Rugged Resonant Pole and Its Applications in Soft-Switching Converter

The soft switching operation principle and operation performance of rugged resonant pole (RRP) is given. The applications of RRP in soft switching DC DC converter and soft switching inverter are discussed in detail. RRP can constitute buck boost soft switching DC DC converter and isolated soft switching DC DC converter with the automatic limitation performance of output power. Partial series resonant DC DC converter with RRP can realize the zero voltage/zero current switching of power devices. RR...

Interleaved-Connected Split Planar Resonant Inductor Design in 1 kV SiC LLC Converters

Design method of split planar resonant inductor in 1 kV SiC logical link control(LLC)converter is proposed,which ensures the converter power density of 93.59 W/in^3 and peak efficiency of 95.73%.Split resonant inductor helps to provide symmetrical resonant current by symmetrical impedance,and improves the distortion of resonant current,which ensures the efficiency of the whole converter.An interleaved winding connecting scheme improves the power density of the planar magnets,which contributes to power density improvement.Design method and calculation process of such split planar resonant inductor are provided.To verify the feasibility of the proposed design method,a 1 kV/48 V 6.6 kW,210 k Hz SiC LLC prototype was built,and the experimental results are given.

Arm Voltage Balancing Control of Modular Multilevel Resonant Converter

Modular multilevel resonant converter is an promising candidate for high voltage applications since it has advantageous features,such as high efficiency,high voltage capability and easy fault-tolerant operation.However,the inequality of arm inductance in practice will lead to imbalance between the upper and lower arm voltages,which will induce large ripples in the circulating current and a dc bias on the voltage generated by modular circuits.To compensate for the voltage imbalance,effects of arm duty cycle changes on arm voltages are discussed.An arm voltage balancing control method is proposed:adjust arm duty cycle according to arm voltage deviation in every switching cycle.Simulation and experimental results are presented to validate the theoretical analysis and the proposed control method.

Performance Analysis of PI and Fuzzy Control for Modified LCC Resonant Converter Incorporating Boost Converter

In this paper, the modified LCC type of series-parallel Resonant Converter (RC) was designed and state-space modeling analysis was implemented. In this proposed converter, one leg of full bridge diode rectifier is replaced with Synchronous Rectifier (SR) switches. The proposed LCC converter is controlled using frequency modulation in the nominal state. During hold-up time, the SRswitches control is changed from in-phase to phase-shifted gate signal to obtain high DC voltage conversion ratio. Furthermore, the closed loop PI and fuzzy provide control on the output side without decreasing the switching frequency. The parameter such as conduction loss on primary and secondary side, switching loss, core and copper also reduced. Simultaneously, the efficiency is increased about 94.79 is realized by this scheme. The proposed converter with an input of 40 V is built to produce an output of 235 V with the help of ZVS boost converter [1] even under line and load disturbances. As a comparison, the closed loop fuzzy controller performance is feasible and less sensitive than PI controller.

Analysis and Design of a Kind of Improved Parallel Resonant Converters

Traditional transformer in high-voltage power supplies has many disadvantages such as high turn’s ratio, large volume and great design difficulties. Parallel resonant converters (PRCs) are widely used in high-voltage power supplies. A kind of high-voltage circuit topology can be formed by combining PRCs and voltage-doubler rectifier, which is called parallel resonant dual voltage converters (PRDVCs). In PRDVCs both voltage-doubler rectifier and transformer can boost voltage, which reduced turn’s ratio and volume of the transformer, making it easier to produce. Thus it not only realizes the high-voltage output, but also realizes the miniaturization of high-voltage power supply. Three modes of the converters were researched and simulated. Converting conditions of three modes were given. At last, PRDVCs was used to design a 5000V/50mA high-voltage power supply. The waveforms and results of the experiment were given, which validated the feasibility of the converters and its conversion efficiency might be improved to 93%.

