A Novel Polygon Based 18-Pulse AC–DC Converter for Vector Controlled Induction Motor Drives

This paper presents a novel configuration of an autotransformer based 18-pulse ac-dc converter for improving the power quality at the point of common coupling (PCC) in variable frequency induction motor drives (VFIMDs). The polygon based connection of autotransformer for achieving 18-pulse rectification is utilized to result in reduction in rating of the magnetics. The design of the autotransformer is carried out for an 18-pulse ac-dc converter feeding a vector controlled induction motor drive (VCIMD). Moreover, the autotransformer design is modified for making it suitable for retrofit applications, where presently a 6-pulse diode bridge rectifier is used. The effect of load variation on VCIMD is also studied and the performance of the proposed 18-pulse ac-dc converter is compared in terms of different power quality indices on both ac as well as dc side with other ac-dc converters. A laboratory prototype of the proposed autotransformer based 18-pulse ac-dc converter feeding a 10-hp induction motor drive is developed to verify the design and simulated results     

A Novel ZVS Resonant Reset Dual Switch Forward DC–DC Converter

This paper presents a new topology named zero-voltage switching (ZVS) resonant reset dual switch forward dc-dc converter, which, compared with resonant reset single switch forward dc-dc converter, maintains the advantage that duty cycle can be more than 50%, at the same time disadvantages of high voltage stress for main switches and low efficiency are overcome. In addition, ZVS is achieved for all switches of the presented topology. Therefore, this proposed topology is very attractive for high voltage input, wide range, and high efficiency applications. In this paper, the operation principle and characteristic of this topology are analyzed in detail. Next, the design consideration is presented. Finally, the advantages mentioned above are verified by experimental results     

Optimum Trajectory Switching Control for Series-Parallel Resonant Converter

The series-parallel resonant converter (SPRC) is known to have combined merits of the series resonant converter (SRC) and PRC. However, the SPRC has a three-element LCC structure with complex transient dynamics, and without control of the resonant circuit's dynamics, the converter's closed-loop bandwidth to switching-frequency ratio will be much reduced compared to that of pulsewidth-modulation (PWM) converters. This paper presents the optimal trajectory enabling any SPRC's steady state be achieved within one cycle. Dynamics using the state-plane analysis is presented, and the optimal state trajectory for transients is derived. Experimental results with comparison to frequency control show much reduced resonant circuit response time for step changes in output voltage. This improved resonant circuit control allows subsequent current and voltage-loop controls of the SPRC to be treated as that of a conventional PWM voltage source     

半桥串并联谐振变换器的分析与设计

详细介绍了串并联谐振变换器(LCC型)在f_s>f_r下的工作原理,根据等效电路给出了稳态分析及最佳设计原则。最后以100kHz半桥ZVS-SPRC实验电路为例,给出了简单设计步骤、实验结果及相关波形。     

Experimental Study of a Soft-Switched Isolated Bidirectional AC–DC Converter Without Auxiliary Circuit

An isolated ac-dc converter topology includes a capacitively snubbered voltage source converter (VSC) and a cycloconverter, coupled by a medium frequency transformer. The topology offers the possibility of bilateral power flow as well as three-level pulse width modulation on the ac side. It is shown that by alternately commutating the VSC and the cycloconverter it is possible to achieve either zero-voltage or zero-current switching conditions for all semiconductor devices in all points of operation. This is the case without any need for auxiliary semiconductor devices. At low load the transformer current may be insufficient for recharging the VSC snubber capacitors. In this case, however, it is possible to utilize the cycloconverter for providing a current path by which a quasi-resonant commutation can be made. The design and operation of a 40-kVA prototype converter system is described. It is shown how the rather complex switching logic required for implementing the chosen algorithm for commutation and modulation can be realized by using modern programmable logic devices [field programmable gate array (FPGA)]. Measurement results from the prototype converter are presented and analyzed. The measurements indicate that the studied commutation algorithm works well in practice     

