Turn-On and Turn-Off Characteristics of a 4.5-kV 3000-A Gate Turn-Off Thyristor

A 4.5-kV 3000-A gate turn-off (GTO) thyristor has been developed for use in high-power motor drive control equipment such as inverters and choppers. The high gate turn-off current of 3000 A is achieved by decreasing the variation of on-state voltages as well as turn-off times between segments which compose the GTO thyristor. This idea is supported by observation of infrared radiation during the turn-off process in the parallel operation of two segments with different on-state voltages or turn-off times. The parallel operation behavior is well simulated by a two-dimensional numerical simulation. Such design considerations and electrical characteristics of the newly developed high-power GTO thyristor are described. The device has a forward blocking capability of 4.5 kV, a maximum gate turn-off current of 3000 A, on-state voltage of 3.0 V at 3000 A, turn-on time of 10 ?s, and turn-off time of 25 ?s.     

Application of MTO thyristors in current stiff converters withresonant snubbers

This paper addresses the impact of power devices switching characteristics on design and performance of pulsewidth-modulated current stiff converter (CSC) topologies with resonant snubbers. The MOS turn-off (MTO) thyristors were selected for this study due to their high voltage and current ratings, simplified gatedrive circuitry, unity gain turn-off, greatly reduced storage time allowing higher switching frequencies, and reverse voltage blocking capability. The analysis presented in this paper is supported by experimental data obtained from a CSC commutation cell capable of reproducing all the commutation processes in the current stiff converter topologies with active resonant snubbers. Issues involved in the implementation of the commutation cell itself and MTO characteristics relevant for their operation in CSC topologies with resonant snubbers are addressed in detail in this paper     

逆变器开关管变驱动电流技术研究

传统的逆变器驱动电路中,驱动电流是按开关管最大关断电流下的最高电压尖峰来设计且是固定的,但在最大关断电流以下的工作状态,关断电压尖峰较小,IGBT有较大的安全电压裕量,牺牲了器件效率。为此提出一种逆变器变驱动电流技术及电路。该电路的驱动关断电流随开关管关断电流的下降而上升,提高了开关管在全负载范围下的关断速度,降低了IGBT的关断损耗。设计的原则是,关断电压尖峰不会超过最大允许值,且调节是实时进行的。讨论了关断电压尖峰与关断电流、驱动电流和漏感之间的关系。在一个230 V DC输入/80 V AC交流输出/500 W额定负载的单相半桥逆变器上进行测试,结果表明采用所提驱动电路,额定负载下效率较传统驱动提升近0.7%,实现了驱动电路的优化。     

Transient-Voltage Characteristics of Silicon Power Rectifiers

The behavior of ten types of silicon rectifiers under transient voltages was studied experimentally. The steady-state peak reverse voltage (PRV) ratings of these rectifiers were from 300-1200 V, and the half-cycle average current ratings were from 25-300 A. The study shows that, at least for the samples tested, the transient-voltage withstand capability of a silicon rectifier does not have any correlation with its PRV rating. A silicon rectifier may be damaged by a transient voltage lower than its PRV rating while it is carrying current in the forward direction. The transient-voltage withstand capability can also be widely divergent for different types of rectifiers of the same PRV rating. It is proposed that the transient-voltage withstand capability of each type of silicon rectifier should be specified along with its steady-state PRV rating.     

SOS半导体断路开关器件研制和实验研究

半导体断路开关是一种新型固体开关器件,具有反向恢复电流高速关断的特性。描述了半导体断路开关器件的工作原理、制造工艺和测试方法。通过杂质扩散工艺实验,试制了不同p区扩散深度和不同基区宽度的半导体断路开关二极管,利用高能电子束辐照方法改变器件中的少子寿命。最后,对试制的不同结构器件的正向导通、反向恢复等特性进行了测试,试制样品具有较低的正向导通峰值压降和较高的反向关断速度。实验表明,通过控制基区宽度和少子寿命,可以得到反向恢复特性很好的半导体断路开关器件。     

