High-power High-efficient and Simplified High-frequency Switching Power Supply for Electrolytic Plating

针对大功率电解电镀开关电源的输入整流级引起的无功和谐波等电能质量问题,研究了一种基于高效PWM整流的高频开关电源。该电源前级整流器仅用4个开关管来进行PWM整流,后级采用半桥逆变器进行高频变换,显著减少了开关数量。针对三相四开关PWM整流器,推导一种基于开关模型的无差拍控制方法,该方法可实现系统的快速、无差整流。针对多台开关电源的并联均流问题,提出一种基于虚拟阻抗的自均流控制方法,可实现多台电源的均流稳定运行。通过仿真与实验验证了所提结构和控制方法的正确性。

A Novel Half-Bridge Power Supply for High Speed Drilling Electrical Discharge Machining

High Speed Drilling Electrical Discharge Machining (HSDEDM) uses controlled electric sparks to erode the metal in a work-piece. Through the years, HSDEDM process has widely been used in high speed drilling and in manufacturing large aspect ratio holes for hard-to-machine material. The power supplies of HSDEDM providing high power applica-tions can have different topologies. In this paper, a novel Pulsed-Width-Modulated (PWM) half-bridge HSDEDM power supply that achieves Zero-Voltage-Switching (ZVS) for switches and Zero-Current-Switching (ZCS) for the dis-charge gap has been developed. This power supply has excellent features that include minimal component count and inherent protection under short circuit conditions. This topology has an energy conservation feature and removes the need for output bulk capacitors and resistances. Energy used in the erosion process will be controlled by the switched IGBTs in the half-bridge network and be transferred to the gap between the tool and work-piece. The relative tool wear and machining speed of our proposed topology have been compared with that of a normal power supply with current limiting resistances.

Charging System of ECRH High-Voltage Power Supply and its Control System

High-voltage power supply (HVPS) of Electron Cyclotron Resonance Heating (ECRH) for HT-7 and HT-7U is presently being constructed. The high voltage (100 kV) energy of HVPS is stored in the capacitor banks, and they can power one or two gyrotrons. All the operation of the charging system will be done by the control system, where the field signals are interfaced to programmable logic controller (PLC). The use of PLC not only simplifies the control system, but also enhances the reliability. The software written by using configuration software installed in the master computer allows for remote and multiple operator control, and the status and data information is also remotely available.

Design and Simulation of a Electrorheological(ER) Control High Voltage Power Supply

Few applications with electrorheological （ER） fluids have been found in industry. One reason is high voltage power supplies cannot meet the requirement for ER effect. In this paper, an ER control high voltage power supply for engineering application was designed which reduced power wastage by adopting soft switch technology; lessened its volume to satisfy micromation when adopting the planar transformer and improved its response character- istic by choosing an assistant discharging circuit. Simultaneously, a simulation analysis has been carried out. As results, the output voltage of this high voltage power supply is 5 kV, and the voltage can be continuously regulated and the voltage ripple is only 0. 7 %, so the requirement of stability is also achieved.

Investigation on latch-up susceptibility induced by high-power microwave in complementary metal–oxide–semiconductor inverter

The latch-up effect induced by high-power microwave（HPM） in complementary metal–oxide–semiconductor（CMOS） inverter is investigated in simulation and theory in this paper. The physical mechanisms of excess carrier injection and HPM-induced latch-up are proposed. Analysis on upset characteristic under pulsed wave reveals increasing susceptibility under shorter-width pulsed wave which satisfies experimental data, and the dependence of upset threshold on pulse repetitive frequency（PRF） is believed to be due to the accumulation of excess carriers. Moreover, the trend that HPMinduced latch-up is more likely to happen in shallow-well device is proposed.Finally, the process of self-recovery which is ever-reported in experiment with its correlation with supply voltage and power level is elaborated, and the conclusions are consistent with reported experimental results.

A Study on the Conducted Interference of Capacitor Charging Power Supply

In this paper, a mathematical analysis of the EMI (Electromagnetic Interference) for a 20 kHz/10 kV capacitor charging power supply in frequency-domain is presented, and a related circuit model considering the transient switching interference is proposed. Due to the high working frequency and the device-switching transitions, the conducted EMI caused by the charging circuit which includes the harmonics of grid frequency, working frequency and device-switching transition frequencies. Thus under certain working situations or loads parallel power supply, the interference may cause charging failure. To solve this problem, a high frequency transformer modeled with stray capacitances and an approximation of the device-switching transition is applied in the Spice-based simulation model, and a mathematical analysis in frequency-domain is presented.

