A detailed mathematical model is developed to calculate the radial temperature profile in silicon rods by heating currents of different forms. The model is based on the heat and Maxwell equations and on an expansion in Fourier series. Sinusoidal, pulsed unipolar and bipolar-like currents and their combinations as well were adopted to investigate the effect. Mathematical models and laboratory devices have been built to implement high-frequency power supply (frequency higher than 50 kHz). The power supply is a resonant inverter with two cells (sub-modules) that contains new technology with modern IGBT-transistors, low induction capacitors and toroidal core from amorphous nanocrystalline alloys. New high frequency transport technology with twisted-pair cable has been used to decrease reactive and active loss power.
