Phase-shifted Full-bridge Converter Research Articles

Half-Bridge Integrated Phase-Shifted Full-Bridge Converter With High Efficiency Using Center-Tapped Clamp Circuit for Battery Charging Systems in Electric Vehicles

In this article, a half-bridge (HB) integrated phase-shifted full-bridge (PSFB) converter with a new center-tapped clamp circuit is proposed to achieve high efficiency in electric vehicle battery charging systems. The proposed converter has the benefits of HB integrated PSFB converters, such as the extended zero-voltage-switching range and the reduced conduction loss on the primary side. In addition, by using a new center-tapped clamp circuit, which consists of two diodes and one capacitor, the proposed converter can solve the drawbacks of conventional PSFB converters, such as the substantial circulating current, the severe voltage stress and switching loss in the secondary full-bridge rectifier, and a large output inductor. With these improvements, the efficiency is fairly increased, and the volume of the output inductor is reduced. In order to validate the feasibility of the proposed converter, a 3.3-kW prototype was built and tested.

Optimal Dead-Time Control Scheme for Extended ZVS Range and Burst-Mode Operation of Phase-Shift Full-Bridge (PSFB) Converter at Very Light Load

Phase-shift full-bridge (PSFB) converter is a widely used topology for high-efficiency and high-power applications, thanks to low voltage/current stress of all components and zero-voltage-switching operation of primary mosfet s. The critical drawback of the PSFB converter is hard-switching characteristics of primary mosfet s at a very light load, which causes severe thermal explosion and extremely high input power consumption, especially with the latest super-junction mosfet . To minimize the switching loss of the PSFB converter at a very light load, a new optimal dead-time control scheme with burst-mode operation is proposed in this paper and its validity is verified experimentally with the implemented 2.2-kW server power supply unit.

Phase-Shifted Full-Bridge DC–DC Converter With High Efficiency and High Power Density Using Center-Tapped Clamp Circuit for Battery Charging in Electric Vehicles

In this paper, a phase-shifted full-bridge (PSFB) converter employing a new center-tapped clamp circuit is proposed to achieve high efficiency and high power density in electric-vehicle battery charger applications. By using a simple center-tapped clamp circuit, which consists of two diodes and one capacitor, many limitations in conventional PSFB converters are solved. The proposed center-tapped clamp circuit provides the clamping path and allows the secondary voltage stress to be clamped to the secondary-reflected input voltage. This results in a greatly reduced conduction loss in the secondary full-bridge rectifier (FBR) due to the low-forward-voltage drop of low-voltage-rated diodes, and the resistor–capacitor–diode snubber loss is eliminated. In addition, the circulating current in the primary side is removed without any duty-cycle loss. Furthermore, the turn- off switching loss in the FBR is substantially reduced due to the decreased reverse-recovery current and the reduced reverse voltage. With these advantages, high efficiency can be achieved. Besides, the size of the output inductor is considerably reduced with the aid of clamping voltage, resulting in a high power density with saving the cost. In order to confirm the effectiveness of the proposed converter, a 3.3-kW prototype was tested. Experimental results show that the proposed converter achieves high efficiency over the entire conditions with high power density.

Reconfigurable Control of the Quasi-Parallel Voltage Regulator for Powering Laptop Processors

The quasi-parallel voltage regulator (VR) topology with a phase-shifted full-bridge (PSFB) converter and a synchronous buck converter (SBC) in quasi-parallel configuration gives high efficiency even with widely varying input voltage at high and medium loads but not at light loads. Moreover, the “loop gain shaping” approach to controller design for this converter does not give satisfactory dynamic performance. Therefore, this article proposes a state feedback controller which meets the stringent dynamic performance requirement of the VRs. Additionally, techniques to reconfigure the state feedback controller are proposed to operate this converter in different light-load operating modes to improve its light-load efficiency so that the converter becomes suitable for laptop VR application. In the light-load modes, the PSFB and the SBC operate alternately to regulate the load voltage, thereby saving the losses of one of the converters. At very light loads, a burst mode operation is proposed where both the converters remain inactive for most of the time, further increasing the efficiency. A unified control method which enables the converter to seamlessly change the operating modes of the converter, based on the computing load on the processor, is proposed and experimentally verified on a laboratory prototype for satisfactory performance.