Generalized Optimal Trajectory Control for Closed Loop Control of Series-Parallel Resonant Converter

The series parallel resonant converter (SPRC) is known to have combined the merits of the series resonant converter (SRC) and the parallel resonant converter (PRC). However, the series PRC (SPRC) has a three-element LCC structure with complex transient dynamics and without control of the resonant circuit's dynamics, the converter's closed loop bandwidth to switching frequency ratio will be much reduced compared to that of pulsewidth modulation converters. In this paper, the generalized optimal trajectory control (GOTC) for the SPRC is presented. It allows the nonlinear resonant circuit of the SPRC having an arbitrary starting state to reach a desired steady state in one cycle with two optimally controlled switching instances. It is a generalized form of optimal trajectory control (OTC) which is restricted to transitions between steady states. Based on GOTC, a traditional controller with inner current and outer voltage state-feedback is designed for an SPRC based dc–dc converter. The GOTC based feedback controller allows use of higher feedback gains compared with one using OTC or frequency control and gives higher closed loop bandwidth. This results in either better disturbance rejection for the converter or the possibility of reducing output filter sizing. Experimental results confirm the theoretical claims.     

一种新型高电压ZVZCS三电平DC/DC变换器的研究

介绍一种适用于高电压场合的新型ZVZCS三电平DC／DC变换器，详细分析了电路的工作原理。设计实例和仿真结果验证了理论分析的正确性。     

一种新型正激零电压零电流转换PWM DC/DC变换器

提出一种新型的零电压零电流转换(ZCZVT)的正激拓扑。拓扑工作频率为300kHz,能实现主开关管的零电压开通(ZVS)和零电流关断(ZCS),同时辅助开关管也能实现零电流关断(ZCS),且变压器的磁通复位不需要辅助绕组。文章进行了拓扑的稳态分析,并且讨论了谐振电路的参数设计。最后,在研制一台48V输入、12V/100W输出样机的基础上,实验验证这种新型正激ZCZVT PWM DC-DC变换器的软开关特性。     

Hybrid Full-Bridge Three-Level LLC Resonant Converter—A Novel DC–DC Converter Suitable for Fuel-Cell Power System

This paper proposes a novel hybrid full-bridge (H-FB) three-level (TL) LLC resonant converter. It integrates the advantages of the H-FB TL converter and the LLC resonant converter. It can operate under both three-level mode and two-level mode, so it is very suitable for wide-input-voltage-range applications, such as fuel-cell power systems. Compared with the traditional full-bridge converter, the input current ripple and output filter can be reduced. In addition, all the switches can realize zero-voltage switching from nearly zero to full load, and the switches of the TL leg sustain only half of the input voltage. Moreover, the rectifier diodes can achieve zero-current switching, and the voltage stress across them can be minimized to the output voltage. A prototype of 200-400-V input and 360-V/4-A output is built in our laboratory to verify the operation principle of the proposed converter     

一种DC/DC变换器的设计与实现

本文介绍了一种新颖的具有升降压功能的DC/DC变换器的设计与实现，具体地分析了该DC/DC变换器的设计（拓扑结构、工作模式和储能电感参数的设计），详细地阐述了该DC/DC变换器控制系统的原理和实现，最后给出了测试结果。     

A Novel Robust Control Method for the Series–Parallel Resonant Converter

A novel robust control method for the series–parallel resonant converter (SPRC), which moves the inverter switching point to switch in advance or with lag w.r.t. the rectifier commutation point (RCP), thereby varying the converter gain around the load-independent point, is presented. The converter gain is derived using a novel analytical tool that combines state-plane analysis and superposition with added RCP constraint. Unlike traditional fundamental harmonic analysis , the exact gain and frequency expressions for the SPRC at the load-independent point and its neighborhood are obtained with this method. The proposed gain adjustment technique is combined with feedback to form a simple resonant converter controller. This control method is shown to be highly robust to resonant tank parameter uncertainty and circuit/switching delay. It also significantly simplifies the resonant converter controller's design.      