Features and Prototypes of HTS High Q Resonant Circuit

High Te superconductor （HTS） technology has been used to develop a unique high Q resonant circuit. Such circuit or device has some special characteristics such as very high voltage generation. Theoretical study and experimental approaches have proceeded for the concept verification. This paper presents the theory about this high Q resonant circuit. The operation principle of the circuit is described. A practical prototype for HTS high voltage generation is also demonstrated. The experiment result shows that very high voltages can be achieved by the developed method using HTS technology.

基于PowerEsim的开关电源的高频变压器设计

高频开关电源中,变压器受更多寄生参数的影响,对开关电源的影响也越来越大。因此,高频开关电源设计时,高频变压器的设计是重中之重。本文对高频变压器的设计进行了分析,应用PowerEsim软件对变压器的参数进行了优化,提高了开关电源的效率。

A review of high frequency resonant DC-DC power converters:Topologies and planar magnetic technologies

With the development of high frequency resonant DC-DC power converters,the system efficiency,power density and dynamic characteristics have been significantly improved.High frequency resonant DC-DC converters have been applied in DC grid,renewable energy,transportation,aerospace,point-of-load(POL)power supply and many other fields.Under high switching frequencies,switching loss and magnetic loss are the main concerns;thus,the resonant topology and planar magnetic are two key technologies to reduce loss.This review compares different resonant topologies and analyzes the advantages and disadvantages respectively,such as LLC circuit,dual active bridge(DAB)circuit,and other high order resonant circuits.For planar magnetic components,optimal winding structures,modeling methods and integration methods are thoroughly surveyed.With corresponding topics,the opportunities and challenges in the future development are summarized,which mainly focus on the characteristics of wide bandgap devices,such as the dynamic resistance,output capacitance loss and also the integrated module.This review can be a helpful guidance when designing high frequency resonant DC-DC converters.

A new method of analysing the intracerebral haemorrhage signal intensity on brain MRI images using frequency domain techniques

Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) has become an established part of neuroimaging and is used to diagnose and characterize several neurologic disorders. Intracerebral Haemorrhage (ICH) is a severe medical condition, which may develop quickly into a life-threatening situation, and thereby requires prompt medical attention. Early and reliable identification of the age of haemorrhage is essential when choosing the correct treatment, and estimating patient’s diagnosis and outcome. Diffusion Weighted (DW) images presents a variation in the image signal intensity characteristics relative to the different stages of ICH. In the present paper, an effort is made to document the variation in the image signal intensity characteristics of ICH at evolving stages, for 30 subjects, using High Frequency Power (HFP) parameter. Results showed that the difference in the HFP values on DW images for the subjects with ICH com- pared to their contralateral normal hemisphere, were highly significant (p 14 days). There was a negative correlation (r = ?0.81) observed between the RHFP values and the evolving stages of ICH. The results indicate that the quantitative changes in the RHFP values can be assessed to derive information about the stage of ICH, and their adoption in clinical diagnosis and treatment could be helpful and informative.

All-dielectric frequency selective surface design based on dielectric resonator

In this work,we propose an all-dielectric frequency selective surface（FSS） composed of periodically placed highpermittivity dielectric resonators and a three-dimensional（3D） printed supporter.Mie resonances in the dielectric resonators offer strong electric and magnetic dipoles,quadrupoles,and higher order terms.The re-radiated electric and magnetic fields by these multipoles interact with the incident fields,which leads to total reflection or total transmission in some special frequency bands.The measured results of the fabricated FSS demonstrate a stopband fractional bandwidth（FBW）of 22.2%,which is consistent with the simulated result.

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%.

Application of GaN in Hard-switching Converters:Challenges and Potential Solutions

This paper overviews the benefits,challenges,research trends and potential solutions on the design and application of gallium nitride(GaN) technology in hard-switching power electronic converters from the device level up to converter level.

基于频率切换实现恒流/恒压输出的电场耦合无线电能传输系统

电场耦合无线电能传输(electric-field coupled wireless power transfer,EC-WPT)技术的实际应用中,有些用电设备需要系统具有不同的恒定输出特性(恒流/恒压),即系统输出电压或输出电流与负载解耦,此外,系统还需具备在恒流、恒压模式间按需切换的功能。针对该需求,基于LC-CLC谐振网络提出1种具有恒流/恒压输出特性的EC-WPT系统,分析LC-CLC谐振网络特性,推导恒流/恒压输出特性的实现条件以及恒流频率和恒压频率的计算方法,并给出系统参数设计方法,分析系统对工作频率的敏感性。最后通过仿真和实验验证所提出的EC-WPT系统恒流/恒压输出特性及其参数设计方法的正确性和有效性。实验结果表明所提出的系统在输入电压恒定的不同负载工况下分别实现2 A的恒流输出以及96 V的恒压输出,其最大传输效率分别为87.83%及88.17%。

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.

