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The objective of the research presented in this report is to improve the high frequency performance of power filters and components by better compensating the parasitic effects of practical components. A major application for this improvement is in design of low pass filters for power electronics, although some other applications are also explored. In power electronics, the input and output filters are the dominant consideration in limiting electromagnetic interference and susceptibility, and typically represent a major contribution to the weight, volume and price of the whole system. The usual methods of improving the high frequency performance of the filters include using more filter stages and additional components. These methods can add significant size and cost to the system. This report describes new design techniques by which the undesirable effects of filter parasitics can be greatly reduced. These techniques provide an order of magnitude or more improvement in performance of typical filter components. This enables the development of filters with much better high frequency attenuation, and the reduction of filter size and cost at a constant performance level. In filtering and other applications, the ability to reduce the effect of parasitic elements also enables many higher-frequency designs. In this report, two techniques are presented that can be used to reduce the effects of parasitic inductance and capacitance. One technique, termed inductance cancellation, is used to reduce the effect of parasitic inductance in a path of interest. The other technique, capacitance cancellation, reduces the effect of a parasitic capacitance across an inductor. These techniques, enable major improvements in many filtering applications. Extensive experimental results and example applications are presented that demonstrate the feasibility and high performance of the techniques developed here. |
