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Bridgeless Totem-Pole Resonant Single-Power-Conversion PFC Converter
Abstract
This study proposes a bridgeless totem-pole resonant single-power-conversion power factor correction (PFC) converter for aircraft mobilities, which require light weight and small volume for longer flight time. To achieve these requirements, the proposed PFC converter employs totem-pole and voltage doubler circuits on the primary and secondary sides, respectively. By adopting the totem-pole circuit, the diode bridge can be eliminated, thereby removing its conduction loss and reducing the number of active components. In addition, the totem-pole circuit has a smaller common-mode noise compared to conventional bridgeless PFC converters. Furthermore, both the resonant and clamping capacitances constitute the resonant tank along with the resonant inductance, which results in a reduction in the size of the clamping capacitors. The series-resonant operation provides a zero-voltage switching turn-
on
of the primary-side switches and a zero-current switching turn-
off
of all the secondary-side diodes, thereby reducing the switching losses of the active components. The proposed PFC converter can control the input current for a high PFC capability while regulating the output voltage. Hence, the proposed exhibits high power density, power quality, and power efficiency. And, the operating principles and design guideline of the proposed PFC converter are discussed in detail, and a 400-W prototype is developed and tested to verify the circuit functionality.
This paper proposes a method to compensate for harmonics in single-phase inverter application using a phase-based comb filter. The conventional comb filter (CCF) is a harmonic reduction filter that has the effect of connecting multiple notch filters in series. The CCF has the effect of reducing harmonics for a fixed fundamental frequency. However, if the fundamental frequency changes, the coefficients of comb filter or sampling frequency must be adjusted. To address this issue, a phase-based comb filter (PCF) is proposed. The effectiveness of the proposed method is validated through experiments and simulations, with a comparative analysis conducted against conventional methods in term of transient characteristics and computation time.
In this paper, a 1-kW DC-DC buck converter with a four-phase interleaved matrix
inductor is proposed for battery charging applications. It is well-known that the DC
bias on the inductor will cause high core loss as it changes the B–H characteristic.
Typically, the transient conduction mode employed in high voltage applications for
zero-voltage-switching of devices would cause a higher inductor current ripple, results in
higher core loss. The conventional approach to reduce the effect of DC bias and inductor
current ripple is employing multi-phases. However, the cost and size of the converter
will increase significantly. This paper proposes the matrix inductor which has a small
volume and reduces the effect of the DC bias by flux sharing and flux cancellation at the
same time, results in low inductor core loss. With the interleaved operations the output
current ripple can be lower which is suitable for battery charging applications. Besides, the comparison of the synchronous and interleaved operation is presented. A 1-kW prototype is built and the experimental results show that the peak efficiency is 99.1% and 99.2% for synchronous and interleaved control, respectively. Additionally, the output current ripple of the interleaved operation is reduced by 85% in comparison with the synchronous operation.
In this paper, a review of Bridgeless Boost power factor correction (PFC) converters is presented at first. Performance comparison on conduction losses and common mode electromagnetic interference (EMI) are analyzed between conventional Boost PFC converter and members of Bridgeless PFC family. Experiment results are given to validate the efficiency analysis and EMI model building.
Portable electronic devices have grown dramatically at an incredible speed and include many new and sophisticated functions. Thanks to the advent of universal serial bus (USB) power delivery (PD) specifications, power delivery is increased as is the number of applications that can be powered using a USB cable in aircraft. However, the combination of the wide-voltage-gain operation required by the USB PD specification, high step-down ratio, and the lower-pressure environment associated with aircraft puts a lot of stress on converter optimization. This paper presents the DC-DC stage of an integrated, highly compact USB type-C PD charger for aircraft. First, a flying-capacitor-based voltage divider (FCVD) switching bridge is proposed to replace the conventional switching bridge in an LLC converter to improve its efficiency. Second, a printed circuit board (PCB) winding planar transformer is adopted to increase the power density. Gallium nitride devices are used for both the FCVD and the synchronous rectifiers, further shrinking the size and reducing the loss. Critical areas of the converter prone to a high electrical field (E-field) are identified and preemptively addressed with the use of the E-field control methodology that follows the Paschen-curve-based insulation coordination. The prototype is built and tested, and it is verified that the unit successfully operates in rated conditions to achieve a power density of 73.2 W/in
3
and an efficiency of over 90% at all nominal outputs. A high-altitude partial discharge test is also conducted, showing that the proposed prototype meets the partial discharge inception voltage (PDIV) at 10,000 ft.
