电力电子技术(第5版)课后习题解析

第 1 页 共 62 页 目录第2章电力电子器件·····································································3课后习题·····························································································································································3补充练习·····························································································································································4第3章整流电路·············································································5课后习题·····························································································································································5单元练习···························································································································································17补充练习···························································································································································20第4章逆变电路课后习题···························································24第4章逆变电路（5-4版）························································25第4章逆变电路试题(5-4版)······················································28第4章逆变电路补充练习···························································30第5章直流-直流交流电路课后习题·········································31第5章直流斩波电路（3-4版）················································34第5章直流-直流交流电路补充练习·········································39第6章交流—交流变流电路课后习题·······································41第6章交流电力控制电路和交交变频电路（4-4版）············43第6章交流—交流电力变换电路补充练习·······························46第7章PWM控制技术·································································48第7章PWM控制技术（6-4版）··············································48第7章脉宽调制（PWM）控制技术补充练习························50第8章软开关技术·······································································52第8章软开关技术（7-4版）····················································52第8章软开关技术补充练习·······················································53第9章电力电子器件应用的共性问题·······································53第10章电力电子技术的应用补充练习（4版）······················53第 2 页 共 62 页 综合练习·························································································55第 3 页 共 62 页 《电力电子技术（第五版）》课后习题答案第2章电力电子器件课后习题2.使晶闸管导通的条件是什么？答：使晶闸管导通的条件是：晶闸管承受正向阳极电压，并在门极施加触发电流（脉冲）。或：uAK0且uGK0。3.维持晶闸管导通的条件是什么？怎样才能使晶闸管由导通变为关断？答：维持晶闸管导通的条件是使晶闸管的电流大于能保持晶闸管导通的昀小电流，即维持电流，或HAII。要使晶闸管由导通变为关断，可利用外加电压和外电路的作用使流过晶闸管的电流降到接近于零的某一数值以下，即降到维持电流以下，便可使导通的晶闸管关断，即HAII。