Converter Classification ECE 442 Power Electronics 1 FirstQuadrant

Converter Classification ECE 442 Power Electronics 1

First-Quadrant Converter • Load Current i. L flows into the load (+) • Load Voltage is + • Rectifier ECE 442 Power Electronics 2

Second-Quadrant Converter • Load Voltage is + • Load Current i. L flows out of the load (-) • Inverter ECE 442 Power Electronics 3

Second-Quadrant Converter ECE 442 Power Electronics 4

When the switch is closed E forces current through L, load voltage v. L = 0 ECE 442 Power Electronics 5

When the switch is opened ECE 442 Power Electronics 6

ECE 442 Power Electronics 7

First and Second Quadrant Converter ECE 442 Power Electronics 8

S 1 and D 4 operate as a first-quadrant converter. S 2 and D 4 D 1 operate as a second-quadrant converter ECE 442 Power Electronics 9

Second Quadrant Operation 2 S 2 closed S 2 open ECE 442 Power Electronics 10

Third and Fourth Quadrant Converter The load voltage is always negative, but the load current is either positive or negative ECE 442 Power Electronics 11

Third Quadrant Operation S 3 closed S 3 open i. L, v. L are always negative ECE 442 Power Electronics 12

Fourth Quadrant Operation S 2 closed load current +, load voltage – (zero) S 2 open load current +, load voltage negative, (-Vs) ECE 442 Power Electronics 13

Four-Quadrant Converter Load Current can be positive or negative Load Voltage can be positive or negative For fourth quadrant operation, reverse E. ECE 442 Power Electronics 14

Summary of a four-quadrant converter ECE 442 Power Electronics 15

Summary of the conducting devices ECE 442 Power Electronics 16