| 摘要 |
The converter includes:a principal wave shaping circuit (7) having switches, operated by control signals, which are connected to the phases of a motor (9); a control voltage generator (10); a control value converter (21) which converts the base voltage values into final values (U asterisk asterisk ,,V asterisk asterisk ,W asterisk asterisk ) during a time period when the base values are equal, and a time modulating pulse generator (11) which produces control signals for the switches. The converter (21) includes a circuit which makes at least one of the final control voltage values, having a phase different from phases being converted, equal to an average of line voltage with the base voltage values for the phases being converted. The values of the initial control values (U asterisk ,V asterisk ,W asterisk ) are based upon variations in amplitude of sinusoidal waves. Method for controlling the activation of a polyphase load having the following stages; (1) apply a phase voltage to the load via a switch in the principal wave shaping circuit (7); (2) produce base voltage control values for the load phases; (3) convert the base voltage control values into final value during a time interval during which at least two base voltage control values are approximately equal. The final voltage control values corresponding the base values are equal to a maximum or a minimum; (3) submit a carrier wave to a time modulated pulses in response to final control voltage signals so as to produce switching control signals.
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