ACDCConvertePPT课件

1、 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University单相半波可控a. 纯阻性负载b. 纯感性负载c. 阻感负载第1页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University改进单相半波可控第2页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University单

2、相桥式全控a. 纯阻性负载b. 阻感性负载，且=L/RT Z第3页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou Universityc. 反电动势+阻感性负载(=L/RT)b)idOEudtIdOtb)idOEudtIdOtdOEudtIdOt第4页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University第5页/共33页 2021/10/22 Dr. Mao Depart

3、ment of Electrical Eng. &Automation of Fuzhou University单相全波可控整流电路单相桥式半控整流电路第6页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University主要内容2.2 三相 SCR 可控硅Rectifier2.3 变压器漏感对Rectifier的影响2.4 电容滤波不控Rectifier2.5 Rectifier的Harmonics 和PF2.6 Rectifier的有源逆变状态第7页/共33页 2021/10/22

4、 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University一. 三相半波2.2 三相 SCR 可控硅Rectifier应用：负载容量较大，输出电压纹波小 1.电路原理图a. 一次侧三角形,二次侧星形 b. 晶闸管共阴极接法 c. 电压最高的相导通，输出脉动3次（脉波数），周 期2/3 第8页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University. Z=R 自然换相点:各相晶闸管能触发导通的最早

5、时刻, a=0,电角度为30。数量关系：第9页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University第10页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University. Z=R+jL,且=L/RT a30o:与纯阻性负载相同 a30o：不同于纯阻性负载导通角都相同：=2/3第11页/共33页 2021/10/22 Dr. Mao Department of El

6、ectrical Eng. &Automation of Fuzhou University二. 三相全桥1.电路原理图a. 一次侧三角形b. 晶闸管共阴极、 共阳极接法 c. 工作时序/导通相共阴极：电压最高相；共阳极：电压最低的相，即 对线电压进行整流，一个周期输出脉动6次， 即输出电压周期为2/6第12页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University第13页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng

7、. &Automation of Fuzhou University. Z=R -300数量关系：第14页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou Universitya=00a=600a=900第15页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University. Z=R+jL,且=L/RT a60o:与纯阻性负载相同 a60o：不同于纯阻性负载导通角都相同：=/3Re

8、turn第16页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University2.3 变压器漏感对Rectifier的影响ReturniK第17页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University2.

9、4 电容滤波不控Rectifier一. 单相1.电路原理图2工作原理及波形图Ud2，当=RC （3-5）T/2 ；最小Ud2由、R、C决定 第18页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University Rectifier的Harmonics 和PF一谐波与无功危害1谐波(harmonics) 2. 无功(reactive power) 二H与R分析基础1HarmonicsHRi=In/I1*100%，In，I1：RMS THD=Ih/I1*100%，Ih：总谐波电流RMS第

10、19页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University2Power Factor 正弦电路 Active power P =UIcos=P/S=I1/Icos=cosApparent power S= UIReactive power Q=UIsin 非正弦电路 Active power P=UI1cos Apparent power S= UI第20页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Aut

11、omation of Fuzhou University三阻感负载可控整流 1单相桥式全控=cos 2三相桥式全控谐波：奇次谐波=cos 谐波：6k1(k为正整数)四电容滤波不控1单相桥式全控：奇次谐波2三相桥式全控：6k1(k为正整数)谐波五整流输出电压、电流谐波：mk次（m:脉波数） Return第21页/共33页 大功率可控整流电路-带平衡电抗器的双反星形可控整流电路第22页/共33页0a)b)c)d)ia1Id180360ia2iab2iAIdiab2tttt000Id2333Id33IdId323(1+ )Id323(1+)Id33Id13 大功率可控整流电路-多重化-移相控制第23

12、页/共33页 大功率可控整流电路-多重化-顺序控制db)c)iId2 IduOp+第24页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University2.7 Rectifier的有源逆变状态一. 逆变 1. 逆变直流电转换为交流电。有源逆变：交流侧与电网连接；反之为无源逆变。2. 逆变条件 . 900 ，输出电压为负值；. 负载中要有反电动势。第25页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation

13、 of Fuzhou University 直流发电机电动机之间电能的流转a）两电动势同极性EG EM b）两电动势同极性EM EG c）两电动势反极性，形成短路第26页/共33页 2021/10/22 Dr. Mao Department of Electrical Eng. &Automation of Fuzhou University3. 逆变角 逆变角=-，以自然换相点为起始点， 向右计算；以=0,即=为起始点为起始点， 向左计算。Return第27页/共33页uabuacubcubaucaucbuabuacubcubaucaucbuabuacubcubaucaucbuabuacubcuaubucuaubucuaubucuaubu2udtOtOb =p4b =p3b =p6b =p4b =p3b =p6t1t3t2第28页/共33页 晶闸管直流电动机系统2.8.1 工作于整流状态时工作于整流状态时UIREUdMdp23BMBXRRRnCEeMedeCUIRCUncos17. 12Ona1a2a3a3a2a1Id(RB+RM+ )IdCe3XB2p第29页/共33页Oa3a2a1Id分界线断续区连续区a5a4E0E考虑电流断续时不同 时反电动