Quasi-Square Wave Mode Phase-Shifted PWM LCC Resonant Converter for Regulated Power Supply

This paper presents an improved self sustained oscillating controller circuit using LCC components for improving the overall efficiency of the system. It has a micro controller based active controller, which controls the performance from no-load up to full-load. The steady state characteristics are developed and a design example is given in detail. The proposed controller allows zero current switching at any loading condition which results in a reasonable reduction of power loss during switching with a promising efficiency. Analytical and experimental results verify the achievement the design specifications.

Embedded Control of LCL Resonant Converter Analysis, Design, Simulation and Experimental Results

The Objective of this paper is to give more insight into CCM Operation of the LCL Converter to obtain op-timum design using state-space analysis and to verify the results using PSPICE Simulation for wide variation in loading conditions. LCL Resonant Full Bridge Converter (RFB) is a new, high performance DC-DC con-verter. High frequency dc-dc resonant converters are widely used in many space and radar power supplies owing to their small size and lightweight. The limitations of two element resonant topologies can be over-come by adding a third reactive element termed as modified series resonant converter (SRC). A three ele-ment resonant converter capable of driving voltage type load with load independent operation is presented. We have used embedded based triggering circuit and the embedded ‘C’ Program is checked in Keil Software and also triggering circuit is simulated in PSPICE Software. To compare the simulated results with hardware results and designed resonant converter is 200W and the switching frequency is 50 KHz.

Active Current Sharing of LCLC Resonant Converter with Switch-Controlled-Capacitor Technology

In this paper,an interleaved LCLC converter with enhancement-mode(E-mode)GaN devices is introduced to achieve the accurate current sharing performance for data center applications. Any tolerance in the resonant tank elements can lead to large load imbalance between any two different phases. Due to the steep gain curves of LCLC converters,conventional current sharing methods are not effective. In the proposed converter,the impedances of the resonant networks are matched by switching a capacitor,i.e.,switch controlled capacitor(SCC),in series with the resonant capacitor in one or some of the phases,which results in accurate load current sharing among the phases with an accuracy around 0.025%. The load share of a phase is sensed through the resonant current on it,and the control logic applied to such current sharing can be achieved. By this method,accurate current sharing is achieved for a wide input voltage range required for the hold-up time in data center applications. Interleaving is applied in the proposed multiphase LCLC converter,resulting in low current stress on the output capacitor and allowing ceramic capacitor implementation. Moreover,phase shedding accomplishes high light load efficiency. The performance of the proposed interleaved LCLC converter is verified by a two-phase 1 k W prototype with an input voltage ranging from 250 V to 400 V and a fixed 12 V output voltage.

A Resonant Dual Full-Bridge Class-E Bidirectional DC-DC Converter for Fuel Cell Electric Vehicle

The interests on energy storage schemes, bidirectional dc-dc converter and uninterruptible power supplies have been increasing nowadays as there wide researches are undertaken in the area of electric vehicles. A modified bi directional class-E resonant dc-dc converter is introduced here in this proposed topology for the application in electric vehicles. The advantages of soft switching techniques have been utilized for making analysis simple. The main advantage here in this system is that it can operate in a wide range of frequencies with minimal switching loss in transistors. This paper elaborates a detailed analysis on converter design and the same has been simulated and verified in Matlab/Simulink.

ANALYSIS OF ZERO-VOLTAGE QUASI-RESONANT BOOST DC-DC CONVERTER

The zero-voltage quasi-resonant boost switching DC-DC converter has been inves-tigated by using the time averaging equivalent circuit approach of periodically switching linearnetworks.The DC steady state and AC small signal characteristics of the converter are also given.

Fuzzy Logic Controlled Dual Active Bridge Series Resonant Converter for DC Smart Grid Application

Over the last few years, smart grids have become a topic of intensive research, development and deployment across the world. This is due to the fact that, through the smart grid, stable and reliable power systems can be achieved. This paper presents a fuzzy logic control for dual active bridge series resonant converters for DC smart grid application. The DC smart grid consists of wind turbine and photovoltaic generators, controllable and DC loads, and power converters. The proposed control method has been applied to the controllable load＇s and the grid side＇s dual active bridge series resonant converters for attaining control of the power system. It has been used for management of controllable load＇s state of charge, DC feeder＇s voltage stability during the loads and power variations from wind energy and photovoltaic generation and power flow management between the grid side and the DC smart grid. The effectiveness of the proposed DC smart grid operation has been verified by simulation results obtained by using MATLAB and PLECS cards.

