Converters without Reactance on the Alternating Current Side
The switching device, mentioned in the introduction, with its transformers and valves provides during one cycle of the network voltage p different possibilities of impressing transformer voltages across the output terminals on the d.c. side. These voltages, which are derived by means of transformers from sinusoidal voltages and which are therefore themselves also sinusoidal, are assumed to be equal in magnitude and their individual phase positions are, moreover, all displaced relative to the adjacent ones by the same angle 2 π/p. The valves select whatever voltage is the greatest at any particular instant. Figure 2.1 shows for p = 4 the transformer voltages and the trace of the direct voltage which appears across the terminals of the conversion device. Switchings to the successive transformer voltages take place at equal time intervals of 2 π/p.
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