Query: Interleaved LLC series converter with output voltage doubler

Candidate papers:

abstract: A parallel LLC series resonant converter with output voltage doubler is presented in this paper. The interleaved pulse width modulation (PWM) technique is adopted to reduce the ripple current on input and output capacitors. The capacitance of input and output capacitors can be reduced. The high current stress drawback of conventional LLC resonant converter is overcome by the proposed converter. Thus the adopted converter can be applied for high output current applications. Based on the series resonant behavior, all power switches are turned on at zero voltage switching (ZVS) and the rectifier diodes can be turned off at zero current switching (ZCS) Thus the switching losses on power semiconductors are reduced. In the output side, the voltage doubler topology is adopted for high output voltage applications. Compared with the conventional LLC converter, the advantages of the proposed circuit are low ripple currents on input and output terminals, small size and light weight of transformer, and low conduction losses on power semiconductors. In this paper, the principle of operation, steady state analysis and design consideration of the proposed converter are provided and discussed. In order to validate the proposed converter, the laboratory experiments with 24V/40A output for server power supply were provided.
author_names: B R Lin

Wen-Ren Yang

Jyun-Ji Chen

Chien-Lan Huang

Ming-Hung Yu
title: Interleaved LLC series converter with output voltage doubler
venue: The 2010 International Power Electronics Conference ECCE ASIA
year: 2010

abstract: This paper proposes an interleaved Inductor Inductor Capacitor resonant converter with cascaded voltage doubler circuits for deeply depleted plug in electric vehicle battery charging. The use of voltage double circuits extends the operating range of converter by mitigating the effects of transformer's parasitic capacitors. The converter has two modes of operation: simultaneous and independent. In the former mode both interleaving converters operate together at the same frequency and in the later mode only one converter operates. In the former mode, it yields twofold higher gain compared to the later one. Thus, operation with combined mode changing and frequency control results in wider output voltage range. For confirmation, a laboratory prototype rated at input dc voltage of 400 V and output power of 1.5 kW is designed, and implemented. The results obtained from the prototype show that converter achieves a wide output voltage range of 100 420 V when operated in simultaneous mode with simple frequency control and an output voltage range of 50 100 V in the independent mode. With combined frequency and mode changing control, it achieves an output range of 50 420 V. The peak efficiency of converter was measured to be 95.65% at a peak power of 1.5 kW. Thus, the proposed converter is suitable for the dc dc stage of on board PEV battery charger.
author_names: M Imran Shahzad

Shahid Iqbal

Soib Taib
title: Interleaved LLC Converter With Cascaded Voltage Doubler Rectifiers for Deeply Depleted PEV Battery Charging
venue: IEEE Transactions on Transportation Electrification
year: 2018

abstract: This paper proposes an LLC resonant converter with parallel series transformer connection and voltage doubler rectifier (PSVD LLC) i.e. LLC circuit structure in which the transformers are parallel series connected and the secondary side is voltage doubler rectifier. The parallel series connection can reduce the turns ratio of the transformer. And the use of the characteristics of the voltage doubler rectifier circuit improves the efficiency of the system, especially in the application of high frequency, low input voltage and high output voltage. This paper introduces the structure and working modes of the proposed circuit and analyzes the principle of how this circuit improves efficiency. A 1000W prototype of the proposed circuit is established to verify the effectiveness of the scheme.
author_names: Jiaxuan Zhou

Hao Ma
title: Full Bridge LLC Resonant Converter with Parallel Series Transformer Connection and Voltage Doubler Rectifier
venue: 2019 10th International Conference on Power Electronics and ECCE Asia (ICPE 2019 ECCE Asia)
year: 2019

abstract: Conventional frequency modulated LLC topology is unsuitable for ultrawide voltage range applications and suffers from poor voltage regulation performance at light load conditions. To cope with those issues, this article proposes a novel two phase dual LLC resonant converter. The primary side of the proposed converter is two paralleled half bridges LLC, and the transformers' secondary sides are in reverse series with shared full bridge rectifier. Both resonant tanks are driven by two fixed frequency square waves, whose frequencies are always tuned at the optimal resonant frequency. A phase shift is introduced between those two square waves to regulate the output voltage. The proposed topology demonstrates good voltage regulation performance, which is weakly dependent on the load condition. Zero voltage switching and zero current switching are well realized on the power mosfets and diodes in a wide range. A 1 kW rated laboratory prototype is designed to convert 390 V input to 10 420 V output. The prototype demonstrates a 98.1% peak efficiency and good voltage regulation capability. The experimental results agree well with the theoretical analysis.
author_names: Bo Xue

