| 摘要 |
The invention relates to a method for improving the operation of a power control circuit, particularly a dimmer. The power control circuit is realized as a phase controlled power circuit, comprising a control unit and a switching unit, meant to be connected in series with the load; the AC power supplied in the load is controlled by adjusting the phase angle of the supply voltage during each half-cycle. According to the invention, in the method there is defined (701) a first length (T<SUB>m</SUB>) of the half- cycle, there is measured (702, 703) a second length (Tn) of the half-cycle, there is defined (704) a possible difference (?T<SUB>n</SUB> = T<SUB>m</SUB> - T<SUB>n</SUB>) between the first length (T<SUB>m</SUB>)) and the second length (T<SUB>n</SUB>) of the half-cycle, which is interpreted as an error of the second length of the half-cycle, and the defined error (?T<SUB>n</SUB> = T<SUB>m</SUB> - T<SUB>n</SUB>) is taken into account a correcting factor when defining the switching moment (t<SUB>ak</SUB>) proper, corresponding to the phase angle, during the next half-cycle, so that the switching moment (t<SUB>a</SUB>) of the switching unit is shifted as a corrective measure for the magnitude of the defined difference (?T) and in a direction that compensates the error. The invention also relates to an advanced power control circuit applying the method. |
