Circuit arrangement for mains-frequency-independent power control and for linearising it

摘要

The invention relates to a circuit arrangement for the mains-frequency-independent power control and for linearising it in the phase control using a firing-pulse shaper unit in which a firing pulse for a phase control angle is generated by forming a comparison of a closed- or open-loop control voltage with a periodic reference voltage. The variation with time of the periodic reference voltage is influenced in the settled state via an oscillator controlled by circuit means of a digital control loop, in such a manner that at the end of half the period of the mains frequency, the digital/analog converter supplying the reference voltage always reaches a set point as final digital value, and that the reference voltage has a nonlinear characteristic which approximates the power characteristic.