A Practical Approach to the Design of a Highly Efficient PSFB DC-DC Converter for Server Applications

The phase shift full bridge (PSFB) is a widely known isolated DC-DC converter topology commonly used in medium to high power applications, and one of the best candidates for the front-end DC-DC converter in server power supplies. Since the server power supplies consume an enormous amount of power, the most critical issue is to achieve high efficiency. Several organizations promoting electrical energy efficiency, like the 80 PLUS, keep introducing higher efficiency certifications with growing requirements extending also to light loads. The design of a high efficiency PSFB converter is a complex problem with many degrees of freedom which requires of a sufficiently accurate modeling of the losses and of efficient design criteria. In this work a losses model of the converter is proposed as well as design guidelines for the efficiency optimization of PSFB converter. The model and the criteria are tested with the redesign of an existing reference PSFB converter of 1400 W for server applications, with wide input voltage range, nominal 400 V input and 12 V output; achieving 95.85% of efficiency at 50% of the load. A new optimized prototype of PSFB was built with the same specifications, achieving a peak efficiency of 96.68% at 50% of the load.

A Dual Half-Bridge Converter With Current Doubler Rectifier

This article proposes a novel zero-voltage switching (ZVS) dc–dc converter to improve the performances of the traditional phase-shifted full-bridge converter. In the primary side, two half-bridge converters (HBCs), leading-HBC, and lagging-HBC are placed in parallel and are driven in a phase-shifted control. The secondary side is a current doubler rectifier (CDR) circuit consisting of four rectified diodes and two output filter inductors. With this structure, the proposed converter can achieve wide ZVS range, minimized circulating current, and low-current ripple of output filter. Furthermore, the current stress of lagging-HBC is lower than that of leading-HBC; different current-rated switches can be employed for the two HBCs, which is a benefit to optimize the ZVS conditions and cost. In this article, the operational principle and performances of the proposed converter are analyzed in depth. Finally, experimental results from a prototype (320–400 V input, 110 V/10 A output) are presented to validate the theoretical analysis.

High-Efficiency Phase-Shifted Full-Bridge Converter With a New Coupled Inductor Rectifier (CIR)

A conventional phase-shifted full-bridge (PSFB) converter is one of the most promising topologies in high-efficiency and high-power applications because of its small RMS current, inherent zero-voltage switching capability, and clamped voltage stress of the primary switches. However, when the PSFB converter operates with a small duty ratio, a large freewheeling current of an output inductor flows in the primary side, and it causes a large circulating current. In addition, it has a large voltage stress in the rectifier diodes due to a voltage ringing between parasitic components. To solve these problems, a new PSFB converter with a coupled inductor rectifier (CIR) is proposed in this paper. By adopting the CIR structure in the PSFB converter instead of the full-bridge rectifier, the proposed converter eliminates the freewheeling current in the primary side, which significantly reduces the primary circulating current. In addition, the two rectifier diodes of the CIR do not have voltage ringing. As a result, the proposed converter not only reduces the conduction loss in the primary side, but can also use two diodes in the rectifier with a low voltage rating. The effectiveness and feasibility were verified with a 320-400 V input and 56-V/12.8-A output prototype.

