| Abstract |
An ac-dc converter with both modulated switching frequency and modulated duty cycle is presented. Using a combination of a feedforward and feedback control strategy a sinusoidal input current can be achieved by the duty cycle modulation. The mains current distortion is far below the limits specified by IEC regulations. Based on an analytical calculation of the conducted emissions (differential mode), which takes into account the quasi-peak measurement according to ClSPR / 2 / , the modulation of switching frequency has been optimized and results in a level of conducted interference voltages, which is more than 20 dB lower compared with constant frequency operation. |
