PROJECT TITLE :

Unity-Power-Factor Control Based on Precise Ripple Cancellation for Fast-Response PFC Preregulator

ABSTRACT:

Power-factor preregulators are commonly employed in electronic equipments for minimizing the injection of current harmonics into the mains power line. But, the bandwidth of typical preregulators are typically configured to be terribly little so as to achieve near-unity power factor, and this inevitably offers rise to poor dynamic response. Ripple estimation/cancellation technique is employed to eliminate the double-line frequency component from the sampled output voltage before it propagates into the voltage control loop, hence, the requirement of little bandwidth is not mandatory. The prevailing ripple estimation circuits, however, are only accurate under specific conditions, beyond that power factor can be degraded. In read of this, a replacement ripple estimation/cancellation network consisting of an amplitude tuner and a part shifter primarily based on switched-resistor circuits is proposed and verified experimentally on a 200-W boost power-issue preregulator. It is shown that the proposed ripple estimation network not only provides correct ripple estimation over a big selection of operating conditions, it additionally offers a method to decouple the power issue of a preregulator from its controller bandwidth. With the aid of the proposed ripple estimation network, the specified features of quick dynamic response and unity power issue are both achieved.