complex control, 4) dc output voltage is always higher than the peak input voltage, 5) lack of galvanic isolation, and 6) due to the floating ground, some topologies require additional diodes and/or capacitors to minimize EMI. In order to overcome most of these problems, an interesting topology has been introduced with reduced component count. However, the proposed topology in still suffers from having at least two semiconductors in the current conduction path during each switching cycle. In [4] a zero current switch topology is presented. This topology has reduced component count; however, the load is floating with respect to the input. A novel low count topology has been introduced in [5] The proposed topology has low component count with an input stage similar to a boost converter. Here a new bridgeless PFC circuit based on the modified boost converter is introduced and presented Compared with existing single phase bridgeless topologies. The proposed topology has low component count, a single control signal, and non isolating output. Since the topology operates in discontinuous conduction mode, the proposed converter is intended for low power applications. The converter components are fully utilized during the positive and negative ac line cycle [9] Pseudo naming comes because this converters have voltage transformation ratio same as that of conventional boost converter, but it is independent of resonant parameters and duty ratio. Voltage conversion ratio can be further increased by quasi resonant technique [10] BRIDGELESS RESONANT PSEUDO BOOST PFC RECTIFIER Introduction The Bridgeless Resonant Pseudo boost PFC Converter circuitry consists of two MOSFET switches, two power diodes, resonant inductor and capacitor. At input side, LC filter is provided. The Bridgeless Resonant Pseudo boost PFC Rectifiers are designed to operate in discontinuous conduction mode (DCM) during the switch turn on interval and in resonant mode during the switch turn off intervals. As a result, the switch current stress is similar to the conventional DCM PFC converter, while the switch voltage stress is higher [1] Moreover, the two power switches Q1 and Q2 can be driven by the same control signal, which significantly simplifies the control circuitry. Basic circuit of Bridgeless Resonant Pseudo boost PFC Rectifier is shown in Fig 3.1. Referring to Figure 2.1, the switching conduction sequences are as follows: International Journal of Engineering Research and General Science Volume 3, Issue 4, Part 2, July August, 2015 ISSN 2091 2730 98 www.ijergs.org Figure 2.1: The Bridgeless Resonant Pseudo boost PFC Rectifier During positive ac line cycle, Q1, DQ2, D2, D1 ,X (all switches are off) and 2) during negative ac line cycle, Q2,DQ1,D1,D2,X. On the other hand, the switching conduction sequences for the converter are as follows: 1) during positive ac line cycle, Q1, DQ2 D1, D2, X and 2) during negative ac line cycle, Q2, DQ1, D2, D1,X. Thus, during each switching period TS, the current path goes through only two or one semiconductor devices instead of three. As a result, the total conduction losses of the semiconductor devices will be considerably lower compared to the conventional bridgeless PFC converters. In addition, the following assumptions are made: input voltage is pure sinusoidal, ideal lossless components, the switching frequency (fs) is much higher than the ac line frequency (fL) and the output capacitor C0 is large enough such that the output voltage can be considered constant over the whole line period. Based on these assumptions, the circuit operations in one switching period Ts in a positive ac line cycle can be divided into four distinct topological stages. From simulation results, for an input voltage 110 V, fs (switching frequency) 50 kHz, simulation is performed in MATLAB Ra2010. The parameters used includes Lf 1mH and Cf 1 mF, L1 100 mH, C1 65nF and RL 500. Output voltage is obtained as 242V and output current as 0.4A. Output voltage step up. Switching frequency used is 50 kHz. Power factor is obtained near unity, 0.92 and Total Harmonic Distortion is only 2%.Output power is nearer to 100 W, so it is used only for low power application. Working Principle Resonant Pseudo boost PFC Rectifiers are designed to operate in discontinuousconduction mode (DCM) during the switch turnon interval and in resonant mode during the switch turn off intervals. As a result, the switch current stress is similar to the conventional DCM PFC converter, while the switch voltage stress is higher. Moreover, the two power switches Q1 and Q2 can be driven by the same control signal, which significantly simplifies the control circuitry. However, an isolated gate drive is required for the power switch Q1. Table I: Tabulation of simulated results Input Voltage 110 V Input Current 1.5 A Input Power Factor 0.92 THD 2% Output Voltage 242 V Output Current 0.4 A ZCS BRIDGELESS BOOST PFC RECTIFIER For further improving voltage conversion ratio of conventional boost converters a new converter can be designed. An alternative approach to soft switching in modified boost converters is to use quasi resonant (QR) techniques that can be cheaply implemented by using only a few passive components. This converter can operate with soft switching and PFC in low line applications. It is International Journal of Engineering Research and General Science Volume 3, Issue 4, Part 2, July August, 2015 ISSN 2091 2730 99 www.ijergs.org economical because it requires only two active switches and two diodes for the main power circuit and a few passive components for soft switching. ZCS bridgelss boost PFC rectifiers are shown in fig 3.1. Figure 3.1: ZCS Bridgeless boost PFC Rectifier Operational modes: Stage 1: This stage starts when the switch Q1 is turned on. The body Diode of Q2 is forward biased by the inductor current IL1. Diodes are reverse biased by the voltage across C In this stage, the current through inductor L1 increases linearly with the input voltage, while the voltage across capacitor C1 remains constant at voltage VX. Figure 2.1: Mode 1 of ZCS Bridgeless boost PFC Rectifier International Journal of Engineering Research and General Science Volume 3, Issue 4, Part 2, July August, 2015 ISSN 2091 2730 100 www.ijergs.org Stage 2: This stage starts when switch Q1 is turned OFF and diode D1 is turned ON simultaneously providing a path for the inductor currents IL1 .As a result, diode D2 remains reverse biased during this interval. The series tank consisting of L1 and C1 are excited by the input voltage VAC. The stage ends when the resonant current IL1 reaches zero. During this stage, capacitor C is charged until it reaches a peak value as shown in Figure 2.2 Figure 2.2: Mode 2 of ZCS Bridgeless boost PFC Rectifier Stage 3: During this stage diode D1 is forward biased to provide a path during the negative cycle of the resonating inductor current IL1. This stage ends when the inductor current reaches zero. Thus, during this stage diode D2 is switched ON under zero current conditions. Assuming the constant input voltage over a switching period, the capacitor is discharged until it reaches a voltage VX. Figure 2.3: Mode 3 of ZCS Bridgeless boost PFC Rectifier Stage 4: During this stage all switches are in their off state. The inductor current is zero, while the capacitor voltage remains constant (VX) It shall be noted that for this converter to operate as specified, the length of this stage must be greater than or equal to zero. International Journal of Engineering Research and General Science Volume 3, Issue 4, Part 2, July August, 2015 ISSN 2091 2730 101 www.ijergs.org Figure 2.4: Mode 4 of ZCS Bri
author_names: Anna Joy