In this paper, In this paper, a new bi-directional single-stage interleaved totem-pole electrolytic capacitor-less AC-DC converter with high frequency isolation and low components count is pro-posed. The proposed converter is constructed using non-regulating two-phase interleaved totem-pole converter switched with fixed 50% duty in the grid side and a full bridge in the DC-side for active power and DC output regulation. This switching method results in a ripple-free grid current regardless of magnitude of the input inductances, which in turn makes proper design of input inductance secure soft-switching for all switches under wide voltage and load ranges without auxiliary circuit or resonant tank. Hence, the proposed topology overcomes the reverse recovery issue, thereby enabling the use of Si devices in CCM. Moreover, the current spike around the AC main zero-crossing is avoided in CCM operation due to small rectified voltage around zero-crossing. Furthermore, the instantaneous powers at the grid side and DC-side are identical since the proposed topology is electrolytic-capacitor-less with inherent second harmonic ripple current at the DC-side. PFC is inherently performed in the proposed converter without current shaping control loop; and the phase-shift angle is the only control variable; Hence, the control system is simple and reliable.
This paper proposes a control strategy for a Ćuk module-integrated inverter (MII) with hybrid operation mode for low-voltage ride-through (LVRT) capability. The hybrid-mode Ćuk MII operates in unfolding-type power conversion (UPC) mode during normal grid conditions and in two-stage power conversion (TPC) mode during grid faults. It also has the advantages of highly efficient power transfer and LVRT capability but is difficult to control because UPC and TPC modes have distinct system dynamics and suffer from grid voltage disturbances that have different magnitudes. To overcome this control problem, this paper proposes a control strategy that corresponds to the operating mode of the hybrid-mode Ćuk inverter. To achieve zero steady-state tracking error during the grid disturbance, a repetitive controller (RC) is used in the proposed control scheme. Different phase-lead compensators in the RC compensate for different phase lags caused by distinct system dynamics. To reduce the burden from the RC, different nominal duty ratios are used as feedforward control input. To minimize the tracking error during grid faults, a proportional-resonant controller is used in parallel with RC controller in TPC mode. To analyze the stability of different control systems, a unified control system model is presented for the proposed inverter. The procedure to select control parameters is also presented in detail. Simulation results validate the proposed control scheme in the hybrid-mode Ćuk inverter, and experiments are conducted using the 400-VA MII prototype to demonstrate its validity.
In the boost power factor correction (PFC) converters, a low-pass filter (LPF) is generally adopted to eliminate the influence of the double-line frequency output voltage ripple on the controlled input current, which therefore limits the outer-voltage loop bandwidth. Different from the existing alternative schemes to the LPF, which eliminate the influence of the output voltage ripple using output-feedback ways in the outer-voltage loop, this paper proposes a current feedforward scheme in the inner-current loop to remove the LPF. In this proposed scheme the harmonic distortion of the reference current is suppressed by using a current-harmonic feedforward compensation (CHFC) way in synchronous reference frame. Finally, a 225W experimental prototype is built with digital implementation, and the experimental results show a more than 68% improvement of the dynamic response for the case with the proposed scheme compared with the traditional LPF scheme, along with a high quality controlled current.
A single-phase AC-DC converter with dual-output rectifier (DOR) and dual-input DC-transformer (DI-DCX) is proposed in this paper. A voltage-split/sigma (VSS) principle is adopted, that is, the grid voltage is split into two variable DC bus voltages firstly by the front-stage DOR, and then the two bus voltages are combined into an adjustable output voltage by the downstream DI-DCX. DC output voltage is directly regulated by the front-end rectifier. Therefore, no voltage regulation is required for the DC-DC stage, and a DI-DCX with optimized operation condition is employed to improve the overall efficiency of the AC-DC converter. Moreover, since the DOR has two different output voltages, three-level characteristic is achieved naturally to reduce switching losses of the converter. Zero-voltage switching (ZVS) of all the active switches in the DI-DCX are realized as well. Detailed operation principles, control and modulation strategies, and characteristics of the proposed AC-DC converter are analyzed in detail. Experimental results of a 1.5 kW prototype are provided to verify the effectiveness of the proposed converter.