High efficiency and high transmission asymmetric polarization converter with chiral metasurface in visible and near-infrared region

Polarization manipulation of light is of great importance because it could promote development of wireless communications,biosensing,and polarization imaging.In order to use natural light more efficiently,it is highly demanded to design and fabricate high performance asymmetric polarization converters which could covert the natural light to one particular linearly polarized light with high efficiency.Traditionally,polarizers could be achieved by controllers with crystals and polymers exhibiting birefringence.However,the polarizers are bulky in size and the theoretical conversion efficiency of the polarizers is limited to 0.5 with unpolarized light incidence.In this paper,we propose a polarization converter which could preserve high transmission for one linearly polarized light and convert the orthogonal linearly polarized light to its cross-polarized with high transmittance based on a multi-layer chiral metasurface.Theoretical results show that normally incident y-polarized light preserves high transmittance for the wavelength range from 685 nm to 800 nm while the orthogonal normally incident x-polarized light is efficiently converted to the y-polarized light with high transmittance from 725 nm to 748 nm.Accordingly,for unpolarized light incidence,transmittance larger than 0.5 has been successfully achieved in a broadband wavelength range from 712 nm to 773 nm with a maximum transmittance of 0.58 at 732 nm.

A NOVEL PHASE SHIFTED ZERO VOLTAGE SWITCHED PWM CONVERTER

Phase shifted converter realizes zero voltage switching (ZVS) with the use of leakage inductance of the main transformer, however, the realization of ZVS for lagging bridge leg is difficult. This paper proposes a current enhanced principle, and based on the principle, a novel phase shifted converter is proposed, which adds an auxi liary resonant net to the conventional full bridge converter to help the lagging bridge leg to realize ZVS. The principle and the design of the novel converter are analyzed, and the simulational and experimental results verify the principle.

Recent Developments of Modulation and Control for High-Power Current-Source-Converters Fed Electric Machine Systems

The pulse-width-modulated(PWM)current-source converters(CSCs)fed electric machine systems can be considered as a type of high reliability energy conversion systems,since they work with the long-life DC-link inductor and offer high fault-tolerant capability for short-circuit faults.Besides,they provide motor friendly waveforms and four-quadrant operation ability.Therefore,they are suitable for high-power applications of fans,pumps,compressors and wind power generation.The purpose of this paper is to comprehensively review recent developments of key technologies on modulation and control of high-power(HP)PWM-CSC fed electric machines systems,including reduction of low-order current harmonics,suppression of inductor–capacitor(LC)resonance,mitigation of common-mode voltage(CMV)and control of modular PWM-CSC fed systems.In particular,recent work on the overlapping effects during commutation,LC resonance suppression under fault-tolerant operation and collaboration of modular PMW-CSCs are described.Both theoretical analysis and some results in simulations and experiments are presented.Finally,a brief discussion regarding the future trend of the HP CSC fed electric machines systems is presented.

A zero-voltage transition for three-phase double-PWM voltage-fed converter

In comparison with several zero-voltage transition （ZVT） inverter topologies, a double-PWM converter is presented using a simple ZVT topology. The rectifier and inverter of this double-PWM share a set of commutation circuit which can provide soft-switching for the power devices and the diodes. The commutation circuit consists of 1 auxiliary device, 6 resonant inductors, and 12 diodes. Its topology is simpler than the conventional auxiliary resonant converter, leading to low loss and easy control. The control strategy and resonant working modes are analyzed. Experimental results show good performance of the system.

A novel design of power management integrated circuit with 90 plus efficiency used in AC/DC converter

Recently, resonant AC/DC converter has been accepted by the industry. However, the efficiency will be decreased at light load. So, a novel topology with critical controlling mode combined with resonant ones is proposed in this paper. The new topology can correspond to a 90 plus percent of power converting. So,a novel topology of an state of art integrated circuit, which can be used as power management circuit, has been designed based on the above new topology. A simulator which is specifically suitable for the power controller has been founded in this work and it has been used for the simulation of the novel architecture and the proposed integrated circuit.

