One-stage power factor correction (PFC) with output electrical isolation. Two types of PFC converters are proposed here: 1) Multi stage capacitive-switching network low voltage PFC converter and 2) two-switch soft switching PFC converters. This resulted in a near unity power factor AC-DC converter with low voltage output. The second converter uses the power switch in combination with a grounded auxiliary switch to produce soft-switching converter to operate in high switching frequencies. Due to its simplified power stage and control circuit, this converter presents a variety of benefits including better efficiency (87%), lower cost, higher reliability, increased operating frequencies into the hundreds of kilo-hertz range and low operating voltages of less than 5 volts. With PSPICE simulation and experimental results, a measured power factor of 0.99 was obtained by the single switch converter.
This invention relates to AC to DC converters and claims the benefit of priority to U.S. Provisional Patent Application No. 60/176,608 titled "IMPROVED AC/DC CONVERTER WITH POWER FACTOR CORRECTION" filed Jan. 18, 2000 and is funded in part by NASA STTR Contract No.: NAS 10-98064.
A power factor controller for a switching power supply, that in one embodiment couples a power factor control circuit between an AC input and an output wherein a digital controller computes circuit currents for regulating the power supply without direct current measurements.