This paper presents a bridgeless dual-mode single power-conversion ac-dc converter that can achieve high conversion efficiency. By adopting a bidirectional switch, we remove a full-bridge diode rectifier from the grid side of the proposed converter and thereby reduce the number of components and the primary side conduction loss. To adapt the converter to 1-kW power applications with a bidirectional switch, we used a series resonant circuit in the output voltage doubler on the secondary side. The series resonant circuit also provides zero-current switching turn-off at the output diode, and thereby reduces the reverse-recovery loss. To attain medium-high power capability with an appropriate transformer, the proposed converter operates in both discontinuous conduction mode and continuous conduction mode. The operation principle of the converter is presented and analyzed. By using dual-mode control algorithm, the proposed converter achieves high power factor of 0.994 and maximum efficiency of 97.3 %. Experimental results for a prototype 1-kW ac-dc converter verify these characteristics.
This paper presents a highly efficient 3.3-kW single-stage on-board charger (OBC). The proposed OBC consists of two interleaved cells sharing a full-bridge diode rectifier. Each cell is composed of an active clamp circuit and a series resonant circuit. The proposed OBC provides zero-voltage switching of all switches and reduces the reverse-recovery problem by zero-current switching of the output diodes. The interleaved technique maintains the proper power level with high efficiency. The proposed control algorithm enables power factor correction by the OBC without any auxiliary circuit, and balances the input current between the two cells. In addition, the proposed converter requires no electrolytic DC-link capacitor, ensuring compact size and a long lifetime. Owing to these features, the proposed OBC efficiently outputs a high power factor over a wide power range, and achieves reliability with a simply structured, single-power processing step. Therefore, the proposed OBC is potentially feasible for automotive applications. Finally, the theoretical analysis is confirmed in a 3.3-kW prototype, and validated in experimental results.
Thanks to the advantages of high fuel efficiency and low emission, more electric aircraft (MEA) has attracted increasing attention in recent years. For MEA, high reliable power converters which can keep working after multiple unexpected faults, are highly desired in the electrical power system (EPS) to guarantee the safety. In order to fulfill the high reliability requirement, a novel fault-tolerant LLC converter is proposed for MEA in this paper, which can keep working after two ideal shorted-circuit faults occurred on switches with a redundant circuit and topology reconfiguration. The redundant circuit is employed to achieve the first fault-tolerant ability, and when the second switch failure occurs, the proposed converter would be auto-reconstructed with the aid of two additional diodes to ensure uninterrupted operation. Because only two extra diodes are added to achieve the second fault-tolerance, the system reliability is significantly enhanced with low additional cost. Moreover, both the voltage/current stresses and the small-signal models of proposed converter are approximate in all pre-fault and post-fault modes, contributing to simplified circuit design and reliable control system. Finally, a 500W prototype is designed and built to experimentally verify the advantages of proposed fault-tolerant LLC converter.
Charging batteries of light electric vehicles require chargers with high efficiency and a high power factor. To meet this need, this paper presents a bridgeless single-power-conversion battery charger composed of a isolated step-up AC-DC converter with a series-resonance circuit. The bridgeless configuration reduces the conduction losses associated with the input diode rectifier, and the series-resonance circuit reduces the reverserecovery losses of the output diodes by providing zerocurrent switching. In addition, direct and series-resonance current injection enables bidirectional core excitation by the transformer, thereby allowing high power capability. The control algorithm derived from feedback linearization is also developed, which allows the proposed charger to correct the power factor and regulate the output power in a single-stage power conversion. This simple circuit structure leads to high efficiency and a high power factor. The theoretical concepts of the proposed charger is verified experimentally using a 1.7 kW prototype.