Multi-Phase QR ZCS Switched-Capacitor Bidirectional Power Converter for PV System Application

The multi-phase implementation in the QR （quasi resonant） ZCS （zero current switching） SC （switched capacitor） bidirectional DC-DC converter structure has been proposed to reduce current ripple, switching loss and significantly increase the converter efficiency and power density. This approach provides a more precise output voltage to obtain voltage conversion ratios from the double-mode versus half-mode to n-mode versus 1/n mode. This is accomplished by adding a different number of switched-capacitors and power MOSFET switches with a small series connected resonant inductor for forward and reverse schemes. The size and cost can be reduced when the proposed converter has been designed with the coupled inductors. The simulation and experimental results have been used to demonstrate the performance of the two-phase with and without coupled inductor interleaved QR ZCS SC converters for bidirectional power flow control application, and an extending structure for N-phase is mentioned.

一种基于耦合电感的高增益软开关谐振变换器

该文提出了一种具有高增益、软开关的新型谐振变换器。该谐振变换器使用耦合电感来提高电压增益,升压比不仅取决于占空比,还取决于耦合电感的变比,具有高增益的优点。此外,由于采用了有源钳位技术,漏感中的能量可以被回收利用,用来对开关管的结电容充放电提供能量,从而实现软开关。由于采用了耦合电感,所提出的变换器可以在较低的开关管电压应力的情况下实现较高的输出电压,因此可以使用低导通电阻的低压器件,从而提升系统的效率。该文分析了该谐振变换器的工作原理,并推导了输出电压、关断电流应力等参数的解析表达式。在此基础上,从理论上分析了该变换器取得软开关的条件,并对该变换器的各个器件的电压电流应力进行分析,为器件选型提供了理论依据。最后,搭建1kW实验样机,针对该文提出的基于耦合电感的谐振变换器的高增益、软开关、低电压应力、高效率等性能进行了实验验证。通过实验得出所提出的拓扑可以在10倍增益的情况下达到最高97.5%的效率,表明所提拓扑的优越性。

应用于储能系统的CLLLC谐振变换器控制策略研究

动态性能和运行效率是CLLLC谐振变换器的重要性能指标。针对传统电压闭环控制加入电流驱动同步整流后系统动态性能进一步变差的问题,提出一种谐振电流内环的电压电流双闭环变频控制策略,并给出双环控制和同步整流的综合控制方法。首先根据变换器的增益特性,分析电感比和品质因数对增益曲线和效率的影响,并据此进行谐振参数设计;其次根据不同谐振状态下的谐振电流特性实现同步整流;最后引入谐振电流内环控制,实现双环控制和同步整流的综合控制。仿真结果表明,所提综合控制策略能够产生精确的同步整流驱动信号,相比于传统电压闭环控制,能够显著改善变换器对负载扰动和电压扰动的动态性能。

三相CLLC谐振变换器磁集成平面变压器设计与优化

三相CLLC谐振变换器凭借其高效率、大容量、低器件应力等优势而受到广泛关注。然而,多相结构的磁性元件数量多、体积大,是制约功率变换器尺寸的主要因素。随着宽禁带(WBG)半导体器件的出现,功率变换器的开关频率显著提高,这也为印制电路板(PCB)绕组的使用提供了有利条件。与传统绕线式绕组相比,PCB绕组的扁平特性更适用于平面磁性元件。此外,由于高频带来的低电感需求也使得基于PCB绕组的平面磁性元件更有利于实现集成。该文提出一种新型的基于PCB绕组的电感和变压器的集成结构,详细分析磁心结构的磁路模型,并给出集成磁件的优化设计方法,最后通过搭建一台基于SiC器件的800 V/10 kW的实验样机进行验证。实验结果表明,该集成方案可有效减小变换器的体积和损耗,具有高功率密度和高效率。