Dynamic Performance of a Current-Phase Control Method for Zone-Control Induction Heating Systems

Abstract

This paper presents a phase angle control method of coil currents in a zone-control induction heating (ZCIH) system, which has split work coils on a susceptor. The ZCIH system controls the amplitude and the phase angle of each coil current to adjust the heat and temperature distribution on the susceptor. In order to control the current amplitude in a wide range from 0 to 100%, the phase angles of the coil currents are adjusted to be in phase with each other. This paper theoretically deriving the phase angle change of the coil current in transient states, and reveals that the phase angle change can be considered as a first-order response. Experiments have been conducted to verify the validity of the theoretical analysis. Based on the analysis, a phase angle controller was designed and examined in experiments using a two-zone ZCIH system. It is clarified that the designed controller makes it possible to adjust the current phase angle not only in steady states but also in transient states.