This paper presents a single-switch single power-conversion (S3PC) power factor correction (PFC) converter. Using the series-resonant circuit, the S3PC converter provides bidirectional core excitation for the transformer and obtains higher power capability compared with the conventional single-switch PFC converters. Also, the series-resonant circuit provides zero-current switching turn-off for the output diodes, so that the reverse-recovery loss is alleviated. The regenerative snubber not only avoids the voltage spike of the switch but also recycles the absorbed energy. Because these features are obtained with only a single switch and through single power-conversion, the S3PC converter has high efficiency and simple structure. The control algorithm derived from feedback linearization enables the S3PC converter to obtain good controllability. Also, by using this control algorithm, the proposed converter performs both PFC control and output power control through single power-conversion. With these advantages, the S3PC converter provides maximum efficiency of 96.4 % and high power factor in excess of 0.994. The proposed converter is theoretically analyzed in detail, and experimental results are applied to a 1-kW prototype to show its validity.
In this paper, a novel valley-fill single-stage boostforward LED driver is presented, where the valley-fill circuit is modified by adding a range-selection switch. The switch is manually closed under low input line and opened under high line to achieve an optimal performance in universal-line range. And the voltage stress of the high-frequency switch under high line range is also reduced. On the other hand, PWM dimming is employed to overcome the inherent voltage stress problem in light load and make the proposed converter a good choice for medium power in engineering practices. The operation principle, design process, and control strategy are presented. And finally the feasibility of the proposed converter is verified by a prototype with 30-V, 2.0-A output.
This paper presents a control strategy of a flyback microinverter with hybrid operation mode for photovoltaic ac modules. The proposed control strategy consists of two components: the proportional-resonant (PR) controller with the harmonic compensator (HC) and the hybrid nominal duty ratio. Compared to the conventional control strategy using the proportional-integral controller, the PR controller with HC provides a higher system gain at the fundamental and harmonic frequencies of the grid without using a high proportional gain in both operation modes. Then, it enhances the tracking speed and disturbance rejection performances satisfying the desired stability. Moreover, by applying the hybrid nominal duty ratio yielded from the proposed operation mode selection, the disturbance rejection is achieved more effectively, and the control burden is reduced. Finally, the simulation and experimental results were shown to verify the tracking speed and disturbance rejection performances of the proposed control strategy.
This paper presents a multifunctional onboard battery charger for plug-in electric vehicles (PEVs). The proposed battery charger consists of three H-bridge modules including a selective switch, a high-frequency transformer, and inductors. The first duty of the proposed charger is to charge the propulsion battery when PEV connects to the ac grid [onboard charger (OBC)]. In this case, the proposed charger plays a role in ac-to-dc converting with power factor correction. Occasionally, the propulsion battery can supply surplus energy to the grid [vehicle to grid (V2G)]. In this second task, the proposed charger acts as an inverter. The third role is to charge the auxiliary battery via the propulsion battery when PEV is in a driving state [low-voltage dc-to-dc converter (LDC)]. In this case, the proposed charger acts as a step-down converter. In conventional PEVs, the aforementioned functions are done by an OBC and an LDC separately. The proposed charger can implement the three tasks by sharing switches and inductors in an all-in-one system. Thus, the proposed approach can realize a small and light design of the EV battery charger, resulting in the improvement of fuel efficiency. After theoretical analysis, we carry out simulations and experiments using a prototype to verify the validity of the proposed approach. © 2014 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.
In this paper, an effective output voltage control method using adjustable frequency–duty-cycle hybrid control is presented. By using the proposed method, the operating performance of the full-bridge series resonant dc–dc converter applied to the onboard charger in electric vehicles under the constant-voltage charge mode is improved. The proposed control method improves the system efficiency of the charger up to 4% for light load conditions compared with the conventional control method without any extra hardware. A theoretical analysis is described along with a loss analysis in detail, and the validity of the proposed method is verified by experiment with a 3.3-kW prototype onboard charger.
This paper proposes and analyzes a new bridgeless flyback power factor correction rectifier for ac–dc power conversion. By eliminating four bridge diodes and adding a few circuit elements, the proposed rectifier reduces the primary side conduction loss and improves efficiency. The addition of the new elements has minimal effect on the circuit simplicity because it does not need any additional gate driver and magnetic elements. The losses in the semiconductor devices of the proposed circuit are analyzed and compared with that of the conventional one, followed by transformer design guideline. Experimental results with the practically implemented prototype prove its higher efficiency than its conventional counterparts.
