| 摘要 |
A method for reducing the influence of a DC component in a load current of an asynchronous three-phase motor, in which the voltages of two of the three phases are controlled by adjusting firing angles of semiconductor devices of the type turning-off at zero-crossing of the current therethrough comprises the steps carried out for each said controlled phase: detecting turn-off times of the semiconductor devices, calculating a value of a change of firing angle of the semiconductor devices needed for changing the length of the time period between two subsequent turn-off times for compensating for the influence of a DC component, and determining the firing angle of said semiconductor devices in dependence of the result of this calculation.
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