| 摘要 |
The invention is used in a voltage conversion bridge for use in converting an AC voltage to a DC voltage or inverting a DC voltage into an AC voltage. In a three-phase bridge having one of three reference phase voltages UA or UB or Uc associated with each leg, one of the switches S1, S2 or S3 (or alternatively their complements S1*, S2* or S3*) conducts in the time intervals where the associated voltage UA, UB or UC has a higher (or alternatively, smaller) amplitude than the other two reference voltages, and during these times the blanking interval compensation loss is compensated. According to the invention, (a) a three reference voltages UA, UB, UC are supplied; (b) the maximum of these voltages is detected; (c) the maximum is subtracted from the peak value UTP of a triangle wave used for forming the PWM signal; (d) the difference is added to each of the reference voltages to form a three first augmented reference voltages UA min , UB min , UC min to a blanking interval loss compensator; (e) if the voltage conversion bridge is not saturated and adding a blanking interval deviation voltage compensation signal would not cause saturation, a blanking interval voltage deviation compensation signal is added to the first augmented reference voltages to compensate for voltage deviation caused by a blanking interval, thereby providing second augmented reference signals UA sec , UB sec , UC sec ; and (f) the compensated signals are supplied to the PWM section, which in turn supplies PWM signals USA sec , USB sec , USC sec to a three-phase bridge 5. This method minimizes voltage deviations caused by the use of a blanking interval. <IMAGE> <IMAGE> |
