Novel Phasor Transformation for Feedback Control Design for Induction Heating Systems with Experimental Results
Résumé
For analyzing the transients of induction heating systems, time-dependent phasor transformations were proposed so far in the literature. Applying these transformations to a linear R, L, C circuit equations leads to differential equations in the complex domain from which equivalent circuits modeling the envelopes of sinusoidal waveforms were derived. The present work proposes a phasor transformation which is based on fictitiously replacing the real voltage and current signals of a system by complex ones. It leads to transformed system equations in the real domain where instantaneous amplitudes, phases and frequencies appear explicitly, which makes the transformed equations suitable for the feedback control design. The methodology is applied to a parallel induction heating system in order to design a sliding mode controller. The theory is supported by simulations, experiments and comparisons.