4.图2-27中阴影部分为晶闸管处于通态区间的电流波形，各波形的电流昀大值均为Im，试计算各波形的电流平均值Id1、Id2、Id3与电流有效值I1、I2、I3。0022244254a)b)c)0图2-27晶闸管导电波形解：a)Id1=π214)(sinttdIm=π2mI(122)0.2717ImI1=42)()sin(21tdtIm=2mI21430.4767Imb)Id2=π14)(sinttdIm=πmI(122)0.5434ImI2=42)()sin(1tdtIm=22mI21430.6741Imc)Id3=π2120)(tdIm=41ImI3=202)(21tdIm=21Im5.上题中如果不考虑安全裕量,问100A的晶闸管能送出的平均电流Id1、Id2、Id3各为多少？这时，相应的电流昀大值Im1、Im2、Im3各为多少?解：额定电流IT(AV)=100A的晶闸管，允许的电流有效值I=157A，由上题计算结果知a)Im14767.0I329.35，Id10.2717Im189.48b)Im26741.0I232.90,Id20.5434Im2126.56c)Im3=2I=314,Id3=41Im3=78.56.IGBT、GTR、GTO和电力MOSFET的驱动电路各有什么特点？答：IGBT驱动电路的特点是：驱动电路具有较小的输出电阻，IGBT是电压驱动型器件，IGBT的驱动多采用专用的混合集成驱动器。GTR驱动电路的特点是：驱动电路提供的驱动电流有足够陡的前沿，并有一定的过冲，这样可加速开通过程，减小开通损耗，关断时，驱动电路能提供幅值足够大的反向基极驱动电流，并加反偏截止电压，以加速关断速度。第 4 页 共 62 页 GTO驱动电路的特点是：GTO要求其驱动电路提供的驱动电流的前沿应有足够的幅值和陡度，且一般需要在整个导通期间施加正门极电流，关断需施加负门极电流，幅值和陡度要求更高，其驱动电路通常包括开通驱动电路，关断驱动电路和门极反偏电路三部分。电力MOSFET驱动电路的特点：要求驱动电路具有较小的输入电阻，驱动功率小且电路简单。7.试说明IGBT、GTR、GTO和电力MOSFET各自的优缺点。解：对IGBT、GTR、GTO和电力MOSFET的优缺点的比较如下表：器件优点缺点IGBT开关速度快，开关损耗小，具有耐脉冲电流冲击的能力，通态压降较低，输入阻抗高，为电压驱动，驱动功率小。开关速度低于电力MOSFET，电压、电流容量不及GTO；存在擎住效应问题。GTR耐压高，电流大，开关特性好，通流能力强，饱和压降低。开关速度低，为电流驱动，所需驱动功率大，驱动电路复杂；存在二次击穿问题。GTO电压、电流容量大，适用于大功率场合，具有电导调制效应，其通流能力很强。电流关断增益很小，关断时门极负脉冲电流大，开关速度低，驱动功率大，驱动电路复杂，开关频率低。电力MOSFET开关速度快，输入阻抗高，热稳定性好，所需驱动功率小且驱动电路简单，工作频率高，不存在二次击穿问题。通态电阻大，通态损耗大，电流容量小，耐压低，一般只适用于功率不超过10kW的电力电子装置。8.什么是晶闸管的额定电流？答：晶闸管的额定电流就是它的通态平均电流，国标规定：晶闸管在环境温度为40℃和规定的冷却状态下，稳定结温不超过额定结温所允许的昀大工频正弦半波电流的平均值。9.为什么要限制晶闸管断电电压上升律dvdt？答：晶闸管在承受正向阳极电压阻断状态下，2J结反偏，其结电容在晶闸管端电压上升率dvdt过大时，就会流过较大的充电电流（称位移电流），此位移电流流过3J，起到相当于触发电流的作用，易使晶闸管误触发导通，所以要限制dvdt。10.为什么要限制晶闸管通态电流上升率didt？答：在晶闸管开始导通时刻，若电流上升速度过快，会有较大的电流集中在门极附近的阴极小区域内，虽然平均电流没有超过额定值，但在小的区域内局部过热而损坏晶闸管，所以要限制通态didt。补充练习一、填空题1.电力电子器件一般工作在________状态。2.在通常情况下，电力电子器件功率损耗主要为___，而当器件开关频率较高时，功率损耗主要为___。3.电力电子器件组成的系统，一般由________、________、________三部分组成，由于电路中存在电压和电流的过冲，往往需添加________。4.按内部电子和空穴两种载流子参与导电的情况，电力电子器件可分为_____、_____、_____三类。5.电力二极管的工作特性可概括为________。6.电力二极管的主要类型有________、________、________。7.肖特基二极管的开关损耗________快恢复二极管的开关损耗。8.晶闸管的基本工作特性可概括为____正向有触发则导通、反向截止____。9.对同一晶闸管，维持电流IH与擎住电流IL在数值大小上有IL________IH。10.晶闸管断态不重复电压UDRM与转折电压Ubo数值大小上应为，UDRM________Ubo。11.逆导晶闸管是将________与晶闸管________（如何连接）在同一管芯上的功率集成器件。12.GTO的________结构是为了便于实现门极控制关断而设计的。第 5 页 共 62 页 13.功率晶体管GTR从高电压小电流向低电压大电流跃变的现象称为________。14.MOSFET的漏极伏安特性中的三个区域与GTR共发射极接法时的输出特性中的三个区域有对应关系，其中前者的截止区对应后者的______、前者的饱和区对应后者的____、前者的非饱和区对应后者的___。15.电力MOSFET的通态电阻具有________温度系数。16.IGBT的开启电压UGE（th）随温度升高而________，开关速度________电力MOSFET。17.功率集成电路PIC分为二大类，一类是高压集成电路，另一类是________。18.按