Simple soft‐switched phase‐shifted FB converter for reduced voltage stress and negligible duty cycle loss

A simple modified configuration of the conventional phase-shifted full-bridge (C-PSFB) converter, phase-shifted FB converter without filter inductor (PSFB-w/o-L) is proposed in this study in order to reduce the peak voltage stress on the rectifier diodes. As the proposed configuration is devoid of filter inductor, it features lighter weight and low cost. As the proposed configuration is achieved eliminating the filter inductor, the maximum voltage that comes across the rectifier diode is limited to the output voltage, thus eliminating the need for snubber circuit. Additionally, the proposed PSFB-w/o-L has the advantage of negligible duty cycle loss. A comprehensive analysis on the mechanism of the peak voltage problem across the rectifier diode in the C-PSFB is addressed and the way it is eliminated in the proposed PSFB-w/o-L is described. The detailed analysis of the operation and design consideration of the proposed PSFB-w/o-L is presented. Simulation and experimental results are presented to verify the analysis.

Modulation Scheme for the Bidirectional Operation of the Phase-Shift Full-Bridge Power Converter

This paper proposes a novel modulation technique for the bidirectional operation of the phase-shift full-bridge (PSFB) dc/dc power converter. The forward or buck operation of this topology is well known and widely used in medium-to-high-power dc-to-dc converters. In contrast, backward or boost operation is less typical since it exhibits large drain voltage overshoot in devices located at the secondary or current-fed side—a known problem in isolated boost converters. For that reason, other topologies of symmetric configuration are preferred in bidirectional applications. In this work, we propose a modulation technique overcoming the drain voltage overshoot of the isolated boost converter, without additional components other than the ones in a standard PSFB and still achieving full or nearly full ZVS in the primary or voltage-fed side devices along all the load range. The proposed modulation has been tested in a bidirectional 3.3 kW PSFB achieving a 98% of peak efficiency in buck mode (380 V input, 54.5 V output), and a 97.5% in boost mode (51 V input, 400 V output). This demonstrates that the PSFB converter may become a relatively simple and efficient topology for bidirectional dc-to-dc converter applications.

Hybrid Modulation of Parallel-Series $LLC$ Resonant Converter and Phase Shift Full-Bridge Converter for a Dual-Output DC–DC Converter

A novel pulse frequency and phase shift hybrid modulated dual-output dc–dc converter is proposed in this paper. The proposed converter is composed of hybrid modulation of an input-parallel-output-series LLC resonant converter and a phase shift full bridge (PSFB) converter. The output voltage of the LLC resonant converter is modulated by the switching frequency, whereas the output voltage of the PSFB converter is modulated by the phase angle; therefore, the two output voltages are regulated independently and free from cross regulation. The series inductor of the PSFB converter does not need to be specially designed to help achieving the soft switching operation, and the duty cycle loss could be mitigated. Zero-voltage switching can be achieved on the power switches in the whole load range. Finally, a 1.2-kW 400-input 200–400-V and 48-V output prototype is built and tested to verify the effectiveness of the proposed converter.

Hybrid mode control for wide range soft‐switched full‐bridge converter with auxiliary parallel inductor networks

Aiming at the limitations of conventional phase-shifted full-bridge (PSFB) converter, such as, narrow zero-voltage switching (ZVS) range and large duty cycle losses, here, a wide range soft-switched full-bridge (FB) converter using hybrid mode control is proposed. Given using of two auxiliary inductors under light load, the energy that required for soft switching is satisfied and thus, ZVS can be achieved, and, therefore, efficiency of converter can be improved significantly under light load. Furthermore, the duty cycle losses of the secondary side are reduced by using a transformer with the small leakage inductor. Based on these merits, the proposed converter has some advantage for the wide range load variation applications without duty cycle losses. This paper presents the circuit configuration of the proposed converter and analyses its operating principles. Experimental results of an 800 W 200/50 V prototype are presented to validate the effectiveness of the proposed converter.

A PWM Switch Model of Isolated Battery Charger in Constant-Current Mode

In this paper, the pulsewidth modulation switch method was used to investigate the effect of the transformer leakage inductance on the small-signal model in isolated full-bridge converter. A galvanic isolated hard-switching full-bridge converter that operates in constant-current mode is analyzed, confirming that leakage inductance significantly affects the small-signal model, and the influence of leakage inductance can be equivalent to a resistance in series with the converter's output LC filter just as that in phase-shifted full-bridge converter. However, the same leakage inductance in these both converters will lead to different equivalent resistance due to different operating principles. Results of the modified model, simulations, and the experiments are compared to verify the correctness of the model. Moreover, this paper also shows that the Norton equivalent circuit of the charger operates in constant current mode, which can be used to estimate the dynamic behavior of the system.

