Totem-pole Bridgeless Research Articles

A Multi-Objective PFC Boost Inductor Optimal Design Algorithm Based on Pareto Front

In this study, the inductor optimization design is performed by applying the Pareto optimization technique. As environmental problems emerge, the electric vehicle market is expanding, and accordingly, volume reduction and high efficiency of the onboard charger (OBC) are required. An OBC consists of a PFC stage and a DC/DC stage. The inductor is a major component in a converter and affects the volume and efficiency of the entire converter system. However, reducing the volume of the inductor leads to an increase in loss due to an increase in the change in flux density. Therefore, it is important to derive a suitable design for the target between the two parameters in the trade-off of loss and volume. This paper introduces the optimal design algorithm for boosting inductors of PFC converters in terms of volume and loss. Volume and loss are difficult to compare with each other, making it difficult to set weights. Therefore, Pareto optimization was applied which can be selected according to the needs and purposes of the decision-maker, without weighting as an optimization method. Through a series of procedures of applying Pareto optimization to the inductor design, several optimal inductor designs can be derived. At this time, the optimal designs become a set of designs in which the loss does not decrease without an increase in volume, or the volume does not decrease without an increase in loss. A designer can select a design with an appropriate volume and loss that meets the purpose of the design or preference. Therefore, through the proposed method, the inductor can be flexibly designed according to the target of the application. The proposed algorithm is applied to the interleaved totem-pole bridgeless boost PFC converter, to review its effectiveness. As a result, several inductor designs are derived in the search space, and various optimal designs are visualized through the Pareto Frontier. This facilitates comparative analysis of various inductor designs and helps designers select reasonable inductors. The validity was verified by selecting one of the obtained optimal inductor designs and driving the experiment with the resulting inductor.

Efficiency and PF Improving Techniques with a Digital Control for Totem-Pole Bridgeless CRM Boost PFC Converters

A totem-pole bridgeless boost converter is one of the most promising topologies for the power factor correction (PFC) stage in high-power applications due to its high efficiency and small number of components. However, due to the totem-pole structure of the field-effect transistor (FET), very high switching loss occurs via the reverse recovery current of the body diode. To solve these problems, critical mode (CRM) control is a good solution to achieve the valley switching technique. With valley switching of CRM control, the switching loss decreases drastically with decreasing turn-on voltage. But, although the CRM control enables valley switching, it is hard to make an exact valley switching control with general zero-voltage detection circuits. In addition, when a frequency limitation scheme is applied to prevent a very high frequency, the switch can operate with hard switching at the boundary of the frequency limitation. Furthermore, the CRM boost PFC has a low PF and high total harmonic distortion (THD) under light-load conditions due to the large negative current resulting from resonance between the inductor and parasitic capacitance. It becomes worse at near-zero input voltage since the resonance current becomes larger near zero-input voltage. Therefore, in this paper, a totem-pole bridgeless boost PFC converter with high efficiency, high PF, and low THD is developed using TMS320F28377 by Texas Instruments. Based on the basic digital structure of the totem-pole bridgeless converter, the proposed controls help with exact valley switching, PF and THD improvement, and frequency limitation. The prototype converter is verified using 90–264 VAC input voltages and 450 V/3.3 kW output specifications.

Digitalized Control Algorithm of Bridgeless Totem-Pole PFC with a Simple Control Structure Based on the Phase Angle

Compared to the conventional boost power factor correction (PFC) converter, a totem-pole bridgeless PFC has high efficiency because it does not have an input diode rectifier stage, but a current spike may occur when the polarity of the grid voltage changes. This paper proposes a digital control algorithm for bridgeless totem-pole PFC with a simple control structure based on the phase angle of grid voltage. The proposed algorithm has a PI-based double-loop control structure and performs DC-link voltage and input inductor current control. Rectifying switches operate based on the proposed rectification algorithm using phase angle information calculated through a single-phase phase-locked loop (PLL) to prevent current spikes. The feed-forward duty ratio value is calculated according to the polarity of the grid voltage and added to the double-loop controller to perform appropriate power factor control. The performance and feasibility of the proposed control algorithm are verified through a 3 kW hardware prototype.

