Topic 15Main contentsLine-Frequency Diode Rectifiers
Main contents • Line-Frequency Diode Rectifiers Topic 15
5-6Three-Phase,Full-BridgeRectifiersIn industrial applications, it is preferable to use three.phase rectifier, compared to single-phase rectifier,because of their lower ripple content in the waveformsand a higher power-handing capabilityADeC.太D4±D6±D2·Commonly used3
3 5-6 Three-Phase, Full- Bridge Rectifiers In industrial applications, it is preferable to use threephase rectifier, compared to single-phase rectifier, because of their lower ripple content in the waveforms and a higher power-handing capability. • Commonly used
·The circuit consists of atop group (positive) and abottom grope (negative)(5-64)Vd = Vpn-VNn·Four types of load:UPnnUdDCUNnD6ND4
4 •The circuit consists of a top group (positive) and a bottom grope (negative). = vPn −vNn vd (5−64) • Four types of load:
5-6-1ldealizedcircuitwithLs=0Consider rectifier model with large inductor load (R-L load)D太D5UPnUdUdDUNnD6太D4太D6D2ND4NldK(b)(a)Figure 5-31 Three-phase rectifier with a constant dc current
5 5-6-1 Idealized circuit with Ls=0 Consider rectifier model with large inductor load (R-L load)
Voltageand CurrentWaveformsThewaveformsforthevoltages Vpn and VNn,12VLlconsist of 120°segmentsArea(b)of the phase voltages;Va(t) = /2Vu cosot120°-609元元ot<66When DconductingWhen D, conducting0neitherD,orD4conductingFigure 5-32Waveforms in the circuit of Fig.5-31
6 Voltage and Current Waveforms 0 6 a d Id i = − I (− t ) The waveforms for the voltages vPn and vNn, consist of 120°segments of the phase voltages; vd (t) = 2VLL cost 6 When D1 conducting When D conducting 4 neither D1 or D4 conducting