A Novel Hybrid Mode Control for a Phase-Shift Full-Bridge Converter Featuring High Efficiency Over a Full-Load Range

A novel hybrid mode control technique for a phase-shift full-bridge (PSFB) converter is proposed in this paper. The proposed method can improve power efficiency under both the light-load and heavy-load conditions. The basic concept of the proposed control technique is to decrease the turns ratio to reduce the circulating current, hence resulting in lower circulating losses. However, the output voltage under heavy load may not be stabilized using phase-shift control if smaller turns ratio is utilized. Therefore, the proposed technique employs asymmetrical pulsewidth modulation to achieve higher output voltage. To further improve the efficiency, an adaptive dead-time control method, which determines the dead-time value according to the load level, is also proposed. To validate the correctness and effectiveness of the proposed method, a 480-W PSFB converter is constructed and experiments are carried out accordingly. Comparing with a conventional PSFB converter, the efficiency of the proposed method can be improved up to 3.2%, 1.3%, and 0.6% under light-load, 30% load, and full-load conditions, respectively.

Design of Charging Module for DC Charging Pile Based on Two Level Power Conversion

In order to to solve the demand of electric vehicle for high power and high performance DC charging pile, this paper presents a design scheme for charging module of DC charging pile based on two stage power transformation. The pre stage part of the scheme is the VIENNA rectifier controlled by hysteresis current and the phase shift full bridge converter controlled by the average current. The parameters of the main circuit and the control circuit are calculated. At last, the simulation research on the three conditions of the rated load, two times overload and load fluctuation is carried out. The results show that the charging module can achieve high power factor, low harmonic distortion rate, zero voltage switch, low loss operation, strong carrying capacity, good dynamic performance, high steady state precision and simple and easy operation.

A Simple SR Gate Driving Circuit With Reduced Gate Driving Loss for Phase-Shifted Full-Bridge Converter

The phase-shifted full-bridge (PSFB) converter with synchronous rectifier (SR) is one of the most attractive dc–dc converters for the server power supply due to its high power capability and small secondary ripple current with the output inductor. Moreover, it can more reduce the secondary conduction loss by using parallel-connected mosfet s in SR. However, due to large input capacitance of the parallel-connected mosfet s in SR, the PSFB converter has large SR gate driving loss, which particularly degrades the light load efficiency. Thus, in this paper, one additional resistor is added to the conventional SR gate driving circuit to recycle the gate driving energy. As a result, the proposed circuit can improve the light load efficiency of the PSFB converter without operation mode change, additional controls, and complex circuits. The most advantage of the proposed circuit is that it is very simple and available to any other SR gate driver IC. The validity of the proposed circuit is confirmed by experimental results from a prototype with 340–400 V input and 12 V/66.66 A output.

An Active Voltage-Doubler Rectifier Based Hybrid Resonant DC/DC Converter for Wide-Input-Range Thermoelectric Power Generation

To develop thermoelectric power conditioning systems that are highly efficient over a wide range of input voltages and support medium-rated power, this paper introduces a hybrid resonant dc/dc converter using an active voltage-doubler rectifier. When the input voltage is higher than the preset nominal input voltage, the converter operates in the phase-shift full-bridge series-resonant converter mode, in which it achieves high efficiency by softly switching the primary-side switches and reducing the conduction loss. When the input voltage is lower than the nominal one, it operates in the resonant boost mode that boosts the resonant inductor current. By using the active voltage-doubler rectifier on the secondary side of the converter, we can build the converter with less number of active components. As a result, the proposed converter achieves, at low cost, high boost-ratio and high efficiency over a wide range of input voltages. A detailed analysis of the converter operation is presented along with the design procedure. At 35-55 V, a 600-W/360-V prototype of the proposed converter has been built and tested to demonstrate its effectiveness.