AC-DC Fuzzy Linear Active Disturbance Rejection Control Strategy of Front Stage of Bidirectional Converter Based on V2G

Aiming at the problems of output voltage fluctuation and current total harmonic distortion (THD) in the front stage totem-pole bridgeless PFC of two-stage V2G (Vehicle to Grid) vehicle-mounted bi-directional converter, a fuzzy linear active disturbance rejection control strategy for V2G front-stage AC-DC power conversion system is proposed. Firstly, the topological working mode of the totem-pole bridgeless PFC is analyzed, and the mathematical model is established. Combined with the system model and the linear active disturbance rejection theory, a double closed-loop controller is designed with the second-order linear active disturbance rejection control as the voltage outer loop and PI control as the current inner loop. The controller can realize self-adaptive tuning of the proportional gain coefficient of the active disturbance rejection controller through fuzzy reasoning and realize self-adaptive control. Simulation and experimental results show that this method can better solve the problems of slow system response and high total harmonic distortion rate of input current and effectively improve the system’s robustness.

A High-Frequency Dynamically Coordinated Hybrid Si/SiC Interleaved CCM Totem-Pole Bridgeless PFC Converter

A high-frequency dynamically coordinated Si/SiC hybrid continuous conduction mode (CCM) totem-pole bridgeless PFC (TPBPFC) converter is reported in this article. The proposed hybrid TPBPFC converter is interleaved with a low-current high-frequency SiC phase and a high-current low-frequency Si phase, in comparison to the prior-art design of two half-capacity SiC phases, resulting in a considerable cost reduction. A coordinated Si/SiC control strategy is proposed to address the un-compensable range issue in hybrid-frequency interleaving topologies, and to dynamically distribute power load between the Si and SiC phases for optimal efficiency and performance. An average current mode control (ACMC) based control algorithms and sequences are discussed in detail to enable the unique operation. A 3.3-kW hybrid TPBPFC prototype made of Si IGBTs and SiC MOSFETs is built and tested to validate the proposed design concept. Compared to the prior art two-phase all-SiC interleaved TPBPFC design, the proposed hybrid TPBPFC has demonstrated nearly identical power efficiency, THD, power factor, and effective frequency, while offering 33.5% device cost and 15.1% total cost reductions.

A Variable Inductor Controlled Single-Stage AC/DC Converter for Modular Multi-Channel LED Driver

Light-emitting diodes (LEDs) are widely used in street lighting, landscape lighting, liquid crystal display (LCD) backlighting, healthcare, etc. As an important part of LED lighting products, LED driver plays a vital role in maintenance costs reduction, energy saving and lifetime prolongation. In this paper, a single-stage LED driver is proposed, which is integrated by a totem-pole bridgeless power factor correction (PFC) unit and several modular LCL-T resonant rectifiers. The totem-pole bridgeless PFC unit and the LCL-T resonant rectifiers are integrated by sharing switches, which can simplify the circuit and reduce the system cost. The output current can be regulated by applying the variable inductor control. Constant duty cycle and fixed switching frequency operation can be achieved as well. The operating principle and the performance of the proposed converter are analyzed in this paper. In addition, a precise parameter design method is proposed by considering the high-order harmonics. At last, an experimental prototype is established to validate the proposed parameter design and variable inductor control method.

Comparison of the power balance in a Totem-Pole Bridgeless PFC topology with several inrush current limiting strategies

Abstract Limiting inrush currents is usually necessary when AC-DC conversion is used to supply DC loads such as battery chargers in particular, it must comply with IEC 61000-3-3. This document discusses the suitability of an active inrush current limiter that can be used to replace traditional thermistors and NTC relays. This strategy is based on the control of the phase shift of thyristor type power components. It has been implemented in a totem-pole bridgeless power factor corrector (PFC). Experimental results show that this solution differs from traditional solutions to ensure high energy efficiency (higher than 95%) while limiting inrush currents.

Modified Power Factor Correction (PFC) Control and Printed Circuit Board (PCB) Design for High-Efficiency and High-Power Density On-Board Charger

This paper presents a modified power factor correction (PFC) ON/OFF control and three-dimensional (3D) printed circuit board (PCB) design for a high-efficiency and high-power density onboard charger (OBC). By alternately operating one of two boost modules of the PFC stage at a 50% or less load condition, the proposed PFC control can reduce the load-independent power loss of the PFC stage, such as core loss and capacitor charging loss of switches. It enables OBCs to have high efficiency across a wide output power range and better thermal performance. The 3D-PCB design decouples a trade-off relationship of the PCB trace design and heat spreader design, increasing the power density of OBCs. A 3.3 kW prototype composed of an interleaved totem-pole bridgeless boost PFC converter and full-bridge (FB) LLC converter has been built and tested to verify the proposed PFC control and 3D-PCB effectiveness design. The prototype has 95.7% full power efficiency (98.2% PFC stage efficiency) and 52 W/in3 power density.

