Dual-output LLC Resonant Converter Research Articles

Review Of Control Methods of Dual-Output Half-Bridge LLC Resonant Converter

Dual-output half-bridge LLC resonant converters are widely used in data centres, aerospace, portable electronic devices, new energy vehicles and other fields due to their superior performance of high frequency, high efficiency and high power density. This paper analyses the topology and operating principle of the dual output LLC resonant converter; introduces the traditional control methods and the new control methods in recent years. For each control method, its principle, characteristics, advantages and disadvantages are described. Finally, the future research direction and development trend of dual-output half-bridge LLC resonant converter are outlooked.

Effect of leakage inductance on steady-state cross-regulation of dual-output LLC resonant converters

ABSTRACT Steady-state cross-regulation is a critical issue for dual-output dc-dc converters. The effect of leakage inductance on steady-state cross-regulation of dual-output LLC resonant converter is analysed in this Letter. It is revealed that a proportional relation between leakage inductance and load resistance of dual-output LLC resonant converter ensures zero steady-state cross-regulation. Furthermore, the variations of steady-state cross-regulation with regards to leakage inductance and load resistance are concluded. Finally, experimental results are provided to verify the theoretical analysis.

Design Methodology of Tightly Regulated Dual-Output LLC Resonant Converter Using PFM-APWM Hybrid Control Method

A dual-output LLC resonant converter using pulse frequency modulation (PFM) and asymmetrical pulse width modulation (APWM) can achieve tight output voltage regulation, high power density, and high cost-effectiveness. However, an improper resonant tank design cannot achieve tight cross regulation of the dual-output channels at the worst-case load conditions. In addition, proper magnetizing inductance is required to achieve zero voltage switching (ZVS) of the power MOSFETs in the LLC resonant converter. In this paper, voltage gain of modulation methods and steady state operations are analyzed to implement the hybrid control method. In addition, the operation of the hybrid control algorithm is analyzed to achieve tight cross regulation performance. From this analysis, the design methodology of the resonant tank and the magnetizing inductance are proposed to compensate the output error of both outputs and to achieve ZVS over the entire load range. The cross regulation performance is verified with simulation and experimental results using a 190 W prototype converter.

A High Step-Down Multiple Output Converter With Wide Input Voltage Range Based on Quasi Two-Stage Architecture and Dual-Output <italic>LLC</italic> Resonant Converter

In this letter, a quasi two-stage architecture is proposed for wide input voltage range (voltage ranges ≈ 1:2) and high step-down multiple output conversion. A dc-DCX, which operates as a dc-dc converter with regulated output when the input voltage is low and as a dc-dc transformer with unregulated output when the input voltage is high, is adopted in the first stage to provide optimized intermediate dc-bus voltages for the second-stage point-of-load converters. The input and output of the dc-DCX are in series and connected to the total input voltage. Hence, part of the input power is directly transferred to the intermediate bus without conversion. The devices' voltage stresses and the transformer turns ratio of the dc-DCX are reduced by using the proposed quasi two-stage architecture. Thus, the conversion efficiency is improved significantly. Furthermore, a dual-output LLC resonant converter with hybrid center-tapped and full-bridge rectifier is proposed for the dc-DCX to achieve high efficiency and high power density. A 100-W prototype with three outputs is built and tested to verify the analysis.

A Very Low-Profile Dual Output LLC Resonant Converter for LCD/LED TV Applications

The concept of low-profile power supply becomes a current issue because of the recent trends in LCD/LED TV consumer market. Realizing a low-profile power supply with high power density is a challenging work due to the size limitation of passive components. In this paper, a very low-profile dual output LLC resonant converter proposed by considering the criteria of 10 mm component height limit without any drop-in cuts on the surface of printed circuit board. The simulation model of the converter is applied to the SPICE tool in order to estimate the performance and borders of the passive components. On the basis of theoretical approach and simulation results, two low-profile transformers are utilized in order to acquire a prototype with 200 W output power (24 V/6 A and 12 V/4.5 A). LLC series resonant converter prototype with the dimension of 140 mm × 291 mm × 10 mm achieves 89.4% efficiency at nominal load conditions. The input voltage range is between 330 to 400 V and the nominal input voltage is specified as 400 V. Operating frequencies are obtained as 65 and 81 KHz at 330 and 400 V, respectively, under the nominal load conditions. Thermal and electromagnetic interference performances of the proposed converter are included in the paper to validate experimental study.

High-Efficiency and Low-Cost Tightly Regulated Dual-Output $LLC$ Resonant Converter

A new high-efficiency and cost-effective dual-output LLC resonant converter is proposed in this paper. It can achieve tightly regulated dual-output voltages by using the only one auxiliary switch and pulsewidth modulation IC. Therefore, it features a simpler structure, less mass, and lower cost of production. Furthermore, since all power switches are turned on or off under zero-voltage or zero-current switching, it has several favorable advantages such as high efficiency, low switching loss, and reduced burden on the cooling system. To confirm the operation, validity, and features of the proposed converter, the operational principle, theoretical analysis, design considerations, and experimental results from a 420-W 200-Vdc/50-Vdc prototype applicable to the plasma display panel TV power supply are presented. The prototype shows as high power conversion efficiency as 96.5% at full load condition.

LLC 공진형 컨버터를 이용한 독립제어 가능한 2 채널 LED 구동회로

The independently regulated dual-output LLC resonant converter using only one power stage and one control IC is proposed in this paper. The conventional dual-output LLC resonant converter requires the extra non-isolated DC/DC converter to obtain the tightly regulated slave output voltage, which results in the low power conversion efficiency and high production costs. On the other hand, since the proposed converter controls the master and slave output voltages by pulse width modulation(PWM) and pulse frequency modulation(PFM), it can achieve tightly regulated dual output voltages without the additional non-isolated DC/DC converter. Therefore, it features a high efficiency and low cost. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a 40W LED driver prototype are presented.

Analysis and implementation of a dual-output LLC resonant converter

This article analyses and presents an LLC resonant converter with a high power factor for LCD-TV applications. It integrates the advantages of power factor correction and the LLC resonant converter. It can improve not only power quality but also circuit efficiency. Since the power factor corrector is used in the first stage of the LLC resonant converter, it is suitable for wide input voltage range application. On the basis of the resonant behaviour, zero voltage switching is achieved for the power switches and ZCS is achieved for the rectifier diodes. An experimental prototype of 90–260V rms input and 12V/10A and −12V/10A outputs with 92.6% efficiency for 32″ LCD-TV application is built in the laboratory to verify the operation principle of the adopted converter.