摘要 |
A method is for the pulse width modified control of switching elements in a frequency converter having N phases, in which for each phase the control pulses of the switching elements are derived from, in each case, one P-periodic control voltage. The P-periodic control voltages correspond to a superposition of sinusoidal control voltages of period P, that are shifted by 360/N degrees with respect to one another, by an N*P-periodic offset voltage that applies to all phases. The offset voltage is selected such that, at any time, exactly one of the P-periodic control voltages lies effectively on a modulating limit for the derivation of the switching pulses. Using this method, the excitation of resonances at the star point of a connected load may be clearly reduced.
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