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Operatingmodes

The same topology of the H-bridge can be used in four-quadrant operation with

inductive loads. Regenerating is done via the freewheeling diodes D

1

and D

4

or D

3

and

D

2

.

H-bridge (full-bridge converter)

An established topology to convert DC into AC voltage is the voltage source inverter

(VSI)

shows its basic structure. An (assumed) ideal constant DC-bus voltage

U

DC

supplies the B6 full bridge consisting of six IGBTs and their associated free-

wheeling diodes. By appropriate control of the IGBT switches, voltage pulse patterns

U

U

, U

V

and U

W

are generated at the outputs U, V and W, which cause a sinusoidal

current with an inductive load. TheVSI is thus used to provide variable frequency output

voltages and currents of different values.

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