电力电子技术王兆安第五版课后习题答案 新.pdf

目录 第 1 章 电力电子器件········································································· 1 第 2 章整流电路·················································································· 4 第 3 章直流斩波电路 ······································································· 20 第 4 章交流电力控制电路和交交变频电路·································· 26 第 5 章逆变电路················································································ 31 第 6 章PWM 控制技术····································································· 35 第 7 章软开关技术············································································ 40 第 8 章组合变流电路 ······································································· 42 第1 章 电力电子器件 1. 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。 2. 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最小电流，即维 持 电流。 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。 3. 图1-43 中阴影部分为晶闸管处于通态区间的电流波形，各波形的电流最大值均为 Im ，试计算各波形的电流平均值Id1、Id2、Id3 与电流有效值I 1、I2、I3。  0   2 0  5 2 0  2 4 4 4 2 a) b) c) 图1-43 晶闸管导电波形 I 1  m 2 解：a) Id1= 2π 4 Im sintd(t) = 2π ( 2  1 )  0.2717 Im 1  2 Im 3 1 I = (I sint) d(t) =   0.4767 I 1  m m 2 4 2 4 2 I