idLd(0thy/3+EdUd20L,I dEα =Va = 0.9V. cosα(a)元Vaa3Id=Id002αiEd=Edl(b)Figure 6-16(a) Thyristor inverter with a dc voltage source. (b) Va versus la
s d s 2 L I Ed = Vd = 0.9 V cos −
=180°-(α+u)(uthy'32wtoα3,4(iq1,2(iq)3, 4otn-wt0Figure 6-17 Voltage across a thyristor in the inverter mode.·Importance of extinction angle in inverter mode
=180 − ( +u) o • Importance of extinction angle in inverter mode
6-4 Three-Phase Full-BridgeConvertersNa大。大(b)(a)·Common-cathode group and common-anode group ofthyristors·Numbering of the 6 thyristors indicates the trigger12345612sequence:
6-4 Three-Phase Full- Bridge Converters •Common-cathode group and common-anode group of thyristors •Numbering of the 6 thyristors indicates the trigger sequence: 1→2→3→4→5→6→1→2→
6-4-1 ldealized Circuit with Ls=0 and ia(t)=ld3TT达T5DaT天T6ATNN22(a)(b)Figure 6-19 Three-phase thyristor converter with L, = O and a constant dc current
6-4-1 Idealized Circuit with Ls=0 and id (t)=Id
1 anlysisthe instant of natural conduction.the crossover pointof phase (or line) voltage (wty,wt2,wt3,wt4,wts,wt)UdUPnVeaUbnTVanUen3iaVdoot(a)0Vdwt=0ia66Thewaveformsofα=O°ia = iT1-iT43/2V.sinotdot=1.35VLL(6 -36)doTE-mail:xihuang@bitu.edBu.cn
1 anlysis • the instant of natural conduction.——the crossover point of phase (or line) voltage (ωt1 ,ωt2 ,ωt3 ,ωt4 ,ωt5 ,ωt6 ) π 1 3 2π E-mail: xjhuang@bjtu.ed3u.c3n d0 ia = iT 1 −iT 4 V = (6 −36) π 2VLL LL sintdt =1.35V The waveforms of = 0º vd