Выбор параметров многофункционального трансформатора

Abstract

The article considers power supply sources for electrotechnological installations involving induction heating, which include semiconductor converters for producing sine-wave and rectangular voltage pulses, in particular, symmetrical bridge and half-bridge circuits, as well as ferromagnetic frequency multipliers with an even frequency multiplication ratio. Methods for increasing the frequency by a factor of two and four by means of multifunctional transformers are investigated taking as an example their connection to converters with sine-wave and rectangular output signals. Graphic dependencies of the voltages across the winding terminals and fluxes in the multifunctional transformer core when being energized by signals with the above-mentioned waveforms are presented, which confirm that the output signal waveform across the load does not depend on the signal waveform applied to the multifunction transformer. The advantages of using a combination of cascade-connected semiconductor and ferromagnetic frequency multipliers are described. The working processes occurring in the system during its operation with different durations of the multifunctional transformer core saturation intervals are analyzed. A technique for parametrically synthesizing a ferromagnetic frequency converter using an approximate harmonic analysis (the Bessel method) is given. The article presents basic correlations for determining the converter electromagnetic parameters with the use of a hyperbolic sine approximation, namely, the amplitudes of the second and fourth induction harmonic components in the idle mode and for operation with a series and/or shunt capacitive compensation capacitor, and the induction component from the bias winding. The current through the compensating capacitor is calculated, and its capacitance is determined. Brief conclusions from the study results are formulated.