Comparison of the Punch-Through and Non-Punch-Through IGT Structures

The insulated gate transistor (IGT) has been modeled as a wide-base bipolar junction transistor (BJT) driven by a MOSFET. Therefore, the vertical wide-base BJT structure influences the following IGT characteristics: 1) the forward current-voltage characteristics, 2) the fall time/forward-voltage drop trade-offs, 3) the high-temperature blocking, and 4) the turn-off current tail. An IGT with punch-through (PT) BJT yields lower forward voltage than that of an IGT with non-punch-through (NPT) BJT due to the thinner base of the PT BJT structure. The punch-through IGT has lower off-state (leakage) current and also shorter turn-off current tail due to lower current gain of a PT BJT than that of an NPT BJT. Both PT and NPT IGT's have large safe operation areas.     

The reverse blocking GTO as a very fast turn-off thyristor

The high-frequency operation of GTO's (gate turn-off thyristors) in parallel inverters with resonant load for induction heating is investigated. The load-forced turn-off process of devices with reverse-blocking capability is analyzed on the basis of experimental results. The behavior of anode and gate voltages and currents during turn-off and during reapplication of forward voltage is analyzed considering various operating parameters (rate of decrease of anode current, rate of rise of anode voltage, reverse-bias amplitude and duration), and in particular gate-command timing. Appreciable benefits in terms of commutation losses, turn-off time, and snubber reduction are obtained as compared with the usual performance with chopper operation. Indications for an optimal gate-control strategy are also given     

对称控制全桥谐振PWM软开关变换器

针对传统对称控制全桥变换器不能实现软开关而导致变换器效率较低的现状,提出了对称控制全桥谐振PWM(FB-RPWM)变换器,详细分析了FB-RPWM变换器的工作模式及其稳态特性。分析结果表明:FB-RPWM变换器虽然采用对称控制,却仍在全负载范围内实现了所有桥臂开关管的零电压开通(ZVS)和输出二极管的零电流关断(ZCS),且其输入输出电压传输比与负载、开关频率和占空比无关,呈现出直-直变压器(DCX)的工作特性。与移相全桥(PSFB)变换器相比,FB-RPWM变换器减小了两个开关管的关断电流,且变压器一次侧采用隔直电容,实现了励磁电感电流的零直流偏量,降低了变压器损耗,进一步提高了变换器的效率。最后,搭建了一台400V输入、50V/10A输出的实验装置,验证了理论分析的正确性。     

电压质量调节器中晶闸管的强制关断技术

常规电压质量调节器VQC(Voltage Quality Conditioner)的串联补偿部分使用变压器串联到配电网中,但是变压器存在磁饱和问题,易产生破坏性的冲击电流。提出利用双向晶闸管构成开关设备取代变压器结构来解决该问题,并分析了其结构特点及应用。针对晶闸管自然关断带来的滞后补偿问题,提出VQC中晶闸管的强制关断技术原理和控制策略。根据VQC中负载的特性、负载的大小以及逆变器的输出电压幅值和方向对晶闸管关断的影响研究,确立了强制关断原则,分析了晶闸管关断时间与逆变器输出电压、负载特性、负载大小之间的对应变化关系。仿真与实验分析验证了所提出强制关断策略的有效性与可行性。     

A highly reliable press packed IGBT

A newly developed press packed reverse conducting IGBT (RCIGBT), the ST1000EX21, having ratings of 2500 V and 1000 A, has successfully been introduced in high‐reliability application areas. A multiple‐chip press packed RCIGBT structure, containing IGBT chips and fast recovery diode (FRD) chips, has been achieved by using basic experimental results and a stress analysis using the finite element structure analysis program ABAQUS. Excellent electrical characteristics, especially a robust turn‐off capability, such as I_c = 5000 A, V_cp = 2800 V at T_j = 125 °C, have been obtained. High reliability, withstanding a thermal cycling (fatigue) test of more than 50,000 cycles and a high‐temperature voltage blocking test for 2000 hours, has been confirmed. The device is now available and is being successfully used for transportation systems and other applications that require high reliability and long‐term stability. Voltage and current ratings in IGBTs and IEGTs (Injection Enhanced Gate Transistors) will be raised in the future. © 2000 Scripta Technica, Electr Eng Jpn, 131(1): 78–85, 2000     