一种低延时低功耗PWM比较器电路设计

设计了一种基于HHGrace 0.35μm BCD工艺的低延时低功耗电压型静态脉冲宽度调制(Pulse Width Modulation,PWM)比较器,主要应用于高频低功耗的开关电源系统。设计中包含动态尾电流源和改进型正反馈放大器,以改进传统跨导放大器(Operational Transconductance Amplifier,OTA)型比较器高延迟和高功耗等问题。仿真结果表明:在1.2~5.0 V供电电压范围内稳定工作,最大上升沿延时35 ns,最大下降沿延时41 ns,支持6 MHz开关频率的系统,比较精度8 mV,失调电压439μV,静态功耗仅为2.5μA(1.2 V供电)和4.4μA(5.0 V供电)。

机载雷达开关电源新型防浪涌电路设计

针对机载雷达开关电源防浪涌电路在瞬态频繁开关机情况下失效率高的问题,研究了一种新型防浪涌电路。通过将栅源驱动电路和主功率充放电回路分离,分别对两个充放电时间常数独立设计,消除相关性,实现开关电源在瞬态频繁开关机状况下的有效防冲击保护。文中对常规和新型两种防浪涌电路进行了对比分析,仿真和试验结果证明了新型防浪涌电路的有效性。该电路同时具备输入防反接功能,已广泛应用于机载雷达开关电源设计。

基于FSM的并联谐振中频电源整流逆变调功控制

并联谐振晶闸管中频双控感应加热电源调功系统由整流和逆变两部分构成。调节整流单元的移相角,改变逆变单元的功率因数角都可影响谐振槽路的中频电压的输出,进而控制输出功率。在分析槽路中频逆变电压同晶闸管整流装置的移相角、逆变单元的功率因数角关系的基础上,提出了基于有限状态机(FSM)的并联谐振晶闸管中频电源整流-逆变调功方案。该方案采用控制层与调度层结构。控制层将中频电压作为闭环控制对象,分别以整流环节和逆变环节作为执行单元,设计具有鲁棒稳定性的移相整流控制器和锁相逆变控制器;调度层采用FSM结构,可根据加热工艺需求实现整流-逆变轮换调功和联合调功。该方案已经应用于多台大功率并联谐振晶闸管中频电源中,其可行性和有效性得到验证。

混合级联十一电平逆变器功率与开关损耗双均衡倍频调制方法

混合级联多电平逆变器可以利用较少的开关器件实现较高电平输出,进而得到了广泛应用;但实现高低压单元间功率均衡难度更大。直流侧采用电池组模块进行供电时,功率达不到均衡会使得各H桥单元对应的电池组模块处于不同的放电特性,增大了故障概率和维修难度且增加了后期的维修成本。针对此问题,提出2种1:1:1:2混合级联十一电平逆变器功率和开关损耗双均衡倍频调制方法。首先,2种方法分别对3个低压单元采用三角载波、重构载波进行移相,从而实现在全调制度范围内将逆变器的等效开关频率由fc提高至6fc/12fc;使得低压单元各开关器件开关次数均围绕在60次/174次左右上下浮动,实现了低压单元内开关损耗均衡;使得调制度M=0.9/0.6/0.3时低压单元输出功率均围绕在657.5 W/293.5 W/73.5 W上下浮动,实现低压单元间的功率均衡,其次对高压单元采用阶梯波低频调制,随调制度的变化对导通角进行动态调整,使得高压单元各开关器件开关次数均为1次,实现了高低压单元内开关损耗均衡;使得调制度M=0.9/0.6/0.3时高压单元与低压单元输出功率均围绕在1317 W/657.5 W、586 W/293.5 W、146.5 W/73.5 W上下浮动,实现了高低压单元间功率均衡,之后对比分析2种方法各自的优缺点及其适用场合。最后,通过实验验证该方法的正确性和可行性,并给出了直流电压比为1:1:1:...:x的混合级联H桥逆变器双均衡的普适方法。

基于LC谐振的半桥式高压除尘电源研究与设计

随着环保意识的加强,人们对各种工业尾气的排放要求越来越严,给厂矿企业带来了很大压力,针对该情况,研制一种可以产生高电压、小电流的高压除尘电源.设计了电源的LC谐振主电路和控制电路、保护电路,保证电源工作的安全性和可靠性.通过实验验证了电源具有工作频率范围宽,电压调节宽度大等特点,电源实用性强,具有广泛的推广应用价值.