This paper presents an isolated on-board vehicular battery charger that utilizes silicon carbide (SiC) power devices to achieve high density and high efficiency for application in electric vehicles (EVs) and plug-in hybrid EVs (PHEVs). The proposed level 2 charger has a two-stage architecture where the first stage is a bridgeless boost ac–dc converter and the second stage is a phase-shifted full-bridge isolated dc–dc converter. The operation of both topologies is presented and the specific advantages gained through the use of SiC power devices are discussed. The design of power stage components, the packaging of the multichip power module, and the system-level packaging is presented with a primary focus on system density and a secondary focus on system efficiency. In this work, a hardware prototype is developed and a peak system efficiency of 95% is measured while operating both power stages with a switching frequency of 200 kHz. A maximum output power of 6.1 kW results in a volumetric power density of 5.0 kW/L and a gravimetric power density of 3.8 kW/kg when considering the volume and mass of the system including a case.
This paper proposes a new bridgeless single-stage half-bridge ac-dc converter for power factor correction. The proposed converter integrates the bridgeless boost rectifier with the asymmetrical pulse-width modulation half-bridge dc-dc converter. The proposed converter provides an isolated dc output voltage without using any full-bridge diode rectifier. Conduction losses are lowered by eliminating the full-bridge diode rectifier. Zero-voltage switching of the power switches reduces the switching power losses. The proposed converter gives a high efficiency, high power factor, and low cost. The effectiveness of the proposed converter is verified on a 250 W (48 V/5.2 A) experimental prototype. The proposed converter achieves a high efficiency of 93.0% and an almost unity power factor for 250 W output power at 90 Vrms line voltage.
This paper suggests another candidate for high-power onboard charger for electric vehicles. It is based on a discontinuous conduction mode (DCM) power factor correction (PFC) converter with harmonic modulation technique that improves the power factor in DCM PFC operation and a two-stage dc/dc converter composed of a resonant converter and a DCM buck converter. Separating the functions of the dc/dc stage into control and isolation helps to reduce the transformer by using high-frequency resonance. The feasibility of the proposed charger has been verified with a 6.6-kW prototype.
In this paper, a novel single-stage soft-switching ac-dc converter for universal line applications is presented. Unlike the conventional single-stage designs, the proposed input-current shaping scheme is intentionally arranged to be charged in the duty-off time. With this design, the switch current stress in the duty-on time is significantly reduced. Meanwhile, this design produces AC modulation effect on the charging time of the boost inductor so that the input i -nu curve drawn by the proposed converter has nearly linear relationship. Moreover, an active-clamp flyback-forward topology is used as the downstream DC-DC cell to alleviate voltage stress across the bulk capacitor. By deactivating the flyback subconverter and keeping the forward subconverter supplying the output power at light-load condition, the bulk-capacitor voltage can be alleviated effectively and guaranteed below 450 V in wide ranges of output load and line input (90-265 Vrms). Experimental results, obtained from a prototype circuit with 20-V/100-W output, have verified that three achievements can be obtained simultaneously, including the compliance with the line-current harmonic regulations, the reliable alleviation of the bulk-capacitor voltage stress, and the substantially promoted conversion efficiency.
This paper proposes a dc power supply system to give high power factor and low current distortion on the rectifier side and provide stable dc voltage on the isolated dc/dc converter side. The proposed dc power supply system uses a new zero-voltage-switching (ZVS) strategy to get ZVS function. Besides operating at constant frequency, all semiconductor devices operate at soft switching without additional voltage stress. A significant reduction in the conduction losses is achieved, since the circulating current for the soft-switching flows only through the auxiliary circuit and a minimum number of switching devices are involved in the circulating current path, and the rectifier in the proposed dc power supply system uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. An average-current-mode control is employed in proposed dc power supply system to detect the transition time and synthesize a suitable low harmonics sinusoidal waveform for the input current. A design example of 1000-W soft-switching single-phase dc power supply system is examined to assess the converter performance.