99% Efficient 2.5-kW Four-Level Flying Capacitor Multilevel GaN Totem-Pole PFC

In this article, a high-efficiency and high-density 2.5 kW four-level flying capacitor multilevel (FCML) totem-pole bridgeless power-factor-correction (PFC) rectifier with 200 V GaN devices is analyzed, designed, and tested. This 2.5 kW four-level continuous conduction mode (CCM) GaN totem pole PFC operates with 360 kHz current ripple frequency which significantly reduces the inductor size while keeping a very low switching loss. This article compares the device loss of the four-level and two-level CCM GaN totem-pole PFC with the same ripple frequency (360 kHz) and shows that the four-level CCM GaN PFC has much less device loss. In addition, this article introduces the detailed design of a compact and low-profile matrix inductor based on the commercial composite inductors. This article also introduces the design of a high-density and low-loss flying capacitor. A 2.5 kW four-level FCML GaN totem-pole PFC prototype with 120 kHz switching frequency (360 kHz current ripple frequency) is developed and tested in this article. The tested peak efficiency is 99.25%. The PFC system power density is 104 W/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , without a heatsink and with forced air cooling.

Open-Circuit Fault-Tolerant Design of the Cascaded H-Bridge Rectifier Incorporating Reactive Power Compensation

This paper proposes an open-circuit fault-tolerant design for the cascaded H-Bridge rectifier incorporating reactive power compensation. If one or two switching devices of the H-bridge modules are fault, the drive signals of the faulty H-bridge modules will be artificially redistributed into the bridgeless mode (including the boost bridgeless mode, the symmetric boost bridgeless mode, the totem-pole bridgeless mode and the symmetry totem-pole bridgeless mode) and cooperate with the normally operated H-bridge modules. In this case, the faulty cascaded H-bridge rectifier is not only able to achieve active power transmission, but also can still provide part of reactive power compensation when injecting reactive power from the power grid. Nonetheless, the reactive power that it can supply will be limited, due to the unidirectional characteristics of the bridgeless mode for the faulty modules. Therefore, a method for calculating its adjustable power factor angle range is also presented, which provides the basis for the faulty modules switching to the bridgeless mode. Then, a control strategy of the cascaded H-bridge rectifier incorporating reactive power compensation under the faulty condition and normal operation is presented. Finally, an experimental platform with a single-phase cascaded H-bridge rectifier containing three cells is given to verify the proposed theories.

An Interleaved Totem-Pole Bridgeless Boost PFC Converter with Soft-Switching Capability Adopting Phase-Shifting Control

This paper proposes an interleaved totem-pole bridgeless boost power factor correction (PFC) converter with soft-switching capability. In the proposed converter, an inductor is added compared with the conventional interleaved totem-pole bridgeless boost PFC converter. The added inductor is located between two PFC converter units, and by utilizing the energy of the added inductor, all switches can achieve the zero voltage switching (ZVS). In addition, by applying the phase-shifting control between two PFC converter units, the proposed converter can control the magnitude of the current flowing on the added inductor as an optimal value. Therefore, the proposed converter can achieve the ZVS operation, while minimizing the additional conduction loss and core loss of the added inductor. As a result, the proposed converter can achieve the high efficiency. The feasibility of the proposed converter is confirmed with 180–264 Vrms input and 1.6 kW (400 V/4 A) output prototype.

Optimized Hybrid PWM Scheme for Mitigating Zero-Crossing Distortion in Totem-Pole Bridgeless PFC

A totem-pole bridgeless power factor corrector has been widely used in high-power ac–dc power conversion for its low component count and high energy efficiency. Its active bridge is configured to operate the power circuit as a synchronous boost converter over the line cycles. However, due to some intrinsic and extrinsic factors, input current distortion near the zero crossings is unavoidable. A hybrid pulsewidth modulation (PWM) scheme for mitigating such zero-crossing distortion is proposed. The concept is based on changing the PWM modulation schemes dynamically around the zero crossings, so that the line current can still be profiled with a switching scheme that does not require tracking the polarity of the grid voltage accurately. A generalized model for describing the variation of the inductor current, which is also the input current, from its average value in a switching cycle is formulated and is used to derive the optimal alignment of the PWM pulses for giving the smallest transient variation upon changing the modulation scheme. Results indicate that the voltage pulses generated by the active bridge are preferably symmetrical and center aligned in a switching period. A 1-kW 85–265-Vac/400-Vdc 47–63-Hz SiC-based prototype has been built and evaluated.