Haoyu Wang

Junrui Liang

Qi Cao

Zhiqing Li
title: Phase Shift Modulated Interleaved LLC Converter With Ultrawide Output Voltage Range
venue: IEEE Transactions on Power Electronics
year: 2021

abstract: The low transfer efficiency occurs in low line condition for general conventional power factor correction rectifier. This drawback can be improved by proposing Power Factor Correction (PFC) with voltage doubler characteristic and the topology can be seen on Salmon [1] and Maksimovic and Erickson [2] The Voltage doubler circuit applied in boost PFC converter to gain 400 V output was reported on Musavi et al. [3] However, PFC circuit should have multiple switches to realize function of double voltage in low line condition, it is not suitable for server power due to the issues of efficiency, reliability, and cost. Besides, the electric vehicle with plug in charging storage system can be charged through outside recycling system. The charging infrastructure always composes of AC/DC converter with power factor correction function in conjunction with series DC/DC buck converter structure. Preliminary stage AC/DC converter is important power stage module of electric vehicle (EV) battery charger as stated in Musavi et al. [3] is redrawn as Figure 1. The other literatures as Lai and Ho [4] Ryu et al. [5] Moon et al. [6] are the controlled the algorithm methodology related to EV application circuits and converters. The proposed PFC boost converter with voltage double characteristic improves efficiency of current interleave bridgeless PFC operated in low line and light load condition and meet input current harmonics specification as well. It can reach high power factor and high efficiency and suitable to apply for EV battery storage and charging system to have power reaching 3.4 kW. 2. OPERATING ANALYSIS
author_names: Chihchiang Hua

Ching-Chun Chuang

Hung-Chi Lee

Chih-Wei Chuang

Chuan-Ming Niu
title: Research on a Bridgeless Interleaved PFC Boost Converter with Voltage Doubler Feature
venue: J. Robotics Netw. Artif. Life
year: 2020

abstract: A family of two phase interleaved LLC (iLLC) resonant converter with hybrid rectifier is proposed for wide output voltage range applications. The primary sides of the two LLC converters are in parallel, and the connection of the secondary windings in the two LLC converters can be regulated by the hybrid rectifier according to the output voltage. Variable frequency control is employed to regulate the output voltage and the secondary windings are in series when the output voltage is high. Fixed frequency phase shift control is adopted to regulate the configuration of the secondary windings as well as the output voltage when the output voltage is low. The output voltage range is extended by adaptively changing the configuration of the hybrid rectifier, which results in reduced switching frequency range, circulating current, and conduction losses of the LLC resonant tank. Zero voltage switching and zero current switching are achieved for all the active switches and diodes, respectively, within the entire operation range. The operation principles are analyzed and a 3.5 kW prototype with 400 V input voltage and 150 500 V output voltage is built and tested to evaluate the feasibility of the proposed method.
author_names: Hongfei Wu

Xiaohai Zhan

Yan Xing
title: Interleaved LLC Resonant Converter With Hybrid Rectifier and Variable Frequency Plus Phase Shift Control for Wide Output Voltage Range Applications
venue: IEEE Transactions on Power Electronics
year: 2017

abstract: ABSTRACT High efficiency and simple structure are the main reasons for the widespread use of LLC converters. Nowadays, the application of LLC converters is still in development. In general, increasing the power level to use a parallel converter is quite popular. However, this method uses a separate transformer, which will lead to an obvious decrease in power density. Moreover, the separate transformer will also cause current imbalance due to the error of the magnetic material characteristic. Therefore, this study proposes an integrated transformer for a conventional interleaved LLC converter. This proposed structure can effectively increase the power density and decrease the problem of current imbalance. The operating principle of the interleaved LLC converter and an analysis of the integrated transformer are presented. Finally, experimental results are recorded for a prototype converter. The specifications are as follows: DC input voltage is 380 VDC, output voltage is 12 VDC, maximum output current is 50 A, output power is 600 W, and maximum conversion efficiency is approximately 95.5%
author_names: Yi-Feng Lin