A Quasi-Resonant ZVZCS Phase-Shifted Full-Bridge Converter with an Active Clamp in the Secondary Side

A novel Pulse-Width-Modulation (PWM) quasi-resonant active-clamp phase-shifted full-bridge converter is presented and analyzed in this paper. In the proposed topology, an active-clamp switch and a clamp capacitor that resonates with the leakage inductance of transformer are employed at the secondary side. The active-clamp circuit helps all of the primary switches in achieving both zero-voltage switching (ZVS) turn-on and nearly zero-current switching (ZCS) turn-off over the entire load range, and resets the primary current during the freewheeling interval. The operation of the active-clamp circuit eliminates voltage ringing across the rectifier. In addition, the secondary diodes can achieve ZCS turn-off, which removes the reverse recovery problem of diodes, and the active-clamp switch can achieve ZCS turn-on. A 3.5-kW prototype was built to verify the performance of the proposed converter. A maximum efficiency of 97.6% was achieved under a 2-kW load, and an efficiency of more than 96% was achieved even under a light load.

Reducing Common Mode Noise in Phase-Shifted Full-Bridge Converter

The phase-shifted full-bridge (PSFB) converter has been widely used in medium-to-high power applications because of simple topology and ease of achieving soft-switching for power switches. However, with the phase-shifted control, the electric potential variation of the two phase-leg midpoints happens at different times, and the displacement current generated by two midpoints through associated parasitic capacitance (including the parasitic capacitance between two midpoints to ground and the transformer inter-winding capacitance) cannot be cancelled by each other, resulting in a serious common mode (CM) noise. Moreover, the resonant inductor voltage affects the electric potentials of the transformer terminals, which also generates CM noise. To reduce the CM noise in the PSFB converter, this paper proposes a symmetrical resonant inductor together with symmetrical transformer configuration to eliminate the influence of the resonant inductor voltage on the CM noise. Then, a passive cancellation circuit is introduced to cancel the effect of the voltages between the midpoints and the ground on the CM noise. A 1-kW PSFB converter prototype has been fabricated and tested in the lab, and the experimental results are provided to verify the proposed methods.

Interleaved Current-Driven Phase-Shift Full-Bridge Converter With Magnetic Integration and Voltage Doubler Rectifiers

This paper presents an interleaved current-driven phase-shift full-bridge converter for plug-in hybrid electric vehicle (PHEV) applications. In the proposed converter, soft switching of the active switches can be realized for a wide range of operating conditions by using a simple auxiliary circuit. Due to the current-driven nature of secondary rectifiers, the proposed converter is able to eliminate the voltage spikes across the output diodes and provides smooth commutations for the secondary rectifiers. Thus, diodes with lower breakdown voltage rate and lower forward voltage drop can be used to further improve the efficiency. All the passive magnetic components are integrated into the main transformer. The numbers of the output diodes are minimized because of the voltage doubler rectifier configuration. The input filtering requirements, as well as the current stresses of the switch devices, are also significantly reduced owing to the interleaving approach. Therefore, the proposed converter would be a good candidate for PHEV applications. The steady-state operation and relevant analysis results of the proposed converter are presented. Experimental results obtained from a 2-kW prototype with a peak efficiency of 97.4% validate feasibility of the proposed converter.

Design and implementation of an automatic charging system for intelligent patrol robot

ABSTRACTThis paper is concerned with the design and implementation of an automatic charging system for the intelligent patrol robot. An economic and practical method combined with the infrared sensor and laser sensor is developed to realize the accurate automatic charge docking. The phase-shifted full-bridge ZVS-PWM converter is adopted to design an automatic charging pile, which uses a constant voltage limited current charging mode and improve the efficiency of the charging. Several simulations and experiments are implemented to test the automatic charge docking system, and the results could demonstrate the effectiveness and superiority of the system.