Analysis and Design of a Single-Stage Bridgeless High-Frequency Resonant AC/AC Converter

A single-stage high-frequency resonant ac/ac converter converts the ac-line input voltage into the high-frequency sinusoidal output voltage, which consists of two power conversion units, i.e., a power factor correction (PFC) unit and a high-frequency resonant dc/ac unit, and it can be used to derive a modular multichannel constant current LED driver. By adopting a totem-pole bridgeless PFC boost rectifier to reduce conduction losses, a single-stage bridgeless high-frequency resonant ac/ac converter is proposed in this paper. The operating principle is described, and the performance analysis is presented in detail. Moreover, the quantitative parameter design method of the main circuit is presented, which is suitable for other single-stage ac input converters, such as a single-stage PFC rectifier. Finally, a 130-W prototype has been built and tested to verify the correction of related theoretical analysis and parameter design.

EMI Prediction and Reduction of Zero-Crossing Noise in Totem-Pole Bridgeless PFC Converters

EMI Prediction and Reduction of Zero-Crossing Noise in Totem-Pole Bridgeless PFC Converters

Review of GaN Totem-Pole Bridgeless PFC

Switching-mode AC/DC converters are widely used in modern power supplies for computers, data centers and telecommunication equipment. Achieving Power Factor Correction (PFC) and high efficiency are the two most important requirements. In many cases, high power density is also of tremendous interest. Both power efficiency and power density are greatly influenced by the power devices, the topology and the control used. Compared with conventional Si power MOSFET and Si super-junction MOSFET, the newly introduced 600 V GaN devices not only eliminate the reverser recovery, but also have much lower switching and driving losses. These excellent properties enable the emergence of the totem-pole bridgeless AC/DC converter as the next generation preferred solution for PFC instead of the state-of-the art Si-based boost PFC. In this paper, the key technologies and designs for both hard-switching and soft-switching GaN totem-pole PFC are reviewed and the key performance metrics are compared. A soft switching, 3.2 kW totem-pole PFC prototype with 99% efficiency and 130 W/inch3 power density has been achieved in the author's group as a proof of the concept. Based on the power density comparison, the high frequency soft-switching GaN totem-pole PFC is the preferred choice to achieve both high efficiency and high power density at the same time.

Thermal analysis and improvement of cascode GaN device package for totem-pole bridgeless PFC rectifier

The totem-pole bridgeless power factor correction (PFC) rectifier has a simpler topology and higher efficiency than other boost-type bridgeless PFC rectifiers. Its promising performance is enabled by using high-voltage gallium nitride (GaN) high-electron-mobility transistors, which have considerably better figures of merit (e.g., lower reverse recovery charges and less switching losses) than the state-of-the-art silicon metal-oxide-semiconductor field-effect transistors. Cascode GaN devices in traditional packages, i.e., the TO-220 and power quad flat no-lead, are used in the totem-pole PFC boost rectifier. But the parasitic inductances induced by the traditional packages not only significantly deteriorate the switching characteristics of the discrete GaN device but also adversely affect the performance of the built PFC rectifier. A new stack-die packaging structure with an embedded capacitor has been introduced and proven to be efficient in reducing parasitic ringing at the turn-off transition and achieving true zero-voltage-switching turn-on. However, the thermal dissipation capability of the device packaged in this configuration becomes a limitation on further pushing the operating frequency and the output current level for high-efficiency power conversion. This paper focuses on the thermal analysis of the cascode GaN devices in different packages and the GaN-based multichip module used in a two-phase totem-pole bridgeless PFC boost rectifier. A series of thermal models are built based on the actual structures and materials of the packaged devices to evaluate their thermal performance. Finite element analysis (FEA) simulation results of the cascode GaN device in a flip-chip format demonstrate the possibility of increasing the device switching speed while maintaining the peak temperature of the device below 125 °C. Thermal analysis of the GaN-based power module in a very similar structure is also conducted using the FEA method. Experimental data measured using the fabricated devices and modules validate the simulation results. The developed new package in a flip-chip configuration enhances the thermal dissipation capability of the cascode GaN device in the stack-die format. The GaN-based power module built using the same packaging structure also demonstrates desirable thermal performance.

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.