Chuanbiao Chen

Zong-Xian Jiang

Jing-Yuan Lin
title: Interleaved LLC half bridge series resonant converter with integrated transformer
year: 2021

abstract: An Interleaved Voltage Doubler Boost Converter (IVDBC) using digitalized average current control to achieve Power Factor Correction (PFC) is proposed in this paper. The basic circuit configuration of proposed IVDBC is a two phase interleaved boost converter and a full wave voltage doubler rectifier in series. The capacitors of the voltage doubler circuit are charged alternately by the two phase interleaved operation; therefore, the voltage conversion gain of the IVDBC is twice that of a conventional interleaved boost converter. Consequently, the proposed IVDBC is probable to be used for high voltage applications. A TI TMS320F28335 is used in this paper to design and implement the average current control scheme for the IVDBC. A prototype circuit with an AC input voltage of 110V, DC output voltages between 400V to 700V and a rated output current of 1.4A is realized in this paper. Experimental results indicate that the Total Harmonic Distortion (THD) and power factor of input current of the proposed IVDBC for PFC can conform the requirements of international regulations. Besides, a maximum conversion efficiency of 94.07% can be achieved.
author_names: Bo-Jia Huang
title: Interleaved Voltage Doubler Boost Converter for Power Factor Correction
venue: 2018 International Power Electronics Conference (IPEC Niigata 2018 ECCE Asia)
year: 2018

abstract: A new interleaved high step up isolated DC DC converter with zero voltage switching (ZVS) is proposed in this paper. The configuration is composed of the active clamp circuits and voltage doubler circuits with parallel input series output structure. The active clamp circuits are used to achieve ZVS performance for the power switches such that the switching losses are reduced. The voltage doubler circuits are used to obtain high voltage gain. The voltage stresses on the power switches are greatly lower than the output voltage such that the low voltage rated MOSFETs with low on resistances can be adopted to reduce the conduction losses. The input ripple current is reduced by the interleaved operation. The energy stored in leakage inductances of the coupled inductors is recycled to avoid the voltage spike on the main switches. The operating principle and steady state analysis of the proposed converter are presented in detail. Finally, a 1000 W prototype converter with 36 V input and 380 V output is built and tested in the laboratory. The experimental results are presented to validate the feasibility and the performance of the proposed converter.
author_names: Shin-Ju Chen

Shang-Yi Yang
title: Analysis and Implementation of An Interleaved High Step Up Isolated DC DC Converter with Zero Voltage Switching
venue: IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society
year: 2020

abstract: This paper presents a tightly regulated multi output isolated converter that employs only an independently regulated synchronous Single Switched Post Regulator (SSPR) The proposed converter is a highly accurate single ended secondary side post regulator based on a Series Resonant Converter (SRC) furthermore, it has a voltage doubler characteristic. The proposed post regulator requires only one auxiliary switch, in contrast with a bulky and expensive non isolated DC DC converter. Moreover, the added voltage doubler can tightly regulate the slave output current. In addition, the voltage doubler can improve electromagnetic interference characteristics and reduce switching losses arising from the Zero Current Switching (ZCS) operation of all power switches. The validity of the proposed converter is verified using experimental results obtained via a prototype converter applicable to an LED 3D TV power supply.
author_names: Sang Gab Park

Byoung-Kuk Lee

Jong-Soo Kim
title: Optimal Design of Multi Output LLC Resonant Converter with Independently Regulated Synchronous Single Switched Power Regulator
year: 2020