两种新颖的准谐振型电流陡脉冲整形电路

为了减小瞬变电磁发射机电流脉冲关断延时、提高下降沿线性度、改善电流正负下降沿波形一致性，提出耗能型、馈能型两种准谐振型电流陡脉冲整形电路。推导关断延时、下降沿线性度与整形电路元件参数、供电电压、电压应力的关系，提出电路参数优化计算数学模型。通过与RCD电路的对比分析、软件仿真和实验，结果表明两种整形电路关断延时小，线性度较好，电流无过冲现象，并具有与供电电压无关的特性。其中馈能型整形电路具有上升沿提升能力，耗能型整形电路具有关断延时更小的特点，适合大电感负载情况下产生稳定的、精准的电流陡脉冲，目前耗能型整形电路已在瞬变电磁发射机中得到成功应用。     

SiC和Si混合PiN/Schottky二极管的模拟和设计

介绍一种具有肖特基正向持性和PN结反向特性的新型整流器－混合PiN/Schottky二级管（MPS0，它速度快，击穿电压高，漏电流小，正向压降低，适合功率系统使用。理论分析了该器件的正向导通，反向阻断和击穿特性。主要考虑4H SiC，模拟和优化设计了器件的外延层掺杂浓度和厚,肖特基接触和PN结网格宽度，PN结深度和掺杂浓度等主要的结构参数。     

Fast-switching-speed,low-forward-voltage-drop static induction (SI) thyristor

A static induction (SI) thyristor using a normally-off planar-gate structure in a low power class has been developed to be used as a power switching device in a three-phase inverter circuit. A 600 V-15 A class SI thyristor with very fast switching time (tgt, tgq) and low forward voltage drop (V_TM) was designed and created. This design was performed with a reasonable wafer structure (n^?/n/p⁺), an n^? base carrier concentration and thickness, and a gate structure (gate diffusion length and gate-gate pitch). Microscopic processing was used to obtain this SI thyristor. The performance trade-off between turn-off time and forward voltage drop is controlled by a lifetime control process using proton irradiation that results in a very fast switching time with tgt of 500 ns and tgq of 500 ns with V_TM of 1.5 V (at I_T= 18 A). At a current level of I_T = 18 A, the current density in the active area becomes 200 A/cm², which indicates that the performance of the SI thyristor is superior to that of conventional IGBTs and MOSFETs.     

New Generation High Current Low Losses Thyristors for UHVDC Applications

New six-inch phase control thyristor(PCT)platform with enhanced current handling capability has been developed to enable an optimal design of converter valves for next generation Bulk power transmission.Silicon(Si)resistivity and wafer thickness of PCT are optimized to fulfil the demands laid on blocking capability while increasing the rated current.The parameters of electron irradiation are optimized for the best technology curve between the on-state voltage drop and reverse recovery charge.A narrow reverse recovery charge band has been identified for a safe voltage sharing in series connection with minimal demands on redundant PCT.Full utilisation of six-inch wafer and the optimized layout of cathode(snow-flake design)improves the on-state current ratings by nearly 20%compared to prior art thanks to the reduced on-state voltage by 10%.The on-state current rating for 7.2 kV device is up to 6.25 kA.The surge current capability increased by 30%and maximum surge current up to 63.5 kA is qualified for the 7.2 kV/6.25 kA device under the same test condition with improved packaging and reduced on-state voltage.Together with 30%lower value of circuit commutated recovery time,the new thyristor platform enables more efficient,powerful and stable converter valves for next generation ultra high voltage direct current transmission(UHVDC)systems with rated power beyond 10 GW.     

