Methodology and results of experimental and analytical determination of the parameters of the inductor of high-frequency induction unit for milk heating

Abstract

Induction heating is a promising heating technique which allows reducing unproductive energy consumption for heating the intermediate coolant and simplifying the design and increasing the reliability. The working tool of HFC induction devices is an inductor. One of the requirements for such installations is to ensure the resonant mode of the oscillating circuit R, L, C; the inductor parameters: its active resistance and inductance, should be known. The known methods of determination (voltmeter-ampereter, bridge method) are not valid. It is possible to use the resonance method. The research goal was quantitative assessment of the inductor parameters based on the analysis of experimental voltage oscillograms. The research methods were experimental oscillographic recording of the transient process of voltage change on the inductor and analytical processing of experimental results. Using the experimental resonance method for determining inductance supplemented by an analytical analysis of the oscillograms of the decaying oscillatory transient voltage process during the discharge of a capacitor bank on the studied inductor, it was found that the inductance of the studied inductor L₂ was in the range of 0.0134 to 0.038 μH, and its active resistance R₂ was within 0.0512 to 0.091 Ω. Given the small values of the obtained quantities, the result can be considered satisfactory for further practical calculations. The results obtained using the method of experimental oscillography of the oscillatory attenuating discharge of a capacitor bank onto the studied inductor of a high-frequency induction installation, supplemented by an analytical determination of the active resistance of the inductor and its inductance may be used to determine the resistances of an electrical equivalent replacement circuit and substantiate to improve the design (number of turns, current in the inductor, matching the resonant frequency of the inductor and a high-frequency generator), ultimately, to increase the energy efficiency of the milk heat treatment process (electrical and thermal efficiency, power factor cosφ) during operation of a HFC induction device with a heat exchanger, it may be used in modeling an induction heating system.