新型三相谐振直流环节逆变器

为实现三相逆变器的高效率运行,提出了一种新型三相谐振直流环节逆变器拓扑结构,其在直流环节设置了结构简单的辅助谐振电路.分析了电路的工作流程.实验结果表明开关器件实现了软切换,而且逆变器输出电流波形无明显畸变.因此,该逆变器能实现高效率稳定运行.     

DC/DC Buck-Boost Converter with Single Inductance

Russian Microelectronics - The results of a study on the energy and noise characteristics of a DC/DC converter for battery-powered devices that maintains a stabilized output voltage at an input...     

一种新的应用于开关电容DC/DC转换器的补偿电路

采用Chartered 0.35μm CMOS工艺,设计实现了输入电压范围2.7～5.5 V,负载电流高达200mA的降压式开关电容型DC/DC转换器.为了在整个输入电压和负载电流范围内稳定输出电压,并且提高输出电压精确度,在对开关电容转换器环路建模分析后,提出了一个新的应用于开关电容DC/DC转换器的频率补偿电路.该...     

一种针对LLC串联谐振变换器的精确设计方法

本文针对LLC串联谐振变换器提出了一种新颖的基于时域分析的精确分析方法，给出了设计。的准则和流程。LLC串联谐振变换器具有拓扑结构简单，高效率和易高频化的特点，目前得到了广泛的应用。为了优化设计并澄清其设计准则，充分理解该拓扑的直流增益特性以及各参数对效率的影响显得尤为重要。而基于基波近似的传统频域分析方法难于给出准确的结果。本文依照所提出的精确分析设计方法，搭建并测试了一个MHz的LLC串联谐振变换器，其效率达96％。试验结果证实了所提出的时域分析方法和设计准则的有效性。     

单＋5V供电的计算机固态电源变换器

论述了一种可以从＋５Ｖ电源得到±１２Ｖ的新型开关电容ＤＣ－ＤＣ变换器。它的结构中不含电感，因而便于集成，使计算机系统组成和联接简化。对电路的工作原理、效率、纹波及设计作了深入的探讨。ＳＰＩＣＥ仿真和实验结果均证实了该设计方案的可行性     

带有箝位二极管的ZVS全桥三电平DC/DC变换器的研究

介绍了一种改进型的带有箝位二极管的零电压开关(ZVS)全桥三电平DC/DC变换器,详细分析了电路的工作原理。设计实例和仿真结果验证了理论分析的正确性。     

一种自驱动型LLC半桥谐振变换器的研究

在三谐振LLC变换器基础上,简化控制电路,提出了一种新型的LLC型自驱动半桥谐振变换器拓扑,并分析了该变换器的工作原理。由于它与传统谐振变换器相比,省略了昂贵的半桥驱动芯片和复杂的变频控制策略,实现了全负载范围内零电压开关,提高了变换器的效率、可靠性及功率密度,降低了成本。所以该拓扑十分适合应用于中间母线式变换器中,文中详细讨论了其参数设计。     

A Novel High-Power-Density Three-Level LCC Resonant Converter With Constant-Power-Factor-Control for Charging Applications

This paper proposes a variable-frequency zero-voltage-switching (ZVS) three-level LCC resonant converter that is able to utilize the parasitic components of the high turns-ratio transformer. By applying a three-level structure to the primary side, the voltage stress of the primary switches is half of the input voltage. Low-voltage MOSFETs with better performance can be used in this converter, and zero-current-switching (ZCS) is achieved for rectifier diodes. By applying a magnetic integration technique, only one magnetic component is required in this converter. The power factor concept of resonant converters is proposed and analyzed, and a novel constant power-factor control scheme is proposed. Based on this control strategy, the circulating energy of resonant converters is considerably reduced. High efficiency can be obtained for high-voltage high-power charging applications. The operation principle of the converter is analyzed and verified on a 700-kHz, 3.7-kW prototype, with which a power density of 72 ${hbox {W/inch}}^{3}$ is achieved.