IGBT集电极漏电流特性及影响分析

绝缘栅双极型晶体管(IGBT)集电极漏电流是评价其性能的一个重要电气参数,反映的是正向阻断特性,与阻断电压和温度相关.基于IGBT结构和PN结反向电流原理,分析了IGBT集电极漏电流的组成特性,在低温阶段以阻断电压引起的产生电流为主,在高温阶段以温度引起的扩散电流为主,低温至高温的转变温度约为125℃,并从热平衡角度分...     

一种谐振型高压侧调制的电流型双向变换器

针对传统电流型变换器存在的关断电压尖峰问题和硬开关现象,提出一种谐振型高压侧调制的电流型双向直流变换器。该变换器通过引入变频控制和高压侧调制策略,可以实现低压侧开关管的自然换流和零电流关断(ZCS),消除了低压侧开关管关断电压尖峰。首先分析电路的正向工作和反向工作模式的工作原理,然后对变换器进行详细的特性分析和设计,最后建立一台400W的样机并进行了测试。实验结果验证了所提电路拓扑及控制策略的优势与可行性。     

电流源型半桥变换器启动冲击及开关管关断电压尖峰问题研究

针对电流源型半桥变换器存在的启动冲击电流过大以及开关管关断电压尖峰问题展开研究与分析。在介绍电流源型半桥变换器稳态工作原理的基础上,分析了电流源型半桥变换器开关管关断电压尖峰产生的原因以及启动冲击电流过大的原因,针对这两个问题提出了改进措施,增加了有源吸收电路,并给出了启动时的控制方法。最后搭建了一台28 V输入/180 V输出、250 W的电流源型半桥变换器样机进行了实验研究,研究所提出的电路改进措施和控制方法的可行性。     

并联谐振逆变器控制策略的软件实现

传统的逆变器工作在硬开关条件下,即电压、电流是突变的,会带来开关损耗与器件损坏、二极管反向恢复、感性关断、容性开通和电磁干扰等一系列新问题。为解决这些问题,以一种新型并联谐振PWM逆变器为研究对象,阐述了其结构组成及工作原理。为了实现逆变器的零电压开通,针对其特点提出一种基于软件的控制策略实现方法,并进行了仿真和实验。仿真与实验的对比证明了控制策略的软件实现方法与理论分析相吻合,该方法是有效、可行的。     

Electron transport properties of electrically doped guanine nano-sheet based bio-Zener diode: a first principle paradigm

The quantum ballistic transmission properties of an electrically-doped guanine-nanosheet-based bio-Zener diode are investigated using density functional theory and nonequilibrium Green’s function-based first-principles calculations. The bio-Zener diode is gate-bias modulated, and its various quantum-electronic properties, for example, the V–I characteristic, the transmission spectra, and the device density of states, depend on both the electrical doping concentration and on the applied gate bias voltage. The junctionless highly doped bio-Zener diode shows high levels of reverse-bias current which is dominated by majority charge carriers. It is also found that, due to the presence of a wide bandgap and the backscattering effect, the forward-bias current is highly suppressed. The quantum simulation results confirm a strong reverse gate-bias-modulated biased current–voltage response as well as a charge transport phenomenon through the effective device region. The bio-Zener diode exhibits a specific reverse breakdown that can be varied from ?0.78 to ?3.2 V without affecting the forward current–voltage characteristic. The current findings are obtained by including the coherent tunneling and incoherent hopping processes with a minimal Hamiltonian model approach.

     

PCCM下推挽正激变换器的研究与实现

提出了一种24V/15A直流变换器的设计方法.主电路采用推挽正激电路,通过在传统推挽电路的基础上增加一个箝位电容,起到抑制偏磁和开关管关断电压尖峰的作用.控制采用峰值电流控制方式(Peak Current Controlled Model,简称PCCM),为了克服其对占空比要求的限制,加入了斜坡补偿环节.在进行详细的理论分析基础上,给出了主电路和控制电路一些关键参数的设计步骤;最后通过原理样机的研制,验证了理论分析的正确性.