§2 AC-DC Converte中学英语课件

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity§2AC/DCRectifierDr.Maoxingkui2023/7/31CollegeofElectrical&Automation

Engineering,FuzhouUniversity§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity单相半波可控a.纯阻性负载b.纯感性负载c.阻感负载§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity改进单相半波可控§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity单相桥式全控a.纯阻性负载b.阻感性负载，且τ=L/R»TZ§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversityc.反电动势+阻感性负载(τ=L/R»T)§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity单相全波可控整流电路单相桥式半控整流电路§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity主要内容§2.2三相SCR可控硅Rectifier§2.3变压器漏感对Rectifier的影响§2.4电容滤波不控Rectifier§2.5Rectifier的Harmonics和PF§2.6Rectifier的有源逆变状态§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity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2π/3

§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity①.Z=R自然换相点:各相晶闸管能触发导通的最早时刻,a=0,电角度为30。数量关系：§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity②.Z=R+jωL,且τ=L/R》T

a≤30o:与纯阻性负载相同

a>30o：不同于纯阻性负载导通角都相同：θ=2π/3§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity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2π/6§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity①.Z=R-300数量关系：§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversitya=00a=600a=900§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity②.Z=R+jωL,且τ=L/R》T

a≤60o:与纯阻性负载相同

a>60o：不同于纯阻性负载导通角都相同：θ=π/3Return§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity§2.3变压器漏感对Rectifier的影响ReturniK§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity§2.4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Ud=1.2U2，当τ=RC≥（3-5）T/2；最小Ud=0.9U2θ由ω、R、C决定

§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity§2.5Rectifier的Harmonics和PF一．谐波与无功危害1．谐波(harmonics)

2.无功(reactivepower)

二．H与R分析基础1．HarmonicsHRi=In/I1*100%，In，I1：RMS

THD=Ih/I1*100%，Ih：总谐波电流RMS§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity2．PowerFactorλ正弦电路

ActivepowerP=UIcosФλ=P/S=I1/IcosФ=νcosФApparentpowerS=UIReactivepowerQ=UIsinФ非正弦电路

ActivepowerP=UI1cosФ

ApparentpowerS=UI§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity三．阻感负载可控整流

1．单相桥式全控λ=νcosа=0.9cosа

2．三相桥式全控谐波：奇次谐波λ=νcosа=0.955cosа

谐波：6k±1(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：6k±1(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§2AC-DCConverte24-Jan-22DeltaEnergySystems§2.6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§2AC-DCConverte24-Jan-22DeltaEnergySystems0a)b)c)d)ia1Id180°360°ia2iab2'iAIdiab2wtwtwtwt000Id2333Id33IdId323(1+

)Id323(1+)Id33Id13§2.6大功率可控整流电路-多重化-移相控制§2AC-DCConverte24-Jan-22DeltaEnergySystems§2.6大功率可控整流电路-多重化-顺序控制db)c)iId2IduOap+a§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity§2.7Rectifier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

①.α≥900，输出电压为负值；②.负载中要有反电动势。§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity

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§2AC-DCConverte24-Jan-22DeltaEnergySystems

2023/7/31Dr.MaoDepartmentofElectricalEng.&AutomationofFuzhouUniversity3.逆变角

逆变角β=π-α，α以自然换相点为起始点，向右计算；β以β=0,即α=π为起始点为起始点，向左计算。Return§2AC-DCConverte24-Jan-22DeltaEnergySystemsuabuacubcubaucaucbuabuacubcubaucaucbuabuacubcubaucaucbuabuacubcuaubucuaubucuaubucuaubu2udwtOwtOb=p4b=p3b=p6b=p4b=p3b=p6wt1wt3wt2§2AC-DCConverte24-Jan-22DeltaEnergySystems§2.8晶闸管直流电动机系统2.8.1工作于整流状态