Neena Joseph Mani

Acy M Kottalil
title: ZCS BRIDGELESS BOOST PFC RECTIFIER
year: 2015

abstract: This Paper presents a two stage LED driver topology fed via a single phase Vienna Rectifier which is modified form of a single leg of three phase Vienna Rectifier. Use of Vienna Rectifier in place of conventional bridge rectifier not only improves power quality with high input power factor, lower Total Harmonics Distortion (THD) half the number of switch requirement, higher efficiency with reduced voltage stress on active switches and probable standards within IEC61000 3 2 for class C load. LED works on constant current or constant voltage mode which is driven by a driver circuit (AC DC system) .Effective LED driver topologies comes in two or three stage configuration to improve the power quality and efficiency, here second stage is driven by a Boost converter controlled by Average Current mode controller to obtained the desired Phase Margin and Gain Margin for stability. The modeling, control and simulation of the driver circuit is presented for LED load.
author_names: Vinod Kumar Yadav

Arun Kumar Verma

Udaykumar R Yaragatti
title: Modelling and Control of Two Stage High PFC LED Driver Circuit using Average Current Control Method Driven by Vienna Rectifier
venue: 2020 IEEE 9th Power India International Conference (PIICON)
year: 2020

abstract: The utilization of wide band gap devices has enabled high frequency operation of totem pole bridgeless PFC rectifier. However, most of the designs reported in the literature with frequency higher than 100 kHz operate under discontinuous conduction mode or critical mode to reduce the switching loss. This paper proposes a zero voltage transition (ZVT) technique for totem pole PFC rectifier under continuous conduction mode operation which enables efficient operation at switching frequencies well above 100 kHz. A simple auxiliary circuit consisting of a small auxiliary inductor and two active switches is placed in parallel with the main input filter inductor to achieve zero voltage switching of the main switches. The auxiliary switches operate with zero current switching (ZCS) and conduct current as short resonant pulses only during the critical turn on transition which results in very low losses in the auxiliary circuit. The timing of the auxiliary switches is adaptively controlled with respect to the grid voltage angle for optimized overall efficiency. The effectiveness of the proposed ZVT scheme has been validated through experiments based on a 2.4 kW 400 kHz hardware prototype with 98.35% peak efficiency.
author_names: Ziwei Yu

Yinglai Xia

Raja Ayyanar
title: A Simple ZVT Auxiliary Circuit for Totem Pole Bridgeless PFC Rectifier
venue: IEEE Transactions on Industry Applications
year: 2019

abstract: A bridgeless AC/DC converter for the power factor correction application is proposed in this paper. The diode bridge rectifier is removed in this converter by providing two separate paths of current for each half cycle of the AC voltage source; conduction losses are alleviated by decreasing the total number of switches in the conduction path of the current. In the proposed converter of this paper, switching losses are reduced by providing zero voltage switching (ZVS) condition for power MOSFETs using an auxiliary active clamp branch. By utilizing a series resonant circuit, zero current switching (ZCS) turn off is achieved for output diodes, and the reverse recovery losses are eliminated.
author_names: A Valizadeh

