| The field of Active power factor correction is investigated for the purpose of developing both simple control techniques as well as efficient power conversion techniques. Two new classes of power factor correction control are proposed and developed, and several new efficient power conversion techniques are analyzed and evaluated.; The proposed controllers enable simple control of continuous conduction mode (CCM), pulse width modulated (PWM) power converters. The first technique, based upon a linear current programmed modulator, achieves high input power factor in all basic PWM converters without requiring the synthesis of a current reference signal. The input current shaping occurs inherently, once a linear current programmed modulator is designed into the current feedback loop. No input voltage sensing is required, and in many of the controller implementations, the current loop exhibits inherent stability. The technique is generalized for constant frequency, variable frequency, leading-edge, and trailing-edge modulation. The second control technique known as Passive linear current programmed control exploits the negative current feedback which is inherent in a large class of zero-voltage transition or zero-current switching power converters in order to achieve "automatic" power factor correction. This is accomplished for converters operated in continuous conduction mode without the use of current sensing, and without the need for a current reference signal. Only input voltage feedforward is required.; In addition to the two control techniques, three soft-switching power stage topologies are developed which significantly improve the power conversion efficiency of the power factor correction pre-regulator. Two of them achieve zero-voltage-transition switching of the power semiconductors, and zero-current-switching of the auxiliary switch. The third technique achieves zero-voltage-switching of the main and auxiliary switch, and zero-current-switching of the rectifier diode. These topologies offer advantages over other leading soft-switching topology solutions.; Experimental results verify both the proposed control techniques as well as the power conversion techniques. Control techniques are verified at 300 watt for buck, and boost converters, and at 230 watts for a buck-boost converter. Power conversion techniques are prototypes for three soft-switching topologies, at power levels ranging from 300 to 730 watts, and switching frequencies ranging from 200 to 600 kHz. |
