Search

In recent years, improving of power factor and reducing harmonic distortion in electrical instruments are needed. In general, a current conduction mode boost converter is used for active PFC (Power Factor Correction). In a PFC boost converter, if a duty ratio, a load resistance and an input voltage are changed, the dynamic characteristics are varied greatly. This is the prime reason of difficulty of controlling the interleaved PFC boost converter. In this paper, a robust digital controller for suppressing the change of step response characteristics and variation of output voltage at a DC-DC buck converter load sudden change with high power factor and low harmonic is proposed. Experimental studies using a micro-processor for controller demonstrate that the proposed digital controller is effective to improve power factor and to suppress output voltage variation.

The voltage-current characteristic of solar cells that provide power for a spacecraft can vary over a wide range. For maximum power transfer from the solar cells to the battery system a power converter has to be designed that adjusts its input impedance to a value equal to the output impedance determined by the operating power characteristic of the solar cells. This paper discusses a circuit and calculations for a design to match this condition. The proposed power converter is simple, lightweight, and reliable and will be used in the Sunblazer satellite.

The power handling portion of most regulated dc-to-dc electronic power conditioning circuits using a single self inductor for energy storage and transfer can usually be represented by one of three basic or canonical circuit forms. The circuit elements, consisting of an inductor, a transistor switch, a diode, and a filter capacitor may be arranged with appropriate topology to yield a voltage step-up converter, a current step-up converter, or a voltage step-up/current step-up converter. The design of a power converter requires making a number of decisions relating to the parameters of the circuit, including choice of semiconductor elements, filter capacitor, magnetic core material, magnetic path configuration and winding wire size. In the past, converter designs generally have required that several trial combinations of core size and permeability be tested by hand calculations. Experience and intuition were relied on to narrow the range of core size and permeability before starting the trial design computations. Recently, several computer-aided procedures have been described for use in the design . of the inductor for a single type of converter) This paper presents the results of the development of a series of nine programs which may be used to design the inductor in each of three basic converter forms in which the transistor switch is cont rolled by a regulator employing a constant frequency, constant on-time, or constant off-time pulse-width modulator. These nine programs, which contain the design algorithms and evaluation segments, are augmented by three additional programs which generate displays on a storage oscilloscope driven by the computer. These displays have proved to be extremely useful in evaluating the characteristics of the various converter-regulator combinations from an overall or global point of view.