Ali Yazdian Varjani
title: A Bridgeless Soft Switching PFC AC/DC Converter With Active Clamping Auxiliary Circuit
venue: 2021 12th Power Electronics, Drive Systems, and Technologies Conference (PEDSTC)
year: 2021

abstract: This paper presents a new four quadrant bridgeless boost type rectifier with the use of Active Virtual Ground (AVG) technology. The presented topology can step up the AC grid voltage to a regulated DC voltage under a stable bidirectional current flow with real power or reactive power delivery. By using bridgeless rectifier configuration and 3 level switching method, only two high frequency switches are required through the four quadrant operation. Small input current ripple is guaranteed by the AVG circuit. A high efficiency system is also able to be guaranteed by low semiconductor loss. Benefit from the AVG technology, a LCL filter is formed at the input during the operation. The filter capacitor clamps the voltage ripple between the grid and the DC bus terminal. Hence the leakage current in the bridgeless PFC is minimized and causes a low common mode (CM) noise system. The differential mode (DM) noise is also maintained in a small value due to the small grid current ripple. Finally a high efficiency and low noise four quadrant rectifier is built. The presented topology is successfully implemented on a 750W prototype and the performance is experimentally verified which show a good agreement with the theoretical knowledge. The operation principles and the controller implementation are also described in details.
author_names: Ken King Man Siu

Carl Ngai Man Ho

Dong Li

River Tin-Ho Li
title: A four quadrant active virtual ground rectifier by using two high frequency switches
venue: IECON 2017 43rd Annual Conference of the IEEE Industrial Electronics Society
year: 2017

abstract: A novel bridgeless interleaved boost PFC rectifier is proposed for improving power efficiency and system performance in this paper. By combining the conventional bridgeless topology and the interleaved technology, this rectifier is comprised of two interleaved boost branches without the front end diode bridge. Each branch operates in every half line cycle, together with the current following through a minimum number of switching devices. By using the interleaved approach, this topology not only decreases the current stress of the switching devices but also reduces the current and voltage ripple. Moreover, as operating in critical conduction mode (CrM) all the switches can achieve soft switching characteristics to reduce the switching loss and evidently raise the conversion efficiency. Using a conventional interleaved controller, simple control scheme can be employed to the proposed converter. The operational principle and theoretical analysis of the proposed converter are presented. Finally, simulations based on actual semi conductor models were carried out to verify the feasibility and exactness of the proposed rectifier.
author_names: Guoen Cao

Hee-Jun Kim
title: A novel critical conduction mode bridgeless interleaved boost PFC rectifier
venue: 2014 International Power Electronics Conference (IPEC Hiroshima 2014 ECCE ASIA)
year: 2014

abstract: An improved bridgeless interleaved boost PFC rectifier is proposed to improve power efficiency and component utilization in this paper. By combining the conventional bridge less PFC circuit and the interleaved technology, the proposed rectifier is comprised of two interleaved boost branches without the front end diode bridge. Auxiliary diodes are employed to eliminate undesired circulating loop. The magnetic component utilization is improved by symmetrically coupling two inductors on unique core. According to the interleaved approach, each switch can operate in the whole line cycle. Moreover, this circuit not only decreases the current stress of the switching devices but also reduces the current and voltage ripple. As operating in critical conduction mode (CrM) all the switches can achieve soft switching characteristics to reduce the switching loss and evidently raise the conversion efficiency. Using a conventional interleaved controller, simple control scheme can be employed to the proposed converter. The operational principle and theoretical analysis of the proposed converter are presented. Finally, an 600 W experimental prototype was built to verify the theoretical analysis and feasibility of the proposed converter. The system efficiency was achieved up to 97.3% with very low current THD.
author_names: Guoen Cao

Hee-Jun Kim
title: An improved bridgeless interleaved boost PFC rectifier with optimized magnetic utilization and reduced sensing noise
venue: 2014 IEEE International Conference on Industrial Technology (ICIT)
year: 2014

abstract: The power conversion circuit of a three phase Vienna or Modular Boost switching power factor corrected (PFC) rectifier uses three controlled switches, eighteen diodes and two output split capacitors. Three PFC controller circuits are necessary for conversion circuit's voltage regulation, power factor control and input current waveform improvement. The circuit has been modified to have fewer active and passive components in the power circuit. The input voltages and currents are sensed and conditioned to one voltage and one current signal for the feedback controller circuit. Reduction of controlled switches, diodes of the power circuit, sensors, isolation, base drive supply circuits makes overall operation of the circuit reliable. The proposed three phase boost PFC rectifier circuit is easy to design, fabricate, operate and maintain. It occupies less space and is lighter in weight. Disadvantages of unidirectional power flow and only step up voltage gain characteristics of conventional three phase Vienna/Modular Boost rectifiers remain in the proposed modified circuits.
author_names: M Nasir Uddin

Amina Hasan Abedin

Khandaker Lubaba Bashar

Samia Islam

M A Choudhury
title: Three phase one switch modular boost/vienna power factor corrected (PFC) rectifier
venue: 2017 IEEE International Conference on Industrial Technology (ICIT)
year: 2017