Power Factor of an AC-AC converter with resistive load
Power factor of an AC-AC converter with resistive load:
Fig: Operation of a Phase Angle Controlled AC-AC converter with a resistive load Fig: Variation of various performance parameters with triggering angle
- The power factor of a nonlinear deserves a special discussion. The waveforms for the operation of a phase angle controlled AC-AC converter with resistive load shows the supply voltage and the non-sinusoidal load current.
- The fundamental load/supply current lags the supply voltage by the φ1, 'Fundamental Power Factor' angle.
- Cosφ1 is also called the 'Displacement Factor'. However this does not account for the total reactive power drawn by the system. This power factor is inspite of the actual load being resistive.
- The reactive power is drawn also y the trigger-angle dependent harmonics. Now
- The Average Power, P drawn by the resistive load is
The portion within square brackets the equation for the average power is identical to the first part of the expression within brackets in the equation for the fundamental current, which is called the Fourier coefficient 'B1'.
- The rms load voltage can also be similarly obtained by integrating between α and π and the result can be combined with the equation for the average power to give