3 Phase-controlled DC motor drives

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• The thyristor requires small reactors in seriesto limit the rate of current rise, andsnubbers, which are resistors in series withcapacitors across the devices, to limit the rateof voltage rise.• The transfer characteristic of the three-phase<strong>controlled</strong> rectifier is derived asVdc=1∫π / 32π/ 3+απ / 3+αVmsin( ωst)d(ωscosα• The characteristic is nonlinear (as shown inFig. 3.13).t)=3Vπm
• A control technique to overcome thisnonlinear characteristic is that the controlinput to determine the delay angle ismodified to beα = cosv(V−1 c −1cm) = cos(vcn)where v c is the control input and V cm is themaximum of the absolute value.• Then the dc output voltage is3 3−13 ⎡ 3 Vm⎤V dc = Vmcosα = Vmcos(cos vcn) = [ Vm]vcn= ⎢ vc=π ππV⎥⎣πcn ⎦Krvc
Page 1 and 2: 3 Phase-controlled DC motor drives
Page 3 and 4: • In field control, the applied a
Page 5 and 6: • Fig. 3.1
Page 7 and 8: • Similarly, the air gap power is
Page 9 and 10: 3.2.5 Four-quadrant operation• Du
Page 11 and 12: • Fig. 3.5 illustrates the speed
Page 13 and 14: • Two basic methods by using stat
Page 15 and 16: • The bridge conduction is delaye
Page 17 and 18: • In the case that the load curre
Page 19: • Fig. 3.10 is a three-phase thyr
Page 23 and 24: Control modeling• The gain of the
Page 25 and 26: • Fig. 3.15 is current source con
Page 27 and 28: • Fig. 3.17 is a half-controlled
Page 29 and 30: • Fig. 3.20 shows the converter c
Page 31 and 32: • The normalized electromagnetic
Page 33 and 34: where ω s = 2πf s , β = tan -1 (
Page 35 and 36: • Fig 3.24
Page 37 and 38: 3.6 Transfer functions of the subsy
Page 39 and 40: • Converter (after linearization)
Page 41 and 42: • Fig 3.30 is current-control loo
Page 43 and 44: • The closed-loop transfer functi
Page 45: 3.9 Four-quadrant Dc motor drive•

3 Phase-controlled DC motor drives

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